Giving Up Alternating Current

An anonymous reader writes: Yesterday we discussed Soylent, the artificial food substitute created by Rob Rhinehart and his team. As it turns out, this isn't Rhinehart's only unusual sustainability project. In a new post, he explains how he gave up on alternating current — a tough proposition for anyone living in the U.S. and still interested in using all sorts of modern technology. Rhinehart says, "Most power in the US is generated by burning coal, immediately squandering 67% of its energy, then run through a steam turbine, losing another 50%, then sent across transmission lines, losing another 5%, then to charge a DC device like a cell phone another 50% is lost in conversion. This means for 100 watts of coal or oil burned my phone gets a mere 16."

The biggest hindrance was the kitchen. As you might expect for the creator of Soylent, he doesn't cook, and was able to get rid of almost all kitchen appliances because of that. He uses a butane stove for hot beverages. He powers a small computer off batteries, which get their energy from solar panels. For intensive tasks, he remotes to more powerful machines. He re-wired his apartment's LED lighting to run off direct current. Have any of you made similar changes? How much of an effect does this really have?

Comments

Outdoor

[Anonymous Coward]

It's the new outdoor trend anyway. All the lighting is obviously LED, so no problem there, the gadgets all transform their AC to DC anyway, so no problem there as well, you just need a decent lab trafo.

Washers and dryers that use solar heated water are no problem either, they mix warm and cold as they need it.
Even the small 12 Volt Camping washing machines work very well nowadays.

You cook by gas and use a gas refrigeration unit as well.

There's a German project the 'direct current house' (in German obviously)
http://www.dasgleichstromhaus....

They have solved many problems.

Re:Outdoor

[Technician]

Due to the very poor selection of DC appliances and often their RV bloated price tags, I have opted to keep AC, but generate it locally. Instead of buying a DC to DC supply for a laptop to get 19V for about $100, I bought a 1KW inverter instead for about the same price. If I don't want all my lights to be Fluorescent Cool White in color, I can use the 9W 3K bulbs instead in a warm white with high Color Rendering Index >94%. Try it. Try to find 12V RV bulbs that are not Amber, Red, or Cool White 6K. Most of the outlets in my RV are running off the inverter. Only the kitchen and bath loop are still on traditional shore power or generator along with the AC. This limits the generator runtime where shore power is not handy.

I have not trimmed my home use enough yet to cut loose from the grid. Heat pumps and long wet winters on solar just is not a match yet. They haven't fixed the solar when the sun doesn't shine problem yet.

I don't have to mess around with trying to adapt everything to 12 or 24V. With a good size deep cycle battery, even normal microwave oven, blow dryer, other short duration high amperage loads are possible that is simply not an option on DC.

Re:Outdoor

[FlyHelicopters]

I'm pretty sure that's called a battery.

And when the sun doesn't shine for a month?

Twice in the past 6 years, we've had a month of cloudy skies and rain. In 2007, we had 45 straight days of rain, set a record.

Re:Outdoor

[Barsteward]

they still work but at a much reduced capacity so if you had double the panels you usually require, you should be ok-ish.

Re:Outdoor

[Mr D from 63]

Due to the very poor selection of DC appliances and often their RV bloated price tags,

Smaller market means lower production numbers means higher cost per unit. Then, there is the wealthy segment of the RV market who is willing to pay higher prices. At present, big margins on less sales brings a better return than increased sales with low margins.

Re:Outdoor

[Anonymous Coward]

> gas refrigerator
Sounds lovely.
My father watched someone burn to death after refilling one of those things.
Somehow they lit themselves on fire after spilling gas on themselves and lit up like a torch.

Re:Outdoor

[FlyHelicopters]

When you consider that my roof is only large enough to provide about 1/3 of my total power needs, that becomes a problem.

Plus, you've just doubled the cost of the system. Worse, when it snows in the winter, I now need a way to get snow off the panels.

Re:Outdoor

[Technician]

I can tell you are not from the Pacific NorthWest. One or two days in winter won't keep the battery charged.
Seattle has an average of 152 non rainy days per year. They claim 58 sunny days a year. Pacific Northwest is not a great place for solar.

Re:Outdoor

[FlyHelicopters]

What will happen when you run out of coal or oil? It the same problem. You ration and prioritise.

First, we aren't going to run out of either in our lifetimes. There is so much oil and coal in the world, we're swimming on top of it. Trillions and trillions and trillions of barrels of it.

Second, that is what nuclear is for. Yea, yea, "oh my god the nuclears!", but either we get over that or we keep burning oil and coal. That is reality and it is a shame that so-called environmentalists keep holding us back.

Re:Outdoor

[FlyHelicopters]

I can tell you are not from the Pacific NorthWest. One or two days in winter won't keep the battery charged.
Seattle has an average of 152 non rainy days per year. They claim 58 sunny days a year. Pacific Northwest is not a great place for solar.

A whole lot of people on this site aren't from the north in any respect... they clearly have a world view that doesn't know what 5 feet of snow looks like. Shame, because Boston and the North East got all that coverage recently for the massive snow storms, what good would solar have done in all that? Wind wouldn't work there either in those conditions.

This is why, at the end of the day, nuclear is what we really need.

But, sadly, the environmentalists are against that too.

Re:Outdoor

[bobbied]

they still work but at a much reduced capacity so if you had double the panels you usually require, you should be ok-ish.

Oh ye of great faith and frail engineering ability...

What are you going to do? Buy twice as many solar panels so you can charge your battery to hold you though the night? And as the original poster said, you planning to live without electricity for 6 days when the sun is behind the clouds for a week?

There are ways to make this work, but you have to understand that you will have to pay for capacity you don't usually need in both your batteries and solar panels and then still accept that there will be times you will run out of power. Plus you will REALLY drive up your cost per watt. I'm thinking you will likely pay about 4x what it costs for just a daytime system that carries your needs when the sun shines. You will need more than double the panels and add batteries to carry your load for a specific number of days.

If you want a week of "standby" for that rainy week, then you will need 7 days of battery capacity (ouch) plus enough additional collection capacity to charge these batteries. Say you want to recharge in 3 days, then you will need to have 2.5 times the panels it takes to carry your load for a day (plus the original panels that carry you a day). So for a system with 7 day backup and 3 day recovery, you will require 3.5 times the original collection capacity and enough batteries to hold 7 days of use.

Solar is not competitive economically when you are not talking about charging batteries. Going totally off grid requires significant investment in capacity BEYOND just your daily needs, unless you don't mind being in the dark pretty often and then the costs multiply, making an already bad ROI much worse.

AND I would like to mention that MOST batteries have losses when you charge and discharge them, some being as high as 30% losses... Just think about how many more solar panels you will need to buy for this scheme.... It's going to be nearly 4 or 5 times as many.... Good luck making that pay..

Re:Outdoor

[rogoshen1]

you should amend to that to 'west of the cascades'. Most of OR and WA are semi-arid desert areas that get copious amounts of sunshine!

Re:Outdoor

[Jarik C-Bol]

I lived in a house that was totally off grid. It actually was never on grid, because the owners already had a wind turbine back in the day when the utility companies where doing the rural electrification project, and declined to be added to the grid. This house had coal heat, gas and wood stoves, gas refrigeration, and no AC at all. Located in central Montana, it was equipped with a bank of around 12 CAT bulldozer batteries, (which replaced about twenty 1 gallon square glass jars with lead plates) over 200 square feet of solar panels, a small wind turbine (about a 2 foot blade) and a backup propane generator, that was set up to automatically start up and top up the system if it dropped below a certain charge level. So basically, all the system had for load was incandessent bulbs, and occasionally a television. In the winter, that generator ran intermittently during the day, and after dark, it ran until you went to bed, and shut all the lights off. Obviously, using LED's and more power efficient TV's is possible now, but it takes a hell of a setup to go all off grid. (you could not run a modern computer or a microwave on that system, the computers where to sensitive to the square sin of the inverters, and would randomly restart. Microwaves would pop breakers if not plugged in directly to the generator.)

Re:Outdoor

[RabidReindeer]

I can tell you are not from the Pacific NorthWest. One or two days in winter won't keep the battery charged.
Seattle has an average of 152 non rainy days per year. They claim 58 sunny days a year. Pacific Northwest is not a great place for solar.

And Florida is not a great place for hydro-power.

One Size Doesn't Fit All.

Re:Outdoor

[PIBM]

Wow.. In the winter, with the (extremely) cold days that we get I use over 200kWh per day, most of it at night (yes, the shining sun does reduce the load in the day by quite a wide margin with high quality windows). But then the sun is only up for 8 hours and some, and beside it takes an hour out on both sunrise and sunset before it manages to hit the house and lose it early. Not even talking about the bad angle of the sun, it means we would need way too much solar panel to be able to provide for a days worth of energy, and a lot of capacity to store it. And that's not even taking into account that we have a lot of days where we don't get to see the sun at all because of the extremely deep cover.

Lets say we want to be able to provide 3 days of energy without functionning panels (or a bit longer with some energy in), that takes a minimum of 600kwh, or about 95 tesla powerwall units with a 90% efficiency inverter. Where you trolling or do you really think this small battery is a revolution ? Speaking of revolution, I would rather have a large sized flywheel dug somewhere nearby.

Re:Outdoor

[LynnwoodRooster]

A whole lot of people on this site aren't from the north in any respect... they clearly have a world view that doesn't know what 5 feet of snow looks like. Shame, because Boston and the North East got all that coverage recently for the massive snow storms, what good would solar have done in all that?

Duh, you simply use your solar panels to run heaters to keep the snow off the panels!

Oh wait...

Re:Outdoor

[cptdondo]

As someone who works in the RV industry, you're right to some extent. But also, appliances in houses do not get shaken, bumped, subjected to temps from well below freezing to 120*F, so the testing and quality is far more stringent.

Lastly, we use a lot of appliances common to boats, and durability and repairability are also important. You can't go to Walmart when you're on a boat; you fix, patch, or do without.

Our customers who installed dorm fridges because RV fridges are too expensive have found that the dorm fridges don't last too long.

Re:Outdoor

[cptdondo]

How exactly do you spill propane on yourself?

Re:Outdoor

[Lumpy]

Many people have lived off grid with DC for most of their needs for decades. This is not new in any way.

Re:Outdoor

[Lumpy]

Then the windmills will be turning like hell. Because when the sun is not shining the wind is blowing.

Re:Outdoor

[Lumpy]

I had a solar powered and wind powered home in the Michigan Upper peninsula. where we average 30 FEET of snow in the winter.

It is absolutely doable. You cant be a bran dead sloth like the typical american though. you have to do some maintenance. About 20 hours a years worth.

Re:Outdoor

[FlyHelicopters]

Then the windmills will be turning like hell. Because when the sun is not shining the wind is blowing.

Not always... and windmills have a limit to what conditions they can work in, when the wind is too strong they have to shut down...

Re:Outdoor

[Damarkus13]

Something like this should allow you to run a small desktop, and most laptops just need 19vdc. I'm not sure what you could do about the microwave, but if electricity is in short supply cooking with it seems like a waste.

Re:Outdoor

[Damarkus13]

Seattle's electricity is already generated from ~90% non-carbon sources. You can put up solar panels if you want but it's not going to reduce your carbon footprint noticeably.

Re:Outdoor

[Wycliffe]

and windmills have a limit to what conditions they can work in, when the wind is too strong they have to shut down...

I don't believe this. A lot of windmills are designed for a narrow operating range and have to shut down when wind is stronger than this
but there is no reason that you couldn't continue to run wind mills designed to run in high speed winds or work on designing windmills
that work in a larger range of wind speeds.

Re:Outdoor

[Bartles]

You mean they can go to hell because they'll run out of the fossil fuels that you dont want to allow them to use anyway? Their Hell is you.

Re:Outdoor

[FlyHelicopters]

I don't believe this.

http://energybible.com/wind_en...

Re:Outdoor

[LinuxIsGarbage]

Kerosene models do exist

Really they just need a source of heat.

In any case the risk of "burning to death" could be possible with any liquid fuel powered device (even eg: Lawnmower, or car).

Re:Outdoor

[Noah Haders]

have you thought of mounting your solar panels in a vertical orientation. this will minimize the accumulation of snow.

Re:Outdoor

[Wycliffe]

I don't believe this.

http://energybible.com/wind_en...

Yes, I know that wind generators have a maximum rated speed but there is no reason that you can't design them for faster wind speeds. The problem only comes with highly variable wind speeds as something that works well in 100mph winds will probably have a high cut-in speed and won't activate at lower speeds. The solution is not to not use wind but rather to design a system that is fairly efficient in variable conditions. This can easily be done with diversification whether that is different wind generators with differing range of cut-in and cut-out speeds or even adding in some solar panels or other power sources to help even out the load. Steady load power plants like nuclear have a similar problem where they can't change to meet peak demand and this is easily solved with on-demand natural gas generators. People need to stop trying to find a one size fits all approach to power. The best power grid will be one where there are potentially dozen of power sources working in tandem. Yes, there might still be coal or natural gas plants for peak demand or cloudy days but if that's the only time they are used then our usage of fossil fuels has still been reduced dramatically.

Re:Outdoor

[evilviper]

Try to find 12V RV bulbs that are not Amber, Red, or Cool White 6K.

Okay, done.
* http://www.amazon.com/Daiwl-68...

Instead of buying a DC to DC supply for a laptop to get 19V for about $100

WTF are you even talking about? Here's a $15 unit:
* http://www.dx.com/p/universal-...

Re:Outdoor

[FlyHelicopters]

have you thought of mounting your solar panels in a vertical orientation. this will minimize the accumulation of snow.

Sure, but then they'd put out maybe 1/3 of their rated output, give or take...

Making them even more expensive and pointless...

I hate to say it, but solar might make sense for some people, and that's fine, but for many of us, it makes zero sense.

If it it works for you, great!

Re:Outdoor

[FlyHelicopters]

Steady load power plants like nuclear have a similar problem where they can't change to meet peak demand and this is easily solved with on-demand natural gas generators.

Actually, that isn't always true either...

Nuclear plants can spin resistors to burn off excess power and turn it into heat. It doesn't make sense to turn a nuclear power plant up or down, if they need to take it off line, or reduce its power output, they can turn on spinning resistors that just burn away energy to heat. This is of course wasteful, but it is an option.

A much better option would be to use that excess energy with a pumped water storage system. These can't be located everywhere, but it is another way to balance excess energy.

Also, if we can develop new wind turbines that you describe, then we can develop new nuclear reactors that also spin up and down faster. :)

Re: Outdoor

[PIBM]

My floor heating system in the basement is 5kw, my distributed hot air is 27kw, and I have 6kw of extra heating element (convectair). Worst days (-30C down to -45C) the 27kw will be used 20h+ and the other elements will pick up the slack. Thats a baseline of 540kwh for a day. Luckily they aren't that common...

Re:Outdoor

[Alioth]

Double isn't anywhere near enough. I did some experimentation with a solar panel and decided it was not worth it. From memory: the results

* Cloudless day, sun perpendicular to panel - full rated power
* Cirrus clouds, with shadows still being cast - about 60% rated power
* Bright overcast day with faint shadows - about 40% rated power
* Bright overcast day with no shadows - about 20% rated power
* Heavy overcast day - about 5% rated power

Solar is great if you live somewhere where you frequently get completely cloudless days, especially if you have a sun tracking device (power very rapidly falls off when the sun gets more than about 30 degrees off direct). But anywhere where clouds are frequent it's just not cost effective. Even haze makes a measurable reduction on the power you get.

Re: Outdoor

[Jarik C-Bol]

Clearly, your Dad' system is far more modern than the one I lived with, which was a hodgpodge of equipment, some dating back to the 1930's. ( we replaced the original lead acid glass jar batteries while I lived there). I assume the solar cells we had would be far less efficient than what are available now, as they where not particularly new, and this was in the early 90's. Glad to hear the consumer available tech has come so far.

Re:Outdoor

[dcw3]

I'm curious how well these work under blizzard, and sub-zero conditions? Is this really a solved problem?

Re:Outdoor

[xophos]

At current prices multiplied by up to 1.5, the world uranium supply will last about 90 years at current consumption rate.
If you increase consumption by replacing oil and coal plants with uranium, it will be gone in a very much shorter time.
Also using fission for energy production is at the moment barely profitable when you leave most environmental concerns out of the cost structure.
Without subsidising no new nuclear plant could compete with a wind water solar mix (even with the trouble of temporarily storing energy for peak uses).
With higher priced Uranium i have no idea, why anyone would want to build one.
Oh and if you think of nuclear reprocessing, that's even more expensive.

Re:Outdoor

[FlyHelicopters]

There is little demand for uranium, so the supply isn't growing much, that can be solved.

The cost of the fuel is trivial compared to the cost of building the plant.

Wind and solar currently get subsidies, take those away, tax carbon, and nuclear will make sense again, if of course you don't keep blocking it at every turn.

Re:Outdoor

[cornjones]

Presumably he was talking about 'white gas' that people used to use to start fires when camping. presumably there were other uses too but the only things I ever heard about were near misses of similar cases as above.

Re:Outdoor

[Shirley Marquez]

Laptops aren't fussy about power because the battery smooths it all out. Desktop systems are another story.

Re:Outdoor

[lott11]

Ho you people are limited in thinking. If you live in the north or south latitudes past the 30 to 75 degrees you can use the biggest magnet. That would be the planet you are living on, Just make 2 helix coils tuned to your location 7.893 to 8.478 Hz, one coil is under ground the other in the air. This will give you a DC current, a helix coil with a spiral reflector on top and bottom will produce 34.73 volts. All the time. The more active the sun is, more power you will have. Higher the atmosphere charge more power you will have, you will need to regulate this power. But it is all in the air, this is and antenna just like the ones that are sold for cell phones. But this is tune to the earth's magnetic field, think of your cell phone induction charger it is the same. You have to tune both coils the one under the ground and the one in the air to get the most power. Think of this as 2 variable condensers like dose in an old radio, that is it. This my bit for reducing CO2 emissions and getting your self off the grid, you do with this as you like. Could this be patented no, this are the bases of old radio communications and also Nicola Tesla. You do not believe me?> Just use a ground rod then a spiral on pole measure the voltage between ground and air and see. Why isn't any one using this, because like most things in this world they can not charge you for it. Ho one more thing the spiral are directional just like your toilet, do you get it.. Just like a hurricanes in the north they turn left and in south to the right. Good luck and use your heads.

Re:Outdoor

[bobbied]

The wave length of a 8 Hz EM field is 37,500,00 meters and a half wave dipole would be the most efficient collector is still 18,750,000 meters long. So that little cell phone antenna you are talking about is totally unusable at these frequencies without some SERIOUS loading.

So, you made this up right?

Re: Outdoor

[PIBM]

I didn't claim a year long average of 200kwh/day, only a winter average of this value ( dec. 21 to march 21). The worst time is usually around mid january to mid february but it can vary quite a lot depending on the years. Also, to have that 'low' 200kwh/day, I switch to a high efficiency wood stove when the province consumption grows to be close or higher than our production. It cost about a third to heat with wood but it's not as clean as hydroelectricity, but when they switch to buy from afar I don't mind the limited side effects of wood burning. But then, I'm not that near to a city - for which wood stoves are very bad when it's very cold.

Anyway, I'll be revisiting the heating source for my property, and I'm thinking about going to a heat pump + propane for the main loop (I'll still keep the stove though). Average daily consumption in the summer is less than 60kw / day (out of which I expect 30+ kw are computers & monitors) so I expect that I could reduce the electricity bill by 9000 kw / year, but I haven't been able to get straight numbers on what to expect to pay for the propane so it's still hard to establish if and when I would pay back the investment.

Re:Outdoor

[lott11]

No I did not make this up. Let me ask you this, have you ever seen a full length antenna. No because you always cut that length to what.. .25 or .675 nope 1/1000 or 1/10000 1/1000000 length. why? Because it is to darn big!! right. Like I stated an old radio, do the math. A variable condenser for the helix coil to do what, adjust what the frequency. The spiral coil is the antenna, you the length to what scale that is up to you. More copper means more what current, so shorter length means what gauge wire. Thinner no. More current means a heavier gauge, here is the last tip, just look at a Tesla coil. The base is a resonator the spiral is the antenna, and yes I have done this it works. To make this simpler what dose an induction coil do, if you put iron on top or inside. It heats up if the gauge is some what heavy. If the gauge is thin you will get a magnet and a hot coil. The cell phone charger, how dose it charge, the same way. It is all RF signal, what pulses at 60? what and how dose it move? Last tip, you do this one wire to ground to a condenser 1.5 volts to LED the other wire to the air. And see the LED pulse on and off, you tell me why. This will cost $4 to $10 bucks, or just measure volts no condenser no LED just 2 wires. You be the judge.

Re:Outdoor

[lott11]

no this was not a cell phone charger. i stated 34.73 volts DC this is what i have gotten at the equator. So where would you have more charge more winds.

Re:Outdoor

[n4bme]

While those type voltage converters are fine for smaller electronics I have nothing but trouble trying to use those on any type of computer equipment. They don't have enough voltage to run the unit and charge the batteries and/or do not last very long. These are one of those items where you get what you pay for. They will work but not very well or very long.

Re:Outdoor

[bobbied]

This is crap and it won't work for practical power generation, TRUST me on this, I'm an electrical engineer.

BTW... Power is the issue here. Voltage is but ONE part of how you get power. You can have a thousand volts, but if it can only supply a few micro amps, you don't have much power.

So you are waving around a big coil of ware and measuring a voltage across it.. Big deal, the question is HOW MUCH POWER are you getting? 37 volts is NOT a measure of power, but Electro Motive Force. You need CURRENT to go with that 37 volts, or this whole exercise is pointless.

For the LED experiment you describe, I don't doubt you can get 60 cycle power by placing a long wire along a power transmission line. (50 Cycles in Europe) But that's not "free" energy from the sun. In engineering school one of the home work problems we did was EXACTLY about this. We where asked to calculate how much wire it would take to get 100W off of that standard power transmission line. Using both magnetic and electric fields, the amount of wire was HUGE and when you added in I^2R losses of copper to find the gage you needed it became very expensive indeed.

So, remember what this ol' engineer told you.. Interesting experiment, but very much not practical on any scale that is useful.

Re:Outdoor

[lott11]

OK it looks like no one gets the point. Quote this is not a cell phone charger. The way that I explained how things work, was giving examples & or things that are in use today. Like the cell phone charger, or a welding gun, or an induction field cooking top. Because most people do not know what and induction field is, or how it works. Most of you have never used tubes, or variable condensers, much less how they work. Most of you learn from books that are made after 1975, the books never explained how things work. All that you got out of them is formulas that is it. So lets get down to basics, coil can be used for different things like magnets, transformers, motors. Did you know that they are also use to transmit RF signals, and to filter power for RF signals. Condenser where at one time call lighting jars, others are call filter, capacitors. Point this it all depends to who you talk and from what era in time for your terminology. So with that out the way, Magnetic fields move particles from south to north poles & fields all the way around. So that means the place we are in, has several things moving ionized particles and magnetic fields. There are others but we are not dealing with them at this time. The earth core sends magnetic fields and the stratosphere has ionized particles the are close in frequency. If they where the same frequency we would not be here, they would cancel each other as lightning. But on a massive scale all the time. The way that this pulse generator works, is that you would tune the ground coil to magnetic field. Then you tune to ionized field, there by getting electrical current charge at the point of both contacts. This will go in to capacitors then to transformer to get a constant current and a regulated out put. You made the point that it is just voltage no amps. On a normal generator will induce low volts high amps, or high volt and low amps depending on coil wire gauge. The transformer dose the conversion from low volts to high volts & high amps to low amps. To convert it back to what ever you need it at the pulse with that you would like. So at the equator I get 34.73 volts 200 MilliAmps, those I never stated the Amps I forgot it at that time. But could this maintain or charge a battery after it go through a few capacitors an a transformer. Mind you this is 24/7 ho lets say 12 volts and just keeping the same .2 MilliAmps would this work. Let say for LED lights that run at 12 volts or even LED'S 5 volts. Give that 1W = 3.412141633 BTU/hr or that V = A × that would my system put out almost 6.5 Watts. That would be a perfect world but after the resistance, we really get 2.3 Watts at 12 volts. Would charge some batteries and the unit that made was only 22.78 inches tall 32.47 wide at 32 feet above the ground. And the other unit was only 52 inches under the ground. The spiral was only 1/8 inch tubing, not my best work but I will make it right next time. You wanted numbers you got them. Now go and look at how a resonance coil work and it is built in the 1930's to 1950's. And see what Tesla used for resonance in the transmitter, you would be surprised. Many transmitters where built to transmit for long distance using the ground not the Atmosphere. But lets see that is not what they teach this days now is it. So next time before you jump the gun read, see what the examples that where placed. Also the language that I was using to explained the concepts. They do not teach everything at MIT nor at Stanford not even at UCLA. Something I learned in the field and of my elders and father. Most of your generation is fast to speak or in your case to flog wild not listening or reading carefully. Ho BTW this was for high plasma field hens the BTU formulas, using a capacitor bank.

Re:Outdoor

[evilviper]

These are one of those items where you get what you pay for.

Actually not. A DC boost circuit that only needs to double the voltage is just a few cents worth of components. The one I linked is likely not super reliable, but you can get much cheaper ($4) and still very reliable boost circuit (if you add a fan) hardware like this:

http://amazon.com/dp/B008NKNHS...

Re:Outdoor

[lsatenstein]

I can tell you are not from the Pacific NorthWest. One or two days in winter won't keep the battery charged.
Seattle has an average of 152 non rainy days per year. They claim 58 sunny days a year. Pacific Northwest is not a great place for solar.

A whole lot of people on this site aren't from the north in any respect... they clearly have a world view that doesn't know what 5 feet of snow looks like. Shame, because Boston and the North East got all that coverage recently for the massive snow storms, what good would solar have done in all that? Wind wouldn't work there either in those conditions.

This is why, at the end of the day, nuclear is what we really need.

But, sadly, the environmentalists are against that too.

Who says that solar must replace everything electrical in the house. I live in Montreal, with more severe cold days than are found in the North East. I would use solar to extract the heat for my 60 gallon hot water tank, and in winter, to produce hot water for the radiators. (The heating is done by circulating hot water). In my case, ethylene glycol filled garden hose, resting on some panels on the roof would transfer the suns heat to one or the other. Possibly, an even more efficient way for heating and cooling is to use a ground source heat-pump. (Geothermal). Too bad I can't run a long long EG filled hose through the city sewer line on my street to extract the heat therein.

Re:Outdoor

[FlyHelicopters]

Who says that solar must replace everything electrical in the house. I live in Montreal, with more severe cold days than are found in the North East. I would use solar to extract the heat for my 60 gallon hot water tank, and in winter, to produce hot water for the radiators. (The heating is done by circulating hot water).

Again, how does that work when you have 2 feet of snow on your roof? For a month...

Re:Outdoor

[vandamme]

I'm curious how well these work under blizzard, and sub-zero conditions? Is this really a solved problem?

They work better in the cold, if that's what you were asking. It's darkness that they don't like.

Re:Outdoor

[jwhitener]

Solar panels still generate power when it is cloudy and raining...of course not 100%, so you do need to 'over buy' a little bit if you want 100% off grid year round coverage, but it isn't like having to double or triple the amount of panels and storage you need.

http://pureenergies.com/us/home-solar/solar-basics/solar-myths/

Fact: Solar panels work just fine in ambient light and will produce significant energy in the fog or on overcast days. In fact, solar panels are actually more efficient at cooler temperatures than hot ones. Although this might seem counter-intuitive, consider that solar panels on a rooftop in cool, foggy San Francisco produce only one percent less electricity than one in nearby Sacramento, where it’s sunny and hot. Consider too that Germany leads the world in residential solar right now, and doesn’t have a sunny climate. Here’s some more info on how solar works in fog.

Re:Outdoor

[jwhitener]

See also a worse case scenario: Super foggy san fran http://pureenergies.com/us/blog/do-solar-panels-work-in-fog/

Re:Outdoor

[jwhitener]

I think there are a bunch of people on the site that have a strong bias against renewables. They post the same thing over and over again about it not working, not being ready, too expensive, etc..

They are either astro-turfing or intentionally keeping themselves ignorant. Simple google searches shows solar working just fine in cloudy climates.

Re:Outdoor

[bobbied]

You have to design your system to the WORST case scenario that you need to support. That means that if on the worst day your solar panel won't put out more than 1% of it's designed capacity because it is raining all day, and you don't want your lights to go out, then you need storage capacity to keep the lights on and generation capacity to recharge the batteries.

So all this talk about, "It's not usually that bad" has very little engineering impact when designing a system that can sustain a certain minimum level of performance when off grid or no other generation capacity is used (such as a fossil fueled generator).

Now, if you are connected up to the grid and using it for backup, THEN this average power generation DOES matter. If you are selling power back to the power company, then the average enters into the ROI calculations because excess power makes you money. However, even in that situation and where solar has a high availability rate (like in the southwest) it's ROI is somewhat lacking over just buying power off the grid..

Re:Outdoor

[jwhitener]

I don't think it will ever be the norm to totally disconnect from the grid.

more than 1% of it's designed capacity because it is raining all day

Yeah, but you seem to missing the point that right now in cloudy climates like San Fran, Germany, Seattle, etc.. solar panels never dip to 1%, never even dip to single digits. The worse case is way less worse than you seem to assume.

It (solar panels producing most of someone's needs) is happening right now. It isn't a theoretical thing anymore. Lots of people in less than optimal climates are producing a significant amount of their power needs with fairly standard sized solar installs.

Re:Outdoor

[bobbied]

I've seen a foggy day in San Fran, I can assure you that solar panels will be largely ineffective during those events... But my point here is that if you loose half of your capacity on some day, you will need to be prepared with the storage necessary to tide you over pulse additional capacity to charge that storage when the sun is shinning.

Most people don't realize that this can multiply the capacity necessary by multiple times and increase costs by many multiples over the "It works on a sunny day" kind of installation. This is the PROBLEM with solar really... Yea, when the sun shines it's great stuff, but any other time it's either useless or WAY too expensive for what you get and you end up needing to be on the fossil fueled grid anyway.

Its made from People!

[chriskovo]

Shouldn't it be powered by his sense of self importance? Or at least by PEOPLE!!

Re:Its made from People!

[Cpt_Kirks]

Ars tore that goof a new one.

Only HERE would his silly drivel be taken seriously.

I think he has been chugging too much soy.

i did this

[Anonymous Coward]

it didn't get me out of the AC section of my final in circuit analysis

Nonsense

[Anonymous Coward]

He's still living on the electrical grid, he's just not using it at home.

Also, WTF? "I enjoy doing laundry about as much as doing dishes. I get my clothing custom made in China for prices you would not believe and have new ones regularly shipped to me."

Re: Nonsense

[Anonymous Coward]

Wow I didn't even make it that far. This guy is clearly an idiot. He didn't get rid of his dirty fuel burning ways, he just outsourced them to others. Ordering new clothes is way worse than washing some. And as far as this soylent stuff is concerned wasn't it proven that supplements aren't very good and you need actual food to be healthy? Absorption rates of supplements aren't good from what I read and they should be used to supplement an actual healthy diet.

Re: Nonsense

[Talderas]

And as far as this soylent stuff is concerned wasn't it proven that supplements aren't very good and you need actual food to be healthy? Absorption rates of supplements aren't good from what I read and they should be used to supplement an actual healthy diet.

Why do you think he's making such questionable choices regarding dirty fuel burning ways?

Re: Nonsense

[Hognoxious]

It appears that DC razors only do one side of the face properly.

See the bits at the sides (well, one of them) that normally make it into a Fu Manchu/Charles Bronson jobbie

His looks an unfastened padlock, the twat.

Re: Nonsense

[TWX]

The line losses are a NIMBY problem, people don't want power plants near their houses.

The fuel-source problem is people not being willing to pay for more expensive renewables, or in electing politicians that oppose them while continuing to subsidize fossil-fuels.

Those things can be fixed only if people as groups are willing to accept these differences and their costs, or if someone decides to put solar panels, at increasing personal expense given the utility companies' objections, on their property.

Re: Nonsense

[tlhIngan]

Wow I didn't even make it that far. This guy is clearly an idiot. He didn't get rid of his dirty fuel burning ways, he just outsourced them to others. Ordering new clothes is way worse than washing some. And as far as this soylent stuff is concerned wasn't it proven that supplements aren't very good and you need actual food to be healthy? Absorption rates of supplements aren't good from what I read and they should be used to supplement an actual healthy diet.

Exactly. He "cut his consumption" down by externalizing it all. Basically pushing it off somewhere else and hiding it.

That's like every other company out there - they pollute because the cost of pollution is basically free - the cost is externalized (well, it was until Obama introduced those regulations). When people complain about the "cost of complyihg" it means they're no longer externalizing the cost (free) and now having to pay for it.

Basically this idiot is making himself feel better by making society worse. He doesn't do laundry - but the charity he donates clothes is forced to do it. He's basically pushed the environmental impact, energy and cost of laundry onto some other 3rd party. Or if they deem it too dirty, they'll just toss it in the garbage. To him, he's "in the clear" still because he didn't throw it away directly.

Basically, the stuff this guy did was offload onto someone else - you can conceptualize this by asking - what happens if EVERYOHE did it? If it's truly for the environment, then if everyone did it, we'd be better off. If not, then no, it's not as good.

For an example - say check your tire pressure - most people will probably be on the slightly low side. But if everyone then pumped their tires to the right pressure, society benefits from the reduced fuel consumption, cleaner air (less fuel, less pollutants, etc). That's a real net plus.

Using less energy - that's a good thing too - or more renewables. But if you're claiming your coal-powered server in a datacenter isn't your concern if you remote into it, well...

What this guy did would be like RMS asking someone to open Microsoft Word for him because he needs to do something, while claiming to be only using free software. (Yes, I know RMS doesn't do this, but it's an example).

Plus, I'm sure he's got the income to support this kind of lifestyle - enough to make a point, but really, I think I'd give it to the climate change deniers. For they can poke enough holes in his "living arrangements" to basically say "if we agree to cut back, look at how we'll live - and look ,he's not even green if he needs all that stuff!".

I'd say he's among the worst kind of "environmentalist" around - a green-washer.

Re: Nonsense

[ThatAblaze]

Exactly.

Worrying about the amount of waste in the conversion is ridiculous when you compare it to the amount of waste you incur when you try to buy off brand DC items.

I pay the electric company 8% extra to get the power from renewable sources/burning trash. Problem solved, no off brand anything.

Re:Nonsense

[jandrese]

It's a real shame this guy hasn't found a generator that can run off of his sense of self satisfaction. It would end his energy problems forever.

Re: Nonsense

[jandrese]

I have to admit, I expected him to have a full mountain man beard after reading the article. I wonder how long he can maintain this lifestyle before giving up shaving and grooming as too much of a hassle?

Re: Nonsense

[Tailhook]

he just outsourced them to others

How is that different than what we're doing to ourselves as a matter of policy? Every time we tighten the screws on some industrial chemical or fossil fuel we simply chase another industry to Asia or damn up another Canadian river. He's just following this pattern on an individual level.

Re: Nonsense

[Electricity Likes Me]

The line losses are a NIMBY problem, people don't want power plants near their houses.

The fuel-source problem is people not being willing to pay for more expensive renewables, or in electing politicians that oppose them while continuing to subsidize fossil-fuels.

Those things can be fixed only if people as groups are willing to accept these differences and their costs, or if someone decides to put solar panels, at increasing personal expense given the utility companies' objections, on their property.

No a NIMBY problem is one which is stupid, like people not wanting nuclear plants anywhere near them "just in case". Living near an actual coal power plant is actually dangerous for your health in all sorts of ways including radiation.

Re: Nonsense

[TWX]

There was a NIMBY problem when a whole bunch of rich twats wouldn't accept a windfarm in the bay that they lived adjacent to. No nuclear at all.

Re: Nonsense

[WolfWithoutAClause]

No, careful here. Outsourcing CAN actually improve the environmental aspects of what you do.

For example, centralised servers have far more chance of being run by renewables than your home computer. Google for example, is tending to do stuff like build their servers near hydroelectric plants or where there's wind farms or solar available.

So outsourcing your needs CAN actually be a good thing; and if everyone did it, it's a net positive.

Re: Nonsense

[j2.718ff]

For example, centralised servers have far more chance of being run by renewables than your home computer.

Good point. Also, there's a good chance those servers are more efficient with respect to per computing cycles per unit of electricity, since they're probably sitting idle less than your average home PC.

Re: Nonsense

[kheldan]

I couldn't make it past the first sentence without getting that look on my face. 'I have a magnet implanted in my hand', indeed! Then the sanctimonious wailing and figurative ripping of clothing over the electric grid in general.. sure, we need to move away from fossil fuels, but this guy comes off as a wacko environmentalist, and he really doesn't understand some things, and as you (the AC I'm responding to) and others are pointing out, he's just making his wastefulness indirect instead of direct, so as to keep his own hands clean. Not impressed one bit. Want to impress me? Then stop using electricity and fossil fuels entirely, both directly and indirectly, and do things with your own two hands, or just don't do them at all anymore.

Re: Nonsense

[TWX]

Actually I have. We did a road-trip into and through California when I was about 22 and we were all poor; we slept in the car at the rest-stop along the I-10 that's located in the San Gorgonio Pass and the San Gorgonio wind farm. No problems sleeping with the car windows down; couldn't hear turbines but could hear plenty of strong wind.

Besides, out in the bay where the turbines are visible near the horizon aren't going to amount to a hill-of-beans for houses so far from the project, other than that they're visible.

Re: Nonsense

[Orgasmatron]

And what do you think the hydroelectric plant was doing with that power before the data center showed up? Dumping it in the ocean?

Of course not. It was going to homes and industries. Every watt of smug power that Google uses for their datacenters is a watt of hydrocarbon or nuclear generated power next door.

A datacenter with 10,000 servers may be more efficient because of scale than 10,000 homes with one server each. But if you are on grid power, each watt that you use comes from a combination of coal, nuclear and smug sources, in the ratio of your grid and the grids your grid is tied to.

Just because your local power utility company is willing to sell you the fiction that you are exclusively on one source or another doesn't make it so.

Re: Nonsense

[YttriumOxide]

And as far as this soylent stuff is concerned wasn't it proven that supplements aren't very good and you need actual food to be healthy?

While I do think this guy is a nutcase in general, there's nothing inherently wrong with the concept of soylent. I've been living off the European "Joylent" for nearly a year now and have never felt in better health.

As long as the body is getting everything it needs in a form that it can correctly process, it will be healthy. The biggest concerns are "is there anything missing that the body needs that wasn't accounted for?" and "are the ratios/quantities really correct?". Of course, these are also valid concerns from any normal food intake if you don't vary your food a lot, which is - in the modern day and age - an increasingly common situation.

It's important to remember that it's not a "supplement", but a "food replacement". Supplements are - as the word suggests - something to supplement an existing intake giving you the things you might be missing. A food replacement on the other hand is designed to give you everything you need. Whether or not it meets that goal is a matter of debate, but there are actual food scientists researching that actively at all the major suppliers of these 'soylent' products.

(to note: the common wording amongst consumers of these products and in this reply here uses "Soylent" (upper case S) to refer to the specific brand, and "soylent" (lower case s) to refer to the type of food in general. Soylent is a soylent; Joylent is a soylent; Joylent is not Soylent)

Re:Nonsense

[slashways]

Why giving up something efficient and optimized for large power output, to a gadget like resource optimized for low power output: Nonsense

Re: Nonsense

[TheRaven64]

He doesn't do laundry - but the charity he donates clothes is forced to do it. He's basically pushed the environmental impact, energy and cost of laundry onto some other 3rd party

That's fairly minor in comparison with the energy cost of having a new set of clothes shipped all of the way from China every time whatever he's wearing gets dirty. Does he really think that producing new clothes and shipping them half way around the world has a lower energy cost than running a washer-dryer for a couple of hours?

Re: Nonsense

[Solandri]

For example, centralised servers have far more chance of being run by renewables than your home computer. Google for example, is tending to do stuff like build their servers near hydroelectric plants or where there's wind farms or solar available.

So outsourcing your needs CAN actually be a good thing; and if everyone did it, it's a net positive.

No, it's a net negative Building your server farm near hydroelectric plants doesn't reduce the amount of fossil fuels burned. It increases them. The entire electrical grid is connected. If Google's server farm weren't there, the hydroelectric power would be transmitted to fill a need somewhere else. All Google does by locating their servers there is cause someone else to use fossil fuel power instead of hydroelectric power.

Put another way, certain power plants produce as much power as they can (wind, solar, to some extent hydro and nuclear). Other plants scale their production so that total generation matches demand - coal for day/night variability in demand (they're shut down overnight), gas for instantaneous variability in demand. If you add a server farm on the demand side, it doesn't matter which power plants are nearest to it. The net effect is that additional gas and coal must be burned to handle the added power demand.

The only way to add a server farm and reduce fossil fuel consumption is to build additional non-fossil electrical generation capacity along with it.

Re: Nonsense

[coofercat]

If everyone (or even a significant proportion or people) did it, then the charities that this guy sends his clothes to for washing and redistribution would start rejecting clothes in preference to other items. Then what? People start throwing their clothes away, and all you're left with is more consumption (and by extension, more energy use).

Even outsourcing your servers is questionable by the way (although I agree it's likely an improvement over trying to run them yourself). I use my laptop for some dev work, so run a bunch of LAMP stuff on it. My laptop is sufficiently powerful to do all this - all in one box. If I were to switch to using a Raspberry Pi for my terminal but remote into a server some place else, then I've got two powered devices, plus I need all the networks and intermediate devices between them. Again - this is far more consumption than is strictly necessary, and although I couldn't calculate it, I'll bet it uses more energy than doing it all on my laptop. Also, the remote machine would likely be on 24x7, whereas my laptop hibernates when I'm not using it. You'd be right in saying that this way some proportion of that energy is renewable, but I'd guess that if servers are anything like cars, the cost of production massively outweighs the cost of usage - so less servers in the world is better than more of them (and if you must have one, make it sweat 24x7).

Re: Nonsense

[WolfWithoutAClause]

Server farms run as virtual machines, so you're only using a fraction of one machine, and even then, only when it's being accessed, so the fact that the actual machine it's on is available 24x7 makes no difference, the server farm provides compute power for web servers for other countries when you're asleep.

Actually keeping your laptop on all the time almost certainly uses more energy.

Re: Nonsense

[WolfWithoutAClause]

No, because if they're near a hydroelectric plant they can also build wind turbines and solar.

Wind turbines and solar don't always produce power, but when they do they can turn down the hydroelectric, and when the wind drops they can turn it back up again.

The net result is that the data centre uses no hydroelectric power, on average, and generates no pollution (other than that to make the turbines and solar panels which is a lot less anyway.)

No smog, no pollution, and it's irrelevant what the main power source on any local grid may be.

Re: Nonsense

[jwhitener]

Solyent isn't a supplement. I don't know if that is how it is technically labeled in order to be sold, but the product is supposed to be a complete replacement. It is liquid food. I ordered some. I haven't tried it yet. But basically there is a dry powder and a bottle of oils. sly You mix the powder, oil, and water, to create a 'complete' meal.

https://soylent.zendesk.com/hc/en-us/article_attachments/200262729/Screenshot_2014-07-30_18.36.05.png

Fat, sugar, carbs, protein, every vitamin under the sun, etc.. I assume the oil vial contains things like essential amino acids.

But despite all that, I am only planning on using the product as an emergency food or occasional quick breakfast if I'm running late. Who wouldn't rather have real food?

He wasn't able to give it up.

[FictionPimp]

"For intensive tasks, he remotes to more powerful machines".

So he can't survive without it....

Re:He wasn't able to give it up.

[MikeDataLink]

Exactly my thought. That is cheating. That's like not owning a car, and then riding in taxis the exact amount you'd have driven.

Re:He wasn't able to give it up.

[daniel.daugherty]

Computers to include large data centers run on DC power at the machine level. BIG datacenters like Facebook and Twitter have custom racks and servers that do not have AC power supplies. The Racks are fed DC power and that is distributed to the machines. Now most of the DC comes from a AC source be this lets them put together a high efficeny AC-DC converter. They can also use solar power directly. AC power advantage is when transmitting over long distances. DC power requires superconductors to be transfered over long distance without LARGE losses.

Re:He wasn't able to give it up.

[MrDoh!]

Hmm, would it help if remoting to a datacenter in the NorthWest being powered/cooled by hydro? Ok, still the comms gear local but perhaps we can shift resources to where the power is with a bit of smarts. Sync'd machines over the US to take advantage of where the sun/wind/hydro is most efficient! Makes little sense in small scales, but scaling up, doable perhaps (depending on the tasks).

Re:He wasn't able to give it up.

[ciaran2014]

If you had to remote to another machine for every intensive task, do you think you'd maintain the same volume of intensive tasks?

In summary, he reduced a bunch of things to zero, and another heap got reduced greatly, and then some smart aleck comes along and says he did nothing because this thing over here didn't get reduced much. Someone's missing the point.

Re:He wasn't able to give it up.

[viperidaenz]

DC is better for transmission lines. Google "HVDC"
AC is easier to manage. It's easier to switch and convert. To switch high voltage DC mechanically you need physically large switches, since any arcs generated will be sustained by the DC current flow. With AC is gets stopped at the end of the cycle.

Re:He wasn't able to give it up.

[Bing Tsher E]

Central Processing Units run on AC. Typically AC at much higher frequencies than 60 Hz. But it's Alternating Current.

Re:He wasn't able to give it up.

[renderhead]

Exactly my thought. That is cheating. That's like not owning a car, and then riding in taxis the exact amount you'd have driven.

Which he does. Well, he uses Uber instead of taxis, but the idea is the same.

Re:He wasn't able to give it up.

[khasim]

If you had to remote to another machine for every intensive task, do you think you'd maintain the same volume of intensive tasks?

Yes. AND EVEN MORE! I have machines dedicated to running a single task each and I remote to them.

If I had to run all of those tasks on one computer which was also my daily use computer I would run far fewer tasks.

Re:He wasn't able to give it up.

[vux984]

"Computers to include large data centers run on DC power at the machine level."

While the HVAC is all still running AC.

" Now most of the DC comes from a AC source be this lets them put together a high efficeny AC-DC converter."

Exactly. They moved the AC-DC box out of all the cases and centralized it (saves space in each server, moves a heat generation point out of each server, and lets them improves efficiency etc). But it amounts to plugging an AC/DC box next to my computer and then plugging a DC computer and cellphone charger into it. Big whoop. Its still an AC power supply. Sticking a DC convertor in and pushing the A/C source 20 feet back out of sight doesn't make it 'sustainable DC'.

"They can also use solar power directly."

True. But almost nobody but a few off the grid survivalist types are just running on solar.

Re:He wasn't able to give it up.

[AaronW]

HVAC uses 3-phase AC power which is actually pretty efficient for motors, especially if you want motors that are going to last a long time. Pretty much all brushless motors are driven by AC (even computer fans have a controller inside to generate AC). 3-phase is great for motors that run at a single RPM, such as what is used in compressors and pumps for HVAC.

Re:He wasn't able to give it up.

[Guspaz]

DC has lower loss for transmission lines, but nearly all power plants produce AC, so you're going to suffer additional losses converting the AC from your turbines to DC for transmission, and then back to AC for local distribution (to avoid the massive losses of low voltage DC), and then back to DC for the actual appliances.

HVDC has its place, but it would be very inefficient to switch from HVAC to HVDC everywhere...

Re:He wasn't able to give it up.

[Anonymous Coward]

No they don't.
I assume you're talking about the clock.
CPUs are not powered by the clock, they are powered by the ground and Vcc rails.
Drawing power from the clock would be stupid, since it would increase capacitance causing clock skew, jitter, and all kinds of BS you want to avoid on your clock network.

Re:He wasn't able to give it up.

[Electricity Likes Me]

Maybe so, but big data centers are starting to have big solar installations and a bunch of Google and Facebook ones are notionally self-sufficient if still grid tied.

So plus a few base-load nuclear power plants and they automatically become coal-free, which becomes more practical with reduced residential electrical demand.

Re:He wasn't able to give it up.

[bobbied]

AC by virtue of alternating, passes though zero current flow and zero voltage 120 times a second in this country. When you have an arc, you are passing an electric current though a plasma and that requires that you keep it hot and ionized. It is the current that keeps the plasma hot and ionized.

As a switch contact opens, initially the distance between the contacts is under the flash over voltage and an arc of plasma is formed. This arc requires current to keep flowing though it to be maintained and as the contacts separate further the resistance of the plasma path increases, lowering the current. Eventually in AC circuits, the voltage needed to maintain the plasma path starts to cycle under this minimum value for longer and longer times and current starts to fall off on average. This falling current, makes the arc plasma start to fade and will eventually extinguish the arc during the times when the current and voltage cross the zero level.

DC has no regular fall off in the plasma because it is always there, full on, full current. This means that switching similar voltages and currents in DC requires additional distance over AC. DC starts the arc and builds the plasma without stopping and only the resistance of the plasma as the distance increases is what will cause the current to get lower and lower until the arc extinguishes. There are no "off" times like there is in AC so the arc exists over a larger distance.

ALSO, on very high voltage AC circuits, it is possible to disconnect the circuit during a zero crossing. In that case, assuming you can get the contacts far enough apart to avoid flashing over, there never will be an arc to start with. Even though it's mechanically difficult to move things that fast, they sometimes do this kind of thing to suppress the arc in AC. This doesn't work in DC because there is never a zero crossing.

Re:He wasn't able to give it up.

[geoskd]

HVAC uses 3-phase AC power which is actually pretty efficient for motors, especially if you want motors that are going to last a long time.

No, no it doesnt. Commerical and residential HVAC is almost all 240VAC (two phases 180 degrees out of phase). Only industrial HVAC is 3 phase, as 3 phase is generally only needed / installed in an industrial setting.

Pretty much all brushless motors are driven by AC

Again, no they aren't. A very large portion of brushless motors including those used in large appliances, automotive (drivetrain and otherwise), computers, etc... are AC/DC brushless motors that will function on any power source. There are plenty of DC brushless motors and AC/DC brushless motors available that are equal in efficiency, longevity and power to their AC only cousins.

3-phase is great for motors that run at a single RPM, such as what is used in compressors and pumps for HVAC.

This is probably the closest to correct you have been. For commercial and residential power, 2 phase AC motors have traditionally been used, but they are largely inefficient in their use of power compared to modern options because it is difficult to operate a fixed speed heat pump efficiently under a varying load. More recently, we are beginning to see modulating heat pumps that offer a variable power setting. These require the use of PWM drive DC motors, or expensive / inefficient AC inverters to drive the pump motors. These modulating systems are almost ideal for operation from DC sources like solar and wind drive because they can be designed to function directly from the DC feed without the need for DC to AC conversion, visa-versa, or both. They consequently have the lowest operating losses, transmission losses and conversion losses of any available options.

disclaimer: I work for an HVAC controls company

Re:He wasn't able to give it up.

[TheRaven64]

Huh? The clock line is not a power line. You're not using 2GHz AC to drive your CPU, you're using DC to power the transistors and a 2GHz clock signal (which you could probably describe as AC, though it stretches the term a bit) for switching.

Re:He wasn't able to give it up.

[omnichad]

No...DC fed into a crystal to generate a clock signal to synchronize everything, but all DC. A transistor works a lot like a diode, and they only let current flow in one direction through them.

Re:He wasn't able to give it up.

[omnichad]

Yeah, last time I checked my house doesn't have 3-phase power.

Re:He wasn't able to give it up.

[bobbied]

A vacuum has less atoms there to create the ionized gas to make a plasma trail. It also has a higher breakdown voltage and should you get an arc, more resistance. Other gasses are sometimes used because they are harder to ionize either do to the valiance electrons being tightly bound in filled orbits or tightly held by chemical bonds. That is why they use the noble gasses for this kind of thing, they are very unreactive with the top level electron orbits being full.

Stone Age...

[Anonymous Coward]

So he gave up refrigeration?
an ac synchronous motor is much more efficient than DC alternatives.

Why doesn’t he just use a gas stove?
At that point why heat drinks at all? It’s wastefull.
His low power computer? He’s just using AC remotely.

Why not just move to a mud hut in east Africa?

Re:Stone Age...

[avandesande]

I don't think the OP even thought this through this far and is an obviously trash post, but for the sake of discussion I looked at a solar panel house and there are dc washing machines and refrigerators that work off of propane instead of electricity. It's actually pretty interesting... the biggest issue was there was no electricity for the well pump and water had to be trucked in so we passed on the house.

Re:Stone Age...

[drinkypoo]

the biggest issue was there was no electricity for the well pump and water had to be trucked in so we passed on the house.

You can get a solar well pump too, meaning DC and either 12 or 24V. But presumably, you'd have needed to expand the solar system for that purpose. It also works best when you have a water storage tank sufficiently elevated above the point of use to produce useful pressure, because then you can make hay (or pump water, anyway) while the sun shines, and you don't need a bunch of battery — or, potentially, any.

Re:Stone Age...

[thinkwaitfast]

I live on solar off grid. It's easily do-able, but maybe 5% more inconvenient which makes it a non-starter for most people. I have a big inverter and run all regular appliances, including standard full size dishwasher, double refrigerator, etc from Home Depot. I have 30A to use (never needed anywhere close to that).

AC simplifies wiring, allows you to buy standard, mass produced appliances rather than specialty products that come with a whole host of problems. Who do you call when your semi custom dishwasher breaks? Also safety concerns. And unless you bump up your voltage to a couple hundred volts, run geared down high speed motors, you are going to have to run big thick cables for anything that draws substantial current (coffee pots, hair dryers, AC).

Re:Stone Age...

[avandesande]

I think the one they had installed was 120v and replacing the pump was several thousand bucks... don't remember the details. (10+ years ago) Also running a 12v line with the amps to handle the load 50 or so yrds would have been costly. I guess there was some bad planning on the part of whoever built the house and solar was not nearly as advanced a decade ago.

Re:Stone Age...

[TWX]

Yeah, that seems like a rather silly argument if that was the principal reason for not buying an otherwise appealing property. Humans have had methods to raise water for literally thousands of years. Adapting one to an unpowered well shouldn't be that difficult or expensive.

Re:Stone Age...

[Anonymous Coward]

So he gave up refrigeration?

and his girlfriend. She's over here in my AC powered hot tub drinking a frozen drink from my AC powered freezer, blended with my AC powered blender. Tonight, we are going to make love under my ceiling fan.

Re:Stone Age...

[Mr D from 63]

I don't think the OP even thought this through this far and is an obviously trash post, but for the sake of discussion I looked at a solar panel house and there are dc washing machines and refrigerators that work off of propane instead of electricity. It's actually pretty interesting... the biggest issue was there was no electricity for the well pump and water had to be trucked in so we passed on the house.

The propane needed to be trucked in as well. Sounds much less efficient than getting the power off the grid. Best to spend money on high efficiency instead.

Re:Stone Age...

[mlts]

I've looked at an off grid cabin for weekend vacations. A few portable propane cylinders would cover the fridge (assuming a pound/liter of LP gas a day), and it would also cover a water heater.

Solar wouldn't be cheap, but for a few thousand, I could place a number of solar panels, have them feed in via 1-2 decent MPPT controllers into a set of AGM batteries (so watering the batteries isn't an issue), then have a decent PSW inverter coming off for use. Because lead-acid batteries destroy themselves if they go under 50% SoC, take the expected ampere-hours you plan to use, and double it, at the least. This would easily handle almost anything but heating/cooling and the well pump (which can use 1500-2000 watts each.)

The trick with the well pump and an off-grid cabin, would be to run a generator so the pump can move water into an above ground storage tank 250-2500 gallons, then from there, a much smaller pump that runs from 12 volts can pump water from the tank into the cabin.

Of course, come Texas summers, that is what a generator is for on a weekend basis. I can get 8-20 hours of use from three gallons of gasoline in a 3000 watt Yamaha inverter generator, and for a small cabin, a 10k BTU A/C is more than enough to cool it down, assuming some semblance of insulation [1]. As an added bonus, with a converter (rectifier), it is a way to help keep the batteries topped off if the panels can't keep up with use.

Disclaimer: This is a vacation cabin. For a real house, it would cost over $40,000 for a solar panel setup that can handle the amp draw of the well pump and the A/C.

Of course, there are other items like waste water (I like using a cassette toilet and having cartridges on hand, since those can be dumped down the commode safely and legally once back home, and gray water can be filtered and recycled in a settling tank so it doesn't destroy the ground around it.)

[1]: Ironic thing is that if solar panels are mounted with air space between them and the rest of the roof, they function as shade, doing a decent job at keeping the place cooler, even though the panels are likely at around 150 degrees (66 degrees C) on a hot day.

Re:Stone Age...

[Mr D from 63]

So he gave up refrigeration?

and his girlfriend. She's over here in my AC powered hot tub drinking a frozen drink from my AC powered freezer, blended with my AC powered blender. Tonight, we are going to make love under my ceiling fan.

lol

Re:Stone Age...

[drinkypoo]

I've looked at an off grid cabin for weekend vacations. A few portable propane cylinders would cover the fridge (assuming a pound/liter of LP gas a day), and it would also cover a water heater.

Solar wouldn't be cheap, but for a few thousand, I could place a number of solar panels,

Instead, build yourself a nice peltier cooler. Start with an existing ice chest or cooler, then add even more insulation. Peltier junctions and heat sink/fan combos are readily available, but I scavenged my junctions and sinks from peltier-equipped ice chests with fan problems sourced from yard sales. The junctions run well on 12V and they're very simple. Thermostatic switches with a remote bulb are easy to come by. An extra couple of inches of styrofoam all around a cooler with a lid on the top and built into a counter, with some simple PC-style ventilation. There's just not much to it. Make it permanent with thermal epoxy or use high quality long-life thermal compound like you would use on a PC.

The trick with the well pump and an off-grid cabin, would be to run a generator so the pump can move water into an above ground storage tank 250-2500 gallons, then from there, a much smaller pump that runs from 12 volts can pump water from the tank into the cabin.

The best solution would probably be a windmill pump and an elevated water tank. You can get by with around 25 psi, which takes some fifty feet of rise. Obviously, this is most readily available in hill country. Make sure to get some appropriate exposure. Flat land is bad land anyway. It seems convenient while you're working on trucks or whatever...

Re:Stone Age...

[dwywit]

I can't recall the link/s, but there was discussion at some point about running a loop of water pipes from the feed to the hot water system, along the underside of solar panels serving to both cool the panels, and pre-heat the water.

Re:Stone Age...

[PPH]

You know what they say: Power is the ultimate aphrodisiac.

60 Hz more so than 50.

Re:Stone Age...

[geoskd]

an ac synchronous motor is much more efficient than DC alternatives.

Not any more. 30 years ago that was true, but DC brushless motors have seen a great deal of improvement in the last three decades. High power and high efficiency are pretty normal in DC induction and DC PM motors these days. The biggest contributing factor has been orders of magnitude improvements in power electronics (where most of the efficiency losses used to be). It is not uncommon to find motor / control electronics packages now that are pushing 95% efficient up to tens (or even hundreds) of horsepower. (Thats tens to hundreds of kilowatts for those of you who are so inclined).

Re:Stone Age...

[raxx7]

A DC brush-less motor is nothing more than an AC synchronous motor with a variable voltage/variable frequency drive bolted onto the casing.

Re:Stone Age...

[KGIII]

I can not speak about them but in my case I have a bunch. They are on two custom metal racks put in by the installer. Each layer has three deep and eight long so, twelve, marine batteries. There are four layers so each has 48 batteries. There are two so there are ninety six batteries. I have a salt-box, envelope, that has the south-eastern side as the long side. It is covered in solar. I have two additional arrays on the lawn. I have one windmill. I have one diesel generator for backup and I still had a live grid connection brought in. It is not cheaper for me. Expense is not why I had it done.

Re:Stone Age...

[geoskd]

A DC brush-less motor is nothing more than an AC synchronous motor with a variable voltage/variable frequency drive bolted onto the casing.

Some are, some are not. It all depends how its designed. Typically, PM motors with PWM drive controllers are refereed to as brushless DC motors.

DC is more dangerous

[circletimessquare]

this experiment is fine if you're doing little LED lights and laptops, but if you're running something like air conditioning or a washing machine you're building a fire hazard and a mortality risk

the decision to use AC over DC was not random nor taken lightly, there are many factors involved (heck, it was a major engineering, corporate, and PR war between Edison and Westinghouse: https://en.wikipedia.org/wiki/... ), but the right decision was made

for our modern world where some people only care about their laptop and smartphone, it does indeed seem silly and wasteful to convert to AC then back to DC, especially if you've ever tried charging electronics in a car. but there are of course many other uses for electricity, and the navel gazing small electronics crowd is but a minor topic

but i do see a time in the future as more people use local solar and other renewables, that a small DC subsystem is made available in the house for electronics like computers

Re:DC is more dangerous

[drinkypoo]

this experiment is fine if you're doing little LED lights and laptops, but if you're running something like air conditioning or a washing machine you're building a fire hazard and a mortality risk

AC and DC are both dangerous. We chose AC because it was cheaper at the time. These days you can do low-current MPPT for a song, so you can convert between DC voltages relatively efficiently. But just generating AC from DC was expensive at the time when we had to choose between them.

for our modern world where some people only care about their laptop and smartphone, it does indeed seem silly and wasteful to convert to AC then back to DC, especially if you've ever tried charging electronics in a car.

Well, they do make converters specifically for that purpose, and they are not so inefficient as using the cheapest possible inverter which fits in your soda can hole coupled with your laptop's normal power supply. Also, cars really ought to go 48V already, what year is it anyway?

Re:DC is more dangerous

[iggymanz]

actually, high voltage DC is far more efficient for long distances, so countries like India are going to that

Re:DC is more dangerous

[TWX]

AC has one significant advantage in that it generates much less heat on the wire, and the higher voltages, within reason, allow for smaller wires to do the same work, as wire size need is a function of amps.

Re:DC is more dangerous

[Anonymous Coward]

actually, high voltage DC is far more efficient for long distances, so countries like India are going to that

Correct, after a certain distance (too lazy to look it up) the AC power lines become an antenna. So there is a maximum length for AC power lines.
But with AC lines you can use 3 phase wiring, cutting the required quantity of metal in half compared to DC. (3 phases balance, and therefore do not need a return wired)

Re:DC is more dangerous

[drinkypoo]

AC has one significant advantage in that it generates much less heat on the wire, and the higher voltages, within reason, allow for smaller wires to do the same work, as wire size need is a function of amps.

Except now that it's cost-effective to regulate DC to relatively arbitrary voltages, we can use HVDC... or just relatively high voltages. For example, some automobiles are beginning to move to 48V because they can use much smaller wiring, saving weight.

The prohibitive cost and lack of efficiency in DC to DC conversion really was the sole reason AC won. It was practical. Today, we are using more and more DC in our long-haul links. But the same technology that makes it feasible to use DC also makes AC cheaper.

Re:DC is more dangerous

[circletimessquare]

thank you, dc genuinely has greater fire hazard implications than ac

as for health, it is a bit more nuanced and complex than i said:

Direct current (DC), because it moves with continuous motion through a conductor, has the tendency to induce muscular tetanus quite readily. Alternating current (AC), because it alternately reverses direction of motion, provides brief moments of opportunity for an afflicted muscle to relax between alternations. Thus, from the concern of becoming "froze on the circuit," DC is more dangerous than AC.

However, AC's alternating nature has a greater tendency to throw the heart's pacemaker neurons into a condition of fibrillation, whereas DC tends to just make the heart stand still. Once the shock current is halted, a "frozen" heart has a better chance of regaining a normal beat pattern than a fibrillating heart. This is why "defibrillating" equipment used by emergency medics works: the jolt of current supplied by the defibrillator unit is DC, which halts fibrillation and gives the heart a chance to recover. ...

One of the reasons that AC might be considered more dangerous is that it arguably has more ways of getting into your body. Since the voltage alternates, it can cause current to enter and exit your body even without a closed loop, since your body (and what ground it's attached to) has capacitance. DC cannot do that. Also, AC is quite easily stepped up to higher voltages using transformers, while with DC that requires some relatively elaborate electronics. Finally, while your skin has a fairly high resistance to protect you, and the air is also a terrific insulator as long as you're not touching any wires, sometimes the inductance of AC transformers can cause high-voltage sparks that break down the air and I imagine can get through your skin a bit as well.

http://physics.stackexchange.c...

Re:DC is more dangerous

[circletimessquare]

i was talking about a more local electrical arrangement

but yes, long distance, that's a complicated topic, what distance are you really talking about and what other interconnections do you need? dc does have advantages in many cases, especially very long distance

but now we are very far away from the topic of a guy charging his laptop and running some LED lights

The advantage of AC has always been that it is easy to change the voltage up and down with a transformer; DC requires more equipment and some losses to convert.

That being said, transferring AC power between separate grids requires making sure the phase of the power transmitted matches from the two grids (so that the power from the two grids doesn't cancel or ring), which is difficult and expensive. This is not a problem for DC, so DC lines are used in cases such as where power is transferred from another grid to increase the capacity of an existing grid, or between countries that use different frequency power.

Capacitance between the AC phases (usually 3 phases are transmitted at once over a line) or between the line and the surrounding soil or water causes losses that are not a problem with DC. Therefore, undersea high voltage lines tend to be DC.

Overall line loss is also lower per 1,000 km, so very long distance transmission lines sometimes use DC.

http://www.quora.com/When-and-...

Re:DC is more dangerous

[myowntrueself]

this experiment is fine if you're doing little LED lights and laptops, but if you're running something like air conditioning or a washing machine you're building a fire hazard and a mortality risk

AC and DC are both dangerous. We chose AC because it was cheaper at the time. These days you can do low-current MPPT for a song, so you can convert between DC voltages relatively efficiently. But just generating AC from DC was expensive at the time when we had to choose between them.

for our modern world where some people only care about their laptop and smartphone, it does indeed seem silly and wasteful to convert to AC then back to DC, especially if you've ever tried charging electronics in a car.

Well, they do make converters specifically for that purpose, and they are not so inefficient as using the cheapest possible inverter which fits in your soda can hole coupled with your laptop's normal power supply. Also, cars really ought to go 48V already, what year is it anyway?

You can kill an elephant with AC! AN ELEPHANT!!!!!!!!

Re:DC is more dangerous

[WolfWithoutAClause]

KILL?

u mean: "WESTINGHOUSED"!

Re:DC is more dangerous

[serviscope_minor]

HVDC only makes sense on very long haul links. Line losses are lower, but the conversion stations arte much, much, MUCH more expensive, than a few turns of copper wrapped around a chunk of iron and immersed in oil. Also, AC ssystems behave as an infinite bus bar more or less and you can put in and extract energy equally easily at any point. That's much harder with HVDC.

The cost and difficulties assosciated with HVDC aren't going to displace AC in the small to medium haul any time soon.

Re:DC is more dangerous

[Smidge204]

DC is harder to turn off safely. A high current contactor will arc under both AC and DC - but an AC arc tends to be self extinguishing. Solid state switching is less efficient and requires power to activate. They also tend to go up in flames when they fail.

HVDC is used only for long distance transmission, where the capacitive load for AC systems becomes a major source of loss. The only other time it makes sense is when the current required is so high, the skin effect at AC frequencies results in cables that need to be substantially larger. In cases like that, though, it's often easier to go with multiple smaller cables anyway.

AC is demonstrably easier to engineer around, and safer as a whole. There are some good arguments to be made that DC might be safer under some circumstances should you become part of the circuit - but the whole idea is that people should not become part of the circuit in the first place, so that's a non-issue.

Also, regulating DC to various voltages just means it converts it to AC first then back to DC... unless you're using linear regulators in which case the unneeded power is dumped as heat!
=Smidge=

Re:DC is more dangerous

[geoskd]

the decision to use AC over DC was not random nor taken lightly, there are many factors involved (heck, it was a major engineering, corporate, and PR war between Edison and Westinghouse: https://en.wikipedia.org/wiki/... [wikipedia.org] ), but the right decision was made

The right decision was made for the time. At that time, no one could have envisioned modern electronics. The advent of the transistor marked the turning point at which DC power would eventually become the better option. It was just a matter of time after that until control electronics got good enough and efficient enough to make DC a better option. We are almost at that point now. DC power line transmission is a better alternative if one assumes that the technology exists to do voltage conversion at high voltages (its not currently there yet, but at the current rate of technological improvement, we will be there in 20 or so years). The conversion to DC is not even something that will need to be done all at once. Individual long haul lines can be converted one at a time until the power form the power company is HVDC all the way to you local transformer. At that point, it will make sense for the power company to offer a HVDC feed for those that want it. This would be advantageous for solar and wind installations because interfacing with these power system would not require complex and expensive phase matching equipment. It would be advantageous for those that have mostly DC appliances because they would save 10% on their electricity costs because they would no longer have to pay the 5% efficiency loss to convert to AC power at the pole, and they would save an additional 5% by not having to convert from AC back to DC inside the appliance. For power utilities it would be cheaper because of less transmission losses as well as less risk of power line phase issues causing transmission line faults and unexpected drop outs. We are still many decades away from HVDC power becoming a reality, but it will come. It will happen because it can happen and the advantages will eventually outweigh the cost of retrofit.

Re:DC is more dangerous

[geoskd]

AC has one significant advantage in that it generates much less heat on the wire, and the higher voltages, within reason, allow for smaller wires to do the same work, as wire size need is a function of amps.

That advantage is not intrinsic to AC vs DC, it is a result of the voltage involved. The transmission losses of a DC system running at 120V is pretty much the same as the losses from an AC system running at 120V. (I know that power factor and all that, but with more and more AC to DC converters pulling power from the AC lines, the power factors are getting royally borked anyways) In many ways DC has an actual advantage. AC transmission lines have a capacitance associated with them. This causes additional losses on the transmission lines that do not occur with DC. (Think of it this way: The line has a giant capacitor on it, and an AC source has to charge and then discharge that capacitor 60 times a second. With DC, the capacitor gets charged and stays charged.) This means that the *effective* resistance of a DC transmission line is lower than the same exact line transmitting AC power.

Re:DC is more dangerous

[TheRaven64]

DC is harder to turn off safely. A high current contactor will arc under both AC and DC - but an AC arc tends to be self extinguishing

There's also the issue of touching the live wire. If you touch a DC main, your hand will spasm and you're likely to end up gripping it. If you touch AC, then you feel a buzzing at the frequency, but it's a lot easier to pull away.

Re:DC is more dangerous

[petermgreen]

AC and DC are both dangerous.

True, the question is what is the relative danger.

One problem is that people conflate the questions of voltage/current with the question of ac/dc. As a general rule for a given load a lower voltage system will have a lower electric shock risk but will have a higher fire risk.

DC is far more prone to sustaining arcs than AC. DC is also far more prone to causing unplanned electrochemical activity.

Re:DC is more dangerous

[petermgreen]

Correct, after a certain distance (too lazy to look it up) the AC power lines become an antenna. So there is a maximum length for AC power lines.

Well every power line is an antenna to some extent. Obviously the affect gets bigger with distance but there isn't some magical distance beyond which AC power transmission becomes unfeasable. It's more of a gradual thing with the question being balancing the lower line losses of DC

The real advantage of DC include
1: the lack of losses to electromagnetic radiation
2: a massive reduction in the impact of line capacitance and inductance( if rate of power transfer was constant they would have no impact but if it's not constant they will still have some impact). While capacitance and inductance don't dissipate net power in themselves they can cause extra current flow and/or extra voltage drop which increase losses elsewhere.
3: the lack of skin affect which pushes currents to the surface in large AC cables
4: the lack of need to syncronise systems before interconnecting them.
5: insulation strength requirements depend on peak voltage, achivable power transmission depends on rms voltage and current. For DC peak=rms for AC peak=sqrt(2)*rms

But with AC lines you can use 3 phase wiring, cutting the required quantity of metal in half compared to DC.

bullshit.

(3 phases balance, and therefore do not need a return wired)

The same is true of a centre tapped DC or single phase AC system.

Re:DC is more dangerous

[Blaskowicz]

What if I need 24V or 19V and my power source is 12V? (car battery, small "solar" deep cycle car or even an ATX PSU)

There doesn't seem to be consumer appliances available to boost DC voltage up. A high quality 24V power brick isn't that cheap either, it's more expensive than the device that needs it (a class D amplifier for hi-fi sound)

Ditto getting 48V from 12V or 24V.

Re:DC is more dangerous

[drinkypoo]

There's also the issue of touching the live wire. If you touch a DC main, your hand will spasm and you're likely to end up gripping it. If you touch AC, then you feel a buzzing at the frequency, but it's a lot easier to pull away.

The problem with this idea is that the muscles which grip are a lot stronger than the muscles which open the hand, so AC will make your hand clench anyway.

It's nice to have ideals

[gavron]

I respect the man for having ideals and trying to live up to them.

Of course he has fresh water. That comes from his pipes. Some requires transport from the Colorado River and that uses fuel. Some requires desalination from the Pacific Ocean and that uses fuel. With a water bill comes a related sewer bill. Sewer and effluent treatment require chemicals and fuel.

Of course he has batteries. That's how his solar cell provides his DC power. Both solar cells and batteries cost exotic chemicals/components, and take fuel to produce. Solar cells don't degrade as much over time but the typical deep-cycle battery requires replacement every 24-36 months [depending on the charge, cycle, use, etc.]. This also applies to the TMO cellphone battery he uses to power his TMO Internet.

Of course he buys his clothes from China - has them shipped - and throws away old clothes. This way instead of using water and detergent and some electricity (or some 25 coins and a laundramatt) he uses a lot of jet fuel, some delivery truck fuel, throws away cardboard boxes and plastic wrappers (think hydrocarbons which could be used as fuel, and fuel itself). He feels better because he donates his old clothes. I'm not sure that he thought about this much because ***ALL THE OLD CLOTHES HE DONATES ARE WASHED BY GOODWILL*** or whomever prior to putting on the shelf. So he costs the environment more, not less.

Lastly... that TMO Internet again... he is one of the people who encourages TMO to have towers. Towers have little generators on them so they don't lose power in storms, power outages, etc. Those use fuel which goes bad after a year and must be replaced. That means once a year cellphone tower generator fuel tanks are purged and dumped and new fuel is acquired and put in the tank. [Yes, some carriers have a 2yr schedule and some don't discuss their schedule, but if we're talking ideal... here you go.]

It's good to have ideals. It's nice try and live by them.

Ehud Gavron
Tucson, AZ, where 4 months out of the year the temperature is above 100F and the humidity above 40% so if you don't have an air-conditioner using direct-expansion gas (not a "swamp-cooler" or "mister") you will bake. They don't make any that run on DC. Even if they did, that would be a LOT of solar cells!

Re:It's nice to have ideals

[Holi]

The typical deep-cycle battery does NOT need to be retired in 24 to 26 months lead acid deep-cycle batteries are more like 4 to 8 years longer if you treat them well. If you want to double that spend a little more (ok a lot) and get surrette deep cycle batteries, typical lifespan range is 7 to 15 years.

Re:It's nice to have ideals

[Nemesisghost]

Yeah, and I love that he thinks eating paste or eating out is actually using less energy that simply cooking fresh food that's locally sourced. Heck, growing a garden is trivial, even in an apartment and would reduce your carbon footprint, save energy, and cost you much much less. And I'm sure there are storage methods that would allow you to get rid of both your fridge & your stove if you really wanted to. But this guy didn't want to do that. His lifestyle is not about saving anything, but showing how much better he is than the rest of us plebes.

Re:It's nice to have ideals

[TWX]

Tucson, AZ, where 4 months out of the year the temperature is above 100F and the humidity above 40% so if you don't have an air-conditioner using direct-expansion gas (not a "swamp-cooler" or "mister") you will bake. They don't make any that run on DC. Even if they did, that would be a LOT of solar cells!

Actually they do make one with an AC/DC dual voltage motor. Lennox sells one. It's ridiculously expensive without even including the panels, but it was an option that we looked into a couple of years ago when we had to relace a 2.5 ton unit that had failed. The replacement alternating current model has a 30A circuit breaker on a 240VAC circuit, so it can draw a max of 7200 Watts. This 8000W system would be enough to power that air conditioner and have some to spare.

I have enough roof space for probably 40,000W of panels. The thing causing me to hold back is the electric utility. I want grid-tie with intentional islanding and battery storage if the grid loses power, and I don't want to get hammered with utility company fees like they're trying to get out of us if we go that route. I'd also like to get reimbursed a fair rate for the power I'd supply back to the grid during peak usage, but they're not interested in doing that either. I'm hoping that Solar City wins their lawsuit against the utility so that I can feel comfortable proceeding at some point down the road with this.

Re:It's nice to have ideals

[viperidaenz]

Except it's not a DC motor, requires 200V and a motor controller.

Re:It's nice to have ideals

[Phs2501]

The AC in a prius runs directly off of the HV DC batter pack. Go find a junked prius and loot the AC if you need some DC powered cooling.

No, the Prius air conditioner compressor is AC. The Prius inverter electronics converts the HVDC to the correct AC frequency to run the motor. So you'd need both the compressor and inverter assembly, which also includes the inverters for the motor-generators that move the car. And a 200V DC power supply. And all the right computers to get the inverter assembly to do something useful.

You'd wind up with a whole bunch of a Prius just to get a silly air conditioner.

From Special Issue: Inside the Toyota Prius: Part 5 - Inverter/converter is Prius' power broker:

The Prius also uses an electric air-conditioning compressor motor so that cabin cooling is maintained even when running in electric mode only. A second dc/ac inverter, with circuits located on a second ICU controller circuit board ringed with TO-packaged IGBTs, is deployed to power the electric A/C compressor from the HV battery pack. The A/C inverter IGBT packages are bolted to one face of the substantial heat-sinking enclosure of the ICU.

Re:It's nice to have ideals

[AaronW]

The AC is actually hooked up to the main inverter since the AC uses an AC motor. DC motors require brushes and are typically less efficient than AC motors. There's no such thing as a purely DC motor. A "DC" motor typically uses brushes to generate AC for the coils.

Re:It's nice to have ideals

[Electricity Likes Me]

If you break it down like that everything in the modern world looks like a lot of work for "something so simple". Consider the mechanicals of that air conditioner for "just some cool air in a car".

AC motors are very efficient but in no way are they enabled by AC line voltages - efficient AC motors always do multiple conversion steps to produce AC current matched to the present speed and position of the motor. The simple AC motors you find in cheap power tools are nowhere near as efficient (and a DC motor is usually better anyway because it'll torque its way through just about anything).

Re:It's nice to have ideals

[FlyHelicopters]

I have enough roof space for probably 40,000W of panels.

You have a big roof! Wish I had that much room!

The thing causing me to hold back is the electric utility. I want grid-tie with intentional islanding and battery storage if the grid loses power, and I don't want to get hammered with utility company fees like they're trying to get out of us if we go that route. I'd also like to get reimbursed a fair rate for the power I'd supply back to the grid during peak usage, but they're not interested in doing that either.

In fairness, the electric utility isn't completely wrong in wanting a fair shake.

For example, are you asking for net-metering where they pay you retail for your power, or are you asking for wholesale rates when you sell them back your power? The former is not reasonable, the latter is totally reasonable.

Generally grid-tie systems need to shut down automatically when the power goes out, this is for the safety of the linemen working on the downed lines.

Re:It's nice to have ideals

[Phs2501]

Yeah, I know that, I was just responding to the simpleminded idea that "Oh, you want an air conditioner that'll run off some solar panels with no inverter? Just get the AC unit out of a Prius and hook it up!" It's just not that simple.

Re:It's nice to have ideals

[TWX]

I have enough roof space for probably 40,000W of panels.

You have a big roof! Wish I had that much room!

I have a nearly 1000sqft detached workshop with a flat roof and parapet walls in addition to a large portion of my house having a flat roof with parapet walls. If I don't put any panels on the south-facing sloped roof I still probably have 2500sqft of flat roof with direct sun exposure for the bulk of the day, concealed behind the parapets.

The thing causing me to hold back is the electric utility. I want grid-tie with intentional islanding and battery storage if the grid loses power, and I don't want to get hammered with utility company fees like they're trying to get out of us if we go that route. I'd also like to get reimbursed a fair rate for the power I'd supply back to the grid during peak usage, but they're not interested in doing that either.

In fairness, the electric utility isn't completely wrong in wanting a fair shake.

For example, are you asking for net-metering where they pay you retail for your power, or are you asking for wholesale rates when you sell them back your power? The former is not reasonable, the latter is totally reasonable.

I'm not unhappy to make back less than the going rate for a given time of day, but they want to pay-back the rate during the peak of the day that they charge in the middle of the night to time-of-use customers. So they take power from me during the hottest, highest-demand and highest-customer-cost part of the day and pay me something like 1/8 of what they charge. They also want to charge a separate fee, that they don't charge to non-solar properties, to tie me to the grid, and it's not insubstantial. Their crap-reimbursement plus high fee for simply being tied to the grid (and it's not permissible to not be tied to the grid) means that it costs the same to have solar as to not have solar. If they charge every customer the grid-tie fee and then put actual charges for their electric use on properly I bet that many customers would find that half of their monthly bill was simply for the grid-connection. That's my problem; they're intentionally screwing-over solar customers because they don't want anyone to be able to do without them. Eventually a tipping-point will come where we don't need them; storage capacity will make that so. They're attempting to swim against the oncoming flood.

Generally grid-tie systems need to shut down automatically when the power goes out, this is for the safety of the linemen working on the downed lines.

I don't disagree, that's why I want a controller that can detect when the grid is down and island the property from the grid, so that linemen aren't working on energized lines coming from my house.

Re:It's nice to have ideals

[geoskd]

Lets be honest, if Toyota were any good at building the electric part of a hybrid, they would be building the cars that tesla is building. There is a reason Tesla motors is king of the electrics and everyone else is playing second fiddle. You wont find an AC induction motor powering a teal any time soon. The only advantage that Induction motors have is that they are cheaper to build than DC brushless. That is the only real advantage. They are harder to control, have worse efficiency, the control electronics costs more. It is not at all surprising to me that an established auto company is doing things all crabbed when it comes to electric vehicles. They are still functionally retarded when it comes to electronics.

Re:It's nice to have ideals

[YesIAmAScript]

You're wrong about the AC draw.

AC motors require a LOT of start current. And breakers allow that draw as long as it is short. That compressor probably runs on 12A 240V AC, but it won't start with much less than 100A available.

Re:It's nice to have ideals

[TWX]

Isn't that what the motor run capacitor is supposed to help with? I've repaired both automotive and residential HVAC systems and I've worked on light-duty commercial air compressors. I've never needed more than a 50A breaker, and I'm using reasonably quick-acting breakers.

Re:It's nice to have ideals

[petermgreen]

Isn't that what the motor run capacitor is supposed to help with?

No, the capacitors in a single phase AC motor are to make the magnetic field rotate rather than merely oscilate. Some motors switch the cap out once started, others leave it in.

I've never needed more than a 50A breaker, and I'm using reasonably quick-acting breakers.

Can you be more specific about what breakers you are using? I know here in the UK we have two common types, "type B" breakers trip quickly at 3-5 times overcurrent while "type C" breakers trip quickly at 5-10 times overcurrent. Smaller overcurrents are handled by the thermal part of the breaker which trips much slower.

Re:It's nice to have ideals

[Muad'Dave]

The startup time of a large motor is just a couple of seconds, and as Figure 1 in this PDF shows, a typical breaker is made to withstand 6-20x its rated current for 3 seconds.

IIRC the start capacitor doesn't store charge to help with startup current; rather it provides a phase shift in the aux winding to get the armature moving.

Re:It's nice to have ideals

[omnichad]

Never heard of a brushless motor? A stepper motor?

Re:It's nice to have ideals

[samwichse]

This guy's building a nice homemade inverter/controller for a Prius A/C compressor:

http://www.diyelectriccar.com/...

Might as well be dead! No! More butter, more wine!

[jabberw0k]

No birthday cakes, no cherry pies, no fresh baked bread, no roast pork with caramelized potatoes, no steaks, no cauliflower broccoli cheese casserole, not even any homemade French onion soup? I shudder to think what Julia Child would say to that.

These changes...

[Pollux]

He doesn't cook, and was able to get rid of almost all kitchen appliances because of that. He uses a butane stove for hot beverages. He powers a small computer off batteries, which get their energy from solar panels. For intensive tasks, he remotes to more powerful machines. He re-wired his apartment's LED lighting to run off direct current. Have any of you made similar changes?

No. I have a wife.

Re:These changes...

[Nutria]

No. I have a wife.

Gah. That's *exactly* what I was thinking. Also that he has a very reduced chance of transmitting his DNA to the next generation...

Re:These changes...

[VAXcat]

I got rid of the stove in my kitchen, but it was to make room for a VAX, not to reduce my use of AC.

Re:These changes...

[techno-vampire]

Also that he has a very reduced chance of transmitting his DNA to the next generation...

From where I'm sitting, that's not a problem. Do you really want smug, sanctimonious hypocrites like him swimming in the gene pool?

Re:These changes...

[Nutria]

Do you really want smug, sanctimonious hypocrites like him swimming in the gene pool?

lol. There are a *lot* of people that I don't want swimming in the gene pool. (But I'm sure that there are many who don't want relatively stable corporate drones like me in the gene pool either...)

Re:These changes...

[ponraul]

I cook on an induction heater. Not sure how to do that efficiently with DC.

Somewhere Thomas Edison is Tenting his Fingers and

[mykepredko]

saying "Excellent".

50% is lost in AC to DC conversion?

[vadim_t]

Sounds like he's badly confusing something. I think he's badly misunderstanding how a rectifier works. Some waste of course happens, but not nearly that much.

Re:50% is lost in AC to DC conversion?

[Anonymous Coward]

it is true for the worst case: a linear regulated supply. those things are rare beast these days.
chalk it up to hyperbole in the pursuit of his already concluded end result.

Re:50% is lost in AC to DC conversion?

[daniel.daugherty]

79.549342% of all statisitcs are made up on the spot.

Re:50% is lost in AC to DC conversion?

[slowdeath]

No where near 50% is lost these days in modern AC/DC or DC/AC conversion devices.
Solar panel DC/AC inverters run at 95% to 98% conversion efficiency.
Likewise modern AC/DC converters can easily achieve 90 to 95% conversion efficiency.
Unless he uses very bulky low voltage, high current cables, he could easily be losing 3-5% of transmitted DC power in those.

He would be better off keeping his residence on AC and covering his roof with as many solar panels as he can fit.

Re:50% is lost in AC to DC conversion?

[stackOVFL]

Yeah, your right. The low efficiency of a DC power supply is in the 80% range. http://www.xppower.com/pdfs/TA...

Re:50% is lost in AC to DC conversion?

[Mariner28]

Typical 12Vdc smart battery chargers used in the marine and RV industry are more than 80% efficient - the Magnum Energy MS2812 inverter/charger I have installed on my sailboat is 85% efficient when charging the batteries (converting 120Vac to 13.8Vdc) and 88% efficient when inverting (taking 12Vdc nominal and converting it to 120Vac).

Re:50% is lost in AC to DC conversion?

[kheldan]

Yeah, I raised an eyebrow at that, too. A properly designed switching power supply, even a small one, can be >90% efficient, as opposed to a linear supply with even an LDO linear regulator, which wastes power as heat.

Re:50% is lost in AC to DC conversion?

[Omega Hacker]

It's the loss between the absolute physical heat energy from the combustion source and the effective electrical output of the entire plant.

http://www.eia.gov/tools/faqs/faq.cfm?id=107&t=3

This shows that for 2013, the average heat efficiency of a US coal-fired plant is 32.62%, while that of a natural gas plant is 42.92%.

The fact that nuclear, coal, and oil are all similar implies that the actual steam conversion cycle is the primary limit here (as opposed to the summary which claims that the steam cycle is *another* 50% loss, which it is not). That begs the question in my mind though: how do natural gas generators beat that, and can whatever tricks those are be applied back to coal/gas/nuclear?

Re:50% is lost in AC to DC conversion?

[paulpach]

I don't understand what the 67% loss in combustion is...

When we burn fuel, we are only able to convert a fraction of the potential chemical energy into work (pushing something like a piston). Then we convert the kinetic energy into electricity and again we are only able to convert so much. Some fuels are more efficient than others, and the performance of generators also differs greatly.

What the author is refering too is the fact that from the total potential chemical energy in fossil fuels, we are only able to collect less than half in the form of usable electric power. The rest of the energy is simply dissipated in the form of heat, and other non usable forms.

Re:50% is lost in AC to DC conversion?

[Fallen Kell]

I as well as others thought the same thing. Maybe 60 years ago we lost 50% (as well as on things that still used techniques and technology created from that time which in some instances were still being used 30-40 years later). But modern AC->DC converters can and are in the 90+% efficient.

Re:50% is lost in AC to DC conversion?

[Chris Mattern]

In addition to inevitable losses in the machinery, any heat engine (which is what any fossil fuel or nuclear power plant is) generates usable power from the difference in temperature between your heat reservoir and your cold reservoir (where you dump your wate heat). This difference imposes a basic limit to how much heat you'll convert to usable work, that efficiency being greater with a greater temperature difference. This efficiency ceiling is known as the Carnot limit. The reminder of the heat generated must be lost as waste heat. For the average power plant, the Carnot limit is around 60% (the average car engine, which is also a Carnot heat engine, has a limit of about 25% to 30%). Other losses reduce the efficiency to about 40%, so he's actually about right here (he needs an education in electric circuit design, though; he doesn't understand AC to DC retification at all).

Re:50% is lost in AC to DC conversion?

[cdrudge]

Liar! Yesterday I read that 143% of all statistics are made up on the spot.

Re:50% is lost in AC to DC conversion?

[thoriumbr]

If his phone charger is only 50% efficient, it will be very hot. And it will be on the top of the list of the most inneficient charges ever built.

Re:50% is lost in AC to DC conversion?

[sribe]

That begs the question in my mind though: how do natural gas generators beat that, and can whatever tricks those are be applied back to coal/gas/nuclear?

Modern natural gas generators drive big-ass high-speed high-efficiency turbines directly for primary generation, then use a steam cycle to squeeze a little more out of what would otherwise be waste heat.

Re:50% is lost in AC to DC conversion?

[willworkforbeer]

What about the other half?

Re:50% is lost in AC to DC conversion?

[jabuzz]

Utter bollocks. A 50% efficient charger for a smart phone would be illegal to sell in the EU and the USA. It would also be frigging difficult to make, even a bog standard old fashioned transformer and linear regulator will be better than 50%, but even a cheap as chips charger would be switched mode and in excess of 80% efficiency.

Re:50% is lost in AC to DC conversion?

[bdubSOv1iKIJ403M]

The other way to beat the 67 % initial loss, is to START with a solid oxide fuel cell, then do a steam cycle afterwards with the waste heat; with considerably higher total efficiency.

Solid oxide fuel cells are basically like normal fuel cells, except instead of using a proton exchange membrane, they use an oxygen exchange membrane, giving them flex-fuel capability and the ability to burn almost anything. Only catch being that the "oxygen exchange membrane" needs to be pretty hot before it starts working at reasonable throughput; which makes everything else outrageously expensive because the coefficient of thermal expansion of all the metal contacts have to be matched, and the ceramics crack if warmed up too quickly. The most widely commercialized solid oxide fuel cells today, are in the 50 kw - 1 mw scale and sold for building-scale backup power . . . only 1000x - 20,000x scaleup required before we can replace a single coal plant.

Re:50% is lost in AC to DC conversion?

[tsotha]

The most efficient plants are combined cycle, which sort of rules out nuclear (at least for LWRs), and combined cycle coal plants are very rare.

Also, I'm not sure heat efficiency is a hugely important metric for nuclear plants. With nuclear you generally have more heat than you know what to do with (sometimes literally).

Re:50% is lost in AC to DC conversion?

[thegarbz]

Single voltage with known source and target load requirements are absolutely trivial to get into the 90%+ efficient range. In fact making such a charger was part of a 3rd year assignment at my university and we had to demonstrate a measurable 95% efficiency. It all came down to part selection, and they were selected by a formula. The theoretical values almost perfectly matched our final chosen values to achieve what we needed.

Efficiency becomes a problem when you start wide ranging your inputs or your outputs. I.e. you need 5-48V DC inputs (120V - 230V isn't too hard), or you need a wide ranging current output .05-5A all while staying within a tight tolerance. Then efficiency becomes a problem as you hit some trade-offs.

As a side note a transformer + rectifier + linear voltage regulator is more than 50% efficient. These are now banned in Australia due to efficiency laws.

Re:50% is lost in AC to DC conversion?

[geoskd]

I once had a car lighter socket to USB power adapter that started to flake out on me. When I opened it I found ten diodes in series. That was the whole show. Turned out the "problem" was my car battery was about to die, which was why the "power adapter" was not producing 5 volts anymore...

Re:50% is lost in AC to DC conversion?

[lastman71]

It looks like he corrected the post: "then to charge a DC device like a cell phone another 20% is lost in conversion"

Re:50% is lost in AC to DC conversion?

[Alioth]

Good grief, who designed that? I'd have to imagine 2 capacitors and a 7805 linear regulator would work out cheaper and perform better than all those diodes in series for whoever was making it.

Re:50% is lost in AC to DC conversion?

[petermgreen]

Efficiency becomes a problem when you start wide ranging your inputs or your outputs. I.e. you need 5-48V DC inputs (120V - 230V isn't too hard), or you need a wide ranging current output .05-5A all while staying within a tight tolerance. Then efficiency becomes a problem as you hit some trade-offs.

And that is the thing with a phone "charger"*. I can well imagine it's efficiency while actually deliverying 1A is pretty good but what is it's overall efficiency in typical use.

* Really a power supply, the actual charging circuit is in the phone and has losses of it's own on top of those in the power brick.

Re:50% is lost in AC to DC conversion?

[petermgreen]

how do natural gas generators beat that, and can whatever tricks those are be applied back to coal/gas/nuclear?

When it comes to heat engines you have something called the carnot efficency which is an upper bound on the possible efficency. The carnot efficiency is 1-(thot/tcold) where thot and tcold are absoloute temperatures. While real efficiencies are obviously lower than carnot it is still generally true that widening the gap between thot and tcold improves efficiency.

For a given type of heat engine the hot end is limited by material considerations wihle the cold end is limited by size considerations and/or ambient temperatures. However different types of heat engine work in different temperature ranges. By combining gas turbines which work at very high temperatures with steam turbines which operate at lower temperatures the temperature range can be widened and the efficiency improved.

However gas turbines are internal combustion which limits the fuel types. IIRC someone did try running one off powdered coal but the ash destroyed the turbine blades. I guess you could in theory build and external combustion gas turbine but you would need a very high termpature working fluid to carry heat to the turbine which I suspect would create practical engineering problems and drag down your overall efficiency. People have also run them off coal gassification systems but losses in gassification drag down the overall efficiency. So that leaves oil and gas.

Oil isn't used much* for electricity generation due to being substantially more expensive** than coal or gas. I expect the oil efficiency figures are dragged down by use in peak load plants, supplies for isolated communities and similar situations which are too small and/or too rarely used to justify CCGT.

* https://flowcharts.llnl.gov/co...
**http://www.eia.gov/tools/faqs/faq.cfm?id=107&t=3

Re:50% is lost in AC to DC conversion?

[Newander]

Gas plants spin the turbine by burning the gas. There is no conversion to steam.

Re:50% is lost in AC to DC conversion?

[thegarbz]

The great thing about averaging overall efficiency in a charging circuit is that as charging current drops off inefficiencies tend to accumulate at a slower rate. If I spend 80% of the time at 1A with 90% efficiency, and 20% of the time at 0.1A with 50% efficiency (it will still be higher than that anyway), the former figure dwarfs the latter and the overall charging cycle was still 88.3% efficient.

Think about the children!

[Media Archivist]

He has decided upon a very specific, and limiting, style of living. Bravo. Now try applying his philosophy to a household with children. Or a household frequented by guests. Try this in less sunny locales.

I think it is admirable to try to be different, and to advocate alternative. I am completely turned off by his holier than thou attitude and his dismissiveness towards that which does not fit his chosen lifestyle.

Re:Think about the children!

[ponraul]

Nah, he probably just offers his guests some room temperature Soylent 2.0. It saves all that time that would have been inefficiently used to socialize.

Re:Have any of you made similar changes?

[Narcocide]

I just don't turn my lights on. That's even more efficient than LED!

The past reaches out and grabs the future

[Virtucon]

queue up the Thomas Edison/Tesla fanbois out there the current wars have returned.

Re:The past reaches out and grabs the future

[Virtucon]

"Time loops, this is what happens when you use Alternating Current" - Edison

Small potatoes

[ibpooks]

Okay, sure so DC for gadgets and lighting that consume about 1% of household energy. When he has a realistic solution for replacing central heating, cooling, refrigeration, normal kitchen usage, well pumps, water heating and other meaningful uses of electricity then it might be worth listening to.

Re:Somewhere Thomas Edison is Tenting his Fingers

[Fire_Wraith]

Meanwhile, Nikola Tesla is spinning in his grave (probably at about 120hz).

Answers to questions posted in the summary...

[frank_adrian314159]

"No" and "Who gives a shit" respectively. Show us that the conversions needed to do this provide enough financial benefit to make any sort of sense. I don't think it will pencil out.

Re:Answers to questions posted in the summary...

[magarity]

Speaking of giving a shit; the story mentions he drinks more red wine and so uses the restroom less but I'm surprise he didn't regale the reader with a story of the composting toilet he installed in his apartment.

Re:Answers to questions posted in the summary...

[Bing Tsher E]

The word that flagged my attention first was 'apartment.' Like, uh, does he go out into the hall of the apartment building often?

Gross

[ZombieBraintrust]

This guy is not washing his cloths. He is wearing them till they are dirty. Then he donates them unwashed somewhere. (I assume he tosses his underwear, or wears diapers)

check out recreational vehicle stores

[roc97007]

I have a detached structure that runs entirely off solar/batteries. (There being no legal way to run power to it -- long story.) For the one or two things that actually require A/C I have an industrial inverter, but I try to use it for as few things as possible. To that end, all the lights are 12 volt DC.

I didn't have to rewire anything -- you can get 12 volt bulbs (even CFLs) that screw into standard sockets at any RV supply store.

The plugs in the wall of the structure are car-type cigarette-lighter round plugs. (Except for 2 standard AC which go to the inverter.) I use car adapters for electronics like laptops and music and phones. The lighter-type wall plugs use the same size and shape wall opening as a standard 110 plug.

The point is, most of this stuff already exists, and will retrofit easily into an existing home. You don't have to replace the light fixtures, and replacing the wall plugs is dead simple.

I have natural gas for cooking and heating and hot water. The gas stove and central heat are backed up with a wood stove, so I could even lose the gas and not be inconvenienced too much. Wood instead of propane, because I can go out and chop down a tree myself, whereas I can't refine propane by myself.

Re:check out recreational vehicle stores

[drinkypoo]

Wood instead of propane, because I can go out and chop down a tree myself, whereas I can't refine propane by myself.

You can refine methane by yourself, though. You can refine it with just a membrane. The problem becomes compressing it so that it's useful for more than cooking. That's expensive, because it requires a fancy compressor.

Re:check out recreational vehicle stores

[Hognoxious]

You can refine methane by yourself, though.

You pulled that right out of your butt.

Re:check out recreational vehicle stores

[aaarrrgggh]

Gads!! Don't use cigarette lighter outlets for DC! Huge fire/shock risk. Much better to go with Anderson plugs or something that can be mildly tamper resistant! How do you fuse the outlets?!

Re:check out recreational vehicle stores

[roc97007]

Gads!! Don't use cigarette lighter outlets for DC! Huge fire/shock risk. Much better to go with Anderson plugs or something that can be mildly tamper resistant! How do you fuse the outlets?!

I haven't heard this before. How is this a huge fire risk? 12 volts DC even at high current isn't a shock risk at all, unless you put the leads in your mouth or across your braces. This is one of the advantages of switching to 12 volts DC.

I haven't heard of Anderson plugs until now. (I googled it, and see that they're used in battery backup applications.) I went with lighter-type outlets because they were available and cheap and there are already a lot of device power supplies (example: phone chargers) that will plug into them directly.

Currently there's a fusible link in the cable from the storage batteries to the wall outlets. A direct short will cause some sparks but should pop the link. Were it a bigger installation (it's only one room) I might have put in a fuse box.

Re: check out recreational vehicle stores

[adolf]

The plugs and sockets can (and often are) rated at 30A continuous. This is plenty for what he is doing.

As to shock hazard: no, not really. Not enough surface area to be a danger at 12v, and even then it only affects the finger.

The inverter-fed 120v US plugs and sockets, however...

Hard to take serious.

[bobmajdakjr]

Most of his personal savings just offload the burden of destruction to someone else, like taking uber (fossil fuels) and donating dirty clothes (water use, and being a scumbag donating dirty things) such that I was not entirely sure this was not satire.

Re:Hard to take serious.

[iggymanz]

well to be fair the donation chains wash what is put into the drop boxes regardless

the guy is still a douche for other reasons, adopting his ways for anyone with wife and kids would be quick divorce court path

Re:Hard to take serious.

[viperidaenz]

On the plus side, your future ex-wife won't want to take the house

There are far larger DC projects

[Teun]

Many EU cities now specify LED street lights and this does usually include whole streets being converted to DC.
I've heard of some 40% efficiency gains by avoiding the usual transformers per lamppost.
On a private scale you could start by buying electronics that run on a specific DC voltage and making a home circuit run off a solar charged battery.
This last one is a specific requirement to have an efficient system, although a large single rectifier is better than many small ones you're still better off without any rectifiers.

Re:There are far larger DC projects

[drinkypoo]

I've heard of some 40% efficiency gains by avoiding the usual transformers per lamppost.

No, that's bollocks. But it might be 40% overall when you consider the ancient (passive) ballast, and redesign with reflectors to angle more of the light down to the street. There is very little efficiency difference between an arc lamp with a modern digital ballast, and an LED with its driver circuit. The difference between an old-school ballast and a modern one is not as big as you imagine; it's measurable, but it doesn't even begin to approach 40%.

Re:There are far larger DC projects

[WaffleMonster]

Many EU cities now specify LED street lights and this does usually include whole streets being converted to DC.
  I've heard of some 40% efficiency gains by avoiding the usual transformers per lamppost.

Old school low pressure sodium lamps are more efficient than LEDs for the same amount of light output.

----
"Finally, we will access, disclose and preserve personal data, including your content (such as the content of your emails, other private communications or files in private folders), when we have a good faith belief that doing so is necessary."

Re:There are far larger DC projects

[Khyber]

"I've heard of some 40% efficiency gains by avoiding the usual transformers per lamppost."

Or they could go with LEDs driven with very high-persistence phosphors, and run the LEDs direct off the main lines in a rectifier configuration, and have pretty much nil loss associated with a power driver in the first place. Just a proper resistor acting as the bridge element in the center of the diode config is all you would need.

This guy is an idiot

[Nemesisghost]

I've read this guy's blog post & came to the conclusion that he's an idiot. He champions his lifestyle as a way to reduce energy usage, but does so by doing things like having new shirts shipped from China instead of doing laundry. Or that he's saving energy by eating out when he doesn't want to eat his nutritional paste, and somehow that's better than cooking for yourself mainly because he doesn't like going to the grocery store. Nothing this guy has done is scalable beyond just himself.
This guys whole blog post reads almost like someone saying it's better to have a 3d printer because you can print Lego bricks for free.

Steam Turbines...

[BadBlood]

...actually recapture lost Gas Turbine work. So running through a steam turbine is actually very, very good for the overall efficiency of the cycle.

Smug and NOT reducing his reliance on AC

[mykepredko]

Rhinehart is not substantially reducing his reliance on AC, all he is doing is passing it on to others in the service industries.

I gagged at the sentence in the conclusion "To me the real upside is the pleasure in being electrically self reliant." - I guess he could live off the land as long as there were supermarkets around.

I don't believe that going to a restaurant and letting them provide meals, lighting, heat/AC actually constitutes reducing the amount of AC consumed.

There could be a market for this

[quax]

Many parts of the 3rd world are off the grid, yet aspire to a modern lifestyle. His experiences could very well lead to products targeting this emerging market.

Calling actual engineers...

[ckatko]

Anyone with an actual degree in engineering is calling bullshit.

There's nothing magical about AC-DC conversion, and NEWS FLASH, it's much more efficient to transmit AC over long distances than DC. That's HALF THE REASON we use AC. The other half is that it's extremely easy to convert to other forms of AC and DC.

This guy is a moron. You want more efficient power? Go Nuke and enjoy ZERO CO2 EMISSIONS you tree hugging hippy. At that point, you know what happens when you "lose energy from steam turbines"? Nothing. Not a damn thing. The world is exactly the same, except for some resistance heating. Now, efficiency becomes a purely cost measure and isn't connected to pollution at all.

But that's too much of a leap for this moron.

Re:Calling actual engineers...

[TeknoHog]

There's nothing magical about AC-DC conversion, and NEWS FLASH, it's much more efficient to transmit AC over long distances than DC. That's HALF THE REASON we use AC. The other half is that it's extremely easy to convert to other forms of AC and DC.

I'm afraid my degree is in physics, though I've done more engineering than pure research oriented work. In my understanding, long distance transmission efficiency is mainly about high voltage, not AC per se. It's true that you need some AC stages for voltage conversion, so the conversion part is more efficient if you only use AC. However, AC will bleed energy via induction in some cases such as undersea cables, making DC more efficient overall even after conversion losses. In addition, phase matching is an issue you won't have with DC. Then you also have the age-old facts about peak vs. average voltage that make DC easier for things like insulation, so the future of power transmission is actually going more in the way of DC, even if end users still see AC.

Frankly, this entire discussion has little to do with AC vs. DC, it's mostly about the dependence on the grid. I agree we should use more nuclear power, and perhaps educate the people a bit more to end the irrational fears about anything that has the word "nuclear" in it.

Re:Calling actual engineers...

[Mr D from 63]

Nice to see some wisdom.

AC distribution has little to do with losses and much to do with cost and reliability. 3 phase distribution allows for much flexibility in how the distribution is done, in clearing and recovering from faults or dead lines or phases, and in making multiple tie-ins. AC switching equipment is much lower cost and simpler, more reliable.

Re:Calling actual engineers...

[TeknoHog]

Ah, good point about the skin effect. I'd count it together with other inductive losses, none of which exist with DC. You might also say that DC uses more of the wire in a temporal sense, as it doesn't waste time crossing zero all the time. But this is basically the peak vs. average argument again.

Sorry I should have RTFA first...

[mykepredko]

I was expecting an article like yesterday's on the Air Conditioning compressor running off of DC from solar panels not some guy who thinks he reduces his AC consumption by eating in restaurants.

Re:AC is for cows.

[stackOVFL]

A wizard says: Hex-E-Poo-Hex-On-You!

not practical

[Karmashock]

Getting rid of AC for off grid applications makes sense. I'm all for it and look forward to the new DC appliances we're seeing come on market.

however, this article is not going to have people following suit.

I'm not giving up my quality of life. I don't have to and I don't want to and its the 21st century so anyone that disagrees can eat a rail gun round to the face.

I do believe in sustainable living. However, more in the way of breaking free from crumbling infrustructure and gaining a certain amount of logistical indepedence.

I'm a big believer in the backyard green house. I think solar panels and wind mills are a good idea AT YOUR HOUSE. And I am looking forward to economical energy storage systems that work at a personal level.

Am I dumping my refrigerator and cooking food on a camping stove? No.

Really none of this sustainable stuff works in an urban environment. Its sort of odd that so many people that like the idea live in the one place where it isn't possible. Logistically you're going to be depending on a very energy and resource intensive infrastructure and there's just no way around that in a city. That "IS" the city. The city is all the things the sustainable people say they don't like. Live in the suburbs and you have a CHOICE. You have enough property that you can do something. Live rural and you can go completely off grid for everything... food, water, power, whatever... live like the Amish or something. Yabba dabba doo. But in a city you're on the grid. I don't care if you shut off the breakers in your apartment or drink your own pee. You're on the grid because everyone around you is on the grid and you depend on them whether you're drinking your own pee or not.

Here is my suggestion for the urbanites. Support nuclear power. Worship the fucking atom.

Re:not practical

[Kernel Kurtz]

Am I dumping my refrigerator and cooking food on a camping stove? No.

Sums it up well. I know people who wear a sweater in the house in the winter to use less heat, or leave the AC off on hot days. These are not people eating cat food, they can actually afford to make their place comfortable for themselves. HVAC is one of the wonderful things about living in the first world and billions would love to have it.

Some people just seem to need some sort of cilice I guess.

If you're getting 50% efficiency...

[Chris Mattern]

...your adapter is a piece of shit. A good one will give you 80% to 90%. I'll assume his other figures have similar accuracy.

Re:If you're getting 50% efficiency...

[thegarbz]

A crap one will give you 80-90%. This is a simple and known engineering problem with well published and cheap solutions.

Old metal transformer + rectifier + linear regulators achieved better than 50% efficiency and those are now banned in some parts of the world due to poor efficiency.

Re:If you're getting 50% efficiency...

[Firethorn]

I'll assume his other figures have similar accuracy.

They do. He's assuming 16.5% efficient for the coal power plants, they're actually 40-60% for all but the worst of them. A coal plant does NOT immediately toss 67% of the power it produces immediately up the smoke stack or whatever. The steam turbine itself isn't 50% efficient, it's closer to 60%.

Basically, he took the total efficiency figure for an out of date coal plant then multiplied it by 0.5 for 'good measure'. 5% for transmission losses is pretty standard, so he's good there. Losing 50% to charge from AC to a cell phone requires some gymnastics in how you measure it. Even a cheap USB charger should be 80%, and you're going to be at around that for a DC-DC converter(which converts it to AC internally) to get the 12V of solar cells down to a regulated 5V for USB.

To reach 50% you have to consider the internal charge circuits for the cell phone(.9), energy lost charging the battery(~90% for LiIon), etc... Even then I still get ~65%. Most of which can't be avoided by switching to locally generated DC.

Do what people who live on boats do.

[mattotoole]

As many sailors know, a couple hundred watts of solar or wind power can be plenty. Keeping the fridge going is usually the biggest draw, followed by marine radios and computers. Sailing forums are full of threads about which laptops draw the least power, etc. The latest crop have gotten really good, but tablets are even better -- especially when charged directly from 12V, vs. 120V w/ inverter .

12V adapters are available for most small devices, including rechargeable power tools. An inverter can handle the occasional hair dryer or blender (though I'm sure there are 12V blenders). Toasters and microwaves are still a problem.

Lithium batteries are great too, with much higher charging efficiency than lead-acid or NiMH.

Re:Do what people who live on boats do.

[JustNiz]

>> a couple hundred watts of solar or wind power can be plenty.

I live in Phoenix, AZ. yes we have plenty of sun year round, so you'd think it would be the perfect spot for solar but we have plenty of heat too.

It takes an awful lot of space and money's worth of solar panels and batteries to have the capacity to run a small-medium house's AC unit (4 ton). AC is a basic necessity here in the summer when it s 115+ degrees outside, and doesn't hardly drop at night so you need it on most of time when the sun isn't out too.

Re:Do what people who live on boats do.

[drinkypoo]

The latest crop have gotten really good, but tablets are even better -- especially when charged directly from 12V, vs. 120V w/ inverter .

And you can get a ~12VDC to 5VDC@3A with micro-usb or mini-usb for three bucks or so on eBay; I like the "CPT" brand in this price range. I use them for automotive GPS and phone charging. Much more slick to just have a little charging cable tail someplace than to dick around with lighter sockets.

Re:Do what people who live on boats do.

[Locke2005]

Do like the Australian opal miners do, and live underground! Yes, it cost $500/month to air condition McMansions there, but a lot of that is due to heat losses through all that plate glass. (There's also the problem with building codes requiring a window in every bedroom for a fire escape; hard to meet that requirement underground),

Wrong focus

[CanadianMacFan]

If you want to be sustainable then focus on how you can stop burning coal and natural gas to generate electricity.

Coal is losing the War On Coal

[Zobeid]

quote: "Most power in the US is generated by burning coal..."

Coal dropped below 50% several years ago and is falling rapidly. Alpha Natural Resources -- one of the giants of the American coal industry -- has filed for bankruptcy. They're sitting on $3 billion in debt while coal prices have plummeted as a result of utilities switching over to natural gas.

As for the whole DC power thing... If you have rooftop solar, and you are generating your own DC power, then converting it to AC and then back to DC again (which most appliances actually use) is not efficient. As rooftop solar continues to spread, I suspect we'll see more appliances designed to bypass the AC grid.

Re:Coal is losing the War On Coal

[drinkypoo]

Coal dropped below 50% several years ago and is falling rapidly. Alpha Natural Resources -- one of the giants of the American coal industry -- has filed for bankruptcy. They're sitting on $3 billion in debt while coal prices have plummeted as a result of utilities switching over to natural gas.

Which still produces CO2, and which is based on fracking. We reached peak natgas some time ago, if you measure it by readily available sources.

Re:Coal is losing the War On Coal

[david_bonn]

Speaking as someone who actually lived off the grid for 18 months, it was extremely disheartening to realize that a substantial majority of my power was being spent converting from DC to AC then back to DC (I worked it out and actually measured it, it was about 65 percent of the generated power was being radiated away as heat). So I spent several months building 12VDC adapters for my laptop, my satellite internet connection, and the battery chargers for my cellphone and digital camera. Since USB was extremely newfangled I ended up with a design that was a major fire hazard where the adaptors screwed into 12VDC light sockets. It worked, but it was ugly.

I am coming full circle back to solar, largely as a backup power source. My best estimate for a large propane generator and the shack to put it in that will power my well pump, my refrigerator, the infloor radiant heating system, and a few outlets to charge that damned cellphone is around fifteen grand. A comparable solar power system runs about the same, but I won't be paying for propane (nor will my refrigerator or heat be running at night).

Re:The emperors new clothes...

[avandesande]

Funny how Idiocracy seems to become more an more of a template then a comedy.

Why DC is a greater fire risk

[Anonymous Coward]

DC arcs are strongly self-sustaining once ignited, as there's nothing to halt the continuous generation of ions which provide an easy conductive path. In contrast, AC arcs tend to self-extinguish twice a cycle when the voltage drops to zero, and so the AC arc has to re-ignite each cycle once the voltage rises high enough. Even if it does manage to re-ignite, the arc is not usually conducting the full cycle.

This reduced arcing makes AC a significantly lower fire hazard than DC, and the same effect happens to make AC switch contacts last much longer since breaking a circuit rarely arcs for more than a half cycle so contacts don't usually heat up and little metal is carried away from their surfaces.

Re:Why DC is a greater fire risk

[circletimessquare]

+1, informative

thank you

Re:Why DC is a greater fire risk

[thegarbz]

Fires are only one small part of the issues with DC arcing. Simple things like switches need to be sized significantly larger to break a DC arc compared to an AC arc. Fuses become larger, switch mechanisms need to be stronger to overcome the potential for welding shut of contacts, and you don't get to do any fancy solid state switching such as switching on AC zero crossing which has a lot of applications for combining multiple sources of supply and switching between them.

TAE, thou art vindimicated!

[Thud457]

but but but...
If you use DEADLY ALTERNATING CURRENT you run the risk that your pets might get electrocuted!
no, I am not a looney either...

Re:TAE, thou art vindimicated!

[bobbied]

Thomas Edison... Is that you? Thought we settled this already... (Westinghouse)

Standard DC voltage?

[Moof123]

Riddle me this, what voltage does your widget run off of? 1.5V? 3.3V? 5V? 12V? 48V?

AC to the house is 120V single phase of 240V 2-phase which covers all appliances from a few watts to many kW. There is also 3-phase 208V which is a lot less common to residential.

DC is the latest hipster fantasy plan pushed by those who mostly have no clue. It sounds all sexy to be anti-establishment, but in general DC is an awful choice for power distribution. It still need to be run at a pretty hefty voltage to keep the wire gauge reasonable, and you end up having to make a bunch of DC-DC converters (really DC-AC-DC) for each required supply voltage anyway.

120V 60Hz may be an old tired standard, but usually that is better than no standard at all.

Re:Standard DC voltage?

[Virtucon]

enough to kill an elephant standard DC current. 6600 Volts

Re:Standard DC voltage?

[drinkypoo]

It still need to be run at a pretty hefty voltage to keep the wire gauge reasonable

Most of the equipment in use, the wiring and the switches and so on, has insulation rated for up to 250V. So having a pretty hefty voltage isn't really a big problem, is it?

and you end up having to make a bunch of DC-DC converters (really DC-AC-DC) for each required supply voltage anyway.

The converters are pretty cheap when they only have to decrease voltage, though. It's only when they have to increase it that they become expensive.

Re:Standard DC voltage?

[Pontiac]

Just wanted to get one thing straight.. 240v is single phase.. 120 comes from center tapping a single phase 240v transformer.. (your neutral line in the house is the center tap) AKA Split Phase.. https://en.wikipedia.org/wiki/Split-phase_electric_power

In 3 phase the wave form of each 60hz phase is shifted 120 degrees so each peaks at a different time.
https://en.wikipedia.org/wiki/Three-phase_electric_power

Gas powered refrigeration

[sjbe]

So he gave up refrigeration? an ac synchronous motor is much more efficient than DC alternatives.

You can go with a gas or propane powered refrigerator. My family has one at a cottage which is too remote for electricity. Works pretty well though I can't vouch for it being particularly efficient. Uses ammonia as the coolant. I understand they are often used in RVs too.

Not our problem

[daninaustin]

We will never run out of either coal or oil. The price will increase to the point where they are no longer economical but there will still be a lot of both in the ground.

Re:Not our problem

[WolfWithoutAClause]

Nah, we'll have caused civilisation to crash due to global warming long before we get uneconomical fossil fuels due to lack of availability.

But actually at the moment, it's looking like a combination of wind and solar will replace the bulk, and possibly all, of our fossil fuel use; these renewables are becoming cheap and easy enough that people won't build new fossil plants very much, so as the old ones wear out they'll just get shut down.

Re:Might as well be dead! No! More butter, more wi

[Virtucon]

"I'm still dead" - Julia Child

DC conversion efficiency

[technical_maven]

The problem with Rob's assessment is that his efficiency numbers, expect for power transmission, are way off the mark. It is MUCH better than he purports! DC to AC conversion is roughly 90% or more efficient these days so you are not saving much by using DC at home rather than AC. It is simply not worth it to limit yourself so much by having only DC appliances.

Re:DC conversion efficiency

[lastman71]

No, they are all quite correct except for the DC to AC conversion efficiency, and he had indeed corrected his post, with a 80% efficiency that's quite reasonable. Efficiency for a coal plant is indeed about 30-35%. So also this number looks right. More than a post about AC vs DC, it looks like about "in grid" vs "off grid".

Not NIMBY: other factors

[Roger W Moore]

The line losses are a NIMBY problem, people don't want power plants near their houses.

That's not really true. Coal-fired power plants need to be located near a large, reliable water source for cooling and the closer they are to their fuel source the less energy is used to transport the coal. They also have to be of a certain size in order to operate efficiently. Hence even if everyone was willing to tolerate a coal fired power station in their neighbourhood most locations would be unsuitable for their construction, rural communities would be too small to warrant a power station even if suitable and even then there would be an increase in the energy to ship the coal the larger distances required. This means that only small reductions in transmission losses would be possible and since this is already one of the most efficient steps in the power consumption process you'd lose a lot more than you would gain.

Re:Not NIMBY: other factors

[trout007]

That used to be true but not for modern plants. Here is one close to me and it puts out mostly steam and CO2.

http://www.ouc.com/environment...

Not quite a dupe, but...

[Daetrin]

This same general topic was discussed last week: Sharp Announces Sales of DC Powered Air Conditioner, Other Products To Follow

Math issues

[TooTechy]

Not sure where the math came from in the OP but...

100W * 0.33 * 0.50 * 0.95 * 0.50 = 7.8

This clearly is lower that 16W

Might have to look more clearly at the article and see where the discrepancy arises.

Also the OP forgets that the quoted 67% includes electrical generation. ie the turbine.

And a typical phone charger (a Switch Mode PSU) will have an efficiency > 75%. So our calculation becomes:

100W * 0.33 * 0.95 * 0.75 = 23.5

Anti-Tesla Rhetoric!

[s.petry]

I was waiting to read about how AC kills and see some good ole electric chair demonstrations.. *sigh*

Re:Anti-Tesla Rhetoric!

[lgw]

What I find most annoying about all this is less the could of smug, and more the fact that household electricity use is such a small slice of the pie of overall US energy use. From wind power to this DC nonsense, it's obsessing on feelgood measures of little importance to the big picture.

This biggest slice of the pie is industrial energy use where electricity isn't part of the picture: "Primary energy use" by heavy industry for blast furnaces and the like. Industrial electricity use is the next biggest slice, followed by IIRC industrial transportation.

Re:Anti-Tesla Rhetoric!

[cptdondo]

Don't forget agri-business use. It takes a lot of power to pump all that water. The City of Hermiston on the Columbia Gorge uses less power than the single mega-farm just upstream on the Columbia River.

Re:Anti-Tesla Rhetoric!

[smg5266]

What I find most annoying about all this is less the could of smug, and more the fact that household electricity use is such a small slice of the pie of overall US energy use. From wind power to this DC nonsense, it's obsessing on feelgood measures of little importance to the big picture.

This biggest slice of the pie is industrial energy use where electricity isn't part of the picture: "Primary energy use" by heavy industry for blast furnaces and the like. Industrial electricity use is the next biggest slice, followed by IIRC industrial transportation.

False, residential accounts for 22 % of energy use in USA. In fact, buildings in general (commercial + residential) take up the largest slice of the pie. http://scholar.lib.vt.edu/ejou...

Re:Anti-Tesla Rhetoric!

[LinuxIsGarbage]

Statistics I found was 29% Residential, 39% Industrial, 26% Commercial and Institutional, and the remainder for "Public Administration, Agriculture, and transportation"

Industry can be quite energy intensive. A 10MW facility is not going to go off the grid with a couple solar panels, a windmill, and some batteries. Supplement maybe, but not completely replace. Compare this to a house that can have an average demand of less than 1kW.

Re:Anti-Tesla Rhetoric!

[AmiMoJo]

I couldn't find stats for the US, for some reason the government doesn't seem to publish this particular data in an easily digestible form, but compare with the EU: http://shrinkthatfootprint.com...

About 1/3rd of electrical energy is consumed by homes.

Re:Anti-Tesla Rhetoric!

[dcw3]

According to the DOE, it's 29% Transportation, 19% Commercial, 22% Residential, and 30% Industrial. So, while residential is relatively smaller, it's certainly not as insignificant as you are claiming.

http://buildingsdatabook.eren....

Re:Anti-Tesla Rhetoric!

[lgw]

So widespread adoption of crazy hippie ideas might reduce overall energy consumption by 10%? Not worth a reduced standard of living, unless as a feelgood measure that individuals are happier with.

Re:Anti-Tesla Rhetoric!

[dcw3]

I don't disagree, but I'd always be willing to take cost effective steps in that direction. As for "crazy hippie ideas", I haven't done enough homework in this area to know if that's truly the case. I do know that my uncle (he's far from hippy) installed a single solar panel at a lakefront cottage in Ontario, and along with a few marine batteries, it was enough to give the place lighting and run a water heater. The cottage didn't have power or indoor plumbing (we seriously used an outhouse back in the 60s there) previously, so it was a great upgrade.

Westing House....

[bobbied]

Mr. Edison is that you? I thought you died decades ago!

Look, first off the efficiency argument is garbage when you are comparing apples to oranges. If you want to say 100 Watts of power from burning coal, then start to compare how much power your cell phone uses, you have pretty much stepped off the reservation engineering wise. You are talking HEAT in BTU and then electrical power out? Two different types of fruit.

To convert BTU heat into electricity requires a heat engine that takes heat and turns it into mechanical rotation. Thermodynamics demands that even an ideal heat engine has losses, so if you want electricity, that's a price you pay. Our power plants that use heat all pay the same price, and for the most part they are all darned near ideal, even though losses might approach 30% of BTU in to BTU out if you look at it that way, but remember, you still want/need electricity.

Now this author is correct in saying that if all you want is HEAT, then using electricity as a way to transfer energy from a stack of coal over a long distance to your electric stove, vast improvements are possible by burning the fuel locally. However, if you want electricity for running that cell phone or that TV or even that heat pump (air conditioning unit) then burning coal locally doesn't help you at all.

BTW, the electric grid is amazingly efficient given what it does and how much power it transfers around every instant. It's far from perfect, but it's not a huge energy waster. Complaining about this inefficiency is like complaining about a leaky roof getting your furniture wet when it rains while your home is flooded up to the rafters by the river next door.

Re:Might as well be dead! No! More butter, more wi

[ksheff]

no, he goes to a restaurant where someone with talent makes all of that.

Kitchens

[PopeRatzo]

I think Robert Rhinehart is just trolling us. Who could possibly hate kitchens as much as he does? Check out his blog and tell me he's not either a troll or has some serious static in the attic. The section on kitchens is particularly illuminating.

http://robrhinehart.com/?p=133...

With no fridge, no dishes, no microwave, no oven, no range, no dishwasher, no utensils, no pests, no cleaning products nor dirty rags, my life is considerably simpler, lighter and cleaner than before. I think it was a bit presumptuous for the architect to assume I wanted a kitchen with my apartment and make me pay for it. My home is a place of peace. I don’t want to live with red hot heating elements and razor sharp knives. That sounds like a torture chamber. However, it’s not a total loss. I was able to use the cabinets to store part of my book collection.

Wait a kitchen is a "torture chamber"? Slow your roll there, big boy.

I mean, if he wants to make his life "simpler, lighter and cleaner" he could just tear out his bathroom and use catheter. It'd be about as much fun as living on Soylent 2.0.

Re:Kitchens

[Actually, I do RTFA]

Who could possibly hate kitchens as much as he does?

Someone with a monetary incentive to make the use of kitchens equivalent to strangling puppies. I wonder who would benefit from that...

Re:Kitchens

[EdwardFurlong]

He is obviously trolling, I can't believe people are actually are taking him seriously.

It takes about a dollar to wash and dry a load of clothes, there is no way he is able to buy all new clothes for a dollar.

I am down with the concept of simple living, he is probably going to push people away from even trying because of how stupid he sounds.

Why Live Like 21st Century "Flintstones"?

[BlueStrat]

Build thorium reactors and build solar power satellites.

Then, energy costs will be extremely low and energy supply extremely reliable, as well as having a very low environmental impact.

Calling living like 21st century 'Flintstones' a "solution" to energy sustainability and related environmental issues is like calling shooting sick people a "solution" for rising medical costs and availability.

Strat

Re:Why Live Like 21st Century "Flintstones"?

[david_thornley]

There are no thorium reactors and no solar power satellites in normal use currently. People have done some experiments with thorium reactors (and I do want them to continue), but solar power satellites are just theoretical.

It's real easy to say that some scheme that's never been implemented will have all sorts of good qualities, but when we're talking about serious power I'd like to see it working first.

Re:Why Live Like 21st Century "Flintstones"?

[BlueStrat]

It's real easy to say that some scheme that's never been implemented will have all sorts of good qualities, but when we're talking about serious power I'd like to see it working first.

The same can be said for solar or wind as a baseline power source. There are basic physics reasons why solar & wind are problematic at best as a baseline power source. Solar power satellites have been well within technological reach for decades, as have thorium reactors (which have been in wide use at smaller scales in military, industrial, & scientific applications for decades as well).

It's simply the political will to invest & build that is lacking for both thorium reactors and solar power satellites.

Strat

Re:Why Live Like 21st Century "Flintstones"?

[david_thornley]

We've been using wind and solar. We have real experience in how they work, both the good things and the bad. We're not extrapolating from physics here, but have solid empirical evidence. We know how reliable they are under various conditions. We don't have to speculate.

Solar power satellites have potential issues that could cause problems, and currently we do not know all of these potential issues. We have no experience in sending large amounts of power to Earth from orbit, and so it's easy to say there will be none. Small-scale operations often have tiny little glitches or things that will not scale, that are insignificant or easily handled, but which turn into big problems on a large scale. This is based on centuries of experience. The proper technique is to start a small-scale system and observe the problems it has and causes.

What's holding these projects up is economics, not political will. There are plenty of power companies all over the world, and there are no worldwide restrictions on launching satellites or building reactors. If these looked like economic ways to make power, some power company somewhere would make one of these into a real project. The fact that none of them have means that things are not nearly as clear as you make it out, particularly when you blame some vague "political will" that is apparently much the same over a large range of developed nations (and some large developing ones, like China and India).

This doesn't mean that these are bad ideas. It does mean that the people who'd actually have to put up the money, and presumably have looked at all sorts of ideas, have seen complexities that you have not seen.

Re:Why Live Like 21st Century "Flintstones"?

[BlueStrat]

Wind & solar were untested, wild & crazy ideas as well for a long time and similarly lacked investors. The same thing happens with every new technology.

Some of the reluctance to invest is financial/risk based, but much of it is also politically based as well, as old industries press governments to protect their business from competition, including competition from new technologies.

This is particularly true in the US where crony-capitalism is the order of the day. Cheap to the point of nearly-free power takes away a vector for political manipulation of the population as well as threatens current players in the field.

At one point every counter argument you've made against thorium reactors and solar power satellites were made against current methods of power generation & distribution, and in fact against almost every technology we use today. It's simply a matter of overcoming this financial & political inertia. It's not impossible, current wind & solar projects prove that.

I believe it's simply a matter of time and of gathering enough political support to force the politicians in the pockets of the current players to remove disincentives to investment.

There are always risks. If we waited until something was "proven" we would still be riding horses and bleeding the sick as a treatment, and may still have not yet discovered the "New World" (N. America).

Strat

off AC, onto butane?

[YesIAmAScript]

The guy is an idiot.

Re:off AC, onto butane?

[TeknoHog]

On a general theoretical level, it's not necessarily that clear cut. If you want to convert hydrocarbons into heat, it's obviously better to capture the heat directly, rather than doing it via electricity. It's always a shame when low-entropy and concentrated energy such as electricity is degenerated into heat. OTOH, an industrial scale power plant is probably more efficient than a Primus cooker. Plus there's a good possibility that they use something other than butane, like nuclear.

Besides, the terminology of AC vs DC isn't very relevant here, especially when it comes to stoves. Resistive heating doesn't care about phase or frequency, though voltage is obviously an issue if you want to heat something other than cables. If the question is about getting off the grid and going solar, then they should just say it.

Slashdot Arrives Late To The Party As Usual

[westlake]

The walls are buzzing. I know this because I have a magnet implanted in my hand and whenever I reach near an outlet I can feel them.

I enjoy doing laundry about as much as doing dishes. I get my clothing custom made in China for prices you would not believe and have new ones regularly shipped to me. Thanks to synthetic fabrics it takes less water to make my clothes than it would to wash them, and I donate my used garments.

How I Gave Up Alternating Current

555 posters at Ars Technica spent a glorious summer's day ripping Rhinehart to shreds. Op-ed: How I gave up alternating current

"I'm an idiot who doesn't understand the energy footprint of Soylent Green and shipping cotton to china for cheap underwear, then shipping those underwear to my house on a weekly basis. I am so far up the ass of my OCD neurosis that I am living a contrafactual life and pretending it's not destroying the world."

Re:Slashdot Arrives Late To The Party As Usual

[WillAffleckUW]

Most modern data centers run on DC nowadays. The efficiency losses from AC and the cooling and bulk of AC transformers for systems that are literally DC mean we can save from 10-25 percent of our total power usage by running DC. It takes a lot of power to cool down the excess heat from AC transformers.

Pretty much every day I get sales agents trying to sell me on converting our data centers to DC. There's a lot of money in that.

But that's a data center. A kitchen and household appliances tends to be more work than it's worth. But if you're in a remote area and all your power inputs are DC (solar, for example), then it might make some sense.

I saw an annotated post about this recently...

[seebs]

http://genius.it/robrhinehart.com?p=1331 has a discussion of it.

That said, all the comments saying "guy's an idiot" have pretty much nailed it.

Remote

[Lord Bitman]

And this is the real winner. This is finally becoming feasible.

Not practical, but at least feasible.

Only 1/3rd the power needs for the roof?

[Firethorn]

I can't say much about your specific situation, but in general if you're far enough from the equator for snow, the ideal solar panel will have a fair bit of tilt to it. At which point you have some options for snow-clearing. One of the popular ones is to use a relatively small amount of electrical heating once the snow stops to make the panel 'too slick' for the snow, at which point it simply slides off. Then the panels make up that energy through the day. Keep in mind that they're considerably 'slicker' that way than an asphalt roof.

Also, if your roof is only worth 1/3rd your electrical use, that may be something that you want to examine, because you could save considerable money for cheaper than installing solar panels fixing whatever is taking so much.

I say this because I can satisfy my electrical needs using about 2/3rds of my south-facing roof, and I'm in Fairbanks, Alaska. Disclaimer: Annual average; I'd have to sell electricity in the summer and buy in the winter.

Re:Only 1/3rd the power needs for the roof?

[FlyHelicopters]

Also, if your roof is only worth 1/3rd your electrical use, that may be something that you want to examine, because you could save considerable money for cheaper than installing solar panels fixing whatever is taking so much.

For some people, that would be true... in our case, we just use a lot of power...

I have upgraded our insulation, replaced our bulbs with LED, replaced our HVAC with a 16 SEER dual stage, dual speed unit, and replaced our weather stripping on our doors...

We have a fairly big house at 3,800 sqft, but it is two story so it isn't that wide or long. It also has a roof that doesn't hold solar well, we have 6 different sections of roof that face south, so it can't be covered very well.

We've had the solar companies out to price it, we just can't put enough panels up on the space that exists to cover more than about 1/3 of our power use annually.

I can't say much about your specific situation, but in general if you're far enough from the equator for snow, the ideal solar panel will have a fair bit of tilt to it.

I'm in Texas, and yes, we get snow 2 months out of the year here. :) Nothing like what you get, but enough to cover the panels.

Re:Only 1/3rd the power needs for the roof?

[Shirley Marquez]

Part of it is how your house is designed. If you have a multistory house as is typical here in New England, you don't have a lot of roof for the amount of floor space you have. And what roof you do have is likely to be broken up by dormers, leaving even less space for solar panels. If you have a single story house with an unbroken roof line as is common in some areas and your house faces north/south, you're likely to be able to generate a lot more of your electricity needs.

Re:Only 1/3rd the power needs for the roof?

[Firethorn]

You make a good point. In the future I can see them deliberately spacing dormers and such to balance usability and solar energy potential.

That being said, solar panels don't have to be restricted to the roof. I'm tempted to set up a 'solar car park'.

If you don't need house-level water resistance or insulation they're perfectly suitable as a roof surface.

As a bonus, if you write it up as the structural members are to keep it out of the way and from interfering with your car as opposed to being a car park with solar panels on top, the whole construction cost is deductible. Not that structural members to raise the panels 8-10' high are all that more expensive than ones that would only raise it 4'.

Misleading title

[elgatozorbas]

What he actually says is that he cut down his power consumption so drastically that he is self-reliant with a small solar panel and some batteries. Using only low voltage devices and consuming a small power, indeed there is no need to convert to AC.

However, his biggest achievement is being self-reliant (insofar this is true...) and has nothing to do with AC/DC conversion. AC is being used, mainly because it is easy (and highly efficient!) to change its voltage using transformers. There are some other advantages related to shutting down arcs, and disadvantages related to skin effect, but using transformers is the main one.

For any realistic electrical power consumption the currents at low voltage would be so ridiculously high that very thick conductors would be needed to limit the losses (and fire risk), self-reliant or not. The reasonable thing in that case would be to use an invertor to go to 120/230V AC. The losses would easily be offset by the lower demands on the cabling. It is no coincidence that the power grid and, to a lesser extent, homes operate at high voltage.

Nooooooo!

[Greyfox]

You can have my AC when you pry it from my cold dead *BZZZZZT* *THUNK*

No shit

[Sycraft-fu]

Switched mode PSUs, which is what basically every electronic device uses, have gotten real efficient. No surprise, there has been a big efficiency push as of late. Just how efficient does vary, of course, but it can be as high as the mid 90s (like 95%) for the real good ones, and is pretty much about 80% in all cases. It just isn't that expensive to design a reasonably efficient PSU these days.

If you look at a wall wart or line lump type adapter, they generally have a roman numeral in a circle, which is an efficiency metric. These days the US and Canada are requiring IV, the EU requires V. The exact efficiency level that needs varies with wattage, but above 50 watts it is 85% or higher.

So sure, you could save some energy going all DC in you converted the AC with a large, high voltage, SMPS as they are more efficient, but not near as much as he indicated.

Virtually all devices are really DC

[WillAffleckUW]

AC just gets transformed. Look at your store bought computer, it has two switches. One is for 110V AC or 220V AC. The other is for AC or DC. The internal circuits all run 6V or 12V DC. If you bypass the transformer, you can run direct DC, provided it's at 6V DC or 12V DC.

Even the plug for your iPhone works that way. It's why it's so big.

In the event of a major quake that takes down your electric grid power, you just have to turn all your key appliances to DC, add up the resistance, make sure the physical wires don't connect to anything AC, and plug your solar panels into the circuit. Hook up some batteries, or use the DC input for your electric car, to balance the load and you can run without a grid. It's not that difficult. We used to wire S100 bus computers from direct DC, we only added AC later.

The major problem with DC is sending it long distances. That doesn't work so well.

(yes, this is overly simplified, but let's not get into that)

Nah

[Sycraft-fu]

They just co-exist. He's wrong about efficiency of AC/DC conversion. Even inefficient devices are usually 80% or better these days and the good stuff s 95% or more. So it gets converted back and forth as needed.

There are HVDC distribution lines in the US power grid (and of course other grids). They just get converted back to AC. Often they are converted from AC as well, since most generators are AC. There is some loss, but not a ton, and everything has loss, that's just life.

Likewise there are data centers that are DC powered. No magic, they just have big AC/DC power supplies (generally the bigger you go the more efficient they are) and then run DC power to the servers, often with DC-DC voltage conversion at various points.

So no current wars, we'll just have both, and they can be interconnected as needed. The tech isn't a big deal these days, and isn't all that expensive.

Better options than batteries for AC

[Firethorn]

AC is one of those things where a custom solution is often better than just trying to throw more solar panels and batteries at it.

First, you start by designing the house for the region, not forcing it by 'simply' tossing a X ton AC system at it. This can dramatically reduce the heat load. Much better done when building the house, of course, rather than as a refit.

Second, consider your total cooling requirements, at the reduced level. Consider what resources you have. Options include adsorption, absorption, air & ground source heat pump, evaporative, etc... Let's say we're sticking with that our cooling energy MUST come from solar power. We can use solar photovoltiac or solar thermal. Thermal pulls more energy from the sun per square meter and be cheaper, but processes after it are less efficient.

Today you can buy high efficiency heat pumps that work directly off of DC.

Third - get creative with storage. Batteries are not the only option! Thermal mass is an option - you cool down some media - water, bricks, dirt, doesn't really matter. Then use that to keep blowing cool air through the night. In the case of a thermal system, you can dump heat into storage and keep using it to run the absorption chiller overnight. In the case of an Adsorption chiller, you can size the media to last through the night and regenerate it during the day.

Re:Better options than batteries for AC

[JustNiz]

That would be all well and great if I ever actually had the money to get my own custom house built from the ground up.
Unfortunately I am a working schmuck so have the same affordable stucco box as everyone else in my street.

Electricity 101

[TomGreenhaw]

Alternating current solves a major problem in distribution. Very high voltages to transfer energy over long distances with lower current are the way to go.

If you are producing your own energy, say with photo voltaic cells to store in batteries, AC is an unnecessary conversion step.

This is news for nerds???

Keep your options open

[Locke2005]

I plan on running DC power to every room (USB and car cigarette lighter outlets) when I build my house, and using all LED or electroluminescent lighting. I'd also like to install car stereos in every room, with 4 car speakers in the ceiling. Not sure what the most efficient way to do voltage conversion is, probably just run 12v (13.8v) everywhere and convert to 5v for USB. I'm thinking car and RV electronics for most purposes. But, I intend to install AC power everywhere too, and probably propane as well (for stove, at least), and make provisions for solar, wood or pellet heat, because I think multifueling keeps your options open. I kinda like refrigerators, microwaves, and hot showers -- don't think I could live on just what could be stored in a single car battery. I'm open to suggestions on how to run flat-panel displays off 12v without coverting to AC and back to DC inside the display. One would think there would be DC televisions available, but I'm fairly certain there aren't any large DC displays on the market.

Re:Fibre optic

[Locke2005]

My Verizon/Frontier fiber termination included it's own battery backup -- I thought all of them did. I'm pretty sure 24/7 availability is a requirement for 911 emergency service for landlines, so if they can't get power off the wire, they need a backup.

Re:DC distribution is inefficient at most scales

[Locke2005]

I thought a lot of industrial applications were using DC motors anyway? Yes, the distribution problem is the main reason we use AC. Now, if we could just get everybody to use the same line frequency...

Re:Giving up AC

[Locke2005]

How much power does a 12v fridge use? I thought most RVs were still using propane refrigerators.

Not very impressive.

[ShieldW0lf]

So, he eats all his food out at restaurants instead of cooking and buys new clothes instead of doing laundry, and this is supposed to be impressive?

Join the 20th century

[russotto]

We're not using linear power bricks any more. And coal efficiency is ~33%, not half that; that takes the steam turbine into account already. Transmission and distribution is about 6%, and current chargers should be at least 80% efficient. So, actually you get 24% coal-to-phone efficiency, not 16%.

What this guy has done is outsource or hide his power use. He eats processed "food" with the power baked right in, or goes out to restaurants where they have big refrigerators and other power users. He uses a butane stove to avoid having to count the power use for boiling water. He uses Uber and the bus to get around; both these use more energy per passenger mile than a high-efficiency automobile. He uses his clothes until they are too dirty and outsources the energy of the washing to the next owner (and fails to account for the energy of the making).

Re:Somewhere Thomas Edison is Tenting his Fingers

[thegarbz]

We should hook him up to an alternator and generate free energy powered by Rob Rhinehart's bullshit.

Actual, practical solar

[fyngyrz]

The real numbers:

If you figure out what the "just enough" solar panel count would be for your max power needs during the shortest day of the year in full sunlight at whatever angle(s) you'll be able to manage, you'll need five to seven times that many to make sure that on non-sunny days you're good to go.

This is because solar panels produce between 15% and 20% of rated capacity on non-sunny days. Non-sunny days are not "dark", they are only "dim." It is a very rare day indeed where it is so dark as to drive a solar panel below 15% output (major snowstorm which has the atmosphere nearly opaque, that kind of thing.) But dim days can come in very long strings, so that's the target to aim at.

For a reliable system that will never let you down, you do tend to need considerably more space than you would initially think. But it is possible, given that you have the space (lots) and the budget (also lots) required. Panel-wise, it's a quantity issue.

But there's a wolverine in the woodpile: Batteries. To be blunt, they suck, as in, expensive to replace and very short lifetimes compared to the rest of the system.

Until or unless ultracaps reach a point where they are on par with batteries for the service you need, reasonable full-on solar installations remain quite expensive.

Installations that use batteries are regarded highly by their owners only until the first battery replacement. Then their wallets straighten them right out.

I have a lowish-power setup, with an unfortunate number of ultracaps (because capacity is very low, about 1/10th that of a battery right now) as the energy storage medium. I did it both to give my ham gear a constant supply, and to explore what would actually work. It took a custom controller design -- ultracaps don't act even remotely like batteries -- and it took me quite some time to put it all together and make it work like I wanted it to. There are way more panels than you'd expect because of that 15% number (my panels are cheap ones), and there are way more ultracaps than I wanted to expend room for, but I did have the room, so I kept at it. It works great, and it isn't going to need service for decades unless there is an actual component failure or a severe weather event (large hail, for instance.)

Trying to do this for a full house load? A typical US house? Not yet, I'm afraid. There will be tons of compromises to make in appliances, lights, and lifestyle, and in the end, you're not likely to have the same lifestyle you had prior to your switchover.

The battery problem will probably be solved. One way or another. Eventually. I have no idea if solar panel efficiency will get up into a range where the costs and space will fall within the range needed to go truly off grid. That's a physics question in an area where I have nowhere near enough knowledge. But right now? No.

Which brings us to on-grid, grid power use mitigation. Now that is an interesting area, and we can leave batteries right out of it, as peak power also comes during peak power use (right now... electric cars may change that.) But it involves all kinds of compromises for the utilities if it is adopted in any kind of mass manner. They will need power storage, as I understand it at the moment.

Full-on solar is a great, great thing with huge potential (ha, a pun, hooray), but it's not a panacea by any means except in very rare sets of circumstances that involve very large amounts of money and large areas of space for the panels.

Re:Actual, practical solar

[bobbied]

BTW... I didn't say it wasn't possible to go off grid, only that it's WAY more expensive than it initially appears. Now if you want to provide fossil fueled backup, you can save yourself a boatload of cost. Personally, I'll just stay on the grid and be careful with conservation...

Re:DC distribution is inefficient at most scales

[LinuxIsGarbage]

It depends on the specific application, but in industry for pumps, fans, conveyors, compressors, and many other applications, the preferred motor is 3-phase AC induction motor (low maintenance, high efficiency). Where variable speed is required, a VFD can be used, which has an intermediate DC step (which is just straight AC rectified, before being inverted back to AC and sent to the motor), but otherwise an induction motor + across-the-line contactor starter is a very simple setup for industrial motors that is very reliable and low maintenance. VFDs add cost, and lower reliability for applications that don't need them, and generate harmonics that interfere with facility's distribution system.

DC Shunt motors are used in some industrial applications, primarily older ones requiring variable speed because it became possible on DC before AC, and also because they can provide better starting torque. The trend is very much to move to AC motors where possible because the motors are lower maintenance, lower cost, higher efficiency, and higher reliability. In any case the DC drives control the rectification of AC to varying DC voltage to allow control of speed, so it's not like there's a standard DC voltage you can use on these so there's no benefit supplying the drive with DC. The VSD will go straight from 460VAC input to 0-500VDC armature voltage via a bank of SCRs. This generates a very choppy "almost DC" waveform to the motor, and generates a ridiculous amount of of harmonics that can cause major problems on the facility distribution system.

AC really is easier to setup a distribution network, either around a State, or even within a commercial or industrial facility. DC is only used in distribution for looong distance, high capacity runs, where the benefits outweigh the significant costs of conversion.

AC distribution equipment is very simple and robust. Transformers are basically just a coil of wire. Motor starters are just simple contactors (relays). There is a surprising amount of 50 year old electrical distribution and control equipment still in service because it's so reliable.

VFD, VSD, and any DC-DC conversion will rely on power semiconductors (SCRs, IGBTs, etc), and electronic controls. These products are not as robust, are more expensive, and usually become obsolete before their simple counterparts.

The whole benefit of "giving up AC and going DC" might make sense in a small residential 12VDC "off the grid" system where everything is close together and uses the same voltage, but it falls apart in the industrial setting where you need to power 10's, 100's, or 1,000's of kW worth of load, and you need a distribution system. The products required to make a large scale DC industrial facility simply don't exist, and it's like some people are trying to chase after some gain that doesn't exist.

Where is he pulling these numbers from?

[topologicalanomaly47]

I studied a bit of thermodynamics in college some too many years ago and even then the total efficiency of an old eastern europe '80s coal burning design was better than that. If you factor in that during winter the same plant is also providing heating for the adjacent city you get even better numbers. Also switching power supplies (virtually all cell phone chargers made in the last 10 years) are much better than 50% with many (mostly?) over 80%.

Treat it like a car...

[solrac1970]

I did exactly this many years ago at a hunting cabin way out in the Adirondack mountains where power was in short supply. I just treated the entire place like a car or RV. Even the radio came from a car.

Alaskan Solar Power

[Tenebrousedge]

This snow clearing suggestion probably works, except for heavy snowfalls. Upstate New York, e.g., or the Chugach. I'm from Valdez and the concept is hilarious. Plus heating up snow is an energy-intensive operation, and any time you've had snow it must necessarily have been overcast, and in Alaska that means that you're probably dealing with less than six hours of daylight. I'd say the method of clearing the panels with the best ROI would be to say, "Fuck it" and drink until springtime, but that's how I approach most issues with winter in that State. It's a very popular strategy as I'm sure you've noticed.

Re:Alaskan Solar Power

[Firethorn]

This snow clearing suggestion probably works, except for heavy snowfalls.

Just the opposite, actually. Remember, you don't have to melt all the snow. Just a very small layer that's touching the solar panel.

The heavier the snowfall, the less energy you need to spend on heat to make it fall off.

That being said, after doing the math, my answer for solar power in the winter once it snows is indeed 'fuck it', my simulations assume NO power generation for four months/year.

to heat my coffee i ....

[Skapare]

... burn COAL. why coal? because it was FREE. i found a lump of it in my Christmas stocking.

Re:Giving up AC

[adhdengineer]

P = VI so 12 x whatever the current they draw.

DC? Screw that.

[rgviza]

There's no way I'd want 120V DC in my house. With AC you just get thrown, with DC your muscles contract and you become attached to the hazard.

I'm not saying that people have bare wires hanging around the house, and neither do I, but crap happens.

If you get shocked with DC and it's because you grabbed something that's energized, you are dead, kaput. With AC you have a fighting chance. I used to be an electric motor mechanic. DC scares the crap out of me. AC scares me too, especially 270/460 but HVDC? jesus... I've been hit by 120VAC. You don't walk away from HVDC. I'd be dead if that had been DC.

Boats

[pcjunky]

People living on boats have been doing this for years.

Slashdot articles have really taken a nosedive...

[ToddInSF]

This one is just too stupid for words.

For those that may not know...

[martinfb]

AC current is more efficient to TRANSPORT over distances. DC current fades fast on transmission. It is still cheaper to send (power) via AC current and have the endpoint convert to the DC if needed.

Can We Spell "Resistance", Hmmmm?

[Toad-san]

No one's said a word (yet) about the difference in resistance losses between AC and DC when you try to transmit it over any significant distance at all.

http://www.diffen.com/differen...

If you want to give up almost all of your electrical uses in your home or business, feel free: switch to DC. Otherwise, I wouldn't suggest it. If you think those AC losses are significant, they don't hold a candle (heh) to DC.

Don't get all extreme

[cwsumner]

This guy seems a bit extreme. There is no need to go totally solar or totally off of distributed power.

If you can seriously reduce your demand, it will have almost as much benifit for the planet. And there is no reason that solar can't be sent from other timezones via the distribution lines.

The "big new thing" is the LED lights, DC motor controls and Electronic Voltage converters that are -much- more efficient than in the past. That means that solar usage is much more practical. Any amount that you can do will help.

Re: roof?

[GaryHayman]

How big is your yard?

Re: roof?

[FlyHelicopters]

Very, very small...

Security not Safety is the Issue

[Roger W Moore]

Nuclear plants still have the requirement of access to an uninterruptible source of water for cooling. They also have security concerns which is not the same thing as safety. I would have no worries about living near a nuclear plant but I would have a lot of concerns about every neighbourhood having their own. Depleted uranium is easy to obtain and all it takes to convert it into plutonium is a strong source of low energy neutrons like a reactor.

Not me, but another old codger I know of

[nobodie]

My brother's (recently departed) father-in-law, (apologies if he posted already) designed and built a house in Vermont that was not only entirely DC, but also solar powered. Yes, solar naysayers, in northern Vermont. All his electric came from solar, but he did have a small backup generator for just in case (well really, he was in his 70s when he built the place). I got to visit there once (the wedding) and was blown away. Little tiny pump to pump water to the solar hot water heater and then gravity back down to the shower and kitchen. He hadn't finished and the "switches" were just wires sticking out of the wall that you could twist together by hand. The frig was from a boat, as was the stove I think.

So, it is possible, sounds like fun, enough that I have hopes to build one similar but really small on our property in the blue ridge, up on top of a ridge. No wires, no wires...