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Method for $1/Watt Solar Panels Will Soon See Commercial Use
An anonymous reader writes "A method developed at Colorado State University for crafting solar panels has been developed to the point where they are nearly ready for mass production. Professor W.S. Sampath's technique has resulted in a low-cost, high-efficiency process for creating the panels, which will soon be fabricated by a commercial interest. 'Produced at less than $1 per watt, the panels will dramatically reduce the cost of generating solar electricity and could power homes and businesses around the globe with clean energy for roughly the same cost as traditionally generated electricity. Sampath has developed a continuous, automated manufacturing process for solar panels using glass coating with a cadmium telluride thin film instead of the standard high-cost crystalline silicon. Because the process produces high efficiency devices (ranging from 11% to 13%) at a very high rate and yield, it can be done much more cheaply than with existing technologies.'"
ya, but for how long do they last
I have always been worrying the environmental impact of the cadmium. Could some one show me that the cadmium used in the photovoltaic has little or no environmental impact please?
There is a spark in every single flame bait point.
if it turns out to not be vaporware, it may very well actualy make a dent in our use of coal and other fuels for generating electricity.
I've decided to Diversify my Holdings. I've divided my cash between my left and right pockets, instead of all in one.
actualy, a 20x20 foot aray with good batterys and inverters will power a home with a family of four quite nicely. (I myself lived in a house that was totaly off the grid for about 5 years, pure sunlight on a 20x20 grid in the summer, minor supliment by propane generator in the winter months)
I've decided to Diversify my Holdings. I've divided my cash between my left and right pockets, instead of all in one.
The article doesn't mention how many watts per square meter this panel will produce. The cost of the panel is important, but so is the cost of the land required and the return of your investment.
Washington bullets will simply be known as the "Bulle
Well, 1 kilowatt for an hour costs me 25 cents (thereabouts). To make a kilowatt, I would need to spend $1,000 on these. That means that they would have to operate for 4,000 hours for me to make my money back (well, 4,000 hours of electric usage).
Basically, it looks like, if they last a couple years, they would pay for themselves (166 days of full utilization, but that's not going to happen in the real world). Not bad. If they're durable (and last 5-10 years), they could really cut down on electric costs.
Oh, plus the whole saving the planet from destruction thing. I guess that might have some value.
a)How long do they last
b)How fragile are they
c)What temperature ranges can they survive
d)How strong light do they need
e)What environmental impact will the cadmium have
Sure, if it works all will be happy and dandy, but I somehow suspect there are some catches not mentioned here.
Cadmium... so not RoHS compliant, so not saleable at all in Europe and many other parts of the world. Oh dear.
I wonder if RoHS will be relaxed for solar energy?
Oolite: Elite-like game. For Mac, Linux and Windows
Maybe you are thinking of the cost of complete systems. The panels themselves are easy to find in the $4.50/W range. $4.00/W is more of a wholesale price but certainly obtainable.
http://www.solarpanelstore.com/solar-power.large-solar-panels.solarworld_sw.sw_165.info.1.html
Additional plugins are required to display all the media on this page.
Here is one place that specializes in solar panels:
http://www.backwoodssolar.com/catalog/solar_panels.htm
The SW165 is just under $5 per watt, and many are between $5/w and $6/w
To answer your question about a 100w panel for under $800, the MF125UE (125w for $690) seems to be one.
A dingo ate my sig...
One square meter of land on a bright sunny day will get appx 1.6kW of light in an hour. Assuming 11-13% efficiency as mentioned in the article, you'd get just a little over 160 watts per square meter per hour.
Still waiting on Serviscope_minor to wake up to fucking reality and realize that Jessica Price isn't going to fuck him.
There are several houses on my area in Northern California that have photovoltaic installations that produce more electricity than the homes consume. The excess goes to the power company for a credit against future use. These are homes with air conditioning and people that don't live austere lives. Their installations cover less than the entire south facing slope of a conventional roof. The problem is that they wouldn't come close to paying off without big fat gumnt subsidies. At $2.00/Watt they would be economically feasible without subsidies.
Assume the panels are 1/2 the cost of the system so the total system costs $4/Watt, or $8,000 for a 2 kW system. Assuming 6 hours a day generation, that's 4380 kW-hrs a year, or at $0.10 kW/hr that's $438 worth of electricity. 438/8000 = 5.4% tax free return on investment. If you live in the US with a decent income, you would have to earn over $700 to have $438 for your power bill after taxes.
If you don't like my numbers feel free to substitute your own.
Let's be like China and make electricity the man's way - with coal! And let's go back to burning leaded gasoline so we don't have to fuck with this unleaded crap that limits engine compression. Also, catalytic converters suck. I always take mine off after inspection or go to shops that don't care. Also, we need to get rid of welfare and we need George W. Bush for another eight years! And fuck solar cells. Solar cells can't even power calculators properly.
Anonymous Coward Sig 2.0:
--
Write in George W. Bush in 2008!
Right now, the grid acts as a nearly perfect battery by distributing power around as needed. During the daytime, electricity use is far higher than during the night, so solar panels are really very nice in terms of when the provide power. The solar panels installed in houses would decrease daytime load on power plants, resulting in better efficiency throughout the system. Think of it as the solar panels working towards supplementing the grid with enough extra power to handle air conditioning and other day-time power use without running power plants at 100% of their rated output.
Management of the environment is constant compromise since nothing is perfect. However. Since burning coal is the major SOURCE of Cd in the environment ...a quick web search reveals a sense of the tonnage:
http://www.unu.edu/unupress/unupbooks/80841e/80841E0c.htm
a balanced view considers the following.
Which is cleaner?
a) a highly controlled manufacturing process
b) under-regulated coal bonfires belching Cd in the air and
disgorging Cd in the ash.
Bonus question: for extra credit what other nasty stuff comes
out of a smokestack?
---537
Watt is a per-time unit. 1 Watt = 1 Joule per second.
A watthour is a 1 watt, sustained for an hour; a kilowatthour 1000 Watt, sustained for one hour.
"Watt per minute" doesn't make sense, except when talking about things like a change in power.
I believe posters are recognized by their sig. So I made one.
From TFA:
The cost to the consumer _could_ be as low as _$2_ per watt.
Anybody spot the weasel word? Then there is the $2 cost to the consumer, rather than the $1 which is the cited production cost. Also, the article makes no mention of what levels of incoming radiation these numbers were calculated for. $1/W means something quite different in Egypt than it would mean in Sweden. Is the $2/W derived from the peak efficiency under ideal weather conditions, or is it the average over a year?
Essentially, if you want a real estimate of the price of a power technology you don't want price per power, you want Energy per Life-cycle costs. So if these cells last for 10 years you want to know how much total energy they could be estimated to produce during that time, compared to the cost of the panel. Other aspects like intermittent production and so on factor in, but in any way, price per [peak ?] power output is not a very useful number from an economical point of view. For solar cells you want at least the estimated cost over a life cycle with the assumed weather conditions specified. Less than that and you can easily massage the data by making strange assumptions.
The real question here is how will these panels stack up to current poly panels with regards to their life span? All solar panels degrade over time - that is, produce less power as they get older. Rule of thumb for a poly panel is around 25 years. While there are many types of panels only a few are actually in mass production and have the required life spans. If you are looking to install solar now, polycrystalline panels are what you want to get.
:-)
1.5 to 2 KW worth of panels is enough to run a typical house unless you have a machine room. Even if you use more power then your panels can produce, it's actually all to the good because it means the panels are recovering the highest-tier electricity costs for you, dropping you down to a lower tier with your utility company.
You don't want batteries unless you are off-grid, and most people will be on-grid. There are many grid-tie solutions available and costs have come down considerably over the years. Batteries are of course essential if you are off-grid but knowing the many hackers here I'm sure many of you would like to be able to disconnect from the utility completely, survive blackouts, and so forth... but generally speaking, the batteries and equipment required to do that adds a lot to the cost of the system and involve considerably more maintenance and worry.
A straight grid-tie system is completely maintenance free. I literally have not had to touch my system since the day it was installed. I just pop into the garage and stare at the cumulative power display every so often
http://apollo.backplane.com/Solar/
-Matt
Unless they have no alternative to home-generated electricity, the cost of alternative generation systems is an uneconomic solution for most people.
I too live off-grid, in a small observatory at the top of a high mountain. Even though the cost of AC mains to the site was well-beyond my means, the only reason I could afford to generate my own electricity was because I work in the electrical industry and got the batteries, heavy cable, components for regulators and inverters, etc, for free.
The only things I had to pay for was the PV array and that was not a trivial expense, at $10 per-watt, excluding taxes and shipping.
My off-grid system works very well, but it requires a lot of on-going TLC, far more than most people I know could be bothered with providing. They want systems they don't have to think about and which "just work". Few have the self-discipline and willpower required to minimise their loads, letalone perform regular maintenance checks.
I've always been a Renewable Energy geek, but if I could have got an affordable AC mains connection to my site, I would have one. As much as I love playing with windgens and solar setups, with a wife and two kids now, I simply don't have as much free time on my hands as I used to.
The solar constant is about 1300 watts per square meter (in space). On earth the best you can hope for is about 1000 watts peak. So on average we will look at about say 50% of 50% and less on a cold winter day when we need both heating and more lighting. In fact on a winer day at about 51 degrees latitude we get about 8 hours of light and even then its less than 250 watts per square meter.
If we take 10% of 250 we get 25 watts. This is about as much as a high efficiency mini florescent uses.
To run a toaster we will need 40 square meters of solar panel and to roast a turkey and cook on top of the stove as well we look at 40 amps @ 240 volts (check your main panel folks) which is about 385 square meters at 25 watts per square meter.
Thing is that we might want to roast the xmas turkey after dusk, so we better plan on batteries.
A deep cycle 12 volt battery (lead acid) can be expected to hold 60 amp-hours.... at least this is what the Hawker batteries I use for my UPS system are rated for.
12*60 = 720 watts hours. To roast the turkey say takes 4 hours at a draw of say 30% of 40 * 240 which is about 11,250 watt hours. So we need 15 batteries for this. Next if we draw them down any more than about 20% the number of cycles goes into the toilet so we'll need about 5x as many so we can draw each to about 20% of their max rating. We'll need 75 batteries.
New these batteries cost more than $250 bux so that is a battery investment of $18,750.
Clearly one will not be running an electric range off that solar system.
I'm not scoffing at the idea. I think its good but one has to find a way to store that energy and perhaps the best use of it will be to create hydrogen.
The thing is that sure it can feed into the grid during the day. All this does is put idle the current generating infrastructure and we still need that infrastructure for night operation. Of course it would save the fuel needed to operate the plant.
But then what would we use the existing generating stations for when they are idle? Generating hydrogen?
Somehow it doesn't make sense to burn fuel to create electricity to make hydrogen when we can simply for instance chemically take the Methane apart and get hydrogen that way.
One really has to think about how this cheap solar technology fits into the full cycle of energy needs.
Nevertheless I think it is good and maybe we should use it to pump water up hill. Then at night we can let the water flow back through the pump and turn it into a motor-generator. Batteries are just one way to store energy. It can be stored as compressed air, water at the top of a hill, chemically such as hydrogen gas... but it will need to be stored and in great quantities if this technology is going to go anywhere.
Plants such as trees are another good solar collector. We tend not to use them. They are reasonably efficient and serve as their own battery system because if you need more heat you can chuck another log on the fire. Since most of us tend not to use the solar collectors mother nature already created for us, I suspect that there will be huge issues to overcome in order to deploy even cheap man-made ones.
Now here is another thought. The best efficiency of these collectors is say 10%. If we capture the same energy for space heating our houses we can easily get over 80%. Yet, most of us do not even do this.
A super heated house with R70 in the ceiling and R50 in the walls costs about $1 dollar per square foot of building envelope extra during construction. This will eliminate the vast majority of summer cooling and winter heating loads. Here in Calgary for instance a house like this does not need a furnace and we can have winter days that are 40 below for weeks on end. A house like this can get by with a nice fireplace and wood heat and will burn less than 1 cord of wood per year. That wood costs about $100 dollars.
But, most of us don't even do this.
I think solar is a great idea but a low
It doesn't matter if the panels are $0.01/watt if I still need the entire neighborhood covered in them to run the coffee maker
Perhaps making heat is not the best way to use electricity? I have a gas-powered coffee maker, myself.
Here in Taiwan, we just had the annual solar trade show which is becoming a really big deal on the silicon island. Solar has become a huge because it dovetails right in with other semi industry players that get put together in industrial parks.
So this year there was a big dollar-per-watt announcement from Oerlikon. If you don't know who they are, they're a Swiss provider of turn-key thin film or amorphous silicon solar panel factories. They've got several partners in Taiwan already including, most recently, some of the large-scale optical media manufacturers who already use similar techniques and equipment and have some cash to invest.
The local Oerlikon rep was saying that producers will be at sixty cents per watt within forty eight months and that this will mean actual product at the dollar a watt level. Hey, I'm just passing along what the sales rep said. Obviously he's got a reason to overstate his case, but that's what he claimed was coming down the piple.
I think it's also worth noting that a former Slashdot sweetheart that went by the name of Spheral Solar has basically dropped off the map because they realized that amorphous silicon was going to take over.
Oerlikon bought up Excimer laser of the UK last year. One of the repeated steps in doing thin film solar is laser etching.
I'm not too sure about the tech being referred to in this piece, but dollar-a-watt PV, which is what the UN and other agencies have said is the tilting point where solar is cheaper than coal or natural gas, is already being spoken of at industry trade shows and shouldn't be seen as a wildly implausible announcement.
Note that it's very hard to be green with an off-grid system. Off-grid systems tend to use batteries, and for proper operation you don't want to discharge the batteries too deep, and so quite often you overprovision your cells and you end up throwing away the energy from the cells into mostly full batteries a lot of the time. You can try to live greener (more efficient appliances etc.) and that's almost a must off-grid, but the off grid electricity itself is very expensive.
On grid, every watt generated by the panels goes somewhere and does something, because you feed it back to the grid, where it reduces the demand for fuel-burning electricity.
So living off the grid can be rewarding for those who want to be very non-urban, but it should not be confused with being green, energy wise.
Has it been over a year since you last donated to the Electronic Frontier Foundation
Be careful here. In California, which is where I live too, it doesn't get dreadfully hot like it does in the midwest, or at least not for more then a few days a year usually. A solar array of the size normally needed to reach net-zero with the power company doesn't even come close to being able to generate the power needed to run even small whole-home air conditioning systems. As long as the AC is only used a few days out of the year (which is typical in California), then you can still reach net-zero over the whole year. But in somewhere like Texas you wouldn't have a chance. AC is usually not in the cards if you are trying to achieve energy independence.
-Matt
OK, let's see if this is for real.
First, the "story" is a regurgitated press release. For an more critical story by a local reporter, see "AVA Solar enters crowded field", by Tom Hacker.
The AVA Solar web site has almost no useful information. But they have a patent on the manufacturing process, which discloses what they're trying to do. Among other things, the patent tells us that "AVA" stands for "Air-Vacuum-Air". The process is mostly conducted in a low grade vacuum, with some preprocessing in air before the vacuum chamber and some final steps after vacuum processing. The big deal is supposed to be that there's only one trip in and out of vacuum, which simplifies the production process. This patent was filed in 2000, so they've been working on this for a while now.
They're trying to make cadmium-telluride solar cells, which aren't new. The new thing is making them with a continuous process, instead of in batches.
AVA Solar has some job ads on Dice. They're looking for a plant manager, and on Dice they say "200+" employees, rather than the "500+" mentioned in the press release. AVA Solar doesn't seem to actually make anything yet, so they have to build and run a new kind of manufacturing plant of their own design without an organization experienced in doing that. That's hard.
They're supposedly building a pilot plant, to be running by the end of 2007. So wait a few months. If that works, it's worth looking at them again.
Lets see. Assume the competing cost is at present 10 to 25 cents per KW-hour. We'll use the upper end because future power prices will rise whereas the Solar panel is a fixed cost.
So let's see the solar panels are 100000 cents per KiloWatt. if the last 4000 then that's breakeven. We'll assume that the power is available 10 hours per day. That's not realistic for individual use but perhaps with batteries, and selling back to the grid this could be done. So 4000 hours is 400 days. Or about 1 year. Not too bad.
Now that ignores the efficiency of either pushing back to the grid or battery storage. Let's assume 50% loss. Then this is 2 years to payback on the cells. But now we also have to payback on the batteries. Let's assume the batteries needed const aout the same as the solar cells. That would double this payback to 4 years.
Finally this is assuming capital is free. Assume one borrows at 8 % interest. Then this another 5 months to payback.
So the whole operation needs to run undegraded for 4 to 4.5 years I estimate for break even.
That figure could be cut in half if one could sell back to the grid rather than batteries. ( Fine--as long as there is a grid and every one does not do that!. )
If the cells were down to 50% effiency after 4 years then this extends out to ~7 years to payback. If one cannot get that watt for the full ten hours then this gets even longer.
It sounds to me, roughly speaking that at 1 dollar per what things are in the ballpark for breakeven.
Some drink at the fountain of knowledge. Others just gargle.
More is needed, though - even with cheap and plentiful solar cells you're still up against some physical limits. You've only got so many square feet of southern exposure you can put panels on - and it's not anywhere near enough to support your current level of electric power consumption. Keep in mind that solar panels are rated at "full sun" and in the middle of winter you'll be lucky to get 10% of that on a bright sunny day.
So a good place to start is to find ways to reduce your power consumption. Not "feel good" little reductions, but serious cutbacks. Think about things like skylights in kitchens / bathrooms (free lighting), better insulation and weather stripping, and even some automatic controls on things like lighting, heating, etc. - these will remember to shut off the lights, turn down the heat, etc. even when you forget.
Pick up a small watt meter; something like the "Kill a Watt" can help you discover where the power is going. You'll find that a lot of it is pure waste and easily eliminated. Use task lighting instead of lighting up the whole room / house, look for more ways to reduce consumption.
You'll have to make some concessions and adjustments to live a low power consumption lifestyle - it's up to you to determine how far you can comfortably go. But if you can cut your consumption by 50% or more (very possible) then you're getting to the point where those solar panels can supply enough power to keep you going.
And you're going to need some kind of backup generation for those dark and dreary winter days. House sized generators are usually NOT cost effective, battery banks are expensive and troublesome. Grid-tied systems are clean and easy - but get the facts from your local utility before going this way. Some are very reasonable, some want to pay you their "generated cost" (less than wholesale) for the power you put into the grid - but charge you peak rate for the power you pull from the grid. This can wipe out your solar savings; be careful. Choose which ever of these best fits your needs and hope you never need to use it.
Now this hocus pocus about the after tax situation is wrong too. If you want to include that then you have to include it on the 8000 dollars as well so Since the 8000 cost is after taxes, there's no point in calling the return on investment after taxes. Or if you want to then it costs 12300 of pre-tax income to buy the 8000 panels.
The ROI is negative since 437 electricity minus 640 interest is a 200 loss every year.
Some drink at the fountain of knowledge. Others just gargle.
Yes.
And after they place the condemnation notice on your front door, they'll kick your dog.
Seriously, what makes you think that the engineers building this thing are so incompetent that they haven't considered the possibility of hail falling on your roof? They actually do run tests like that. Second to last paragraph here.
I also find it very interesting that you didn't mention the dangers of actually living in a poison-dusted home, but only the danger that the EPA might deny you your God-given right to live in said death trap.
Tell you what, when serious people who actually know about the toxicity and regulatory requirements of cadmium telluride start telling me that this solar technology may present problems, then maybe I'll start worrying.
You want the truthiness? You can't handle the truthiness!
What matters is costs / watt, assuming that the efficiency is not so low that it requires too much space. In the end, homes could start moving to this, and when high efficiency, low costs solar cells via other methods appear, they could move over to that.
I prefer the "u" in honour as it seems to be missing these days.
What is so bad about lead acid batteries? They are 100% recyclable. The lead can be re-used for new batteries.
1.21 Gigawatts at $1 a watt, no thank you I'm sticking to lightning.
I would mod you up for that if I could. I try to not think about places that require AC at night
FWIW, this area has around 30 days over 100 per year. Nights are usually comfortable and the daytime humidity is low.
Shit, durring the summer in TX we're lucky if it gets below 90 at any point durring the night. Last night around 3am it got down to 87, and the AC was off for more than 15 min. AC units pretty much run 24/7 may-october here and a $350 july or august electric bill isn't at all uncommon ($.11-.13 per kw/hr here in Dallas). Temps typically only fluctuate 8-10 degrees between highs and lows here. I think solar would be a great argument here durring the summer...
moox. for a new generation.
If you want to correct people, you should check your facts first. I was referring to deep cycle batteries. They are called that because they can do far more deep cycling than typical car batteries, but in fact if you research it you will find that the deeper you discharge them the shorter their lifespan. Generally you want to design your system to not go below half in ordinary use, and drop down from time to time in peak use.
However, that's actually not relevant to the main issue. You don't want to live close to the edge. You want to be sure you have capacity for when you need it. But you also want your batteries returned close to full by the end of the day to provide your power needs that night and into the next run of cloudy days. So you have to provide enough solar wattage to make sure you do that most, if not all days. Or you need to have an alternate power source for peaks (like a generator.) But most solar people don't want to use a generator.
Anyway, point is on the many days when you use less than capacity and the batteries are fully charged, you are just throwing away the power when the batteries are full. That's not the green thing to do. Certainly the people who go off-grid on a property connected to the grid are being foolishly non-green. The grid provides both a way to get any excess power you need during low solar periods, and a way to make sure all the power you generate goes to good use. That's why government rebates etc. only apply to grid-tie solar installations.
Has it been over a year since you last donated to the Electronic Frontier Foundation
I live in Colorado and I find this story interesting in relationship to another story about a year or so ago about a man in Colorado who installed a roof's worth of solar electric panels which gave him juice to spare. The spare electricity was fed back to the grid, causing his electric meter to spin in reverse. When the local power company found out about it, they installed a "special" meter that would only spin in one direction (in their favor, of course). I think we need some legislation to require power companies to buy back any excess generated power. CB
A 2 foot by 2 foot chunk of window glass in the store is $17.40 at Rona. A square meter is 10.76 square feet. So a 1 meter square piece of glass would cost $46.82 at these rates.
Even the cheapest solar cell should be expected to cost more than plain glass since it includes at a minimum plain glass.
Next.
Solar constant is 1300 watts per square meter in space and max 1000 on the surface of the earth.
One can expect on average 12 hours of darkness. Then we can expect only 50% of this max because most of the time its not high noon. One actually has to integrate the sin curve.
So we can say 12 hours at 500 watts average maximum collection and at best we can hope for about 50% of this. This 50% discount takes into account rainy days and snow blowing on it and maybe it gets a little dirty because people don't wash it often enough.... there are lots of things that can go wrong here. So I pick 50% out of the air as a practical fudge factor to convert to what is theoretically possible to what one might expect.
This is 3000 watt hours per day falling on the panel in a useful way, and the efficiency of the panel is say 10-13% so I'll use 10%. We can expect to get say 300 watt hours per day per square meter. This is 0.3 kwh which in worth say about 3 cents at a rate of 10 cents per kwh. This is still 25 watts per square meter for 12 hours and this is what a mini florescent draws.
But from the article - they say $1 per watt so I assume they mean per watt peak capacity.
This would be 100 watts per square meter since we have 10% of 1000 and the 1000 is peak. The duty cycle is at best 1/4 of this. Nevertheless, $1 per watt * 100 watts is $100 per square meter.
Thing is $100 per square meter is only 2x the cost of a plain glass windowpane so its actually unreasonable to expect they will be able to sell these panels at anywhere near 2x the cost of plain glass. A complete window assembly is in the order of a few $100 bux. Maybe we get the complete panel retailing at $200.
What should we expect to really get out of a $200 panel in terms of energy?
At best, 25% of max and this is about 25 watts per square meter and this is over 12 hours. Hence one should expect the thing to capture at most say 300 watt hours per day.
As I calculated before this is about 0.3 kwh = 3 cents worth of power. $0.03 * 365 = $10.90
Invest say $200 in a panel when it retails and get $10 per year from it in electricity. This is a 20 year pay back not counting installation, maintenance, and so forth. At a 5% interest rate (cost of capital) it has a ZERO Return on Investment (ROI).
Now the real issue. Suppose everyone does this. It will have the effect of destabilizing the grid because it puts the power company in the position of standing by ready to supply energy at night and when the sun doesn't shine but meanwhile when the sun is shinning their expensive infrastructure sits idle. So long before this gets deployed the rules get rewritten.
The thing is that we can already capture solar energy passively and build houses that will save way more than $1000 per year in energy and do this for a capital investment of less than $5,000. All we need to do is put R50 and R70 in the walls and ceilings. We can do a LOT more than this. To capture say $1000 per year with say these high efficiency panels will cost 100x$200 bux = $20,000 of capital and this does not include the control systems.
Air conditioning is ridiculous. That said, using a vapor compression cycle is the problem. Evaporative cooling, adsorption chillers, and desiccant dehumidification (latent heat is more than half the AC load) can by accomplished with solar thermal technology (heat water with collectors on your roof, use low delta T to drive low COP AC equipment). It's not only possible, but it's been around for decades.
You do realise that he was right? The green revolution along with declining birth rates in the western world has ensured that we have enough food - but starvation is a reality elsewhere.
That's the thing about many, I won't say all because I consider myself one, environmentalists don't and won't consider, as people improve their economics they have fewer children. Up until recently the countries with the highest population growth were China and India. However now that their economies are booming their population are leveling off. A concern in China is that in a generation or two there won't be enough working adults paying for an aged population. Whereas now there's something like up to 10 people working for every retired person then there will be only 3 workers. Where population growth is now a concern is in Africa which due to conflicts and politics is doing poor economically.
FalconShould there be a Law?
- Night (50% averaged for the year).
- Suboptimal angling on the panel relative to the sun throughout the day (guessing pi/4 since I'm too lazy to do the integral).
- Weather (highly dependent on location but this report says 54% in the northern hemisphere, let's use 30% to account for light that manages to get through the clouds).
- Panel efficiency (12%).
- Conversion losses. I should be including losses converting solar panel DC into the AC most household appliances use, but let's be optimistic and say these panels spur development of DC appliances.
- Battery efficiency. Unless you plan to use your lights only during the day, you're going to have to store electricity for night use. Lead acid batteries are about 90% efficient. Wild guess, but say a half of your daily electricity use will be drawn off the batteries, yielding an average 95% battery efficiency. Yeah you could draw electricity off the grid at night, but since we're hypothesizing DC appliances and throwing away conversion losses, I think this is the smaller of the two.
Phew. So what do we have? 1600 W/m^2 * 0.5 (atmosphere) * 0.5 (night) * pi/4 (angling) * 0.7 (weather) * 0.12 (panel) * 0.95 (battery) = 25 W/m^2. That's probably a more realistic figure to use if you want to calculate how much electricity use the panels will save you over a year. The average U.S. home consumes about 1 kW (averaged over the year), so to completely take each home off the grid would require about 40 m^2 of panels. You'd probably want more than that to get you through the Winter months and long bouts of bad weather, but that's very location-specific. We'll just use 40 m^2 and calculate a minimum.Assume the $1 per Watt figure is under ideal conditions (companies love to do that). 800 W/m^2 * .12 = 96 W/m^2. So a square meter of this stuff will run you $96. Multiply by the required 40 m^2 to yield $3840 per home.
Figure an average electricity cost of $0.13 per kWh (in the higher priced areas where this stuff will be used first). Average home burning 1 kW (yearly time-average) would thus spend 24*365*1 kWh = 8760 kWh for the year. At $0.13 per kWh, that's $1139/yr in electricity costs. Ignoring installation labor, the panels would pay for themselves in 3 years and 4.5 months at earliest. Adjust up depending on your latitude and weather. Adjust down if you aren't as power-hungry as homes in the U.S.
I think we have a winner.
central montana, refrigerator, freezer water heater and stove where natural gas, house was heated with a wood/coal fired furnace that was later replaced with a gas furnace. so true, it was not powering what one would consider a "modern home" but honestly, i'd rather have a gas stove and water heater any day. true, you would need a MUCH larger array if you planned on running a electric water heater and stove, but i know you can get full size fridges from GE that use the same amount of power as a normal lightbulb. not to go off onto a diatribe or anything, but people forget that electricity is the most ineficiant way of heating water, powering a stove, or heating a house.
I've decided to Diversify my Holdings. I've divided my cash between my left and right pockets, instead of all in one.
How is that "not green"? Do you need it spelled out for you? His point is that if someone is so concerned about the environment that they'd invest in all that solar, going completely off-grid is actually a step backwards because excess power can be fed back into the grid. Every excess solar generated watt that doesn't get used by some smug monied neo-enviro who's disconnected himself from the grid on principle could essentially buy off a "dirty" watt and reduce the generation of CO2, nuclear waste, or other detrimental emission by a grid power plant. Plus, the power company has to pay you for that power, and that money could go to more solar equipment, or soybean curd, or donations to dang Greenpeace, or whatever. There's nothing particularly "righteous" about disconnecting from the grid. It's just a form of lefty dick-waving: "oh yeah? I'm off the grid!" It's something done by little men with inferiority complexes, who need to feel big by physically cutting the lines, rather than just being satisfied with an electric meter that only runs backwards.
If a job's not worth doing, it's not worth doing right.
With 3.4 billion years of evolution behind photosynthesis, plants have managed to do a bit better than that. According to this wiki plants are very efficient:It will take humans quite a while to improve on the efficiency of the houseplant. But then again, plants aren't turning sunlight into electricity.
Not to quibble, but electricity isn't most inefficient in terms of energy usage. It is just a more expensive form of energy (MUCH more expensive, Joule for Joule). For heating it can often be most efficient. With an electric heat pump you can get more energy into your house than you use in electricity. When burning a fuel, you can never get more heat into your house than you burn in fuel. Unless, perhaps, you were to devise some sort of steam powered heat pump. In which case you'd get the heat from burning the fuel PLUS the heat extracted from the outside air or ground.
"THERE IS NO JUSTICE, THERE IS ONLY ME." -Death
You know, it kinda makes me wonder how that increase will happen.
... In which case people buying energy-saving appliances will make almost no difference to the total.
... In which case they can build their own power plants, thank you very much. Electricity can't even be transported over _too_ large distances, so it's not like more space heaters in India will cause brownouts at your power plant in Florida.
Will it be mostly in the industrial sector for example?
Will it just mean more energy used in currently third world countries?
I'm saying that because, alarmism be damned, I just don't see that kind of increase in what people use electricity for. If I look at what I have around the house these days, vs what my parents had back in 75 (to use the same time interval back as what you propose forward to 2040), I'm not sure I actually use more energy than they did. E.g.,
- they had big ol' fashioned 100W lightbulbs all around the house, I have 15W CCFLs. Their (admittedly large) living room alone had 5x 100W light bulbs lighting it, I only have 2x 15W in mine.
- they had 1 fridge, I have 1 fridge. I think mine has better insulation, because, well, people discovered stuff in 30+ years.
- they had 1 washing machine, I have 1 washing machine. Theirs used a lot more power, I think. (When they bought a particular washing machine, we quickly discovered that the breakers kicked in when the washing machine's water heater, fridge and god knows what else, all kicked in.) Plus mine is rated for pretty high energy efficiency, while way back the notion wasn't even invented yet.
- for washing, there's only so much you can save, you know. (Short of stopping washing. Then again, looking at one particularly stinky co-worker... please, please, please don't. Saving the planet be damned, go take a shower;) Heating 1 litre of water by 1 degree has a lower limit on how little energy you can use, because, you know, it's just physics. Plus heating it was always as efficient as it gets: converting electricity to heat, we can do with 100% efficiency. It's only converting to other stuff that starts to be inefficient. The only thing that works differently is the insulation, and I think that's getting better too.
- they had 1 TV, I have 1 TV. You could keep the room warm with theirs, way back. Literally.
Etc.
The only thing that comes to mind as more energy used these days is my computer. Let's say that's, oh, I don't know, 200 or let's say 300W total. Just the lightbulbs in the living room cover that difference comfortably.
A polar bear is a cartesian bear after a coordinate transform.
People with lots of stocks will be allowed into a dome with an artificial air supply.
echo -e 'global _start\n _start:\n mov eax, 2\n int 80h\n jmp _start' > a.asm; nasm a.asm -f elf; ld a.o -o a;
So after the first child, you keep killing until you have the other gender?
878659 - yep its prime.