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Solar Panel Breaks "Third of a Sun" Efficiency Barrier
Zothecula writes "Embattled photovoltaic solar power manufacturer Amonix announced on Tuesday that it has broken the solar module efficiency record, becoming the first manufacturer to convert more than a third of incoming light energy into electricity – a goal once branded 'one third of a sun' in a Department of Energy initiative. The Amonix module clocked an efficiency rating of 33.5 percent."
This page seems to indicate that 33% is kind of weak: http://en.wikipedia.org/wiki/File:PVeff(rev100921).jpg
Maybe that's because those are still small scale in the lab and this one is in production?
Of course the test had a margin of error of 4%
According to wiki this happened in July. Also, for info, they have received over 180 million dollars in grants from the government, and closed their las vegas plant in order to "focus on international opportunities".
Now slap 4 of them on every mcmansion in the country and hook them to the grid.
Bonus: That'll keep a bunch of people employed forever.
What? No? Expensive? Not gonna do it?
Ok... well.. you kids enjoy the world we're leaving you.
If you include external costs, it's a lot closer than you think.
You are welcome on my lawn.
If you include external costs, it's a lot closer than you think.
Go on. Show me the mone...maths!
If you move the panel closer to the Sun, you'll need quadratically less area for the same amount of energy.
Of course, you'll need a parallel laser beam to send the energy to Earth, and a receptor, etc. but those are left as an exercise for the reader.
If Pandora's box is destined to be opened, *I* want to be the one to open it.
That's just about where the miracles stop reliably. You may or may not find some special cases in which those actually make sense (given that we're talking about concentrated solar and 2-axis drives are mandatory, those cases become even more special), but at large scale it's just not worth it - even without considering the need to store the energy, so you have it when you need it.
That is just a matter of time. That is what the Chinese say but the Germans are most advanced.
Agreed.
Efficiency per unit area does not matter much at all, for almost all uses (residential, light commercial) roof area is not really an issue.
Cost / watt is what matters, and durability long term matters.
If you make the 33% efficient panel cost 50% more per watt the economics of using the more efficient panels goes out the window, and the economics are barely there....If I self build a system (my own labor) and I am in an area with $0.1/kwh (and rising) with the 30% government subsidy it still takes around 10 years to pay out ignoring the cost value of money.
Every 6 months on Slashdot we read about higher efficiency solar panels. Virtually none of them are available on the market, and if they are, they're only available to large-scale commercial installations. Right now, the best you can do retail is about 20%; some panels are barely 10%.
A condition for any prize should be "available in half-dozen quantities to individual purchasers."
The best return on investment remains solar hot water - we're talking an order of magnitude in efficiency per area between common solar panels and evacuated-tube hot water collectors. We waste enormous amounts of energy heating hot water and heating homes...
We'd also save billions of dollars if we stopped selling clothes dryers that are hideously inefficiency; elsewhere in the world condensing dryers are the norm and in some cases dry clothes faster.
Please help metamoderate.
This is pretty good. We have a humongous energy radiating source that sends us rays everyday but we've yet to use it properly. Hopefully, more strides in this area can be made...
Unfortunately, this is a concentrated light solution. This means that the figures quoted for efficiency are in the presence of direct sunlight. However, this is only a proportion of energy generated from PV modules, hence the "efficacy" and therefore, total energy production, of concentrated solar solutions is less good than unconcentrated modules.
The reason comes from diffuse sunlight - light that has been diffused by the atmosphere or by clouds. This typically accounts for 10% of module illumination in direct sunlight, and much higher in the presence of atmospheric haze/cloud; even in lightly overcast conditions, you can expect unconcentrated PV to yield approx 10-15% of direct illumination yield because of the diffuse illuminance.
Diffuse light cannot be concentrated by optics, thus concentrated solar PV modules cannot utilise the diffuse light (more precisely, they can utilise it, but not concentrate it - thus if the system uses a 10:1 concentration, then the energy yield from diffuse illumination falls from 10-15% to 1-1.5%).
A boost from 30 to 33% efficiency by switching to concentrating modules could be completely wiped out by the loss of diffuse yield, even in direct sunlight. In non-direct sunlight, hazy or cloudy conditions, the yield can be reduced much more severely; resulting in a net reduction in productivity, despite the higher nameplate efficiency.
This technology is most suited to areas with the most intense direct illumination; e.g. dry areas, at low latitudes (where the role of diffuse light is diminished in proportion).
Nuclear power plant are also difficult to build from stuff that you can find on the market, and they are only available to large-scale commercial installations.
I think the prevalence of gas-powered dryers is a reason the U.S. still uses more inefficient dryers, because the fuel (natural gas) is fairly cheap, and much cheaper than with the electric-powered dryers that are prevalent in parts of Europe. So there's less economic incentive to improve efficiency.
10 PRINT CHR$(205.5+RND(1)); : GOTO 10
If you take solar energy from space that was not falling on Earth, and sending that energy to Earth, then you're still contributing to global warming.
wake me up when they beat 100%
It was new, purpose built, so had some obvious advantages, but what I took away from it was:
Obviously location and climate matter, but at the end of the day it was a viable and practical option, and one that made economic sense as well.
Sooner or later some bright government will figure out that by heavily subsidizing the installation of solar in homes they'll a) Develop a very viable industry b) drop solar costs due to volume c) get relected because everyone's electric bills will drop d) boost the economy because the money that was going to the electric company can be spent elsewhere. Now, I'm still a fan of hydroelectricity - if you need to generate electrical without generating CO2 and pollution, and without the no-nukes crowd at your door, there isn't a better way to go.
Three Squirrels
It already is. Once you set up the panels, the price per watt is 0 (which is less than non-renewable sources, and as low as it will ever get)
We'd also save billions of dollars if we stopped selling clothes dryers that are hideously inefficiency; elsewhere in the world condensing dryers are the norm and in some cases dry clothes faster.
"...All else being equal (i.e. not including household heating/cooling issues), condenser dryers are slightly less efficient than their vented counterparts, typically on the order of ~15%. The real design intent of condenser dryers isn't improved efficiency, but the simple fact that they don't require a vent duct, permitting easy installation most anywhere (ideal for apartment dwellers, etc)..."
"...There IS in fact a true heat pump dryer - the AEG Lavatherm WP - which is very energy-efficient, but it's not available in North America, and is extremely expensive (probably so much so that it wouldn't pay for itself in energy terms)...."
Source: http://ths.gardenweb.com/faq/lists/laundry/2004120958010854.html
At this stage cost a more important factor than efficiency. We have vast amounts of unused space that could be covered in solar PV panels, but the fact that it takes years to recover the investment of thousands of Euros/Dollars is holding back adoption.
const int one = 65536; (Silvermoon, Texture.cs)
SJW, n: "Someone I don't like, and by the way I'm a fuckwit" - AC
Oh, did that fly over your head? Did it make a Woooosh when it flew over?
Really? You're getting 200% efficiency off your solar water heater?
For almost any new building it is worth covering the roof with solar PV. It might take 10-15 years to recover the cost, but then it is all profit. The savings are even bigger if you combine PV with solar heating. Installation is cheaper at the time of construction and the cost is a small fraction of the roof budget, let alone the cost of the whole building. If you are taking a mortgage then the cash from feed-in tariffs will more than cover the extra cost of the panels on your monthly payment.
Note: Based in building in the UK, further south it makes even more sense.
const int one = 65536; (Silvermoon, Texture.cs)
SJW, n: "Someone I don't like, and by the way I'm a fuckwit" - AC
Why troll about how the rest of the world is better than the US?
I want to delete my account but Slashdot doesn't allow it.
It looks like I can buy solar modules for a minimum cost of $1/Watt.
Assume an energy cost of $0.1/kWh. Assume an average of 12 hours of sunlight per day and a 50% of maximum average intensity.
$0.1/kWh * 1 year / 12 * 50% * 12 hours/24 hours = $0.01826
The monthly value that a solar cell generates is $0.01826/watt month.
Assume a yearly interest rate of 5% (monthly is 0.4074%)
Since the cost of a solar cell is $1/watt, work out the number of months that a 1W solar cell must run for to generate $1.
PV = A/i (1-1/(1+i)^n)
PV = $1, A = $0.01826, i = 0.004074
n = 62 months = 5.17 years
The warranty on the reference cell is 10 years product workmanship, 25 years linear power.
So the value of the cell over its 25-year life span is $3.15/watt, with a cost of $1/watt.
This all neglects installation and grid-tie costs, but 50% average illumination per daylight-hour is conservative in most areas. Solar cells ARE worthwhile TODAY and WITHOUT government subsidies.
Efficiencies in solar cells are irrelevant. The only thing that matters is the $/Watt.
Reference Solar Cell: http://www.affordable-solar.com/store/solar-panels/CSI-CS6P-245P-245W-Solar-Panel-STD-Frame
What is the use in increasing the percentage of a free energy source converted into electricity?
The factor that matters is the panel production price, in watts per dollar. Along with life duration, total pollution during production, etc. But not watts per candela!
Call me when you can fly a 747 or F-15 on electricity.
What is the "life expectancy" of PVs?
There are 2 kinds of people in this world: Those who write in decimal and those who don't
So if we get past 100%would that create a black hole that sucks in energy for everything around it and ultimately would destroy the earth? Just askin'
There was an unknown error in the submission.
typically 30 years with 80-90% of the original efficiency, less if you live in a hurricane / tornado prone region.
More efficient cells are usually used with concentrators, aren't they? I'd think that changes the game a little bit.
Ezekiel 23:20
That would be trivial, if you could find a way to plug it in.
25 years for reasonable ones. Of course by the time they wear out you will be able to replace them cheaply as you already have the mounting hardware and electrical infrastructure.
const int one = 65536; (Silvermoon, Texture.cs)
SJW, n: "Someone I don't like, and by the way I'm a fuckwit" - AC
A condensing dryer isn't a slam dunk in efficiency gains. What you need is to have the closed loop, with an available vent, hooked into the rest of the house's HVAC system. Then, the dryer can elect to vent or not, based on what temperature you want inside, and what temperature is available outside.
Providing you use them for over a decade, it is already cheaper in the long term. They just cost a lot more initially.
I have a whole array of panels. Not only have I not paid a penny for electricity for over 8 years, but I actually sell surplus power back to the grid - amounting to an income of almost £1000 a year. Which actually means the panels will soon have paid for themselves.
OMFG if you weren't replying to me I'd mod you to high heavens. I even have mod points now...disappointing :(
Concentrated cells tend to wear out much more quickly. They get much hotter, and junction heat is what determines the life of any semiconductor.
http://ths.gardenweb.com/faq/lists/laundry/2004120958010854.html
"All else being equal (i.e. not including household heating/cooling issues), condenser dryers are slightly less efficient than their vented counterparts, typically on the order of ~15%. The real design intent of condenser dryers isn't improved efficiency, but the simple fact that they don't require a vent duct, permitting easy installation most anywhere (ideal for apartment dwellers, etc). "
A gas dryer is going to be much more energy efficient than an electric dryer considering that ALL the heat generated from the flame enters the tumbler. Typical power plants can only transmit up to ~40%% of the heat from their power source to the dryer heater coils.
Min energy eff electric: 3.01 lb/kWh
Min energy eff gas: 2.67 lb/kWh
Electric is 12% more efficient at point of use
Total heat efficiency including power generation:
3.01 * 40% = 1.2
2.67 * 100% = 2.67
most efficient setup would be an external venting gas dryer in a unheated space like a basement or garage since you would not be adding load to an HVAC system.
Solar cells and silicone sealant share the same property: we have no idea how long they're good for.
Originally silicone cement had a 3 year warranty. Then none failed and they made it 10. Now it's 30. I have aquariums that are forty years old that have just a microscopically thin lawyer of silicone holding hundreds of gallons of water in a glass box. We have no idea how long the stuff will last, it could be a hundred years or more for all we know.
Solar panels started being deployed in the 70s. They all still work and were expected to give 10 years service. To be sure, efficiency diminishes over time, but that's a secondary consideration to the fact newer panels are much more efficient. Somebody can use those old panels though.
Need Mercedes parts ?
Well, if it's a heat exchange system, you can get higher efficiencies than 100%, because the energy is expended in transferring a greater amount of heat from a heat source (usually the outdoors) to the water.
Also shorter lifespan for the roof of a professional sports venue.
Help stamp out iliturcy.
I agree with you, and would love to use as much renewable energy as possible and save money in the long run, but I think the problem is that most people in the U.S. do not actually live in their homes for a long enough time. I've been here 13 years, but I've been looking to move for the past five or so (but haven't been able to for various economic reasons). Before the housing market crash, I read the average duration in any one home had shrunk to only about 7 years, so it's not just me. I'd actually love to buy a brand new home that I've had input on - solar, on-demand hot water (if not solar heated), maybe even geo-thermal... but that only works if I plan to stay there for a LONG time.
Stupid sexy Flanders.
Don't forget every time we see a new solar panel discovery, the big question never comes up: How many watts does it take to fab the silicon, add the secret herbs and spices, stuff the silicon in a panel with a cover, and ship it out.
All this takes energy, and so far, there has been NO solar panel ever made, that has gotten back the energy it takes to produce it. Solar panels need to be compared to alkaline batteries where they do have energy, but nobody ever thinks they are an energy *collection* device.
Lets be real, solar does not give us energy. That is what dino cake (coal) and dino juice do. All it does it allow stuff like an electric fence zapper that is not on the grid to have electric power, or play the game of creative green accounting which is so popular with our politicos.
YES! If you can, put up a clothes line. It can make a huge dent in the amount of energy you use.
I know not everyone lives someplace were they can line dry clothes, but even hanging out clothes for a bit and finishing them in a dryer can make a difference.
It actually continues to work for you even after you leave. Adding renewable energy generation and high efficiency heating/cooling (geothermal) to your home increases your property value, which gives you the option to do the same again, or buy one with the work already done.
PLUS: you get double points on your geek card!
Sent from my ASR33 using ASCII
We'd also save billions of dollars if we stopped selling clothes dryers that are hideously inefficiency; elsewhere in the world condensing dryers are the norm and in some cases dry clothes faster.
You're wrong. If everyone drove half, used 2x efficient appliances, etc it would work until the population doubles. Then we're right back where we started. If they start creating energy from "nothing" like sunlight, we can use all the energy we want at any rate at any population level.
(indirectly)
http://www.bbc.co.uk/news/business-20003704
That would be trivial, if you could find a way to plug it in.
Also trivial. Just need a really long extension cord.
Not really... the point he was making is that the energy is there to be collected, and once the system is installed the maintenance costs are negligible. Many solar installations don't need any maintenance at all beyond keeping the panels clean.
The initial installation costs a lot of money (which is becoming less and less every year), but you can sell any extra electricity you produce back into the grid, and the reduction in your monthly electric bill should be significant enough to make it worth considering. In most cases, the reduction in your bill will be more than enough to cover the cost of the loan to have the panels installed in the first place, and in some cases you'll find yourself in a position where the power company is paying you each month.
I'm suprised no one has mentioned patent trolls.
I know for a fact Siemens have trolled the hydrogen fuel cell market buying up and researching succesful tech that would put big oil out of commision. But I heard 2cnd hand from a researcher who presented a solution to a board at Siemens they (the board) refused to sell the product because it would hurt "their portfolio's". Their stocks in oil are appearently more important to them then their companies success and dominance or the well being of the earth and you at home.
There's no upper bound. Many have warranties above 20 years, and those that made it to 20 years, on older, less stable configurations, are still going strong. Sure, you lose about 1% efficiency per year, but that that's more a financial issue than anything else.
Learn to love Alaska
Average capacity factor for solar in the U.S. is about 0.145. That is, a 100 Watt nominal panel will on average generate 14.5 Watts throughout the year after factoring in everything - night, weather, angle of the sun, etc. In the desert Southwest it's about 0.18 (0.195 in extreme desert regions), but for the country overall it's about 0.145. The NREL assumes a capacity factor of 0.17 for PV installations in the U.S., which are predominantly in the desert Southwest.
Your quick "12 hours a day, 50% max average" assumes a capacity factor of 0.25. Almost twice the actual value.
Correct for this in the rest of your math and you get n = 120, or 10 years payback. That sounds about right as the test cases I've calculated usually wind up between 7 and 15 years.
No, getting 10% efficiency from a solar system is still better than a 100% efficient electric one run off a coal-fired plant. The "efficiency" is in economic terms, not thermodynamic terms. I put in "no" heat and get back more than I put in. Or the natural gas ones where it's 75-85% efficient and still cheaper than the electric version at 100% efficiency because of the cost of energy, so people call the natural gas one "more efficient".
Learn to love Alaska
That's a bad idea. Maybe with a heat exchanger, but most homes are already too damp, so adding moisture is worse than any thermal gains you get.
Learn to love Alaska
So the value of the cell over its 25-year life span is $3.15/watt, with a cost of $1/watt... Solar cells ARE worthwhile TODAY and WITHOUT government subsidies. Efficiencies in solar cells are irrelevant. The only thing that matters is the $/Watt.
That's interesting. Please also compare:
* If you invested $1 in the stock market, and see how much it grew in 25 years, minus the cost of the energy you'd need to buy.
(I suspect that 315% over 25-years is much smaller return than what you'd get from stock market growth).
If grid power wasn't subsidized, then the price of the panel includes all the energy required to make it, and it is a net win today. So they must make more than they take to make them, or the government is heavily subsidizing electrical generation.
Learn to love Alaska
This shouldn't really matter, as any unrealized value of the PV panels would presumably be recouped by increased resale price of the house.
The hang-up is up-front costs. The average home in the U.S. uses 11,500 kWh in a year. So at a constant power draw that's 1311 Watts. Factor in PV solar's average capacity factor o 0.145 and that means you need 9050 Watts of nameplate capacity installed to (on average) zero out your electricity bill (in reality it's a bit less because peak electric prices are during the middle of the day when nobody's home but the panels are generating the most).
If panels are $1/Watt, that's a $9k up-front cost the homeowner has to pay, plus several thousand more for installation, mounting, inverters and regulation, etc. That's simply out of the reach of most homeowners unless they can somehow roll it in with their mortgage.
For almost any new building it is worth covering the roof with solar PV
For a lot of places it would be worth covering the roof with dummy PV panels. The shading would reduce your need to run the air conditioner. I prefer deciduous trees for that though. The trouble with the trees is that you have to be careful about roots, foundations, water and sewer lines. You also have to maintain them and they don't provide much power (very few BTUs from firewood over the life of a tree compared to panels).
You are at least 5 years out of date with that information. Traditional condensing dryers are obsolete, modern ones use heat pumps and are vastly more efficient than vented dryers.
Finally! A year of moderation! Ready for 2019?
That's simply not true.
I was looking to reduce my electricity usage, so I bought myself a decent clothes rack, and stopped using the dryer. But then I actually purchased a meter and measured the power usage of my dryer and calculated that it would take me five years to pay back the $50 I spent on the clothes rack. The amount of power the dryer used was utterly insignificant in the scheme of things. However, since then my dryer broke down, and I've never bothered to buy a new one, because the clothes rack does a good enough job. (It helps living somewhere with low humidity, and lots of sun).
Maybe if you have a large family, and are running the dryer nearly every day then hanging the clothes out would make a difference, but otherwise you're probably better off looking for other places to save energy first.
The population is unlikely to double.
Finally! A year of moderation! Ready for 2019?
Is it clearly cheaper for you in terms of net present value over the long term, or just in absolute outlay of cash?
I don't mean to imply that it's not, I'm just genuinely curious about your situation and if it still holds.
Wait the condensing ones are more efficient?
I know they are vastly more expensive to purchase upfront but I was under the impression they are also terribly inefficient, the advantage is they don't mould up the bathroom with a lot of water condensation?
As low as a couple minutes in tornado alley.
(I suspect that 315% over 25-years is much smaller return than what you'd get from stock market growth).
Stock market growth roughly matches GDP growth in the country. If you think the country's output is going to grow more than 315% in the next 25 years, then that's a good bet.
Looking at the future from the way things stand right now, we're in for a rocky few years at least. It is not at all a sure bet that we will manage to get a 315% return over that period, and the stock market could drop more as baby boomers remove their money from the market. Plan accordingly.
"First they came for the slanderers and i said nothing."
> Call me when you can fly a 747 or F-15 on electricity.
Your wish has been granted:
http://www.aviatorwebsite.com/store/product-details.php?product=1442
If the condensing dryer is a closed loop, then surely the "exhaust" runs over the cooling coils where the moisture is extracted (by condensing...) and the heated again before passing through the basket. There wouldn't be any point in releasing the exhaust, as you'd just have that much further to heat the new incoming air.
Why else would it even be called a condensing drier?
Can you be Even More Awesome?!
$50 on a clothes rack? Was it Martha Stewart Signature Series product?
It doesn't hurt to be nice.
Yes, you are correct. The hot water and heating is one major saver for a buildings in a colder climate. Germany has tons of products for this already. New building are often build with solar heat exchangers, becasue they are easier to be sold to customers who want to invest for long term.
~ Best man at your service.
20+ years I've been reading this crap.
If I had a dollar for every time I've read about fucking breakthroughs in fucking solar and weeping scientists congratulating one another over an efficiency increase of 0.5% but which will NEVER BE MANUFACTURED, I could be living off the grid by now.
Three components to solar
1. Panels. MAKE THE FUCKING THINGS CHEAP AND PLENTIFUL, NOBODY GIVES A FUCK ABOUT MAKING THEM 1% MORE EFFICIENT AND 100% MORE EXPENSIVE except the governments who are paying billions in research grants. I have enough space on my roof to power a fucking meth lab from solar, even using the least efficient Chinese panels I can find. I'd wager that a very high percentage of people with their own roof, does.
2. Charger/Inverter. Cheap as shit.
3. Batteries. WHERE THE FUCK are our high power batteries? Where's Ceramatec's $4,000, 50kWh, 10yr lifespan fridge-sized sodium-sulfur cell? Solar is 100% useless without somewhere to store it. It's cheap STORAGE we need - THAT'S what's holding back solar - BATTERIES - not the fucking efficiency of solar cells.
You are at least 5 years out of date with that information. Traditional condensing dryers are obsolete, modern ones use heat pumps and are vastly more efficient than vented dryers.
Our heat pump dryer is awesome. Expensive, but awesome. Prior to that we were often hanging clothes inside to dry (hanging them outside brings in the pollen which is very bad at this time of year (Spring in AU)). With our one we have to empty out the water tub manually, and it's amazing to see how much water used to be evaporating into the house!!
Installation costs are not exactly insignificant. I ran the numbers about two years ago for my house, and the panels didn't make economic sense, even over 30 year time frames and taking into account the tax benefits. While panels are significantly cheaper today, the total system costs have still not gotten to the point were it makes economic sense for me. Labor costs have risen in my area, offsetting some of the price decrease in the panels plus I have really cheap electricity, roughly half the national average. It can make economic sense in areas where electricity is more expensive.
We'd also save billions of dollars if we stopped selling clothes dryers that are hideously inefficiency; elsewhere in the world condensing dryers are the norm and in some cases dry clothes faster.
"...All else being equal (i.e. not including household heating/cooling issues), condenser dryers are slightly less efficient than their vented counterparts, typically on the order of ~15%. The real design intent of condenser dryers isn't improved efficiency, but the simple fact that they don't require a vent duct, permitting easy installation most anywhere (ideal for apartment dwellers, etc)..."
"...There IS in fact a true heat pump dryer - the AEG Lavatherm WP - which is very energy-efficient, but it's not available in North America, and is extremely expensive (probably so much so that it wouldn't pay for itself in energy terms)...."
Source: http://ths.gardenweb.com/faq/lists/laundry/2004120958010854.html
Bosch and Meile both make heat pump dryers, probably more brands these days - it's a few years since we last looked. We have a Bosch. It is expensive, and probably won't ever pay for itself in terms of energy savings, even in our household of six people, but we can't easily vent a dryer to outside here so the heat pump dryer made a lot more sense. It's also fast.
When we were looking, the condenser dryers sounded awful. Inefficient and really slow to dry.
You might be able to say that for price per Joule maybe since Joules are units you can divorce conceptually from the fixed startup costs. You can't really divorce Wattage from the startup costs that way. You buy a certain amount of equipment and it provides a certain wattage (depending on average conditions at the location, etc.).
I don't agree. There are much better investments available than "get your money back in 10-15 years ignoring inflation". Invest that money now, and while it earns for you, the price of those panels will be going down and their efficacy will be going up.
Actually, while solar cells have an extremely long lifetime, solar modules are much more short lived. Many of the panels deployed in the 70s failed after only a few years. The main reason is that the electrical connections must survive thermal cycling. Thermal cycling also can cause delamination of materials (for example the front glass and the Si wafers). Once the module is damaged, corrosion can continue to further degrade the panel. Modern panels have more engineering to prevent module level failure, but it simply isn't practical to do accelerated testing of panels for more than ~25 yrs equivalent.
Given that most of the failure is due to thermal cycling and CPV systems get significantly hotter each day, I would expect that designing CPV systems to last for 30+ years would be a difficult problem. At 500 suns and 40% cell efficiency, that's 30W/cm^2 that must be continuously passively dissipated.
To put this in perspective, photosynthesis (which powers virtually all life on earth) is less than 1% efficient.
Condensor dryers are old news; heat pump dryers are where it's at :)
you can't build nuclear bombs from solar panel materials.
because western europe has a culture rife with insecurity and individual powerlessness. This breeds passive aggressive behavior such as this. Unfortunately this crap is breeding here in america too.
"The only thing that matters is the $/Watt." Not exactly the entire story. The thing that matters to me is the $/Watt for PV compared to $/Watt for other energy sources. And the "Earth temperature rise/Watt" for each energy source.
How well do they work after being exposed to the elements for 10 years?
What are the long-term maintenance costs?
Why guesstimate solar production? Use NREL's PVWatts application: http://gisatnrel.nrel.gov/PVWatts_Viewer/index.html
Click on your city. Click 'send to pvwatts'. Enter the solar system size in kW (default is 4.0). Click calculate.
Depends a great deal of where you live, of course, because energy prices and solar radiation vary quite a bit across the USA.
What good is a 20 year warranty when the company won't last 5 years?
Not really. Because of the way real estate is sold, anything that isn't on the standard check list is pretty much a loss on the value of a home.
That can't be true. Lawyers are made of 'poxy.
Contribute to civilization: ari.aynrand.org/donate
Around these parts, not only would it not put a dent in the energy used, but it would massively increase the water usage, since you would have to rewash every load of clothes a dozen times before you actually got a set dried without bird crap on it. Of course, if you live in an area without birds, or your personal belief systems encourage wearing clothes with bird crap on them, this would not be an issue.
The hang-up is up-front costs. The average home in the U.S. uses 11,500 kWh in a year. So at a constant power draw that's 1311 Watts. Factor in PV solar's average capacity factor o 0.145 and that means you need 9050 Watts of nameplate capacity installed to (on average) zero out your electricity bill (in reality it's a bit less because peak electric prices are during the middle of the day when nobody's home but the panels are generating the most).
In my region of California, residential electricity costs are tiered, with Tier 3 (starting at 418kWh/month, or about half of the average you stated above) breaking 24 cents per kWh, and continuing to Tier 5, still less than the monthly average usage you quoted, running over 32 cents per kWh.
Any renewable energy system that can take kWh off the top of that stack will pay for itself in very short order around here.
Okay so current panel I bought for $1080 with mounting appears to be producing about $3 of electricity per month. I'll get a $300 credit on my taxes this year.
It's simple and I just plugged it into an out let and my "kilometer" shows it's producing power.
But $700/$36 = 19 years.
It will probably break before it reaches break even.
However--- if electrical power doubles like it has since the 1980's (5 c/pkwh vs 10cpkwh)
Then it would pay off it about 12 to 15 years.
Solar isn't "there" yet.
And the panel went up from $1080 to $1280 after I purchased it.
She was like chocolate when she drank... semi-sweet at first and then increasingly bitter.
I own a solar panel and the kilometer doesn't show your figures.
And solar panels have gone up since I purchased mine.
Here are the challenges
1) It's really hard to get a completely shadefree spot for 12 hours.
2) Unless you have some kind of tracking mounting, you have a steep dropoff (I get under 40 watts til 9am 68 watts before 11am and after 4pm and under 40 watts after 6:30pm til 8:30pm- so about 5 hours of 180watts.) That's during the summer. The total is about 1kwh per day.
4) You can buy power for 10 cents per kilowatt hour. One $1000 panel (with $300 credit from federal government) plus $80 mounting generates about 30kwh per month ($3.00 savings per month).
All this is real world values.
Power has only doubled in price since 1980ish. So we are talking 2040 before a full double again.
She was like chocolate when she drank... semi-sweet at first and then increasingly bitter.
Wrong - Too Many assumptions. As for joe homeowner borrowing money at 5% - yeah, right.
Effective daylight hours over winter and summer are different, and few installs are 100% perfect for positioning.
Then there is a low voltage dropout, say when it drop under 50 volts, meaning you loose 10's minutes either side of sunup/down.
There are calculators that calculate the real numbers but not out there?
Meanwhile in Australia the amount for feed in varies, while other charges go up. Now 22cents a KW plus carbon tax, it is just about economical for everyone to disconnect and run a diesel generator. The electricity companies also UPPED fixed connection costs, meaning sometimes you loose money generating solar. The implementation was deliberately sabotaged, so asset sales got top dollar. (and state tax).
I know a guy who got his energy for that price in Texas, but in California electricity costs more than that. Probably in Arizona too.
More expensive electricity means your panels pay back more quickly.
Also, over the period you own your panels, the price of electricity will almost certainly go up.
http://lkml.org/lkml/2005/8/20/95
Maybe not for you.
Most states have more expensive electricity than $0.10/kWh.
Also, most people who have solar go on a time-of-use rate where they can sell back power in the day when electricity is worth more and then buy it back at night when it is cheaper.
My array will pay back in about 9 years. Less with the tax rebate. And it cost less than $1280/panel installed even before rebates.
When did you measure the panel? Even at $0.10/kWh it should make a little bit more power than that during the summer. My panels are making about 800Wh a day a piece right now and the days are very short at the moment. They make nearly double this much during the summer months.
http://lkml.org/lkml/2005/8/20/95
Christ, I love it when people with zero actual experience with things dump on those things just because it makes them feel good.
Materials price:
Been dropping FAST for about three years.
Install cost:
What? You mean the cost of paying an installer? Or the cost of DIY? Neither is high.
Batteries suck:
"Batteries never die, they're always murdered". Mine are 22 years old and test the same as when new. Why? Because I don't try to fuck them like a big pile of lead-acid bitches.
Motivation:
WTF? Either you want to, or you have to, or you don't. I had to. And I wanted to. You? Guess not.
Home built panels:
Almost "why bother?", considering how inexpensive the commercial models have become.
Hail:
Are you fucking kidding me? Seriously? You do know regular commercial brands are warranted up to golf-ball sized hail? In one insurance claim, an entire RV was written-off due to tornado hail damage. The only thing salvageable? The PV array. It was undamaged.
Listen, there's a whole World of shit I know nothing about. So, what I don't so is talk about that shit as if I'm a fucking expert on the subject. Because I'll just look like a cunt if I do. Give it a try.
And in a storm, they fall on you and come thru the roof of your bedroom and kill you...
Almost "why bother?", considering how inexpensive the commercial models have become.
Even with gov't subsidies, you are looking at a 15 year ROI - you think that is why bother?
Solar panels started being deployed in the 70s. They all still work and were expected to give 10 years service.
All of them? Every single one installed in the 70s?
What electrical entity will produce the thrust of a jet engine and at the same velocity?
$3/month at $0.10 per kWh means your $1,000 setup is giving you 1kW/day??
I'd say your first mistake was letting a solar contractor know that you don't know the first thing about solar. They saw you coming from a mile away.
Stop feeding the birds laxatives.
I exclusively dry cloths on the cloths line outside. There is a lemon tree, a vine with hundreds of flowers, a gum tree and a big ass fig tree around it. We get flocks of lorikeets, galahs, cockatoos, pigeons, and various other birds all year round and I have to rewash 2-3 pieces of clothing at most per year due to bird poo.
yep..and a $20k pool adds about $5K to the resale value of the house....
But the chance to lose money on the stock marked is much higher.
"It's such a fine line between stupid and clever" -- David St. Hubbins, Spinal Tap
first, google gdp vs stock market.
Then google stock market returns.
Then google doubling time of money.
Then google stock market returns in the last 12 months.
While the economy may not be super strong, the stock market has been doing quote well recently. 14% for the S&P 500 the past 12 months. At 10%/yr you will make over 400% on your investment in 25 years.
You didn't include installation and ancillary mounting costs. These are fixed and are proportional to the area of the deployment. That 1$/watt panel ends up being $2/watt deployed on some ones roof.
Also the 12 hours/day at 50% intensity amounts to 25% insolation. That is close to the best in the world. Where I live in Melbourne annual insolation is around 12% - half of your estimate.
So currently panels cost twice as much and provide half the output you estimated.
You only win on decreased deployment costs if you can get the efficiency up.
Strangely enough, I noticed this the other day. The solar panel we buy are increasing in wattage but also in size, for the same price......
OK, some more math
http://www.topten.info/uploads/File/040_Rita_Werle_final_driers.pdf
efficiency of heat pump condensing dryer
best in market (according to report)
0.23 kWh/kg = 8.15lb/kWh
worst in market
0.4 kWh/kg = 5.5lb/kWh
Euro A grade requirement
0.48 kWh/kg = 4.58lb/kWh
efficiency of power generation facilities
http://www.eia.gov/electricity/annual/pdf/table5.3.pdf
natural gas = 3412/8185=41.7%
coal = 3412/10415=32.8% (roughly same as nuke plant)
distribution losses
http://data.worldbank.org/indicator/EG.ELC.LOSS.ZS
US=6%
heat energy delivered to home
natural gas = 41.7%*94%= 39.2%
coal = 32.8%*94%=30.8%
heat pump condensing dryer total efficiency based on power plant fuel source
gas @ 8.15 = 3.19lb/kWh
gas @ 5.5 = 2.16lb/kWh
gas @ 4.58 = 1.8lb/kWh
coal @ 8.15 = 2.51lb/kWh
coal @ 5.5 = 1.69lb/kWh
coal @ 4.58 = 1.41lb/kWh
heat pump condensing dryer ranges in efficiency from 1.44-3.19lb/kWh
http://aceee.org/files/proceedings/2010/data/papers/2206.pdf
gas venting dryer ranges in efficiency from 2.67-3.02lb/kWh
heat pump condensing dryers are marginally more efficient at the very high end with larger min/max range.
from same aceee.org report...
"Analysis by the UK Market Transformation Programme has reached a similar
conclusion: “In the UK, gas-heated tumble driers offer a simple and relatively cheap way to dry
laundry with a carbon efficiency that matches the more expensive and highly efficient
electrically powered heat pump driers” [Market Transformation Programme, 2007].
If the conventional natural gas dryer was further improved with modulating burner
technology, it is expected it would be superior to a heat pump dryer on a CO2, source energy
BTUs, and energy cost basis, while also offering faster drying times and a lower purchase price."
A turbine driven by an electric motor.
So because over at your end, the individual feels all secure and wields a lot of power, there is *less* agressive behaviour.
Uh, sure. Must be this sarcasm thing everyone is talking about...
less aggressive... gotta stop laughing....
He means latitude, as in distance from the equator. It has a substantial effect on PV output. That you missed it makes me question the reliability of the rest of your post, much like someone discussing the finer points of sports cars not knowing what a speedometer is.
PV panels are going to be more efficient every year. More efficient way to utilize solar energy is to build solar heater such as in this tutorial::http://solar.freeonplate.com/diy-how-to/DIY-solar-panels.htm . You can even use scrap material and used pop cans and participate in recycling as well: http://solar.freeonplate.com/diy-how-to/DIY-solar-panels.htm
The goal is now one third of an oracle.
If it takes 10-15 years to recover the cost, then it will never profit. There is this thing called opportunity cost that tells you that. Money earns more sitting in an investment than a doubling every 10-15 years. That's why solar isn't adopted.
Roof budgets are also not fixed nor are they particularly relevant. What matters are the costs of doing ANY solar plan compared the rate of return. Roofs cost more with solar for reasons other than the panels themselves. That's true for passive solar too.
But yes, if the government pays for it in tax incentives then, by all means, grab the cash from your fellow taxpayers. It still doesn't make economic sense.
I guess after 10-15 years its not "all profit" then, huh?
You've really thought this through.
But keeping the panels clean, and replacing them, IS a maintenance cost, as are the replacement of other electrical components and service due to occasional damage. Maintenance costs AREN'T zero and the product has a finite lifetime. There is no such thing as a price per watt of 0 unless you are willing to ignore some of your costs. There are fixed costs and recurring costs and while the recurring cost per watt is 0, the fixed costs are still prohibitive.
Selling excess production back to grid isn't making anyone anything.
Finally:
"In most cases, the reduction in your bill will be more than enough to cover the cost of the loan to have the panels installed in the first place, and in some cases you'll find yourself in a position where the power company is paying you each month."
That proves either your ignorance or your dishonesty, or both.
Oh, yes, the stock market. You could "invest" the money at a craps table, too.
This is a prime example why "capacity" factors and nameplate does not work out.
First off all you only need to have enough solar power to supply energy during your own peak demand. That is far below of your 9050 W.
Secondly, if you think you need 9050W generation, you miss the fact that it won't generate anything at night.
So balancing (artificial) capacity factors with demand makes no sense at all.
Btw: a 1W cell delievers 1W when the conditions are right. There is no 0.145 capacity factor. To plan for a solar plant you need to figure when most power is generated, and what to do with it: air conditioning, selling to the grid, storing ... etc.
Cost free eBook I read (by iBook/Kobo/Amazon/ObookO/Gutenberg etc.): "The Green Odyssey" by Philip Jose Farmer.
Wooosh. His point wasn't about the security, it was about the market/business.
"Batteries never die, they're always murdered".
Ah ha ha ha, love that quote.
At work (railway) we had a location drawing ~200mA that we had to move about 500 meters. Somewhere along the lines, nobody bothered to order a new power drop and the old one had to be removed to make room for something else. We were promised a power connection within a month, so we stuck up 80watts of solar and 100Ah of battery. Problem... the sun window is small (mountains, you win again!) and there's a lot of cloud cover at this location. Solution, 1000watt Honda suitcase generator (sweet little unit) filled up with gas on Monday and Thursday. The generator automatically shuts off once the fuel runs out (excellent feature really) some time when the batteries have (hopefully) enough juice to last till the next time the generator is started.
2 months later with no power utility, we suspected it wasn't going to go as planned, and we didn't want to ruin our marvelous and expensive wet Ni-Cd batteries, so we swapped them out for 3 marine grade deep cycle lead acid batteries from the hardware store with a total of about 270Ah. That ought to do it.
Yeah... not!
Turns out, twice a week isn't enough to keep them full, the charger we had was only 10amp output with a horrible efficiency while power lifting (efficient and reliable at float, and designed to be powered by the grid), and the generator wouldn't run long enough to fill them up. I also suspect the equipment is drawing more current than we were told and nobody bothered measuring it.
Your comment: "Batteries never die, they're always murdered" cracks me up. Basically twice every week we would run these batteries dry. I'm not talking down to 10 or 11Vdc, I'm talking 4Vdc. This piece of equipment was deemed to be unworthy of overtime, so if it failed Sunday some time, it would sit with a load on the batteries until Monday around 10:00 am. Apparently you're not supposed to do this?
7 months in and this location is starting to fail every day and the generator needs to be re-filled almost constantly. We're also being promised a utility connection within a month....
Boss comes in and gives us 300Ah of Ni-CD and 40amps of efficient chargers. He also tells us to take those consumer junk batteries to the trash (recycle), and that the power utility is for SURE getting us power before December (the pole and transformer are up now, so it's looking promising!)
Incidentally... I found a warranty card (12 month replacement warranty) for one of the batteries. Co-worker figures no way the store will honour a warranty for us, but seeing as how the documentation nowhere mentions the name of the railway, I figure it's worth a shot. Wouldn't you know... the minimum wage clerk thinks it is hilarious how fast their diagnostic equipment failed the battery (I tested 7amp leakage current on my bench) and hands me a brand new 90Ah marine battery that is safely sitting on the shelf in my shed connected to a float charger waiting to come camping with me next summer. My co-worker and I now have a special drawer for battery warranty cards.
Except the ones Reagan removed from the White House. Although I've heard those are still working someplace else.
Stock markets are actually not correlated to GDP growth at all. A few example studies:
http://www.virtus.com/vsitemanager/upload/docs/6141_gdpwhitepaper.pdf
http://us.bnymellonam.com/core/library/documents/knowledge/AlphaTrends/Stock_Markets_vs_GDP.pdf
The idea is the expected GDP growth is already baked into prices.
PV = $1, A = $0.01826, i = 0.004074
n = 62 months = 5.17 years
The warranty on the reference cell is 10 years product workmanship, 25 years linear power.
So the value of the cell over its 25-year life span is $3.15/watt, with a cost of $1/watt.
This all neglects installation and grid-tie costs, but 50% average illumination per daylight-hour is conservative in most areas. Solar cells ARE worthwhile TODAY and WITHOUT government subsidies.
Efficiencies in solar cells are irrelevant. The only thing that matters is the $/Watt.
Efficiencies in solar cells are irrelevant - as long as they are constant. The 25 year linear power guarantee is that you will be at 80-90% of the rated power after 10 years, and 60-80% after 25 years. I don't think you will reach a value of $3/watt under those conditions; on the other hand investing that initial dollar at 5% will get you to at least $3.30 by year 25. If you're looking at it as a straight investment proposition I think you need to consider the subsidy vs installation/maintenance/degradations costs to see if you might break even vs putting it in a retirement account. If the new chemistries are more stable (doubtful) and cut installation costs (possible, if you only need to install half as many m^2 of panels) they could improve the balance.
Posting anon due to being from work. Individual powerlessness in Europe? That is a laugh.
Take Swedes. A doctor, lawyer, policeman, waitperson, IT person all earn a decent living. So, living there, a person can choose a career, and make a living.
Take someone from China. They can go in the PLA and make a good living in almost any MOS (or the Chinese equal.) Want to be a security guy? You will make a good living there because unlike in the US, Chinese businesses (which are owned by the government) take security seriously. They don't consider it a mere cost center with no ROI.
Here in the US, you have two paths to actually being able to have any success at all, and that is business management or law. Doctors? Your fight for scraps against the H-1Bs. IT, same. Waitpeople are treated like dogshit here in the US. Even the police are treated like crap with rah rah speeches about their "sacrifices". Even in law, people know this, so in larger states, you have to graduate from a top tier school in order to get any work whatsoever.
Freedom? Do people in Europe know how precarious almost all Americans living in cities are? It doesn't take much for a no-knock warrant to be rubber-stamped and someone hauled off to a (private) jail for a long time, with the burden of proof being on the arrestee. Where I live, if you look under 21, a police officer will arrest first for curfew violations, ask for ID later. To boot, arrests are considered convictions, so if someone is arrested and charges dropped, to employers that is the same thing as a conviction.
The US has a huge private prison system and 48 states are required to keep the bed count at 90% or more, or face RIAA-esque penalties as per contracts. Couple that with zero tolerance laws, and it isn't surprising for people to face years in prison for just having a bag of ganja.
So when people talk about how un-free Europeans are, I want to laugh in their face. All it takes is going one mile over the speed limit in the wrong town, and one's whole fortune can be wiped out defending themselves against marijuana mysteriously "appearing" in their car.
Even on the Internet, it can only take a matter of minutes for someone to be arrested for a post on Facebook. Citizens in European countries (except for the UK where RIPA allows judges to hand out life sentences by repeatedly asking for a password and adding 3 years each time) actually can speak their minds without worrying about the consequences.
Oh, the fact that one can get from London to a Normandy beach without having to have a rectal probe, or be strip searched like an inmate is a nice thing too.
GDP growth is tied to the stock market. The reason we are seeing a disconnect is because of shell games and fancy accounting, as well as a shift to "get our sales numbers up NOW" as a mentality.
There isn't anything being made in the US. Why US stocks are going up is because companies are focusing on BRIC countries. A company whose sole or primary business in the US will at best have a flatline stock.
Of course, what comes up must come down... for every dollar made on the stock market, someone is going to have to pay that dollar in the future.
The idea is the expected GDP growth is already baked into prices.
That's a correlation
"First they came for the slanderers and i said nothing."
At 10%/yr you will make over 400% on your investment in 25 years.
If you make your plans based on this happening, you are as dumb as the California legislature.
"First they came for the slanderers and i said nothing."
Oops, sorry! :D
I just misread "latitude" as "altitude".
It was an honest mistake : I was just trying to find bullshit in every single sentence
Yes, on the ground.
The twin engnies of a 787 produce 36MW of power for 16 hour flight. Please let me know of your electrical source for the trip.
One has to account for the added value of having backup power during grid outages, and the increase in home resale value means you don't have to actually remain the owner for the entire period of the ROI to realize a gain. That, and your 15 year figure is ancient.
Someone had to do it.
[SIGH] I've spent the evening checking out the prices quoted for components for re-building the bathroom. I believe it's a concept called "due diligence". You do check these things before agreeing to a contract, don't you? (Well, I do.) And what do I find in the "News for Nerds" corner of the 'Net where I come for entertainment? Someone who doesn't even think of checking things out before doing them.
Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
4) You can buy power for 10 cents per kilowatt hour. One $1000 panel (with $300 credit from federal government) plus $80 mounting generates about 30kwh per month ($3.00 savings per month).
All this is real world values.
Power has only doubled in price since 1980ish. So we are talking 2040 before a full double again.
For what it is worth, those energy prices are really cheap, at least for some parts of the world. Here in the Netherlands we pay (at least) €0.21 per kwh, or roughly US$0.27. In Australia, Synergy (Western Australia) charges AU$0.25, or roughly US$0.26 per kwh.
For those who are getting electricity at US$0.10 per kwh, solar might well be hard to justify, for a lot of the rest of the world the sums are a lot easier.
"Because I don't try to fuck them like a big pile of lead-acid bitches."
I wouldn't think that would do the batteries all that much harm. If you did manage to, say, cause one to leak, I would think it would do you more harm than the battery and you'd probably never try it again.
As far as I know it's trending 7 now, but it depends on which panels you buy. I think for my specific ones it's 10, but that's because we bought high-efficiency ones since roof-real estate was at a premium (and the govt subsidy which drops it to 7 favored going for more capacity).
But if you've space to use, then you can use cheaper ones and the payoff is much quicker.
That's what I'm saying. If you could plug it in, it'd be easy to do. Obviously, you can't. . .
It certainly isn't. http://www.economist.com/blogs/buttonwood/2009/08/the_growth_illusion
I wasn't talking about the PV panels falling on you, I was talking about the trees falling on you. Trees should not be located where they can fall on people, not near the sides of the roads (where they can ALSO be run into by a car that is forced off the road and the people die) and not near their houses where the trees can fall on those houses and kill the people inside. Everyone thinks the Druid religion is essentially dead, but its not - mention chopping down trees for any reason and people have kittens. I am not so in love with trees - they have their place - but that place is NOT where they can easily result in deaths of people.
And so what? That blog posting doesn't show that there isn't a correlation between GDP and the stock market.
"First they came for the slanderers and i said nothing."
with the new advances in balistic grade transparant materials there is no reason to suspect solar panels will be anything less than as tough as the rest of your house.
Transparant alluminim, gorilla glass, and clear saphire are all powers of 10 more tough than tar shingles and wood pannels used to make most houses.
Far more tough than the mostly silicate glass you use for windows.
I recently bought a solar system for my parents in Australia and based on the system output over winter the system will pay for itself in only 14 months - it is incredible how cheap they are now!
OK, but there are few items on the other side of the ledger too. Such as, do you know what your electricity company will be charging for electricity in 5 years time? If you're generating most of your own, you're much less vulnerable to that sort of uncertainty.
Let's turn this around then. Do you have data to back up your claim that "stock market growth roughly matches GDP growth in the country"?
Sorry but this technology will not work in panels mounted flat to the roof as they require sun tracking to work.
Does anyone doubt that if the US went into a 20 year recession that the stock market would drop along with it?
Dow growth since 1960, 22 times. US GDP growth since 1960, roughly the same.
"First they came for the slanderers and i said nothing."
Does a photovoltaic system really increase resale value? And why not buy a cheap generator for backup? It also works at night and in winter...
Yes, solar makes a lot more sense at those prices.
However $0.10 is on the high side for the U.S.
You can get it for .09 in my state if you sign for 12 months instead of "locking in" a low rate for 36 months like i did.
In many other states, you can get it under .09 if there is a dam anywhere near you.
At $.25/kwh, $2.50 to $3.00 per day per panel average your payout period would be about a year.
FWIW, I get a much better return by replacing lightbulbs with LED and CFL bulbs. CFL still suck so I prefer LED. Even at $20, an LED bulb pays for itself very quickly (under a year) at 6 hours per day. CFL's pay for themselves in about 4 months (compared to a similar incandescent). Key for me: Getting 3000 kelvin bulbs.
She was like chocolate when she drank... semi-sweet at first and then increasingly bitter.
Horrible idea. The way we break the barriers of our current technology is by trying new things. New things are expensive and will always be so unless we find out that it has potential and work towards reducing cost. If we only give out prices to consumer products, that already operate on safe, cheap and tested platforms, then we never get anyone trying out new more expensive techniques, so we never work towards lowering price, so we just get stuck working on infiticimal evolutionary improvements to the current method, improvements such as getting half the staff to produce the same product in half the time. Don't worry, you'll get the new tech down the line if it proves to be viable for commercialization, for now just be glad that people are pushing the boundaries of what we can do, and that improvements are being pursued.
I misunderstood you. You had a bit of a blow recently somewhere in America, didn't you?
I'd disagree. I've had to shovel people's brains back inside their heads after they'd wrapped their car round a tree. Having trees along the sides of roads, close in, so that drivers who are driving too fast for the road know that they are at danger of dieing is a very good use for a tree. After the first couple of decades, the tree generally comes off best. The trees also protect the people and property along the sides of the road from murderous / suicidal drivers.
Slowing down dangerously fast drivers by putting them into fear of their lives is good. It's the same logic as the "Nader spike" - a 2ft razor-sharp barb in the centre of the steering wheel of the car. It reduces the desire of the driver to drive excessively fast for the road conditions. I believe that modern technology could adapt the explosive pre-tensioners for seatbelts so that, after the seat belt has saved their lives, the mechanism garrotts them, slowly. As the saying about admirals goes, "Pour encourager les autres."
On long-distance, out-of-town roads where pedestrians and cyclists are not allowed, yeah, sure, let the cars go as fast as they like ; by definition, they can't hurt non-car users when they're (effectively) separated from the non-car-users. But even there, one of the most cost-effective, low maintenance ways of catching flying cars is scrub and bushes. Sometimes the drivers can even walk away.
Having spent the last 15 years fighting a tree that was too close for my liking to the house, I agree with the conclusion, but for different reasons. A large tree close to a house may - just may, just once in it's life time - be blown down causing injury to the occupants. But it's pretty unlikely. (If you live in a tornado or hurricane belt, YMMV. Your choice.) However, almost every year the tree is going to be causing damage to the foundations of the building, directly by root penetration and indirectly by soil heave associated with the water extraction of the tree.
Rule of thumb : there's as much of a tree below ground as there is above ground. So, if you keep that "overhang" of the tree onto the soil away from the shadow of your house, you're unlikely to get a significant foundation problem. (Note caveats concerning "trees grow", and "drains don't necessarily go where you think".) In the event of the tree toppling, you might get minor structural damage from the distal branches scraping the building, but you could count yourself "unlucky" (but not "reckless", which matters in court) if anyone was injured.
I've done more felling and arboriculture work than most people, and done it with teams of volunteers : when a tree comes down, it makes a hell of a din, and very few people fail to get the message and be "elsewhere" when one comes down. That includes when one tree brings down another (that was a pig of a site to manage). In the unlikely event of me buying a house with a "tree problem" (because I looked for these things when I was house-hunting ; ditto flooding problems), then my friend the bow saw and my bag of "silly rope tricks" would have reduced the tree to an appropriate size within days of moving in. (As it was, the people we brought from had already cut down the potential problems, leaving me with a minor stump problem. Big fucking deal.)
Birds are not dinosaur descendants;birds are dinosaurs, for all useful meanings of "birds", "are" and "dinosaurs"
I think its much more energy efficient just hang the cloths on a cord or clotheshorse.... :-)
okay, something about the math on this one bothered me .. in my defense i posted it at 4:14am while responding to an "on call" problem.
okay... 27 cents kWh (call it $.30kWh to simplify the math) vs $.10kWh would mean
$9 per month instead of $3 per month. That's $108 per year.
Soooo...
at $700 per panel... $108 per year = 6.5.
Even with really expensive electricity your payoff is six and a half years to payoff the panels.
All this assumes no lightning strikes that damage the panels. I know I get one gnarly strike per 10 years currently.
She was like chocolate when she drank... semi-sweet at first and then increasingly bitter.
Nominal GDP 1960: 526B, Now: 15770B. Growth: 30x.
DJIA 1/1/1960: 680, Today: 13067. Growth: 19x.
58% difference in growth rates is not roughly the same. But either way, it is statistically insignificant as one sample.
Yes, a negative change in GDP growth rate could cause a lower stock market. However, that would be a correlation with a *change* in GDP growth rate, not the GDP growth rate itself.
However, that would be a correlation with a *change* in GDP growth rate, not the GDP growth rate itself.
Of course, of course.
"First they came for the slanderers and i said nothing."
but that only works if I plan to stay there for a LONG time.
Or if you plan to sell the house when you leave, instead of just burning it down.
Because western Europe has culture
FTFY
If you think someone isn't free to have a different definition of "freedom" you may be a tyrant.
"lead-acid bitches". That, my friend, makes years of reading slashdot comments worthwhile. Well done!