Tuesday, March 11, 2008
Study shows solar cells’ energy payback is down to 1-3 years
http://www.edn.com/blog/1470000147/post/190023219.html?nid=2432&rid=1199351712If solar panels are such a great way to generate electricity, why aren’t photovoltaic manufacturing plants powered by – solar cells? Well, in the future they might be.
30 years ago, manufacturing a solar cell required about as much energy as the cell could produce over its 20-year lifetime, making solar power less than a break-even proposition. However, improvements in materials and manufacturing processes now make the payback time in energy from 1-3 years, making solar cells a viable energy source. According to a new study authored by Vasilis M. Fthenakis of the Brookhaven National Laboratory and (1) quoted in Science News,
“Much of the improvement is from reducing energy and materials for making solar cells. Compared to those made in the 1970s, modern panels contain about one-third as much purified silicon, which is energy intensive to make. And thin-film solar cells trim back even further by depositing silicon or other materials in layers only a few thousandths of a millimeter thick.”
Here’s (2) a recent article on Nanosolar, the poster child for efficient thin-film solar panels.
(1)
http://www.sciencenews.org/articles/20080301/fob5.asp(2)
http://www.edn.com/article/CA6524103.html?text=nanosolarReader Comments
at 3/12/2008 3:12:29 PM, Jonathan Williams said:
I don't believe it, not for a second. Three years of my electric bills including the electric dryer usage would total approximately $3,600.00 You can tell me that I can install a photovoltaic system that produces a megawatt-hour per month for $3,600.00? What kind of dope are they smoking? Maybe if you compare the cost to power from AA cells, the payback may be three years.
at 3/12/2008 3:16:42 PM, Jonathan Williams said:
Don't get me wrong. I'd love the idea, but I've been charmed by these forward looking claims regarding photovoltaic efficiencies and cost for decades and the changes have been incremental with none of the 'breakthroughs' just around the corner. I'll believe it when I see it.
at 3/12/2008 3:28:23 PM, stiggle said:
Jonathan Williams, with 8 hours of sun average per day and 30 day month, a 4KW solar array will produce nearly one megawatt-hour per month. This is not an unreasonable size solar array that would probably cost around $3600.00. 960KWh is nearly 1MWh, so using the figures you provided, the point is valid. You will probably have to add a few hundred dollars for the power controllers but these will last longer than the 3 year payback and the power will be money in the bank every year beyond three!
at 3/12/2008 3:28:55 PM, Mike said:
at 3/12/2008 3:12:29 PM, Jonathan Williams said: I don't believe it, not for a second. Three years of my electric bills including the electric dryer usage would total approximately $3,600.00 You can tell me that I can install a photovoltaic system that produces a megawatt-hour per month for $3,600.00? What kind of dope are they smoking? Maybe if you compare the cost to power from AA cells, the payback may be three years. The article is not talking about the cosumer breaking even on what they paid. It is talking about the cells producing the amount of energy in 1 to 3 years that was required create the cells.
at 3/12/2008 5:55:44 PM, Bob said:
If the cost of Gasoline goes up so does every type of energy in the market place. It would be an exciting age when solar cell prices could actually drive cost of all energy down. It won't be that long before gasoline engine vehicles are a thing of the past. Electricity and hydrogen are going to rule the world. The best thing would be if oil was only used for a lubricant.
at 3/12/2008 6:00:04 PM, zerona said:
Production plants typically need power 24/7. Power generation also needs to be continuous or be adjustable. Storage of electricity is expensive as well. Putting the excess power back into the grid and getting it back later is also an issue. Ignoring all that, it would make sense to have a panels making money for you as it reduces the bottom line cost. A return on investment of 18 months would help. Also, panels take space, roof, windows, don't know where else you can mount the things unless you have extra acreage that's not doing anything but growing weeds. Also, many manufacturers today don't own the buildings they're in so modifying them for that is not their call. Companies lease space to make the bottom line look attractive to investors. The article is misleading for not looking at why it's not implemented and only looking at payback. For home ownership...18 month ROI? Where do I sign up???
at 3/12/2008 6:27:26 PM, Jonathan Williams said:
Mike: If the article is about the break even point for energy expended versus energy generated, what good is that? Then I would say the article is deceptive. What matters is the bottom line. Stiggle: How do you size an array to get an average of 32 kWhr per day? It's not a 4 kW array. Do you use aiming systems to get the maximum sunlight possible from sunup to sundown, now the cost balloons. Suppose you live in Maryland and not Arizona? Current pricing of panels is running about $4 per watt. That gives us about $16,000 not $3,600. Let's see how long it takes to get down around $1 per watt.
at 3/12/2008 6:39:43 PM, Paul said:
What's wrong with everyone? Didn't you read the article? He's citing the cost of POWER PLANT energy, not residential.
at 3/12/2008 11:57:15 PM, Jet said:
Yes - when we see solar power used to make solar panels - then we know the energy payback works. For now selling price of panels is in the $4 range and installed costs are $8. Not really economical yet but getting close for peaking power in some high priced markets like California. Nanosolar claims they can profitably sell panels for $1 / watt - but they are not doing that because the market is still paying the $4 price. So Nanosolar will skim some cream and probably reinvest profits to expand production capacity. Nanosolar claims a current capex ratio of 10:1 - probably assuming $4 prices. Their capex will still be 2:1 even at $1 panel price. Right now Nanosolar has about 100,000 sq ft of manufacturing space. In three years they could have 10 million sq ft and that will start to make a difference. At the same time there will be a dozen other big players with similar game plans. Look the the Applied Materials equipment sales - in 18 months that equipment will be making panels. Repeat this process around the world. I figure in 2 or 3 years you will go on line click click click and $1/watt panels will show up at your shop three days later. You take them up and lay them out on your shop''s flat roof, plug them together and you got power. That process will then be repeated on all the flat roofs in California. That will then avoid building any new power plants. Some of those flat roofs will be over the plants building the panels. I expect to see an Aluminum plant in Australia using solar to refine Aluminum within 5 years. Aluminum is "solid electricity" and the Aluminum industry alway seeks lowest cost power. In 5 years that will be Solar located next to the mines producing the raw materials. To me the future of energy is pretty clear and is very sunny. My opinion is based on pure technology and economics - nothing to do with environment (though solar will be much better for the environment than coal) China is now building 2 coal fired power plants per week. Coal fired plants are guaranteed to work and China can get any number they want now - China is modernizing and they can''t do it without power. I predict the last new coal fire plant anywhere will be built about 5 years from now. The last one will then be turned off in about 25 years. All good news.
at 3/13/2008 1:14:48 AM, Les said:
My company receives a $200K to $250K monthly electric bill. Show me how this can help me.
at 3/13/2008 12:30:23 PM, Meredith Poor said:
There appears to be some confusion in some of the posts. The energy payback is 3 years. This has nothing to do with financial payback. The market price for solar cells seems to run around $4 per watt. Multiply by 100 to get cents and 1000 to get kilowatts, or 400,000 cents. Divide by your price per Kwh, say ten cents, to get a financial payback in 40,000 hours. Divide that by 1800 hours of effective solar illumination per year, to get what is around 22 to 24 years payback. If the price drops to $1 per watt, which nanosolar claims to have done, payback drops to 6 years.
at 3/13/2008 2:00:35 PM, Jonathan Williams said:
Meredith: You are absolutely right. What we have is an article of virtually no use to anyone because it's not what you can buy.
at 3/13/2008 4:52:51 PM, DavidPL said:
The payback is based on just the power used in the cell producing plant. It ignores the cost of raw material, labor, the frames, shipping, retailing, power conversion equipment, and installation.
at 3/13/2008 5:57:00 PM, JMS said:
Much misunderstanding going on here. Energy payback is a measure not of practicality per se, but of net energy production versus energy input. The 1-3 year number for solar cells is quite good. Assuming an array lifetime of 20 years, that means for every kWh expended in creating the solar cell, you can expect to get 6.7-20 kWh out of it over its lifetime. This compares quite favorably with, say, corn-based ethanol, which has a payback ratio of somewhere between 1 and 3, depending on who is doing the calculations. And 10 cents per kWh may be the national average, but it runs a LOT higher in some areas of the country. Here in California, we have this baseline system. Power use below the baseline is 11.5 cents per kWh, but it goes way up from there. We pay over 30 cents per kWh for over half our electricity. Any solar power would save money at this rate, dropping payback time for a system that delivers half our power to about 10 years. I have a friend who has a 6kW system. He gets about 36kWh per day in the summer and about 20kWh per day in the winter. He added a lead-acid whole-house UPS for nighttime power, so he needs no power from the grid at all.
at 3/14/2008 3:05:35 PM, W17053 said:
Further misunderstanding comes from the misconception that you have to provide 100% of grid power. If you pay a stepped rate, you can use the array to keep you under the next step (similar to 'peaker' units that Malls install to generate electricity to keep the peak power usage lower). If you provide power enough to run your house during the day, this would be helpful. If there is a power failure, you can continue running essential devices. You then don't have to worry about energy storage (batteries).
at 3/18/2008 3:16:06 PM, Chris said:
W17053 is right. When you try to make the energy collected from solar panels last through the night (or worse yet, through several cloudy days in a row) the cost for the storage equipment becomes prohibitive. 100% solar power often isn’t practical. Most of the “100% solar” homes you read about, are so super-insulated that they don’t really need any power input at all to stay warm. For this reason, coal, oil, nuclear, hydroelectric, etc. (and yes, wind) are going to be around for some time. But by using solar power when the sun is shining; we can cut back on our overall usage of fossil fuel. It’s just that we will still need it during the night and on cloudy days.
at 3/18/2008 4:01:42 PM, J.O. said:
Restating from above, there are two entirely different “break even” angles. The first angle is the “green” aspect. The second is the financial payback as compared with power purchased from the grid. Up until now (perhaps…) there was more energy consumed in the manufacture and installation of solar panels than the panels could produce over their expected lifetime in average installations. Consequently, solar panels were a bust as a “green” or “clean air” measure, unless the solar cell plant was powered by a nuke plant or, as suggested above as a real litmus test, by other solar cells (Left out of this discussion are the financial and environmental aspects of the huge, perishable battery systems which accompany most systems. ) On the other hand, solar panels have always had a niche for off-the-grid applications and residential solar panels can possibly make financial sense as a hedge against rising energy prices and potential economic calamity, so those with a “survivalist” impulse and desire to achieve “energy independence” for themselves in the future may decide that paying a premium for their own solar power plant today is a worthwhile investment. The fact that when they order their panels they may be commissioning some solar panel company to burn a few tons of coal and pollute the air to make their panels isn’t an issue in this case. If crazed Al Qaeda types or domestic eco-terrorists shut down the grid, the solar-powered folks will be sittin’ pretty. Of course, if it presently looks like a 20 year breakeven proposition financially and in that time the US brings more nuke plants on line dropping the commercial power rates, or there really are some major break-throughs in solar cell costs, then present day solar investors might look like Cold Warriors in bomb shelters full of food with expired date codes. As with many investments, you need a crystal ball to really know how things will pay off. Naturally, government subsidies or punitive regulations can take something that is both a “green” bust AND a dopey financial proposition (egs. ethanol) and make it appear to some consumers as a good deal. Anyway, there are two different angles here.
at 3/18/2008 6:38:08 PM, Cornstoves said:
TGFI, Yep, If you don''t get it, perhaps you don''t deserve it. Subsidies to Utilities and Big oil has everyone trained to be blind. Meanwhile the obvious has blind sided everyone back to sleep. The low cost energy is local, renewable. Low cost energy is virtually any energy that avoids the cost of energy transportation. If you don''t understand, perhaps you desire not comprehend. A groups of people that know first hand the advantages of low cost local renewable energy
www.groups.yahoo.com/group/cornstoves,
www.groups.yahoo.com/group/cornplace Stay blind and in the dark while we get a local renewable insight with a running start. Anyone using 1500 KwHe utility grid is throwing money away.
