Solar cells down to details...

[sofaspud]

I stand by my last statement.
This thread is mired in worthless political rhetoric. Get back to nuts & volts for pete's sake. Invent the solution with your genius. Or run for office and save us all.

[Chris Smith]

That’s the sort of comment and mentality we are fighting that will keep us buying oil til it runs out very soon.
No cries, just roll overs.

[wolfcreek]

Depending on the type of substrate and thickness of the substrate it takes anywhere from 3 to 8 years to payback the amount of energy used to create a solar cell. This does not include any other factors such as transportation, inverters, batteries etc. This is assuming the cells are located where they can produce their maximum power output every day. Fortunately modern solar cells last 20 to 25 years.

[rshayes]

Tyr doing a google search using "solar cell energy payback". Payback periods from under 1 year to over 8 years are estimated by different people. Some of the references actually identify their assumptions.<p>The most honest estimates for single crystal solar cells seem to be about 8 years. This can be reduced by making some dubious assumptions.<p>One assumption is that solar cells will not be made with virgin silicon, but with remelted scrap from the integrated circuit industry. This is very unlikely. It assumes that an industry that is delivering a square inch or so of integrated circuit to the consumer will generate enough scrap to produce several square yards of solar cell to the same user. Using scrap silicon transfers the energy cost to another industry, which isn't entirely honest.<p>Another assumption is that processes and suppliers will be found to produce a hypothetical "solar" grade of silicon that is about 99.9999 percent pure. Present silicon is either about 99 percent pure, and considered "metallurgical" grade or over 99.999999 percent pure for "semiconductor" grade.
There are some processes suggested for doing this,but no hard information on the actual energy saved, if any.<p>Still another assumption in some of these estimates is that a tracking system is used to obtain the peak power at all times. The cost and maintainance of the tracking system is neglected.<p>Some of these estimates also seem to be based on sunlight for 24 hours a day.<p>Most of these estimates are baseing the energy payback time on electric energy consumed compared to electric power generated. This underestimates the actual energy required, since the power plant generating the initial energy is probably only about 40 percent efficient.<p>The cells with very low payback times seem to be non-silicon cells such as copper-indium-diselenide and cadmium telluride. These are experimental and the estimates are somewhat hypothetical. The useful life may also be shorter than silicon. One reference points out that some of the materials in these cells are byproducts of other industries, and may not be available in massive quantities.<p>Both glass and aluminum are also mentioned as significant fractions of the energy cost of solar cells. Some of the estimates lower the payback time by hypothesizing a reduction or elimination of these materials. This might make the cells more fragile and reduce their useful life, but I saw no discussion of that possibility.<p>Incidently, one reference listed energy payback times for coal, nuclear, and wind power. They were all about 1 year or under.<p>[ April 22, 2005: Message edited by: stephen ]</p>

[sofaspud]

re: "...We are fighting"
Huh? I didn't know this was a political blog or action committee. I thought it was the N&V Techtrax forum.
My point was that the technical discussion was lacking and the editorializing was knee deep.
I'm surprised no one has mentioned the blurb in last month's N&V showing the mirrored parabolic dish-Stirling engine power generator. I have little doubt that the setup is more efficient than any solar panel. Unfortunately there was no information given on operation and maintenance costs, but I can envision practical applications for it in today's world at today's prices.
Regarding the paint concept, I see a couple of problems to overcome. I'm not a chemist, but I think purity is the first factor. I would think that whatever solvent used would need to have 100% evaporation or it would leave impurities. Or perhaps a solvent could be formulated in which the impurities left are actually beneficial. Next is the reaction caused by the second coat being placed over the first. It would need to be engineered so that there was no permeation caused by the second coat, wouldn't it? I don't know, but I would guess that NASA has probably already investigated the idea. If a satellite or spacecraft could be painted to generate power, saving the weight and cost of ordinary solar panels, they would adopt the technique in a heartbeat.

[Chris Smith]

Argument is good...<p>Education,.... not Pessimism or Ignorance, is what we need.<p>All the arguments against Solar seem to come from a ignorant point of view, one that includes “greed must remain”, and we cant proceed because we don’t have [or cant have] any advancements in cost reduction or technology. <p>Only investments can change that, at that starts in DC.<p> Start selling em and the price drops which means the 8 years return drops to three, and keeps dropping. <p>There is no arguments as to why we shouldn’t get started, as our oil reserves are dwindling and going down fast, the price of gas is going up even faster, and third world countries are pissing away YOUR money even faster. <p>Imagine the cost of those old cells when new ones are being produced en mass? They wont be able to give them away! <p>But if its all warm and fuzzy where your at, don’t get out of bed? <p>Keep up the good arguments, it’s a start. <p>Argument: [Websters] Evidence /Proof...”A reason or reasons offered for or against”.

[sofaspud]

The mirrored parabola IS solar power. I'll only speak for myself and say I never claimed to be *against* solar power. Chris, do you own stock in panel manufacturering or something? You seem to be running on a single track.

[Chris Smith]

That’s simple to answer..After watching DC work for a life time, and seeing things go from absurd to stupid, I have a mission in life, kick the oil junkies out. American ones too. <p>In the last thirty years I haven’t seen one politician do one damn thing to make real changes in the energy department. Instead they are leading us down the path to destruction as the public gets more apathetic by the day. <p>If I didn’t know better I would think I fell asleep and when I woke up the tornado took me off the see the yellow brick road. <p>I conserve, I recycle, I minimize everything I don’t need because its not happening much of any where else. And not a single idea has come up in thirty years that will help us tomorrow, aside from small things like forcing Detroit to make more cars that go a little further than they did before. <p>And they had to pull teeth just to get that done. <p>No I don’t own any stock, I teach those of you with a will and a way, to start thinking about your future. Because by the time you retire, gas wont even be in the dictionary while Horses will have a great come back. <p>And DC couldnt give a damn, they will still drive limousines and you will keep paying through the nose willingly and with a smile?

[sofaspud]

I'll keep all that in mind. Compared to your "eve of destruction" view, it is warm and fuzzy here.

[Chris Smith]

Not really, But politicians never tell the truth, so It would seem that way. <p>The current estimations for our oil are thirty to forty years, and ony if we dont meet the growing and increasing needs. <p>But I have worn rose colored glasses before, and then I woke up to the fact that politicians and the meaning of the word, actually states "liar" as the first meaning in the dictionary. But then I learned that lesson several decades ago.

[rshayes]

I would not expect that the solvents used to deposit organic semiconductors are a problem. Most of the common organic solvents, such as acetone, ether, and the alcohols are very volatile and evaporate very throughly. Two layer deposition is used to make organic LED displays, and interreaction between layers does not seem to be a problem.<p>The organic semiconductor materials used are not simple materials. Since light emission is not required, it is possible that simpler materials can be used. Synthesis of these materials might still be difficult. One possibility would be to use chlorophyll as the feedstock for the synthesis process. The "spinach cell" tried to maintain conditions such that the chlorophyll would not degrade. A better approach might be to modify the chlorophyll to be more stable, possibly by substituting chlorine or flourine for some of the hydrogen. This would be simpler than building the whole molecule from scratch.<p>NASA has to play by different rules. Their concerns are weight and reliability. A cell using an organic paint that would last years on the earth's surface might fail very rapidly in a space environment, due to high levels of ultraviolet radiation and other factors. The substrate might aslo be heavier than that of a single crystal solar cell due to the lower efficiency.<p>There was an operating solar power plant near Daggett, CA. This used tracking mirrors to concentrate sunlight on a boiler. Building the tracking hardware and controlling it looks expensive.<p>Collecting heat for heating a building might be fairly simple. The air in an attic gets pretty warm, and this heat could be stored by forcing the air through a gravel bed with an exhaust fan. A reflective layer and insulation on the floor of the attic would probably increase the heat collected and reduce the temperature of the living area. If the thermal mass was high enough, it should be possible to use the heat collected in summer for heating the building in winter.

[ian]

REALITY CHECK

I'm very disappointed by the misinformation in this post. There is a world crisis of overpopulation and energy consumption. We need practical, workable solutions and solar cells isn't one of them. Despite Chris's rants here solar panels are far from realistic for a number of major reasons.
First of all, nobody is realistically pricing the true cost of a major solar installation. Add the following costs to previously erroneous and silly calculations...............<p>1) Replacement of bad, failing solar cells.
2) The cost of borrowing $100,000 for 20 years.
2a) After buying a $200,000 house who has another
$100,000 for a solar system?
3) The cost of insurance for the cells against
theft, wind, storms, vandalism, etc.
4) The cost of a support system, cables
batteries, inverters, power switching etc.
5) Support structures, house re-inforcing.
6) Land.
7) Alarms system for $50,000 worth of panels in
your backyard.
Replacement batteries and parts. This one
especially cracks me up, most pro-solar
luddites assume nothing in a solar system
ever fails.
9) Regular maintenance, cleaning the cells,
checking the system etc.
10) Have I left anything out?<p> The second problem which isn't a problem is that there is a multitude of available technologies far cheaper than solar generation. The most inexpensive being far more efficient appliances, better insulated homes, etc.
I'm sorry to interject reality here but I'm sick of the "oil barons and political forces are keeping solar panels down" argument. It's old, it's stale and it's wrong.
As for mass production pushing the price down..........well, millions have been spent, and continue to be spent, trying to find cheaper manufacturing processes. Things cost what they cost, maybe some day solar panels will be as inexpensive as glass but it's not been done yet and there's no proof it could be done.

[ian]

I forgot to add............
A solar panel system capable of powering and heating a reasonable sized house with the same appliances would cost far more than $100,000.
I know my facts, if you would like to contest this estimate please supply a realistic model of a system. I'm familiar with several system that cost >$60,000 that don't heat the house and are backed up by geberators. You can find them in the homepower publication.

[ian]

Ok, this is bugging me. Here's some practical math.
Most houses today have a 200Amp service. To produce 100 amps at 120V from a solar panel system would require $60,000 in panels alone. I know you don't always need 100 amps so subtract enough panels to buy a battery support system.
This EXCLUDES all factors above. Anybody care to come up with a realistic cost or is it too freightening?
My rough estimate for a full system handling heating and air conditioning is $200,000. Thats the initial outlay. Monthly maintenance costs would be......
$1000.00 interest
$3000.00 amortized depreciation of system
$300.00 monthly maintenance
$ 50.00 insurance
$????<p> Lets say.......$5,000.00 a month in costs?

[jwax]

I'm guessing that $60,000 for a solar setup is Canadian dollars?
A few points- 1.) Solar electricity does not have to be stored- it can be inverted to AC and fed back into the grid for cash. No batteries.
2.) Insurance for solar panels? Somebody going to climb up on your roof and steal them? Tough neighborhood.
3.) Nobody is suggesting 100% replacement of your electric and heat requirements with solar. At this time, a solar-electric assisted approach is reasonable.
4.) There are actually places here down south that do not have much of a heating bill at all. It is an all electric home. With lots of sun days.
What is the price of a liter of petrol in Toronto these days? How about heating oil? Just curious.