energy required to produce 100W photovolatic panel

It sucks

Although it wasn't first obvious, one of the best hopes is for peak load mid day demand when the AC is on. The cost to utility companies for peak load KW is starting to make solar possible. Batteries for storage were always the worst part of solar.

PV by itself is still a ways off because it is not just the cell technology cost to consider. Location, support and protective structures and energy conversion are also issues even if you assume no storage. The electrical grid can be treated as a storage medium, just think of the money transactions and banking process as the storage medium. Solar does win for remote applications already. One thing to consider is using solar PV as a complement to solar thermal collectors. In this way, the cost of location and support structure is shared with solar heat. The PV cells act as the heat absorbing surface for thermal collectors. Even in the southern climates, hot water is needed.

It's how we think about energy. A good 35 watt PV unit costs about $200. If you have 5 hours a day of good sun, 0.175KWH a day is generated. At 10 cents a KWH payback is about 30 years. If you have to pay a minimum $10 a month to be connected to the grid, the payback is quicker.

I took a camp off the grid years ago and operate on about 0.5KWH a day. A friend of mine is trying to figure out how to run his home on an emergency 10KW generator.

Lets say at 4$/Watt commercial PV price. 1$ profit, 1$ material, and 2$ energy goes into the panel.

$0.10/KWH = $0.0001/WH.

Now (2$/W)/($0.0001/WH) = 40,000 Hours or 5000 8-hour days = 13.69 Years.

Almost 14 years to recover the energy expended from manufacturing the panel!, Panel expected life, ~25 Years, so eleven years of energy payback optimistically.

California PV rebate, looks like another slick way of exporting the polution to another place. Might as well long haul the power from Wyoming or another state.

Assuming you can get solid 8-hour days all year round?

TTFN

Reconsidering my figures. I do not think I have really given solor the benefit of the doubt. That is the actual energy, this is my main point. $dollars, pesos, liera, and bolivers is not.

Now $4.00 per watt Say, 1$ profit, 1$ labor, 1$ materials, and 1$ commercial cost of energy, that I will say has a mark-up of 25%.

But the delivered power to the user of AC will have a net efficiency of %85.

Therefore, $1* 0.75= $0.75 of energy required to produce the panels. I wish someone would actually know what the percentage is

Now the payback is 13.69 *0.075/2/0.85 = 6.03 years of 8-hour solar days. (maybe possible with a solar tracker). or 6*8/5 = 9.6 years of 5 hour solar days @ nameplate.

The panels never seem to actually get nameplate Watts, as the rated voltage is usually to high to be actually be usefull for battery charging, unless your voltage drop in your cables is excessive, in my opinion.

Therefore payback is 25/10 =250% over the usefull lifetime of the panels, barring catostophic events of various sort.

250% over 25 years? is that good enough for an investor? Lets set 250%/25=10% per year energy return, non compounding, except that commercial power is probably going to increase over time. Really not bad, relative to the stock market.

I am not a solar advocate, but I have lived using alternative energy for 17 years, solar +wind. The batteries, well maintained is not that bis of a deal, only 2 sets in this period.

PS. no phone either, this is over a 5KHZ wide UHF phone line extender & PS I only have this $#%#%*** spanish spell checker, sorry/

Can't help much but here is some possible usefull info.

An Epitaxial Reactor for doping 300mm silicon wafers uses 411 quartz lamps rated 500W each in a batch cycle of approximately 3 minutes for each dopant on each wafer. I do not know how many dopant layers are necessary for solar cells, nor how many cells can be made from a 300mm wafer.

Additional energy costs would be silicon mining, ore transport, crushing, processing, crystal growth, crystal machining, wafer cutting, robotic handling, polishing, power cell cutting, handling again, assembly, more handling etc. etc. etc., and add the facility maintenance costs of the fabs to do all of this as well.

Bottom line, you make a good point. There is no free lunch.

"Venditori de oleum-vipera non vigere excordis populi"

It is said that electric vehicles just shift pollution from the car to the power plant. From this thread it seems that solar cells shift energy consumption to the fabrication facility. Both these statements ignore key facts. In the case of electric vehicles, you replace many mobile internal combustion engines with fewer, fixed location power generation facilities (which may, depending on your lcation, be hydro or wind powered). Solar power can be used in places where it is impractical to run power lines or set up a conventional generator.

circuit1952,
Don't get me wrong, I am a big proponent of solar for both your reasons and for the fact that it will (hopefully someday) specifically target a large segment of energy consumption at the point where it is needed, Air Conditioning. Since it works best when in full sun, and that is what causes us to want air conditioning, it makes perfect sense to me to utilize solar power for that. I only responded to the OPs issue because I hear many quasi-environmentalists spout uninformed blather about how solar power is so "clean" when in fact it is not as clean as they think it is when these other issues are taken into account. And just to make it clear, the VAST majority f electricity produced in the world still comes from fossil fuels.

"Venditori de oleum-vipera non vigere excordis populi"

I just saw an article in the Sunday paper on the history of photovoltaic cells. Originally developed by Bell Labs fifty years ago. Initial costs were about $1700/watt, but the article stated the current cost is around $3/watt.

So, in terms of offsetting other sources of electrical power, payback would take quite a while.

In early 2003, I remember hearing a radio news report that a photovoltic cell had been developed, which was made mainly of a plastic. It was suppost to be 20 times more efficient than the best silicone. It was suppost to be cheap to make too. I haven't heard anything about it since. I suppose the patent now belongs to an oil company.

My current thought is to stratigically place the (very) large sets of the black in-efficient heat absorbers, in locations that produce massive uplift of the moist lower air. This has two equally benifitial effects. (1) The Global rainfall can be manipulated into areas most benifitial. (2) The lighting produced by this manmade thermal can be harvested for the electrical power and nitrates. A third, less consequential effect is to give the poor, poor, indangered desert squirels and turtles some shade, and good snacks where the rainfall runs off the panels, and grows vegistables.

PS> Dan67, review my initial post, as history has a way of repeating itself.

Geez, it is like i just cut into a big block of lumberger cheeze in a room full of widow ladies.

Happy belated earth day never the less??

cheeze anybody?

Let's talk about the real conspiracy of getting Tesla's free energy. Again it is the oil companies!