Solar cells down to details...

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terri
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Re: Solar cells down to details...

Post by terri » Sat Apr 16, 2005 8:45 pm

Anybody stop to think about the effects of all this shading from "massive" solar panels on the ecostructure below?<p>Sorry, folks, but long, long ago I decided that for the most part, "conservation" was like pushing in on a balloon. It pops out somewhere else.<p>The only genuine, if not realistic, solution is to reduce the population before we cover the earth like the mold on a rotten peach. However, given the notion that businesses need ever-expanding markets, as well as some concepts from other entities headquartered near Rome, this ain't gonna happen.<p>I made up some wallpaper for my monitor a couple of years ago that said, "If we don't do something about overpopulation, Gaia will. And we ain't gonna like the way She does it."<p>And She's doing it.<p>Solar panels. A piffling trifle --a feel-good non-solution --to the real problem.<p>There. I said it and I ain't takin' it back.
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jwax
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Re: Solar cells down to details...

Post by jwax » Sun Apr 17, 2005 5:57 am

terri- I'll consider the effects of shading my roof shingles with photovoltaic panels when I cash the check from the power company. Hell, the roof may last 40 years instead of 30 thanks to the protective shielding! :D

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Re: Solar cells down to details...

Post by terri » Sun Apr 17, 2005 1:57 pm

Note the word "massive." I'm not talking about your (I'm guessing) 2000 sq ft roof.<p>And when I say "shading" I'm also talking about shading from rain.<p>Last I heard, the approximation was about 1 hp (746 W) per square yard of sunlight. Max. One hundred percent efficiency. Tops. <p>So when people talk about 3 - 5 megawatt stations, what then?<p>[ April 17, 2005: Message edited by: terri ]</p>
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Chris Smith
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Re: Solar cells down to details...

Post by Chris Smith » Sun Apr 17, 2005 2:10 pm

Shade is good, sun light takes extra energy to cool down those things in its path, like your home. Solar cells can add to this sum. And solar cells take nothing away from the atmosphere or the environment.<p> The same amount of sun light still strikes earth, it just hits the cells first and it still keep the planet warm, we merely deflect its wasted energy, and re use it else where. <p>Energy, you cant create it or destroy it, but you can utilize if for your needs. <p>Just like water and dams, we don’t destroy the water, we simply catch it a release it like a fish, and use the energy to our benefit. Minimal and acceptable impact to the world is had this way, far less than gas burning. <p>Deserts of the SW can produce power that others cant produce, houses can supplement consumed petro chemical production of power, and when doing so is a double bonus, shade to the underside, and no pollution to the air. <p>Its how we should be doing things if we care about the planet, minimal impact. <p>But if the rabbits, sheep and rats dont stop over populating the planet, it wont matter one way or the other.

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philba
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Re: Solar cells down to details...

Post by philba » Sun Apr 17, 2005 2:26 pm

Actually, the most likely place for solar cell arrays is areas with the most sunshine and thus, little rain. Net temperature effect would be negligible and could, perhaps, even be a positive. However, we arean't talking about things like covering death valley in solar arrays. <p>Even a huge site would be a few square miles at most. Using your number for potential and assuming a 10% efficiency, a 5 MWatt site would only require a touch under 14 acres of space. So the effects would be localized. As such, I think the negative effects from these arrays are significantly less than the benefits of decreasing the use of coal fired generators.<p>I don't disagree that population control is important but its not the first world that's the problem.

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Chris Smith
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Re: Solar cells down to details...

Post by Chris Smith » Sun Apr 17, 2005 5:45 pm

The general rule of thumb for today’s solar cell is 100 square feet per KW, per hour of good sun light. <p>http://www.sdreo.org/oldsite/pvweb/conv ... ciency.htm<p>A Single story house with 2000 square feet will have a roof area just slightly larger, and can produce about 20 squares or 20 KW watts per hour. Times five to eight hours average per day, and we have taken care of most of our energy needs at home. <p>Even a mansion in the desert doesn’t consume 100 kW per day to cool them down or run the house.

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Externet
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Re: Solar cells down to details...

Post by Externet » Sun Apr 17, 2005 9:34 pm

Hi.
No doubt installing solar panels on a roof has many advantages.
The huge problem is cost. $4/Watt is too much.<p>That is why I wondered if there is a simple way of making cells with doped ink. In other words, making a paintable PN junction.<p>Maybe not reaching the typical ~10% efficiency, but hey! whatever decent figure achieved by home making the thing would be great !<p>Back to the same; Imagine an ink with no impurities, and mix cations to it. Apply, let dry.
Then, another ink, mix anions in it, apply on top, let dry.
Then, some indium oxide or conductive clear layer as collector/sealer on top.<p>We need a chemistry expert. It cannot be that much of a mistery... :roll: <p>Miguel
- Abolish the deciBel ! -

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Re: Solar cells down to details...

Post by rshayes » Mon Apr 18, 2005 1:53 am

Actually, there isn't much mystery. Organic semiconductors are available in two forms, electron transporting and hole transporting. They cay be applied from solvent solutions. You can even apply them with ink jet printer techniques if you need a pattern, such as a color organic LED display. The substrate can be plastic. there should be no problem creating a simple junction by painting two layers.<p>About five years ago, I worked at a company that was considering alternate ways of making displays. We looked up the price of some of the chemicals needed. My memory is not very clear, but I remember the cost as being several hundred dollars per gram. That was too rich for us.<p>If the organic LED displays create enough of a market for the raw chemicals, then I would expect the price would come down once synthesis procedures have been worked out and plants built to produce the basic chemicals. Then such a solar cell might become practical.

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jwax
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Re: Solar cells down to details...

Post by jwax » Mon Apr 18, 2005 3:23 am

Economics is always the driver- make them "affordable" and they will sell. However, when you extrapolate the current $4/watt initial cost, add installation and control equipment, over 20 years, the $/KWH is very attractive. It's one of the better investments you could make. :)

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Chris Smith
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Re: Solar cells down to details...

Post by Chris Smith » Mon Apr 18, 2005 8:11 am

Actually the way to bring down the price is to install them on every house. <p>Just like the Model T, the more you produce, the cheaper it gets. <p>A couple of billion square yards a year production will bring down to cost to a couple of pennies per square foot. <p>Lobby those non scientific people in DC, hold their hand if necessary when Explaining the benefits of Silicon over Hydrocarbon.

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Re: Solar cells down to details...

Post by peter-f » Tue Apr 19, 2005 6:42 am

I heard a number this A.M.,
The quality of the report highlights why people don't even start doing it before they're established as independently wealthy.<p>In one example from NY State, it takes 75+/- solar panels (they didn't define or specify size) to power 80% of this house (of unspecified size)...
at a cost of $60,000(+/-) (architectural modifications for installation included?) before federal and state tax credits/rebates, and selling an (unspecified) fraction of the generated power to the local utility.<p>So.. what does it produce? How much does the owner get? How long to recover cost? Jeez... I can see why reporters get low marks for quality of reporting!<p>(to jwax and Chris... you seem to have a firm background in this)
My question... on a 100 sq ft roof (on a shed), how much can I produce for local consumption (not for sale to utility.) At what price? Can this be packaged as a kit.. and what impact would that have on 'Home Depot' style backyard projects?

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Externet
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Re: Solar cells down to details...

Post by Externet » Tue Apr 19, 2005 8:41 am

Hi Peter.
Your ~10m² shed area can yield 1 Kilowatt.
It is about twenty - 50W bulbs.
8 hours of sun could be ~8 hours of those lamps on.<p>The figures the reporter supplied of $60000 for ±75 panels = $800 ! per panel installed.<p>Assumming each panel is 50 Watts;<p>The installer is sucking $600 per EACH $200 panel. [50W x $4 = $200]
Who can afford that abuse ? It is not only the high price of the solar panel, but the wringing of wallets by "specialized" labor sends the factibility overboard.
Everyone wants to become rich in a month?<p>Agree, numbers are based in loose assumed report, other expensive equipment is involved; but won't be too far from real.<p>Find a paint to make PN juctions !<p>Miguel
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Chris Smith
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Re: Solar cells down to details...

Post by Chris Smith » Tue Apr 19, 2005 1:46 pm

This is true, when it become as common as roof repair and not rocket science or your first born for one pannel for the do it your self-er, it will if nothing else cut our Oil consumption down by any acceptable level which is better than running full speed towards the Arabian cliff, like we are doing at present. <p>The argument that it costs to much is off set by ”how much of this country are you willing to throw away to third world countries”? <p>Buy American, and get the ball rolling now, or pay even more in the future when your bent over a oil barrel by some third world oil producer. Why wait for the crash just to act? <p>You hear of anything else on the horizon, something silly like producing hydrogen from crude oil, and keeping that junkie fix to the middle east? <p>Its not a cure just yet, but it will cover at any price, some of the imported oil that other wise is making some sand rich country very rich, off your working back. <p>If it gets into play full swing, then it can even reduce Gas consumption in cars by having a alternative producer of Hydrogen. <p>1 kilo watt panel at today’s prices is outrageous, and doesn’t do that much work,...but spend that kilo watts here or send it to the arabs, your choice.<p> Id rather spend two bucks doing a bucks worth of work here, and knowing Im out sourcing my job to Arkansas rather than to Bangalore India, or Saudi Arabia, which is still producing lots of angry young men who are still learning to fly large air craft.

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sofaspud
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Re: Solar cells down to details...

Post by sofaspud » Tue Apr 19, 2005 4:34 pm

The punchline is... nuts & votes.<p>Create your own joke.

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Re: Solar cells down to details...

Post by rshayes » Wed Apr 20, 2005 5:05 am

The present economics of silicon solar cells are not very good. My electric bill last month worked out to 13.1 cents per kilowatt hour. A $4 per watt solar cell would pay for itself in about 14.5 years, assuming no cloudy weather and a solar tracking system. This would go to about 20 years without a tracking system. If interest were figured on the money required, the break even point might be closer to 40 years or more.<p>Most of that cost was transmission and distribution. The generation costs were about 2.6 cents per kilowatt hour. This puts the break even point for a utility using solar cells at over 35 years, and with the other factors, more like 60 or 70 years to pay back the original investment.<p>Silicon solar cells may not save fossil fuel consumption. The 1968 CRC Handbook describes the major source of silicon as being the reaction of silica (silicon dioxide with carbon in an electric arc furnace. Not only is carbon being used in the reaction, but it is also used to generate the electricity needed for the furnace. The main waste product has to be carbon dioxide. Purifying the silicon is also a high temperature process, with the heat being supplied by electricity, again generated with fossil fuel. Diffusion is anothe rhigh temperature process. I don't have any idea of the time required for a solar cell to pay back its energy costs, but it could be years or decades.<p>The large scale production of silicon solar cells might require the expenditure of massive amounts of fossil fuels and may never break even from an energy standpoint.<p>Germaniun isn't much better. Its chief sources were by products of zinc refining or the combustion of some types of coal.<p>A thin layer of silicon on a glass substrate may not be much better. Possibly a steel substrate would be better, but the mountains of iron ore are disappearing too.<p>There is an experimental solar power station near Daggett, California. It uses mirrors to concentrate sunlight to the point where it can generate steam, which is used to drive turbines. This approach may only be usable on a large scale.<p>There is no automatic economy of scale here. The cost of the silicon may be set by the cost of the materials used to make it, and, in this case, increasing production will not reduce cost significantly.<p>Other approaches may have a much better chance. Biological approaches do not require high temperature. For example, some form of algae could be used to produce sugar by photosynthesis, which could then be converted to alcohol and used in fuel cells. If one on the nutriants was carbon dioxide, this might also supply a way of reducing greeenhouse gases. The efficiency might be low, but large and shallow plastic lined ponds could be very cheap, even when scaled up to several acres.

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