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Flexible Solar Panels July 13, 2010

Posted by OldGuy in Alternatives.
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On Monday (Jul 12) SoloPower announced new line of flexible thin-film solar panels.  Made from a combination of copper, indium, gallium, and selenium (CIGS), these are made to be easily installed on existing commercial rooftops.

SoloPower's high-efficiency flexible thin-film solar panels are lighter and easier to install in commercial or industrial applications.

The company makes  the panels using a roll-to-roll electroplating process,  to be lighter than glass-encased panels.   These thin film solar cells utilize only a 1–4 µm thick layer of semiconducting material to produce electricity, instead of the traditional rigid multi-crystalline silicon wafers that are typically 150 µm thick.

The CIGS process is also more efficient.  SoloPower says they have achieved 19.9%, which is significantly better than most other solar generating systems.  It is also better than tests concluded earlier this year by the U.S. National Renewable Energy Laboratory (NREL) of  aperture conversion efficiencies of 11% – itself an improvement.

These low-cost, high-power, flexible thin-film photovoltaic modules from SoloPower offer a viable alternative to electricity produced from hydrocarbon sources.

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additional material from http://www.prnewswire.com/news-releases/solopower-launches-breakthrough-flexible-cigs-module-product-line-98216074.html and http://news.cnet.com/8301-11128_3-20010229-54.html

Solar Power Prospects Dim September 7, 2008

Posted by OldGuy in Alternatives, solar.
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According to an article in Scientific American, harvesting the sun’s rays for electricity production holds the promise of producing 2/3 our current and projected energy needs by 2050.  “Converting only 2.5 percent of that radiation (that falls on the USA) into electricity would match the nation’s total energy consumption in 2006.

The energy in sunlight striking the earth for 40 minutes is equivalent to global energy consumption for a year. The U.S. is lucky to be endowed with a vast resource; at least 250,000 square miles of land in the Southwest alone are suitable for constructing solar power plants, and that land receives more than 4,500 quadrillion British thermal units (Btu) of solar radiation a year. Converting only 2.5 percent of that radiation into electricity would match the nation’s total energy consumption in 2006.”

Unfortunately, that doesn’t include the costs to improve the technology.  For this magic to work means a 50% increase in efficiencies:  the article assumes 14 percent efficiency, but current state of the art is barely 10%, and efficiencies have been improving only slowly.

It also doesn’t account for the economic incentive to install that systems.  The current break-even point means that the solar generators would have to cost no more than $1.20 per watt, and the current cost is $4 per watt.  That means that when the article says it will cost $400B, the real cost is more than a trillion.

And you’d have to cover vast tracts of land, around 30,000 square miles of photovoltaic arrays. I know there’s a lot of open land in the southwest USA (the area around the Grand Canyon is pretty empty).  But you’d also have to solve transmission problems.

In short, despite the opportunities for solar power, the prospects aren’t near as bright as they’d have you believe.

Could the U.S. meet its energy needs with solar panels alone? April 8, 2008

Posted by OldGuy in Alternatives.
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It’s an interesting question. I’ve been reading posts about whether the US has enough energy capacity to meet existing, much less emerging demands.  Today, Pablo Päster, writing  at Salon.com. asked whether the US could meet its energy demand with solar alone.

Think about it.  Solar energy is free to us.  If not captured, its only purpose is to contribute to global warming.  Päster quotes Dan Berger, senior project designer at SPG Solar, as saying we would need about 54 square feet of solar collectors per person (at current efficiencies and current usage) to meet the annual demands.

(I hope he’s counting for days without sunshine – I spent time in Ohio this week, and it rained.)

How much land is that?  Berger says it would be 586 square miles – about one-third of Rhode Island.   I’ve driven across New Mexico and Nevada, and I know there’s sunshine for most of that sitting empty out there.  But then you’ve got the problem of moving the power to the east coast, where it’s needed.

And the materials.  Berger says that a typical solar panel contains between 800 and 1,570 grams of silicon per square meter.   Given current manufacturing rates, it would take over 12 years to make all the solar panels for the project – if (and only if) we stop using silicone for other purposes, like making computer chips.  So count on 20 years, just to be safe.  By then, the population (and the demand) will be ????

Factor all that in, and the answer is clearly no.  Solar is not the only answer.  It is a valuable component of the solution, but not the only answer.  Still, Päster got us thinking.  By mid-day, when I got a chance to read the post, there were already a number of thoughtful posts, plus a few rants!  Those comments alone make this a top read.

Go see for yourself here.