It takes energy to produce, deliver and install PV. In 1981, Bill Yerkes was asked how much energy is consumed to produce a photovoltaic cell. Bill was one of the 3 Spectrolab engineers who developed low-cost, single-crystal silicon solar cells in 1974 and founded the company that became Arco Solar in 1978. From the September 1981 issue of the Arco Solar News: "The major raw material for most solar arrays is silicon in which the newer processes consume a total of less than 2 kWh per eventual watt of solar array (compared to older processes which consumed about 19 kWh/watt). Converting metallurgical grade silicon (97 percent pure) to the high purity required for the solar cell remains the major energy investment. Fabricating the cell and manufacturing the module adds about 1 kWh per eventual watt of solar array-about 30 percent-to the energy investment. This energy investment is then returned at the rate of about 2 kWh per watt per year. The energy payback period for 1981 solar arrays, using newer processes, is two to three years."
PV production and solar cell efficiency have improved dramatically during the past 31 years. See http://www.nrel.gov/docs/fy04osti/35489.pdf Some people use 180 kWh/day to power their home. And some wrench will use gasoline to power their pickup truck to transport people, tools and equipment to that home to install PV. Both adversely affect the environment. With patient guidance both will improve dramatically over time. Joel Davidson ----- Original Message ----- From: [email protected] To: RE-wrenches Sent: Thursday, March 15, 2012 12:42 PM Subject: [RE-wrenches] embedded energy in pv i recently read that it takes the equivalent energy of between 1 and 4 tons of coal to make a single pv module. this is why i insist my customers do their efficiency upgrades and learn how to be frugal/conserve before i will even talk about pv with them. renewables powering waste is old paradigm thinking. consuming less is always a win win. unfortunately (now that there is an incentive program) the new "solar experts" coming on the scene here make more $$ with bigger systems, so lipstick on pigs is becoming the norm. one customer wanted pv because her electric bill was over $600.00/month or 180 kWh/day!! i said there was something wrong with a power bill that high. maybe a duct on her heat pump had come loose and was blowing hot air into the attic and that should be investigated first with an energy audit. she hired another "expert" who put in a massive system. personally, i find it difficult to support this kind of resource use. todd On Thursday, March 15, 2012 6:26am, "Solarguy" <[email protected]> said: William Attached is a Power Point slide I made that shows the 'energy payback' from PV. The Swiss based IEA Photovoltaic Power Systems Programme takes a very serious look at the PV industry and its long term effects on the planet and PV is already pretty benign. While I don't know the logic behind their calculations my first thought is that with the volume of aluminum being extracted and produced for all industry world-wide, the impact by the PV industry is probably next to nothing. And using a plastic compound would mean using a crude oil based product which is even a bigger environmental blight than aluminum production-imo. Besides, with the PV industries rush to lower prices someone would have discovered a cheaper non-metallic replacement for aluminum if it is out there. Having worked for many years in the composite/plastics industry I can say that the production of a substitute fiber re-enforced compression molded composite for PV frames would be more costly than aluminum and most likely still never match the rigidity of aluminum. Now if the PV industry trended back to smaller modules a 'plastic' frame could become workable but I don't see that moving out of R&D as long as prices and margins are so low. And I don't see a corrosion resistant module becoming a niche market any time soon unless another "Silicon Energy" type entrepreneur decides there is a market. Jim Duncan **** -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of William Miller Sent: Wednesday, March 14, 2012 9:13 PM To: RE-wrenches Cc: 'RE-wrenches' Subject: Re: [RE-wrenches] Installations in High Salt Spray Environments Marco: Are we in need of a new generation of PV modules with plastic frames? How about frame-less modules on recycled plastic racking? What is the energy cost for aluminum frame modules versus plastic or recycled plastic? What is the energy cost of anodizing aluminum frames and racking? There is a need here folks, that is not being filled. Entrepreneurs, where are you? William Miller At 06:51 PM 3/14/2012, Marco Mangelsdorf wrote: >Living here in the middle of the big Blue Pacific Ocean where one is >never all that far from the ocean, I really question how well any metal >is going to hold up over time, no matter what the warranty says. > >Even stainless rusts in these here parts. > >Installer beware and for sure don’t put yourselves at risk by >providing anything more than the modco’s factory warranty. > >marco > _______________________________________________ List sponsored by Home Power magazine List Address: [email protected] Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org <<...>> Sent from Finest Planet WebMail. ------------------------------------------------------------------------------ _______________________________________________ List sponsored by Home Power magazine List Address: [email protected] Options & settings: http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org List-Archive: http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org List rules & etiquette: www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.org
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