On May 25, 2014, at 7:26 AM, Cor van de Water via EV <firstname.lastname@example.org> wrote: > I'd like to know where you heard that (incorrect) tidbit > about solar panels having more energy content than they generate.
My assertion, more specifically, was that that was true for places that weren’t essentially cloudless deserts. And you’re right, and I’m wrong. I was misremembering the primary source of my information as David JC MacKay’s _Sustainable Energy Without the Hot Air_, backed by two different friends in different PV manufacturing companies who’ve told me about the energy costs of refining silicon to the point at which you can make a PV panel that will pass quality control. Which, if I’d been remembering correctly, would have made me secure in my assertion. However it seems only the two anecdotal sources support the high-embedded-cost notion, and they’re not quantifiable. http://www.withouthotair.com/c6/page_41.shtml "The energy yield ratio (the ratio of energy delivered by a system over its lifetime, to the energy required to make it) of a roof-mounted, grid-connected solar system in Central Northern Europe is 4, for a system with a lifetime of 20 years (Richards and Watt, 2007); and more than 7 in a sunnier spot such as Australia. (An energy yield ratio bigger than one means that a system is A Good Thing, energy-wise.) Wind turbines with a lifetime of 20 years have an energy yield ratio of 80.” Also: http://sunlightsolar.com/img/PV-Embodied-Energy_Home-Power-mag.pdf pp. 34 http://www.resilience.org/stories/2006-06-16/energy-payback-roof-mounted-photovoltaic-cells http://www.sciencedirect.com/science/article/pii/0360132395000534 These various sources calculate the payback time in relatively normal environs as being between 1.5 and 12 years. Which, given the number of variables being hand-waved about, is a reasonable degree of variation, and in all cases less than 20. So, thank you for correcting me. -Bill -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140525/4d072151/attachment.htm> -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 841 bytes Desc: Message signed with OpenPGP using GPGMail URL: <http://lists.evdl.org/private.cgi/ev-evdl.org/attachments/20140525/4d072151/attachment.pgp> _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub http://lists.evdl.org/listinfo.cgi/ev-evdl.org For EV drag racing discussion, please use NEDRA (http://groups.yahoo.com/group/NEDRA)