It doesn't drop off that much. 7% less power at 45C vs 30C. Arizona has world class sun and big daytime cooling peaks. Perfect situation for Solar PV. There are also big federal incentives for new grid scale solar. 30% refund and a $0.03/ kWh feed in tariff.
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Why does Arizona have almost no solar? And gets most of it's electricity from coal? Along with exporting coal electricity for 20% of California's demand.
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http://www.reuk.co.uk/wordpress/sola...-solar-panels/
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