Blueprint for 100% Renewable Energy Base in Germany
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The renowned German Fraunhofer research institute presented in 2012 a blueprint of how a 100% renewable energy base could be realized in Germany. From the summary (p31):
It is possible for Germany to have a 100% renewable energy base (electricity and space heating) with a cost comparable with today and equal electricity consumption. Assumed though is a reduction of 50% of energy required for space heating through insulation measures. Wind power opportunities need to be completely exhausted. Long term energy buffering can be done with methane gas produced from renewable electricity. Warm water production from solar collectors and industrial waste heat, combined with seasonal storage. Installed PV: 200 GW (1250 million m2), solar-thermal: 130 GW (190 million m2). 75% can be installed on existing building roof tops. Additional required surface area: 400 km2 (20 x 20 km) or 0.011% of Germany.
[ise.fraunhofer.de] – 100 % Erneuerbare Energien fuer Strom und Waerme in Deutschland (German)