Special window shades at the U.S. National Renewable Energy Laboratory Research Support Facility (RFS) are seen in Golden, Colorado September 4, 2013. The 800 occupants of the RFS building consume ... more 
Special window shades at the U.S. National Renewable Energy Laboratory Research Support Facility (RFS) are seen in Golden, Colorado September 4, 2013. The 800 occupants of the RFS building consume only the amount of energy generated by renewable power on and near the building. REUTERS/Rick Wilking (UNITED STATES - Tags: ENVIRONMENT ENERGY) less 
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Reuters | Photo By RICK WILKING / REUTERS
Mon, Sep 9, 2013 12:43 PM EDT