A year ago, U.S. Marines operating in the Arabian Desert only viewed the sun as the source of the region’s relentless heat.  Recently, the Office of Naval Research (ONR) Advanced Power Generation Future Naval Capabilities program introduced technology that allows the Marines to harness some of that sunshine to help power their field equipment. Fueled by the sun, the Ground Renewable Expeditionary ENergy System (GREENS) is a 300-watt, photovoltaic/battery system that provides continuous power to Marines in the field. ONR began exploring the GREENS idea in fall 2008 in response to a Marine Corps requirement from Iraq for an expeditionary renewable power system. Credit: Office of Naval Research