Hooray, Arrays! Image Courtesy of NREL The National Renewable Energy Laboratory in Colorado. Thanks to its arrays of photovoltaic cells with a total production capacity of 973 kW, the nation's largest net-zero energy-use building produced as much energy as it used on June 22. National Renewable Energy Laboratory researchers in the Dept. of Energy's 220,000-sq-ft Research Support Facility expect the Golden, Colo., building to achieve NZEU for the month of July, assuming the sun continues to shine. DOE's Jeffrey M. Baker, the facility's visionary and ENR's 2011 Award of Excellence winner, reports the year-old building is performing as designed (ENR
Arch dams, classically curved monoliths situated in narrow valleys, are not as common as other types of dams, such as embankment dams and gravity dams. ENR takes a look at some of the biggest arch dams in the world, both completed and under construction.