The U.S. solar energy industry more than doubled its installations in 2010, according to a report released on March 10 by the Solar Energy Industries Association. In total, 878 MW of photovoltaic capacity and 78 MW of concentrating solar power were installed across the country in 2010. The group says the growth was driven by federal programs and the expansion of state incentives as well as by cost declines of about 8% for photovoltaic systems. U.S. solar market installations grew from $3.6 billion in 2009 to $6 billion in 2010, the group says.
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.