The US military has become an unexpected leader in clean energy, writes Chris Mooney in the Washington Post.

A new, one-million watt facility, the Mesquite 3 solar array, was just switched on in Arizona on Friday. The electricity generated will be sent to California, where it will provide power to that state’s 14 naval installations. There are 45 more such large-scale energy projects recently completed or under way—which is all the more impressive when you consider that there were none in the entire country as recently as 2010.

The US Navy and the Marines are experimenting not only with photovoltaics, but also with biofuels for planes, ships and vehicles, as well as encouraging their officers to be more energy-conscious.

Part of the thinking is that using less energy provides a tactical advantage — in some cases, it literally means the ability to fight for longer if you have to.