US Army solar engine project

The United States Department of Defense has announced plans to develop a gigawatt of renewable electricity generation capacity at Army and Air Force installations by 2025.  In pursuit of this goal, U.S. armed forces branches are evaluating their technological options.  For a depot in Utah, the Army has reportedly selected a technology that uses concentrated solar energy to power mechanical engines.

Iconic Utah desert scenery: Delicate Arch, in Arches National Park.

Located about 45 minutes southwest of Salt Lake City, the Tooele Army Depot is designed to be the conventional ammunition hub for the western U.S., as well as a "peculiar equipment center" -- meaning a storage place for unusual weapons, munition and equipment.  Tooele is already home to the Army's first commercial-scale wind turbine, a 1.5-megawatt unit which was commissioned in 2010.

The site on the fringes of Utah's West Desert gets a lot of sun.  This may have led the Army to focus on solar energy technologies for a larger project.  According to reports by KSL, the Army has selected a company called Infinia to develop a solar energy project.   That project will entail 430 Power Dishes, modular units developed by Infinia.  Each Power Dish uses sun-tracking parabolic mirrors to concentrate solar energy on a chamber of helium gas.  The expansion of this gas drives a Stirling engine -- effectively a piston connected to a generator which produces electricity.  Each unit can produce 3.2 kW of alternating current power.

However, a recent vote by the Senate Armed Services Committee may dampen the Department of Defense's ability to develop renewable energy sources and limit the military's spending on renewable energy projects.  By 13-12 votes, the committee voted to block the construction of a biofuels refinery for the armed forces, as well as to prohibit paying more for alternative fuels than for traditional fossil fuels.