The Army says it wants to build what could be the world's most powerful solar power plant, as part of a far-reaching effort to cut back on the service's dependence on fossil fuels. The question is whether the Army will actually make good on its green promises.

Currently, the most powerful photovoltaic array in the country is at Nellis Air Force Base, outside of Las Vegas. It generates about 15 megawatts of power. Other plants are in the works in New Mexico, Arizona and California that could produce up to 300 megawatts.

Yesterday, the Army declared that it would "partner with the private sector to construct a 500-megawatt solar thermal plant at Fort Irwin, California, in the Mojave

Desert, that will provide renewable power on the grid and provide the sprawling Army post with added energy security against disruption of power supply."

The U.S. military has been making all sorts of bold declarations in recent years about the need to wean itself from fossil fuels. It is "imperative" that the Department of Defense "apply new energy technologies that address alternative supply sources and efficient consumption across all aspects of military operations," thundered one Pentagon report.

"Effectively immediately,"

shouted another, Pentagon planners must factor in "energy efficiency"

when designing "all tactical systems." That's because the Defense

Department is not only one of the world's largest consumers of oil and gas — slurping up "110 million barrels of premium fuel and 3.8

billion kilowatts of electricity at a cost of $13.6 billion," as *Defense News *notes. But the stuff is ridiculously expensive: War-zone fuel prices can reach up to $400 per gallon.

The military's record of answering those clarion calls has been uneven, however. For every promising, isolated effort — wind-powered bases, garbage-munching generators in Baghdad — there have been disappointments, too. Long-promised hybrid Humvees never materialized. "Urgent" pleas from battlefield commanders for green power stations were negged by the Pentagon brass.

In a statement, the Army claims this effort will be different, because it's putting in place a "Senior Energy Council to serve as a board of directors focusing on Army energy policy, programs and funding to leverage the Army's nationwide energy-conservation efforts."

The service also announced a number of "test" programs that the new council will oversee. There's the solar plant at Fort Irwin. A

"geothermal project at Hawthorne Army Depot, Nevada, with the capability of producing 30 megawatts of clean power." Six more posts that will experiment with "biomass to fuel" efforts. And the purchase of 4,000

electric vehicles "to replace gasoline-powered vehicles traditionally used by maintenance and operations staff for use on its posts." Whether any of these projects will actually be completed — or whether they add up to any kind of coherent alt-power, alt-fuel strategy — remains to be seen.

UPDATE: Check out Wired Science's fascinating look at a whole new kind of solar array.

UPDATE 2: As RK notes, Pacific Gas and Electric recently announced contracts for 800 megawatts of solar energy – including a 550 megawatt "solar farm" in San Luis Obispo County, California. It's slated to be on line by 2013. Take that, Army!

[Photo: USAF]

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