PHOTO: MMA RENEWABLE Ventures

In the middle of the Mojave Desert, a nondescript two-story building behind a gated fence houses an unlikely group of geologists. Their lineage is strong: several generations of prospectors have been drawn to dig in this dry corner. Within 100 kilometers of the geologists' base near China Lake, Calif., 19th-century gold diggers stumbled on riches, and later oilmen got lucky in the same inhospitable soil. Now these earth-minded fellows have grand ambitions of their own. Their aim is to turn the U.S. Department of Defense into one of the world's largest users of geothermal energy.

Their vision isn't all a pipe dream. The rising cost of fuel has the Pentagon pressuring the four branches of the armed services to cut their energy bills wherever they can. It's easy to see why—every US $10 increase in the price of a barrel of oil costs the Air Force, for example, an extra $600 million. The Army, Navy, and Marines, too, are tearing through their budgets. In response, energy managers at bases across the country are reevaluating how they light, insulate, heat, and cool their buildings. The most ambitious of these managers have begun aggressively adopting renewable-energy technologies. Together they have emerged as a distributed network of clean-energy advocates. The irony, of course, is that these military men and women should form such a group at the heart of one of the most energy-intensive operations on the planet.

Among them are these desert geologists. Employed by the Navy, they are responsible for one of the largest geothermal power plants in the United States, a 270-megawatt generation facility at Coso Hot Springs, at China Lake. In the next few years, these scientists hope to figure prominently in a Department of Defense plan to generate 25 percent of its electricity from renewable sources by 2025.

For an organization that spent $13 billion on energy in 2007 and has a War on Terror to finance, whittling away at domestic electricity bills, which account for only one-fourth of that figure, may seem like a silly exercise. The scale of the projects and the savings, though, prove that the military is not merely indulging in a public-relations ploy. Not counting the geothermal power plant, the Defense Department says that in fiscal year 2007 it had produced or bought enough renewable energy to cover 11.9 percent of its electricity needs, which amounts to about 1.3 trillion kilojoules a year.

“There's been a shift in the last five years, where more people are actively trying to do the right thing inside the agencies, and I don't believe it's simply because of high energy costs,” says John Archibald, a former deputy director of the U.S. Department of Energy's Federal Energy Management Program. “Many are aware of the global-warming issue, and quite a few have signed on that this is something we need to address.” Until recently, military planning and environmental stewardship rarely overlapped, except when it came to cleaning up toxic-waste sites and managing “the bugs and bunnies,” as some government officials refer to habitat-conservation projects on federal land.

That attitude has begun to change. Many defense staffers cite specific legislation—the Energy Policy Act of 2005, which set clean-energy milestones for the federal government, and the Energy Independence and Security Act of 2007, which adopted the 2025 benchmark as a goal for the whole country. But the language surrounding the goal is weak and provides no direction. To Thomas Morehouse, a consultant for the Institute for Defense Analyses, a think tank in Alexandria, Va., the energy legislation alone doesn't explain the DOD's greenish inclinations. “There is no energy policy. There is no coordinated Defense Department program for renewable-energy deployment and no single office in the Pentagon that tracks it,” he says. “The projects so far happened largely because you get a particular base commander somewhere who's enthusiastic about doing this and puts in the effort to make it happen.”

Indeed, bolstered by edicts from the upper echelons of government, energy managers at individual bases have begun to act on a conviction that climate change and a constricted energy supply could make for an ugly future. What has emerged is a patchwork of energy-sustainability projects. Some of them have been record setting, others are barely noticeable, but together they attest to a growing concern about the DOD's annual consumption of some 912 terajoules, almost 1 percent of U.S. energy use.

As Don Juhasz, chief of energy and utilities for the U.S. Army, puts it, “There are enough of us deep within the DOD who see that, long term, if we're going to be here 50 years from now, we need to be leaders and drive the country towards the future we want. We need to set the example.”

The Naval Air Weapons Station, in China Lake, Calif., sits on a hilly plot of arid land about 240 km east of Los Angeles. The California wildfires recently smoldered down from the mountains to the west, but a sudden downpour this past July briefly painted the Joshua trees and ankle-high brush a perky green. From the Geothermal Program Office, manager Andrew Sabin dispatches his crew to check out promising geothermal spots across the Southwest. This summer, they were investigating California's Chocolate Mountains, where the Navy and Marines test aerial weapons. “It's probably one of the hottest spots on Earth, literally and figuratively,” Sabin says. In theory, this region could produce more than 600 MW, an enormous figure given that the total geothermal electric power generation in the United States today adds up to about 3000 MW, according to the Geothermal Energy Association.