Two weeks ago, the Department of the Interior announced plans to open public land to renewable energy projects. Yesterday, it became public that the Department of Defense wanted in.

A memorandum of understanding between the two departments [PDF], signed July 20, outlines ways in which they’ll collaborate in order to “enhance the energy security and reduce the energy costs” of Defense installations. The San Francisco Chronicle reports:

The military also has a “solar car,” of which the less said, the better. (Photo courtesy of the U.S. Army.)

The U.S. Defense Department will encourage companies to build solar power plants and wind farms on 16 million acres of open land surrounding military bases, making each base less dependent on the nation’s aging electricity grid.The plan, announced Monday, will help the military cut its $4 billion annual energy bill and help insulate bases from blackouts. About 13 million of the acres involved lie in Western states, primarily California, Arizona and Nevada. …

Solar, wind, geothermal and biomass facilities developed near military bases will be used primarily to power those facilities. But the projects will be big enough that the private companies that finance and build them will be able to sell some excess energy to other users.

The Defense Department — and, in particular, the Navy — has been pursuing renewable projects across the board. Expanded access to public land will lead to more renewable energy installations.

Elsewhere in Washington, the White House today announced seven major renewable energy projects that will be fast-tracked for permitting. Once complete, the projects (in Arizona, California, Nevada, and Wyoming) will create 5,000 megawatts of energy — enough to power 1.5 million homes.

It’s worth noting that the time frame on some of the permits announced by the administration extend past January 2013 — the date at which Mitt Romney would be inaugurated as president. Given the Obama campaign’s new efforts to attack Romney over the wind tax credit, today’s announcement could also come up on the campaign trail.

It’s certainly refreshing to see Washington (and Arlington) moving boldly on renewable energy. Too bad it’s taken so long.