Washington ? The Navy plans to test-fly its main attack aircraft, the F/A-18 Super Hornet, on a biofuel blend this Earth Day, part of an ambitious push by the Pentagon to increase U.S. security by using less fossil fuel.

While deliberations grind on in Congress about how to shift the nation’s energy away from fossil fuels, the Defense Department is putting plans into action with such things as electric-drive ships that save fuel costs, solar-based water purification in Afghanistan that reduces the need for dangerous convoys, and solar and geothermal power at U.S. bases.

The changes eventually could spread to civilian life. The size of the military’s investment will create economies of scale that help bring down the costs of renewable energy, and military innovations in energy technologies could spread to civilian uses, just as the Internet did.