The US Navy unveiled plans Monday for its biggest-ever biofuel purchase as part of an effort to reduce dependence on imported oil.

US Navy Secretary Ray Mabus said the 450,000 gallons (1.7 million liters) were part of the "largest single purchase of advanced drop-in biofuel in government history." The biofuel also "comes from non-food sources and does not increase the carbon footprint."

The purchase aims to meet President Barack Obama's goal "to achieve more energy security by finding ways to lessen our dependence on oil and fossil fuels," Mabus said.

The Defense Department will purchase biofuel made from a blend of non-food waste, including algae produced by Solazyme and used cooking oil from the Louisiana-based Dynamic Fuels, LLC, a joint venture of Tyson Foods and Syntroleum Corp.

The fuel will be used in the US Navy's demonstration of a "green strike group" in 2012 during the Rim of the Pacific Exercise, the world's largest international maritime exercise off the coast of Hawaii.

Mabus said the entire strike group, including aircraft and ships, will use a 50 percent biofuel blend, mixed with diesel for the ships, and aviation fuel for the aircraft.

By 2016, the Navy aims to send a carrier strike group on a normal, multi-month deployment using 50 percent biofuels for both surface ships and aircraft.

The biofuel is considered a drop-in fuel, meaning no modifications to the engines are required.

US Agriculture Secretary Tom Vilsack, who joined in the announcement, said the move helps improve energy security "by basically producing our own fuels in a creative and innovative way."