The United States Navy is taking a big leap forward in "greening" its 50,000-strong, gas-guzzling fleet of vehicles, committing to a 50 percent cut in oil use by 2015, the Secretary of the Navy Ray Mabus declared in a speech at the Naval Energy Forum. That's not all. Mabus said the Navy will attempt to get 50 percent of its total energy from alternative sources by 2020, including its ships, aircraft, tanks, vehicles and bases. Currently, that figure is at 17 percent. The reason: The Navy's imported oil addiction is socking the service with billions of dollars in losses. The...