June 30, 2016 8:31 AM EDT

The Department of the Navy is switching to renewable energy on land at a rate that’s five years ahead of schedule. That’s good for the environment and for sailors and Marines, who should be safer with fewer oil convoys to defend. Before the Navy set a goal of relying on renewables for half its fuel, “we were losing a Marine killed or wounded for every 50 convoys of fuel we moved into Afghanistan,” Secretary of the Navy Ray Mabus said in May in California. Its so-called “Great Green Fleet” has featured a nuclear-powered aircraft carrier and flotilla of accompanying ships steaming on a mixture of diesel and biofuel.

This appears in the July 11, 2016 issue of TIME.

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Write to Olivia B. Waxman at olivia.waxman@time.com.

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