How the Navy’s Going Green

The USS Makin Island’s hybrid-electric propulsion is the future of aircraft carriers.

Smithsonian Air & Space Magazine
Story by Alan De Herrera and Chris J. Bahnsen
September 25, 2014

The USS Makin Island is a Wasp-class amphibious assault ship based out of San Diego, California. Alhough the ship, commissioned in 2009, is the eighth and last of its class, it was the first built with a hybrid-electric propulsion system that combines gas turbines with auxiliary motors running off the ship’s electrical grid. Having the most technologically advanced engines, Makin Island was also the most expensive of the eight ships to build, at $2.5 billion.

During the ship’s maiden seven-month deployment overseas, its unique propulsion system saved more than four million gallons of fuel—worth over $15 million—compared to a conventional steam-driven ship. Makin Island represents the Navy’s growing commitment to conservation and reducing fossil fuel use. It has been so successful that the Navy is now launching a series of these hybrid-electric amphibious assault ships. The USS America will be officially commissioned in San Francisco on October 11, 2014.

Photojournailist Alan de Herrera visited the Makin Island in May 2014.

Article - Smithsonian Air & Space magazine

USS Makin Island

The USS Makin Island on pre-deployment training ops off the Southern California coast. “We can move this 40-thousand-ton warship with the same power provided by our ship diesel generators that generate electricity to drive my [air conditioning], my lights, my television, my communications,” says Captain Holsey.

Machinist Mate 2nd Class Zachary Long

Machinist Long checks the variable speed drive for the auxiliary propulsion motor. The drive, he says, is “essentially the brains of the motor. [It] tells the motor how fast to go, and it steps down voltage into usable current so the motor will run.”

Hybrid-electric propulsion

The USS Makin Island can use hybrid-electric propulsion about 70 percent of the time. Above, one of two gas turbine engines that provide the ship’s main propulsion system during high speeds of 13 to 25 knots. Gas turbines can get up to speed much faster than a steam-driven, or boiler, ship. A boiler ship takes two to three days to get up to the proper temperature and pressure before it can even depart, whereas the Makin Island can depart the same day. At slower speeds of 12 knots or less, the ship switches to the quieter hybrid-electric motors, part of the diesel generators, which burn significantly less fuel than gas turbines would at slow speed and have zero emissions.

Machinist Mate 2nd Class Zachary Long

Machinist Mate 2nd Class Zachary Long works in the ship's electrical plant. "The console is specifically to monitor the gas turbine while it’s operating the auxiliary propulsion motor," he says. All of the ship's systems are run by a computer network that checks every component and alerts the crew if something is wrong.

USS Makin Island

CH-53E Super Stallion (Copy)

The ship uses a reverse osmosis system instead of chemicals to purify the water onboard. Leftover food is processed, chopped up and pushed over the side. “Everything that goes through the ship is dumped in the ocean clean,” says Captain Alvin Holsey, the ship's commanding officer. Above, a CH-53E Super Stallion leaves the ship in the more traditional way.

USS Makin Island (Copy)

Having thousands of marines and sailors aboard (above, conducting a post-flight inspection on an Osprey) means lots of waste, like plastic bottles and aluminum cans. No problem. “The plastics are separated, the metals are separated, the glass is separated,” says Captain Holsey. “We press them into pucks and turn them in to the city of San Diego when we come to shore.”

U.S. Marine Corps Osprey

In 2016, the Navy plans for biofuels to be used in up to 50 percent of all deploying ships and aircraft. On the USS Makin Island, the Navy expects $250 million in fuel savings over the 40-year lifetime of the ship. Here, a U.S. Marine Corps Osprey launches off the flight deck during training exercises.