Alternative Fuels, Efficient Propulsion Lead Navy Energy Efforts

By OTTO KREISHER, Special Correspondent

In response to Navy Secretary Ray Mabus’ ambitious requirement for a more energy efficient, or greener, Navy, Naval Sea Systems Command (NAVSEA) is working to develop alternative fuels for ships and aircraft and hybrid electrical energy power plants for its ships, the director of NAVSEA's engineering group said May 4.

Much of those efforts are directed toward meeting the secretary’s goal of sailing “the great green fleet” using alternative fuel sources and more efficient propulsion systems by 2016, George Drakely said in a NAVSEA briefing at the Navy League’s Sea-Air-Space Exposition.

On the alternative fuel initiative, the Navy is leveraging efforts in the commercial world, with a primary focus on algae-based fuels, Drakely said. His group is responsible for testing and certification of the proposed fuels.

The Navy’s primary requirement is that the substitute fuel be a “drop-in replacement” for current fuels, able to operate without a change in the ship or aircraft engines, he said. Currently, plans call for a 50-50 mix of the algae-based fuel and conventional fossil fuel.

Another initiative is developing an efficient hybrid electric drive system to propel ships at low speeds, allowing the gas-guzzling marine turbines to be idled until the ship needs to go faster, Drakely said.

An example of what that could mean is the recent trip of the amphibious assault ship Makin Island from the Gulf of Mexico to its new home in San Diego, he said. Using its hybrid electric drive, Makin Island saved an estimated $2 million in fuel during the voyage, he said.

The Navy now is developing a proof of concept for retrofitting a hybrid electric system into an Arleigh Burke-class destroyer, Drakely said. The proposal is to install an electric motor at the main reduction gear of the ship that could drive a propeller at slow speeds.