Navy Innovation Reduces Fuel Consumption at Sea

By Bob Freeman
Special to American Forces Press Service

May 22, 2009 - As the world struggles to manage increasing demands for energy, dwindling natural resources, a highly vulnerable environment and an economic downturn, the Navy is developing new technologies to significantly reduce energy consumption at sea. Lawrence Schuette, director of innovation at the Office of Naval Research, said the Defense Department spent about $17 billion last year on transportation costs.

"Navy ships account for roughly 40 percent of what we call logistics fuel consumption, that is fuel that we use to move something," he explained during an interview on Pentagon Web Radio's "Armed with Science: Research and Applications for the Modern Military" audio webcast, May 20.

Schuette discussed efforts by the Office of Naval Research, in conjunction with the Naval Sea Systems Command, to find innovative technologies to reduce fuel demand, consumption and improve the energy resilience of naval forces.

"We've had a long interest in making ships more efficient at sea, and we've done that by pioneering better hull coatings and better hull forms," he said. "Now we're looking at a hybrid electric drive ... to reduce fuel consumption on ships."

In addition to the obvious benefits to taxpayers of reducing cost, Schuette explained that hybrid electric drives provide greater operational capabilities by allowing ships to operate longer without refueling.

"And then there's the obvious carbon offset," he added. "We're not producing as much greenhouse gas as we steam at sea, and we see all three of these benefits as being important."

A key component of the hybrid electric drive is an uninterruptable power supply. Schuette explained that ships typically run two generators simultaneously to provide shipboard power requirements, with one acting as an emergency back-up for possible power loss. The uninterruptable power supply would allow ships to routinely run one generator.

"Only running one generator at 70 percent load versus two generators at 35 percent load saves about 10 percent of the fuel, somewhere on the order of six to seven thousand barrels of fuel a year. It's amazing," Schuette said.

Now that the hybrid electric drives have proven themselves in the laboratory, the next step is to actually build them for delivery and certify them for shipboard use.

"When it goes on a ship, we're going to understand it, we're going to characterize it, and we're going to make sure that the risks are well known," Schuette said. "Nothing is 100 percent safe, but you have to be able to understand and characterize those risks."

In addition to hybrid electric drives, Schuette said, the Navy is sponsoring research into alternative energy sources such as photovoltaics, hydrogen fuel and microbial fuel cells. When designing systems for shipboard use, space limitations must be considered so power density, an expression of energy concentration, also is an important factor, Schuette explained.

Another research initiative that Schuette discussed was in solid-state lighting. In addition to having significantly longer life than conventional fluorescent lighting, solid-state lights are more compact, require less energy, have no mercury to dispose of and do not require starters.

Schuette said a particular area of interest for naval research is in the development of autonomous systems, including air, surface and underwater vehicles. Using relatively small, unmanned systems to accomplish various operational missions can also result in energy savings.

"You know, we do all of this for three right reasons. It makes our sailors and Marines more capable at sea, it reduces the cost to the taxpayers, and it's also better for the planet," Schuette said.

(Bob Freeman works in the Office of the Oceanographer of the Navy.)