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Panel: Navy will need oil for decades

Even as designers experiment with new ways to power the warships of the future, the surface Navy will remain dependent on fossil fuels for at least the next 40 to 50 years, a panel of naval engineers said Tuesday.

Cruisers, destroyers, amphibious ships and littoral combat ships all will probably continue to need some kind of fuel oil, no matter what advanced propulsion systems are fitted or back-fitted on ships, said engineer Alan Roberts. He appeared with colleagues before a meeting of the American Society of Naval Engineers outside Washington.

His talk underscored a larger theme of the engineers’ meeting: That the Navy must make the most efficient use of the world’s dwindling supply of oil, even though the costs of crude have eased significantly compared to their record-setting peaks this summer.

The Navy and the larger oil-burning world are only enjoying a “holiday” or a “grace period,” on fuel costs, but it wouldn’t last, said another panel member, Capt. (sel) Lynn Petersen, deputy director of the Navy’s electric ships office.

Advanced research, electric propulsion systems and new engine materials are a few of the recommendations panel members offered for the surface Navy to use fuel more efficiently.

An earlier speaker, Congressional Research Service shipbuilding expert Ron O’Rourke, suggested the Obama administration and the incoming Democratic-controlled Congress would support Navy research on using less fuel and cutting back on the Navy’s emissions of greenhouse gasses. That research could produce an alternative to more nuclear-powered surface ships, which key lawmakers have said is the answer to rising fuel costs.

The two senior-most members of the House Armed Services Committee’s seapower subcommittee — chairman Rep. Gene Taylor, D-Miss., and ranking member Rep. Roscoe Bartlett, R-Md. — both have advocated for a new generation of nuclear-powered destroyers, cruisers and large amphibious ships.

Bartlett especially is a believer in the “peak oil” concept, O’Rourke said, the idea that the world will pass a point at which oil production declines, with potentially disastrous consequences. Nuclear power frees the Navy from oil’s financial and operational puppet strings, Taylor and Bartlett have said, but Navy leaders have resisted because of the high upfront costs of building nuclear ships. A new generation of efficient, hybrid electric propulsion plants could let the Navy point to a cheaper alternative to nuclear power.

The technical details of that alternative were the subject of many presentations at the ASNE conference.

Navy surface warships today use mechanical propulsion systems to make them go: Main engines turn drive shafts, which turn the propellers that push the ships through the water. Ship’s service engines, running separately, provide the electricity for the “hotel load” of lights, weapons and combat systems.

Tomorrow’s integrated electric plants would use the main engines to generate electricity, then send that power throughout the entire ship. So the machines turning the ship’s propellers would be powered by electricity, instead of directly by the engines, and the additional electricity would be available for high-powered weapons such as lasers and new power-hungry sensors.

This propulsion system, common in civilian vessels, enables designers to free a ship’s main engines from its interior spaces, said retired Capt. Read Truddenham, a General Electric turbine expert. For example, the luxury liner Queen Mary 2 has its gas turbines “on the roof,” Truddenham said, directly under its funnel, rather than deep below the waterline.

Although they promise greater fuel efficiency and more power, presenters said the integrated electrical plants are much more complex than today’s engine rooms, and still require a great deal of research and work before they realize their potential.

Among other innovations, they’ll require advanced gas turbines made from resilient new materials that better withstand breathing salty ocean air, said Dave Shifler, a turbine expert with the Office of Naval Research. And they’ll require as-yet undeveloped batteries to store energy in case an engine unexpectedly goes down, Petersen said. The key to it all, he said, is continued funding for propulsion research.