The dream of the Great Green Fleet came to life Wednesday as the aircraft carrier John C. Stennis left on its latest deployment, with five biofuel-powered ships alongside for the first time.
The destroyers Stockdale, Chung Hoon and William P. Lawrence, along with the cruiser Mobile Bay and the fast combat support ship Rainier, are all running off a biofuel blend made from tallow, or rendered beef fat, Navy spokesman Lt. Chika Onyekanne told Navy Times.
Navy Secretary Ray Mabus and Agriculture Secretary Tom Vilsack saw the strike group off from a pier in San Diego, the culmination of a seven-year effort by the Navy to deploy a carrier strike group with renewable energy.
The 10 percent biofuel, 90 percent petroleum blend can be used by ships without any change to equipment or procedure. However, it's a step down from the 50-50 goal that Mabus set for the Navy's ashore and afloat operations in 2009.
That plan is still on track, he told Navy Times in September, and the service has met that goal ashore as of 2016.
The Navy has tested a 50-50 blend, which fueled the Nimitz strike group and its aircraft during the first Great Green Fleet demonstration at the 2012 Rim of the Pacific Exercise, a mix of fossil fuel, algae oil and waste cooking oil.
The tallow biofuel, however, is a cost-competitive option that fulfills the Navy's mandate from Congress to purchase the fuels at prices comparable to traditional petroleum.
The tallow itself comes from Midwest cattle ranchers, Onyekanne said, and is then mixed with fossil fuels. The Navy's contract includes 77.6 million gallons of the blend at $2.05 a gallon.
That figure is slightly adjusted, as the real cost of the fuel is $2.19. With funds from the USDA's Commodity Credit Corporation, the Navy was able to cut $0.14 off the price per gallon, he said.
The program is available to help agencies defray costs of domestically-made blends containing 10 to 15 percent biofuel.
Though SECNAV's original vision had both ships and aircraft deploying on renewables, the Navy has not secured a contract for a drop-in jet biofuel blend and so Carrier Air Wing 9 will be operating on traditional fuel, Onyekanne said.
"With every solicitation of fuel that we have — and we have a four or five in the works — with every one, we’re going to solicit more blends of JP-5," he said.
Stennis and its strike group are scheduled for a standard seven-month cruise through 7th Fleet. The carrier Truman will be in 5th Fleet through May, and the Dwight D. Eisenhower deploys in late summer.
At one point, it is possible that Stennis will be the only carrier in either U.S. Central or Pacific Command, officials told Navy Times.
Meanwhile, in the rest of the surface fleet, commanding officers have been tasked with maintaining their own energy conversation initiatives as part of a year-long Great Green Fleet program throughout the Navy.
In a recent message from Naval Surface Forces in San Diego, ship captains were ordered to "make every effort to have at least three energy conservation measures or operational procedures in place whenever operationally feasible."
Some of these measures are already standard, Onyekanne said.
"The destroyers have stern flaps that help ease drag," he said. "Shipboard energy dashboards help them monitor how much energy they’re consuming."
Further suggestions include:
- Calculating optimal speed and using autopilot during transits.
- Using SPY-1 radar in low power when possible.
- Operating Aegis systems on low power when another Aegis ship is nearby.
COs will also have to report their energy-saving measures as of Jan. 1, then provide a weekly, consolidated round-up of their efforts to Surface Forces, according to the message.