The Coast Guard is working to identify energy-saving actions across the fleet. By Henry Canaday CGF Correspondent
Unlike federal agencies that consume energy mostly in fixed infrastructure, the Coast Guard’s largest energy consumers are vehicles like vessels and aircraft, noted Sam Alvord of the Office of Energy Management. Energy density has already been reduced in the Coast Guard’s shore infrastructure. “Our next focus is to reduce energy usage throughout our cutter fleet, whether underway or in port,” Alvord said. The service recently embarked on a series of energy audits of vessels. “We are in the formative stages of understanding where energy is being primarily consumed.” On February 1, the Coast Guard met with stakeholders to produce a preliminary list of possible economizing actions. Future lists could include energy-saving actions ranging from altered operating procedures to equipment modifications. Alvord hopes by the end of 2012 to have a final list of energy-saving actions that meet cost-benefit criteria. He noted that some engine interventions can also save maintenance costs, adding to financial savings. On the other hand, improvements must be assessed by specific ship, because remaining years of service affect returns on investment. A promising energy measure on vessels is upgrading heating, ventilation and air conditioning. These savings on vessel hotel load reap gains according to whether a vessel is operated in Alaska or in a hot, humid environment, and whether it is in port or underway. To assess behavioral or operating changes, the Coast Guard needs an energy dashboard and is collaborating with the Navy and Military Sealift Command as they investigate dashboard concepts. The Coast Guard may parallel certain aspects of the Navy’s Great Green Fleet effort, “but we face unique geographical challenges, like Arctic operations, that may necessitate slightly different approaches to energy
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management,” Alvord explained. In the service’s acquisition of new ships, fuel efficiency is an important element of ship design— even if not explicit in requirements. Commander Erich Bauer, offshore patrol cutter (OPC) ship design manager, noted that “meeting endurance range requirements more efficiently requires a smaller Erich Bauer fuel load on the ship, which leads to a ship with lower displacement. A lighter ship requires less propulsion power to meet high-speed requirements, leading to less powerful propulsion engines. Therefore, having an efficient plant decreases acquisition costs, a key element in design selection, as well as sustainment cost.” Ships’ propulsion systems have historically been optimized for high-speed requirements, resulting in poor performance at low speeds. “Large engines on legacy cutters, which do not have sequential turbo-charging, are not as efficient at low loads,” Bauer explained. In contrast with legacy cutters, the OPC will include requirements for continuous low-speed operation; Bauer said bidders have the flexibility to meet OPC requirements with a variety of configurations involving diesel engines and motors. One configuration is a father-son arrangement of two sets of diesel engines, with smaller ones sized for low speeds; another possibility combines larger diesel engines sized for high and medium speeds with an electric motor sized for low speeds.
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