Monday, July 12, 2010

Hybrid ships sail the seven seas

Going green is gaining popularity around the world and now ships in the U.S. and Indian Navy are joining the movement.
In October, 2009 the U.S. Navy commissioned its first hybrid amphibious assault ship. The USS Makin Island is the first U.S. Navy ship to feature a unique hybrid propulsion system that relies on two gas turbines or two diesel electric motors.
The hybrid propulsion system's gas turbines and electric motors operate independently. The General Electric LM2500+ gas turbines, which provide a total of 70,000 horsepower (hp), are used for high speed service, propelling the vessel to more than 20 knots. The two diesel electric motors combined provide 10,000 hp and are used for low speed operation.
According to the Honorable Ray Mabus, secretary of the U.S. Navy, the vessel's hybrid propulsion system, amongst other overall ship design enhancements, can be credited for helping save on fuel and maintenance costs. "Just two months ago, the Makin Island, our hybrid of the seas that uses an electric motor to power the ship at low speeds, went from where it was built in Pascagoula around to its homeport in San Diego. During that initial voyage alone, she saved close to $2 million in fuel costs. NAVSEA estimates at today's fuel prices the Makin Island will save $250 million over the lifetime of that ship, and it doesn't include reduced maintenance costs." Secretary Mabus said. Not to be outdone, in April, 2010, the Indian Navy commissioned the INS Shivalik stealth frigate at the Indian Navy’s shipyard in Mumbai. This first-in-class frigate is powered by two GE LM2500 aeroderivative marine gas turbines with two diesels in a COmbined Diesel Or Gas turbine (CODOG) configuration. This project marks the first LM2500-powered ship to enter service with the Indian Navy.
The 4,600-ton INS Shivalik measures 143 meters in length with a beam of 17 meters. The stealth frigate can reach its maximum speed of 30 knots when operating the gas turbines, and 18 knots cruising on the diesel engines. The Indian Navy expects to commission two sister stealth frigates -- INS Satpura and INS Sahyadiri -– each powered by two LM2500 gas turbines in a CODOG system.
GE also provided four LM2500 gas turbine kits to Hindustan Aeronautics Ltd. (HAL), Bangalore, which HAL assembled and tested for the Indian Navy’s indigenous aircraft carrier; the keel laying took place on February 28, 2009. This brings the total to 10 LM2500 propulsion modules HAL provided to the Indian Navy.
The amount of money these ships can save over their operational lifetimes is really impressive. We need more of these innovative ideas. Go Navy!

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