Warships going green

USS George Washington in HK

USS George Washington in HK

Blue Skies China took a tour of one of the US Navy’s leading nuclear-powered aircraft carriers, the USS George Washington, in Hong Kong this week, witnessing one of the largest examples of a non-fossil fuelled strike force ahead of the Navy’s first extensive exercise into what it calls the “Great Green Fleet” in the Pacific Rim.

“One of the five energy goals laid out by the Secretary of the Navy Ray Mabus in 2009 is to demonstrate and then deploy a ‘Great Green Fleet,’ a Carrier Strike Group fueled by alternative sources of energy, including
nuclear power,” explained Lieutenant Commander James Stockman, Public Affairs Officer aboard the ship.

The USS George Washington is not part of the Great Green Fleet exercise, but as a US Navy’s only forward-deployed aircraft carrier, it is the same class nuclear powered aircraft carrier as USS Nimitz, which is participating in the 2012 Rim of the Pacific (RIMPAC) exercise, the world’s largest international maritime exercise.

Nuclear ship avoids 240,000 tonnes CO2/yr

Nuclear ship avoids 240,000 tonnes CO2/yr

According to Stockman, USS George Washington’s nuclear plant is consistent with the Navy’s 2009 goal of using alterative sources of energy. “While providing war-fighting advantages when compared to conventionally-powered ships, the operation of a naval nuclear-powered ship also avoids releasing significant amounts of greenhouse gases to the environment,” he said.

An aircraft carrier powered by fossil fuels burns approximately 500,000 barrels of oil per year. ”This, in turn, generates approximately 240,000 tons of carbon dioxide, equivalent to the amount of carbon dioxide generated annually by almost 40,000 passenger vehicles. Since the US Navy has 11 nuclear-powered aircraft carriers and 72 submarines, the amount of carbon dioxide avoided annually by naval nuclear-powered warships is equivalent to over 800,000 passenger vehicles,” said Stockman.

While nuclear power has long been a part of the US Navy aircraft carrier and submarine fleet, other non-fossil fuels have yet to be tested under fire on any large scale.

LCdr. James Stockman

LCdr. James Stockman

For other ships and aircraft, the navy has experimented with biofuel consisting of a 50/50 mix of regular petroleum fuel and algae-derived, hydro-processed oil. This biofuel is cheaper than traditional fuel – its performance in battle will be determined by the Great Green Fleet exercise, the first time the ships have been put through their paces powered by bio-fuel on any large scale.

Approximately 450,000 gallons of 100% “neat” biofuel were purchased in 2011 in preparation for the Great Green Fleet demonstration at a cost of US$12 million. Navy surface ships will be powered using 350,000 gallons of hydroprocessed renewable diesel (HRD-76) blended with an equal amount of marine diesel (F-76). Navy aircraft will burn 100,000 gallons of hydroprocessed renewable jet fuel (HRJ-5) blended with aviation fuel (JP-5).

Republican senator John McCain has criticized the green initiative. “I don’t believe it’s the job of the Navy to be involved in building … new technologies. I don’t believe we can afford it,” he told Reuters.

Additional reporting: Cadence Poon

About James Ockenden (226 Articles)
A writer covering international energy and power markets since 1996
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