Hawaiian Electric Co. has signed up to switch from an oil-based cooling system for its Richards Street office building downtown to using the Honolulu Seawater Air Conditioning LLC cooling system once the new plant is complete and ready for operation in 2013.

“Honolulu Seawater Air Conditioning is offering a renewable alternative to conventional cooling methods to some of the state’s heaviest users of air conditioning,” said Hawaiian Electric executive vice president Robbie Alm, in a statement. “This is an excellent use of local resources – in this case, one of Hawaii’s most sustainable natural resources, seawater – to meet our clean energy goals and ensure we have a diverse portfolio of renewable energy sources.”

Bill Mahlum, president and CEO of Honolulu Seawater Air Conditioning, noted that having large companies like Hawaiian Electric join in will help make the new venture successful.

Current plans call for the project to start construction early in 2012 and begin providing chilled water services to customers in 2013. It will utilize deep ocean water to deliver renewable cooling to both commercial and residential properties. At full implementation it could reduce potable water use for air-conditioning by more than 260 million gallons, reduce sewage by up to 84 million gallons and avoid emissions of 84,000 tons of carbon dioxide annually.

Ultimately this will eliminate the need for 178,000 barrels of oil annually, therefore helping to cut the state’s oil dependence.

Mahlum said the new plant will help put Honolulu on the path to being the ‘greenest’ downtown in the nation.

This project has been a long time coming. Here’s a story we ran on the project in the December 2007 issue of Hawaii Business magazine.