Project uses seawater to cool Waikiki

A company seeking to develop what would be Hawaii’s second seawater air-conditioning project said it has received letters of intent from some of Waikiki’s biggest hotels and other businesses interested in the electrical savings promised by the plan.

Kaiuli Energy has received authorization from the state to issue $200 million in special-purpose revenue bonds for the project that could replace conventional air-conditioning systems in an area stretching from Kaka­ako to Waikiki by 2018.

Potential customers that have signed letters of intent include the Hawai‘i Convention Center, Royal Hawaiian Resort, Royal Hawaiian Center, Sheraton Waikiki, Westin Moana Surfrider, Sheraton Waikiki and the Hilton Hawaiian Village, said Darryl Naka­moto, a partner in Kai­uli Energy.

With roughly 40 percent of a typical hotel electrical bill going to run conventional air-conditioning systems, using naturally chilled deep seawater could produce significant cost savings for hoteliers, Naka­moto said in a panel discussion at the Asia Pacific Clean Energy Summit. The Energy Summit, which began Monday at the convention center, ends today.

"Electric rates are effectively out of control for hotels," Naka­moto said. "Instead of paying HECO for electricity, they can use chilled seawater at a lower cost," he said.

Among the hurdles Kai­uli must clear are obtaining the necessary permits, securing property easements and conducting an environmental impact statement.

Kaiuli Energy will be able to apply lessons learned from a project further along in the development process that proposes to use cold seawater to provide air conditioning in downtown Hono­lulu, Naka­moto said. The start date for that project, first proposed in 2004, has been rolled back several times. The developer, an affiliate of Minnesota-based EverGreen Energy LLC, now expects to break ground on the downtown system sometime next year.

The $225 million Waikiki project would use a pipe to tap frigid waters at a depth of about 1,800 feet and about five miles off Waikiki. The system would pump up 42-degree water and run it through a heat exchanger that would in turn be used to chill a closed loop of fresh water. The freshwater loop would pipe cold water to the buildings for their air-conditioning systems, while the seawater exiting the heat exchanger would be returned to the ocean at a depth of about 350 to 400 feet.

The company tentatively plans to run the intake pipe through the Ala Wai Canal and out to sea through the boat channel at Ala Wai Harbor, Naka­mura said. The company also is considering pumping seawater from the heat exchanger into the Ala Wai Canal to help create better water flow in the canal, he said.