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Plan to cool downtown by sea water advances

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Plan to cool downtown by sea water advances

Source: Honolulu Star Bulletin

With an eye toward laying a pipe to deep water offshore, Honolulu Seawater Air Conditioning has contracted with Fugro Seafloor Surveys for detailed data using this autonomous underwater vehicle, shown off Honolulu with Koko Head in the distance.


Plans are moving forward on a project that intends to help the state take a huge step forward in its ambitious goal of energy independence.

Under the renewable energy project being developed by Honolulu Seawater Air Conditioning, dozens of downtown buildings would be cooled by chilled deep-ocean water pumped to the surface and circulated throughout their cooling systems.

Honolulu Seawater Air Conditioning, which has secured a commitment of $10.75 million in investments from about two dozen Hawaii companies, plans to break ground in June, and filed the draft environmental impact statement for the project last week.

"That is a huge milestone," said William Mahlum, the company's president and chief executive officer.

The draft EIS means processing now can begin on the project's various permits to move the plans forward.

State officials are keeping a close eye on how the project proceeds.

The deep sea water cooling system is one of the "top projects" being watched by the state Department of Business, Economic Development and Tourism, which is charged with implementing the state's energy strategy.

"I am truly looking forward to them proving this concept in Honolulu," said Ted Liu, director of the department. "There are several other dense, urban areas that I think are extraordinarily appropriate for us to roll out this technology.

"In particular, I'm thinking Waikiki."

The concept is nothing new.

Chilled deep water has been used for two decades to cool buildings at the Natural Energy Laboratory of Hawaii at Keahole Point on the Big Island. Other systems have been in place for years at other areas - including Cornell University, Toronto and Scandinavia - where the location provides a deep-water source.

The Honolulu project - estimated at about $152 million - is perhaps one of the most ambitious.

Local investors include Makai Ocean Engineering, Yogi Kwong Engineers LLC, Ace Land Surveying, Lyon Associates Inc., InSynergy Engineering Inc. and The Environmental Co. Inc., among others, according to Honolulu Seawater Air Conditioning. An additional $100 million is coming from tax-exempt bonds authorized by the state Legislature, and $22 million is taxable debt, with the balance to be covered by construction equity.

The system would draw water from the ocean floor four miles off the Kakaako coast at a depth of 1,600 feet, where water temperature is 45 degrees year-round.

That water would be sucked up to a 25,000-square-foot pumping station, to be located near the Gold Bond Building in Kakaako, where it then would be distributed to the air-conditioning systems of public and private buildings in an area roughly bounded by Nuuanu Avenue, Vineyard Boulevard and Ward Avenue along the Kakaako shoreline.

Water is then pumped back out to sea to a warmer, shallower depth.

About 40 clients have stated an interest in converting to the sea water cooling system, officials say. Service would begin in November 2010.

The company estimates that converting to the renewable energy system could cut electrical use by as much as 75 percent.

"It's a very attractive thing to convert your building," Mahlum said. "Under our current presentation to customers, all customers save money the first year. They leave the electricity-intensive project, and they join our system and they save money."

The amount saved depends on the size and type of structure and its existing efficiency standards, he said.

Mahlum said the Public Utilities Commission recently approved a request by Hawaiian Electric Co. to provide a rebate of $300 per ton to help customers convert buildings to accommodate the system. For example, a 1,000-ton building would receive $300,000 to make renovations and improvements to handle the sea water system.

Lt. Gov. James "Duke" Aiona recently toured one such sea water air cooling station, during a break from activities at the Republican National Convention in St. Paul, Minn., last month. Aiona toured the Ever-Green Energy cooling station that provides service to utility company District Energy St. Paul. Honolulu Seawater Air Conditioning is an affiliate of District Energy.

"It's an impressive use of technology, very efficient, so I'm excited," Aiona said after touring the plant. "To think that it will be online, hopefully within a couple years, is even more exciting."

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