COURTESY MYERS COMMUNICATIONS
The planned cooling plant will have a 25,000-ton capacity and will use significantly less electricity than conventional air conditioning systems. It is estimated to reduce electrical use by 77 million kilowatts a year.
New seawater cooling plant in the works
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Up to 40 downtown Honolulu buildings soon may be using renewable energy to power their air-conditioning units.
A commitment announced yesterday from dozens of investors for $10.75 million is a key component in efforts by Honolulu Seawater Air Conditioning LLC to build a seawater air-conditioning plant in Kakaako.
The system, which is estimated to cost $152 million, is set to be completed by June 2010 and already has support from state utility Hawaiian Electric Co.
Honolulu Seawater said the system will reduce electrical demand by up to 16 megawatts.
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A plan to cool dozens of downtown Honolulu buildings with renewable energy took a big step forward yesterday with a $10.75 million commitment from investors.
Honolulu Seawater Air Conditioning LLC, a subsidiary of St. Paul, Minn.-based Ever-Green Energy, said the funding allows the development of a $152 million system to pump deep-ocean water for use in air-conditioning systems in Honolulu buildings.
More than 40 undisclosed investors -- half of whom are from Hawaii -- are involved in the financing announced yesterday. 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.
"This was the real hurdle," President and Chief Executive William Mahlum said. "It's a big project."
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 and would be used to cool fresh water distributed to the air-conditioning systems of public and private buildings. It was originally slated to start in 2007 after four years of planning, but ran into financing delays, Mahlum said.
The company must still undergo an environmental impact assessment, which Mahlum estimates will be completed this summer before construction can begin in January 2009. The station, which is expected to be completed in June 2010, will be located on an undisclosed waterfront property leased from a private owner, he said.
More than half of the station's 25,000-ton capacity has been reserved for future contracts, including the Prince Kuhio Federal Building and Hawaiian Electric Co. HECO will be offering rebates for building owners who sign up, Mahlum said.
Many buildings will be able to connect right into the system, he said, with the biggest challenge being laying the connecting pipes in an already-crowded downtown infrastructure. Mahlum said he is working with the city's water and sewer departments to coordinate construction.
"It's complicated," he said. "We have been through this many times -- we have nine feet of pipe in St. Paul for every foot of pipe we have here."
Standard air-conditioning systems here pump cooled water throughout a building, which is spread throughout rooms by cool air blown across the pipes. The water then returns to a central location to be cooled in systems powered by electricity.
This process can consume four to 12 times more electricity than the seawater system, which transfers the seawater's coldness to water circulating in the closed loop pipe network, with warmed water returning to the ocean through a diffuser located at a shallower depth where mixing requirements are satisfied.
Honolulu's cooling system -- one of a half-dozen the company has worked on globally -- would save 265 million gallons of potable water a year, 174,000 barrels of oil, and 114 million gallons of sewage created by existing air-conditioning networks, while reducing electrical usage by up to 77 million kilowatts a year.