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Seawater AC plans shut down over costs

HONOLULU (AP) — Plans to air-condition many commercial and government buildings in Honolulu using cold deep-sea water have been shut down because of increasing construction costs.

Honolulu Seawater Air Conditioning LLC had pursued the project for 16 years, spending $25 million, obtaining all major regulatory approvals and signing up numerous customers, The Honolulu Star-Advertiser reported Monday.

Customer Service Director Gregory Wong said construction cost estimates increased from $275 million to $400 million. The company is expected to halt administrative functions by the end of January.

The system would have turned seawater into air conditioning by pumping cold seawater to a land-based heat-exchange plant to chill a closed system of fresh water sent to individual building air conditioning systems through underground distribution lines. Leftover warmed seawater would have been returned to the ocean where the water is about the same temperature.

The project originally planned to build a 4.7-mile pipeline tapping seawater about 44 degrees Fahrenheit from more than 1,700 feet below the ocean surface.

Company officials estimated that the system would save building owners and residents up to 75 percent on air conditioning costs and eliminate 77 million kilowatt-hours of electricity used annually, or enough to power about 13,000 homes.