The final environmental impact statement for an environmentally friendly project using chilly ocean bottom waters to cool Downtown Honolulu buildings finds the venture is still feasible, but that its estimated costs have risen to $200 million.

The EIS also shows the project won't start until next year and will take about a year and a half to complete. Developer Honolulu Seawater Air Conditioning LLC also said it has reached an agreement with Kamehameha Schools to lease land in Kaka'ako on which to build a pumping station.

"The benefits are still pretty much the same," said Frederic Berg, project director, noting the system will lessen energy use, cut down on imported oil and reduce the amount of carbon dioxide released into the atmosphere.

Honolulu Seawater has been pursuing the project for several years with it projecting a mid-2009 start when it issued a draft environmental impact statement in October 2008. But since that time the projected route of the large pipes drawing and expelling the seawater has been changed.

The tunneling for the pipes now is projected to begin near the 'ewa end of the Kaka'ako Waterfront Park. The developer previously had thought tunneling for the underground pipes would be several hundred yards east, but possible interference with an offshore University of Hawai'i research station prompted the move. Berg said the new survey work, along with better insight into expenses, raised the cost of the project.

The project entails three distinct parts, including a 63-inch diameter intake pipe that would extend out four or five miles where it would suck in 45-degree water. That would be pumped to a two-story structure behind the former Gold Bond building where it would be used to cool fresh water circulating in another system connected to buildings Downtown.

The seawater would then be returned to the ocean at an outfall about 3,500 feet offshore. Honolulu Seawater said the system would replace systems run by electricity that use rooftop chillers and chemical refrigerants.

In doing so, it could reduce Hawai'i's imported oil consumption by 178,000 barrels annually and save about 77.5 million kilowatts of electricity annually.

The developers estimated it would eliminate about 84,000 tons of carbon dioxide that's produced currently as well as save on water used in chillers, and 84 million gallons of waste water sent into the sewage system from the chillers.

The system may require a portion of the Kaka'ako Waterfront Park be sealed off during the construction, while the developers hope to use a portion of Ke'ehi Lagoon to assemble the pipes.

Funding for the project would include about $40 million to be raised by Honolulu Seawater and issuing up to $145 million of state revenue bonds. The developer also intends to seek federal grants and loan guarantees.

Besides financing, the project also needs to obtain several state and federal permits