First Hawaiian Bank said it is the first customer to sign a contract with Honolulu Seawater Air Conditioning LLC, a renewable-energy company that is developing a system that will use cold ocean water to help air condition downtown Honolulu buildings.

First Hawaiian Bank signed a multiyear agreement with Honolulu Seawater, said Al Yamada, First Hawaiian Bank vice chairman.

"Our bank determined that becoming a customer made environmental and financial sense. We very much wish to encourage the growth of renewable-energy alternatives," Yamada said.

Honolulu Seawater plans to start the $152 million project in July, having identified areas where it wants to lay pipelines that will draw 45-degree ocean water, and having found a site in Kaka'ako for a cooling station where fresh water will be chilled and piped to buildings.