The developers of a project that will use cold ocean water to provide air conditioning for office buildings in downtown Honolulu said today they have signed a long-term lease for a pumping station site that will allow them to begin construction on the system early next year.

Honolulu Seawater Air Conditioning LLC signed a 55-year lease with Kamehameha Schools for a 30,000-square-foot parcel behind the Gold Bond Building in Kakaako that will be home to a pumping station and heat exchange facility that will be the heart of the system.

“We’re very pleased to have that in place and we’re ready to go,” said Bill Mahlum, president and chief executive officer of the HSWAC. He said  the company is in the process of getting all the necessary permits in place, as well as finalizing the financing for the $266 million project.

HSWAC, which as postponed the start date several times, now says it plans to break ground on the project in early 2012. Service to customers is projected to start sometime in 2013, according to the company.