Ulupono Initiative

Honolulu Seawater Air Conditioning

A seawater air conditioning district cooling system that will provide air conditioning to downtown Honolulu buildings.

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In August 2013, Ulupono Initiative announced its investment of $1 million in Honolulu Seawater Air Conditioning, LLC (HSWAC) for the development of the company’s seawater air conditioning district cooling system. In November 2014, HSWAC announced that Ulupono and deep-water cooling company Capital Cooling have assumed ownership of the company.

The system will provide air conditioning to buildings in downtown Honolulu by pumping deep ocean water through a pipeline more than four miles offshore to a cooling station in Kakaako. Customers who have already signed on include the Prince Jonah Kuhio Kalanianaole Federal Building and U.S. Courthouse, Hawaiian Electric Co., Finance Factors, First Hawaiian Center, and One Waterfront Towers.

When it begins operation, HSWAC’s district cooling system will reduce electricity usage by an estimated 77,000 MWh per year, which is equivalent to a 20-megawatt wind farm; or a 40-megawatt solar farm, more than ll of the utility scale photovoltaic systems currently operating in Hawaii. It will eliminate the need for 178,000 barrels of oil per year by saving enough electricity to power more than 10,000 homes. 

Why We Invested

As one of the largest energy-efficiency projects in Hawaii, HSWAC promises significant energy savings that will help move us closer to our goal of more renewable energy use for the state. The system will provide an alternative to using imported fossil fuels to cool downtown Honolulu, which will decrease Oahu’s environmental footprint and the state’s oil dependency.


“We are extremely pleased to be working with Ulupono on this project. Not only do the missions of both organizations – to create a more sustainable future for Hawaii – align perfectly, Ulupono’s investment represents a strong vote of confidence in the potential of HSWAC’s deep seawater cooling technology to greatly improve the quality of life in our island community.”

– Eric Masutomi, president and CEO of Honolulu Seawater Air Conditioning


  • Provides an alternative to using fossil fuels to cool downtown Honolulu
  • Decreases Oahu's environmental footprint and the state's oil dependency
  • One of the largest energy-efficiency projects in Hawaii

At a Glance

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