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Hawaii Gas receives biogas award from City & County of Honolulu

–The biogas from Honouliuli Wastewater Treatment Plant will now generate revenue for the City–

HONOLULU – Hawaii Gas, the state’s only regulated gas utility, was recently awarded the contract to capture and process biogas from the City and County of Honolulu’s Honouliuli Wastewater Treatment Plant after a competitive bidding process.

“This is a great example of how our administration is always looking for ways to leverage resources to benefit taxpayers, even finding a way to use a by-product from our wastewater treatment facility and landfills. As the State’s gas utility, Hawaii Gas was the most qualified to partner with the City to develop this resource, which was previously unutilized. The capturing and processing of biogas is done across the nation as one of the most efficient ways to develop renewable natural gas,” said Honolulu Mayor Kirk Caldwell.

“This is a win-win partnership for the residents of Honolulu and our customers,” said Alicia Moy, president & CEO, Hawaii Gas. “Incorporating cost-effective renewable natural gas as part of our fuel mix is a key priority as we continue to advance Hawaii’s clean energy future. We look forward to working with the City on this project and other projects like it, so that we can provide renewable fuels for our customers, and provide the City with a steady stream of revenue.”

Currently, the Honouliuli Wastewater Treatment Plant produces the equivalent of 800,000 therms of biogas annually. The gas is flared (or burned). By selling the biogas, the City and County of Honolulu will generate revenue. The awarded contract expires December 31, 2024, with a provision to extend the term. Hawaii Gas will invest in the infrastructure to process the raw biogas for use and to connect the Honouliuli Wastewater Treatment Plant to the company’s existing pipeline. The project is estimated to take between 12 to 18 months to become operational, subject to the permitting process and approval by the Hawaii Public Utilities Commission.


About Hawaii Gas

Hawaii Gas is Hawaii’s only government-franchised, full-service gas company manufacturing and distributing gas in Hawai‘i. Hawaii Gas manufactures synthetic natural gas, or SNG, for its utility customers on O‘ahu, and distributes liquefied petroleum gas, or LPG (propane), to utility, tank and bottled gas customers to all islands. Hawaii Gas is the first company to bring liquefied natural gas, or LNG, to Hawai‘i. Hawaii Gas is a wholly owned indirect subsidiary of Macquarie Infrastructure Company. For more information, visit



City Procurement Process

  • The City & County of Honolulu issued a Request for Proposal for the Sale of Biogas from the Honouliuli Wastewater Treatment Plant (WWTP) on July 31, 2015. Proposals were due on October 16, 2015. Hawaii Gas was deemed as one of the priority listed offerors and was asked to submit its best and final offer by April 27, 2016. On July 28, 2016, Hawaii Gas received notification of the contract award.
  • The awarded contract expires on December 31, 2024, with the provision for an extension.
  • Current biogas output at Honouliuli WWTP is estimated to be approximately 800,000 therms per year, which is currently being flared.

Biogas Capture and Purification Infrastructure

  • Biogas is produced at wastewater treatment plants and landfills when biodegradable waste is broken down through chemical reactions and by microbes, or as digested gas is produced inside an anaerobic digester. (See attached graphic.)
  • After impurities are removed from the raw biogas, the end-product is a ready-for-market renewable natural gas (98% methane and 2% carbon dioxide) that Hawaii Gas will blend with the synthetic natural gas (SNG) in its pipeline.
  • The biogas purification equipment and approximately half a mile of pipe will be built at the Honouliuli facility and connect to the existing SNG pipeline.
  • The project will take 12 to 18 months to be operational, subject to the permitting process and approval from the Hawaii Public Utilities Commission.

Biogas Purification


Alan Tang