Hawaii’s First Renewable Natural Gas Facility

with Hawai’i Gas


The Honolulu Wastewater RNG facility produces about 800,000 therms of energy per year, enough gas for 6,000 homes. Through DMT’s two-stage membrane separation technology, biogas from two anaerobic digesters is processed and upgraded to a purified RNG stream which is then injected into Hawaii Gas’ O’ahu utility pipeline to provide thermal energy for homes and businesses.

  • $1.6 million in revenue per year for the island
  • 3% of Hawaii’s total gas supply
  • 98% plant uptime in the field

Project Details

Year: 2018
Location: Honolulu, HI / USA
Product: Carborex®MS
Biogas Inlet: 350 SCFM
Biogas Source: WWTP
Application: Pipeline Injection

About Hawaii’s First RNG Facility

Hawaii Gas became the first in the state to capture and upgrade biogas, using DMT’s membrane separation equipment, the Carborex®MS. In partnership with the City and County of Honolulu, biogas is collected, processed and injected into Hawai’i Gas’ O’ahu pipeline. The renewable natural gas (RNG) generated provides thermal energy for homes and businesses.

“The ability to capture biogas from our sewage (and transform it into RNG) is the type of innovative project that will help us reach our renewable energy goals sooner rather than later.”

– Mayor Kirk Caldwell, City & County of Honolulu

This first-of-its-kind RNG facility is equivalent to eliminating the need for nearly 15,000 barrels of oil. Alternatively, this project reduces greenhouse gases by the amount produced by 400 cars annually.

Moreover, the Honoululu Wastewater RNG Facility produces about 800,000 therms of energy per year, enough gas for 5,555 homes. By selling the biogas to Hawai’i Gas, the City and County of Honolulu estimates they will generate approximately $1.6 million of revenue per year. This $5 million project harvests wasted biogas that was once flared off into the atmosphere.

Hawai’i Gas Project Results

renewable natural gas rng project with hawaii gas
The biogas upgrading project made the cover of Green, a quarterly magazine dedicated to topics of sustainability in Hawai’i. Because natural disasters are common to the islands, this project is an important piece to the state’s energy security and resiliency measures.

DMT’s project was a critical piece to Hawai’i’s resiliency plan for surviving natural disasters as well as reducing the state’s greenhouse gas emissions. As the premier provider of gas solutions since 1904, Hawai’i Gas supplies gas energy to nearly every major market segment. For instance, residents, food service, military, hospitality, health care, education, government, and agriculture all rely on Hawai’i Gas.

After biogas upgrading, Hawai’i Gas’ 1,100-mile underground utility pipeline safely and reliably transports the RNG. This means gas users can still cook and access hot water for sanitation during high winds or power outages.

“Ensuring that all families have access to affordable, reliable and clean energy are important goals. Our RNG project is an important step toward achieving these goals, while at the same time, working towards meeting Hawai’i’s carbon neutrality goals for 2045.”

– Alicia Moy, President & CEO, Hawai‘i Gas

Furthermore, this RNG project represents their vision is to improve Hawai’i’s quality of life. In particular, to develop innovative, renewable energy projects, reduce the state’s greenhouse gas emissions and promote energy efficiency.

“In a way, all of us are making some of that gas and now it’s being used to save our planet and make it a lot bluer and greener and sustainable.”

– Mayor Kirk Caldwell, City & County of Honolulu
Hawaii Gas DMT Award for renewable natural gas hawaii
DMT’s general manager, Robert Lems, (left) shaking hands with Hawai’i Gas’ director of renewable energy, Richard DeGarmo, (right).

Biogas Project of the Year

Operational since December 2018, the project was awarded the “Biogas Project of the Year” in 2019 by the American Biogas Council for the deployment of DMT’s advanced gas cleaning technology on municipal biogas to reduce the carbon footprint of the Honouliuli natural gas system.

“This project was selected because it’s at the leading edge of a wave that will sweep the nation as more and more gas utilities purchase renewable natural gas (RNG) made from biogas.”

– Patrick Serfass, Executive Director, American Biogas Council

Follow the journey of Hawai’i’s first RNG facility with Hawai’i Gas and DMT:

This RNG facility uses the Carborex®MS.

For key biogas contaminants, DMT offers one or a combination of technologies. The technology selection is based on an analysis of your biogas composition, inlet gas flow, pollution load and RNG application. Based on your CAPEX, OPEX and/or TCO needs, we provide our customers with an innovative, economical solution.