Hawaii Gas has released a request for proposals (RFP) seeking supplies of renewable natural gas (RNG) in the form of raw biogas and/or bio-methane as part of its previously announced fuel diversification strategy, which includes containerized shipments of liquefied natural gas (LNG) (see Daily GPIOct. 30, 2014).

In Hawaii, RNG is readily available, according to utility officials, from municipal wastewater treatment centers and landfills, along with biogas producers on the U.S. mainland. The RFP is an effort to further diversify supplies by blending the RNG with the synthetic natural gas (SNG) and LNG now provided to customers.

Since its pioneering effort in bringing LNG to the islands, the Macquarie Infrastructure Co. utility has had to respond to Hawaii Gov. David Ige's plans announced last summer to use 100% renewables in the state (see Daily GPIAug. 28, 2015). Ige previously had supported the use of LNG, which Hawaii Gas is still providing along with SNG and liquefied petroleum gas (LPG), or propane.

In characterizing the RFP, which seeks supply proposals for up to 8,000 MMBtu/d by March 7, a Hawaii Gas spokesperson said the RNG will add to the utility's reliability for customers while contributing to the state's "clean energy future" as outlined last year by the governor. RNG can be blended with SNG and LNG, he said.

The Honolulu-based gas utility plans to sign one or more agreements for RNG, subject to eventual approval by the Hawaii Public Utilities Commission (PUC). Contracts of five to 20 years are being sought and should include the cost of delivering bio-methane to Campbell Industrial Park in Kapolei, or the price point of raw biogas production, the RFP said.

"Adding RNG to our fuel mix is an important priority that will contribute to advancing Hawaii's clean energy future," said Alicia Moy, Hawaii Gas CEO. "By diversifying our fuel supply, we will also further increase reliability for our customers."

According to utility engineers, if Hawaii Gas could capture all of the biogas from the state's wastewater treatment plants and landfills, up to 18% of its current SNG production could be replaced. However, they said it is unlikely that the utility will be able to totally replace all of its SNG or LNG use.

Hawaii Gas has been bringing in LNG in limited quantities since April 2014, and it filed an application with the PUC in October of that year to replace up to 30% of its SNG with LNG. At the end of 2014, the utility proposed to seek bids for larger volumes of LNG from suppliers worldwide, but it is still finalizing the invitation to bid.

Joseph Boivin, senior vice president for business development and corporate affairs, said Hawaii Gas believes "there is a role for natural gas energy as the state moves forward with its commitment to renewable energy. We can blend RNG with our SNG and LNG to provide customers with clean, reliable gas energy."