Gas Turbines

Hawaiian Electric to repower Waiau plant with biodiesel-burning turbines

The 253 MW project was one of several selected as part of a competitive procurement process for firm renewable generation on Oʻahu.
Hawaiian Electric to repower Waiau plant with biodiesel-burning turbines
Rendering of proposed Waiau Repower project, subject to change, when all six new units are in service. (Credit: Hawaiian Electrit)

Hawaiian Electric Company plans to replace six aging oil-fired units with combustion turbines at its Waiau Power Plant in Pearl City.

The 253 MW project was one of several selected as part of a competitive procurement process for “firm renewable” generation on Oʻahu. The proposed repowering of the Waiau facility will be the largest generation project in Hawaiian Electric’s 132-year history, it said.

At approximately 42 MW, each combustion turbine is smaller and more efficient than the oil-fired steam boiler it will replace, the utility said. Initially, the CTs will use biodiesel and could potentially use renewable gas or hydrogen in the future.

Hawaiian Electric said the new additions are intended to be available all the time, flexible to meet the needs of a grid powered by solar and wind.

Waiau Units 3 and 4, aged 76 and 73 years respectively and scheduled to be retired in 2024, will be the first units to be replaced with the new technology over the next several years with an expected in-service date of 2029.

The other four units, which came into service between 1959 and 1968, will be replaced in phases with all units expected to be online by 2033.

The project still requires final approval by the state’s Public Utilities Commission. Details on the price of the project and estimated cost to customers will be made available when the company files its application for approval. Because maintenance and repair costs for the older units will be removed, and because the new units are meant to be more efficient and will run less frequently, savings are expected over 30 years compared to the cost of continuing to run and repair the aging units.

In 2013, Hawaiian Electric announced plans to deactivate 226 MW of oil-fired power generation, to be replaced by renewable energy sources – including two generators at Oahu’s Waiau Power Plant. In 2019, the company put out its desire for close to 900 MW of new renewable energy resources.