Hawaiian Electric proposes to repower Waiau Power Plant

May 22, 2023 | PC Community

Project will replace old units with flexible, firm renewable generation on existing site, reducing operating cost and community impact

Hawaiian Electric is proposing to replace six aging fossil fuel-powered generators at its Waiau Power Plant in Pearl City with smaller, more efficient and fuel-flexible units that can provide reliable, firm generation to back up the expanding portfolio of variable resources like solar and wind on the Oʻahu electric grid.

The new units can run on multiple fuels, including biodiesel and potentially hydrogen if it becomes commercially available in the future. Unlike traditional steam generators built to run continuously and which take hours to come online, the new units are designed to respond quickly to changing needs on the grid, filling the gap when variable resources like solar and wind aren’t available. They will run cleaner, quieter, more efficiently and will operate less frequently than the existing units.

The Waiau proposal was submitted in April to respond to a competitive procurement issued by Hawaiian Electric and overseen by the Public Utilities Commission (PUC), which will make the final determination on whether proposals by Hawaiian Electric and any other bidder are approved. Because proposals are confidential, details on technology, size, cost and bill impacts are not available until the final awards announcement, expected in October.

“This transformation of our generation infrastructure supports the critical need for reliable, 24/7 power that is much more efficient than the technology it replaces,” said Mike DeCaprio, vice president of power supply for Hawaiian Electric. “Some of these oil-fired boilers were built just after World War II and while they’ve served us reliably for decades, they don’t have the flexibility and fast-start capability we need with our expanding portfolio of solar and wind resources.”

By building within the footprint of the 85-year-old Waiau facility and reusing much of the existing infrastructure, DeCaprio said there will be operational cost savings and minimal community impact.

Hawaiian Electric’s Waiau Units 3 and 4, built in 1947 and 1950, are scheduled to be decommissioned and removed over the next several years. Four additional units, built between 1959 and 1968, will be decommissioned and removed in phases through the end of the decade as new firm and variable generation resources come online. While the project will require an Environmental Impact Statement and other permits, no new land acquisition processes or zoning changes will be needed. In-service dates for the first new units will begin in 2029 with other units to follow.