Solar-hydro project moves forward

LIHU‘E — Kaua‘i Island Utility Cooperative signed agreements with The AES Corporation for the development, construction and operation of the cooperative’s solar-pumped, storage hydro project, also known as the West Kaua‘i Energy Project.

A power purchase agreement was also executed and filed with the Hawai‘i Public Utilities Commission on Dec. 31, 2020.

WKEP is an integrated, renewable-energy and irrigation project with several key components: renewable-energy production via hydropower and solar photovoltaic generation, and pumped hydropower and battery-energy storage to shift most of the project’s output into the nighttime peak.

This project will offset the use of 8.5 million gallons of fossil fuels annually and supply irrigation water delivery to support diversified agriculture on state-owned lands.

The project will also rehabilitate the existing Pu‘u ‘Opae, Pu‘u Lua and Mana reservoirs and the related ditch-system infrastructure.

In addition, historic diversion structures in Koke‘e will be modified to restore and increase flow to the Waimea River in compliance with the instream flow standard established by the Waimea Watershed Agreement and adopted by the Commission on Water Resources in April 2017.

“This project’s integration of pump-storage hydropower with large-scale solar power is unique in the energy industry,” said David Bissell, KIUC president and CEO.

”Working with AES helps keep this important project moving forward while minimizing risk to our cooperative. Upon completion, the facility will operate at a cost that will benefit KIUC’s members for decades,” said Bissell.

”AES is a trusted partner with the expertise and experience to bring this complex project to successful completion.”

When operational, the solar array will contribute up to 35 megawatts directly to the grid, and will store up to 240 megawatt hours for dispatch during evening peak. The hydro resources are expected to produce 24 megawatts on average daily, which includes 12 hours of storage to be used overnight.

KIUC has completed two solar-plus-storage renewable projects in partnership with AES: a 20-megawatt facility in Lawa‘i and a 14 MW facility at the U.S. Pacific Missile Range Facility at Barking Sands.

AES has more than 200 MW of solar, solar-plus-storage, and wind resources in operation or under development across Hawai‘i.

“AES has been a long-time provider of low-cost electricity for Hawai‘i, and we are honored to continue our successful partnership with KIUC to support Kaua‘i and the state in transitioning to 100% renewable energy,” said Woody Rubin, AES clean energy chief development officer.

“We look forward to continuing to work with the Kaua‘i community and stakeholders to develop this project responsibly, and to realize the agricultural, economic and environmental benefits the project offers.”

“WKEP will deliver many benefits to KIUC’s members and the community at large,” Bissell said.

“To name just a few, the project will move Kaua‘i beyond 80% renewable generation, stabilize and lower electricity rates over time for our members, open up dormant agricultural lands for production, assure adequate streamflow and increase public access and recreational opportunities associated with the Pu‘u Lua Reservoir.”

Rehabilitation of the reservoirs will also assist first responders in addressing wildfires, he added.

The project is expected to meet roughly 25% of Kaua‘i’s electricity needs.

Environmental studies for WKEP have been ongoing. A draft environmental assessment is expected to be filed with the state Department of Land and Natural Resources in the first quarter of 2021.