LIHU‘E — Engineers used photovoltaic and hydroelectric technology to explain design choices behind the West Kaua‘i Energy Project, at the Kaua‘i Island Utility Cooperative’s third “Talk Story Tuesday” meeting dedicated to the initiative.
Currently, KIUC routinely meets 100% of the island’s daylight energy demands using renewable resources. But battery limitations and lack of sunlight force the cooperative to rely on fossil fuels during early morning and nighttime periods.
“That’s really the intent of West Kaua‘i Energy Project,” KIUC Engineering and Technology Manager Cameron Kruse said. “What can we do in terms of a technology that can really get us this longer-duration storage for the grid, to offset our use of fossil fuels?”
The answer, according to KIUC and AES Corp. personnel, involves the 300-acre solar field and open-loop, pumped-storage hydroelectric system planned under WKEP.
The hydro-electric system is a chief topic of interest among residents concerned the proposed construction will hurt ecosystems and activities connected to the Waimea River.
“Hydro is a centuries-old technology. It’s been on the island for over 100 years,” Rob Cooper, of AES, said. “Essentially, just water flows, spins a turbine, produces energy.”
Pumped-storage refers to two reservoirs at different elevations connected by a penstock, or pipe. A solar-powered plant would pump water up the penstock during the daytime. Water would then flow down the penstock to generate energy at night and in the early morning.
Other renewable options were deemed inappropriate for a variety of reasons related to feasibility, cost and threat to endangered wildlife.
“This project, when it’s complete, will meet roughly 25% of our island’s energy needs. When cranking at full capacity, it will have enough power to energize 18,000 homes on our island,” KIUC Communications Manager Beth Tokioka said. “On the environmental side, it would be reducing our fossil fuel usage by 8 million gallons a year and reducing our greenhouse gas emissions by 80,000 tons of C02 per year.”
WKEP is also projected to bring KIUC beyond 80% renewable energy by 2025.
A handful of residents asked questions and made comments following the KIUC and AES presentation. One, Kaua Mata, asked what recourse residents could expect, should the Waimea River level drop in the future.
“What is KIUC’s plan to ensure that when the water does run out, or when the water is running low, when will they stop taking water? Because our loved ones get really low,” Mata said.
The current streamflow standard, which determines how much water must stay in Waimea waterways and how much can be diverted, was set in 2017 under a mediation agreement between KIUC, local farmers, the Department of Hawaiian Home Lands, the Kekaha Agricultural Association and the Agricultural Development Corporation.
However, that standard can be revisited anytime by state regulators, the Commission of Water Resource Management.
“We would be beholden to whatever decisions are made by the Commission,” Tokioka said. “I would fully expect that if streamflow changes were to significantly change, CWRM … will revisit that interim streamflow standard and probably reduce the amount that we could use.”
KIUC Chief Operating Officer Brad Rockwell said such a reduction could affect WKEP, given certain conditions.
“If that 11 MGD (millions of gallons per day) now goes to 10 MGD, then you’re looking at somewhere close to 10% impact on that flow through hydro, and the irrigation production that we can provide to DHHL and the other users that are relying on some of that water from the ditch,” Rockwell said.
Why everything has to be done on the Westside? We got Mount Opala, now you want solar panels and Hydro? Do it on the North Shore, they have way more rainfall then the west.
Always dumping on the west is getting old.