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Solar, pumped hydro project to help KIUC meet peak evening loads

image credit: Photo 111153707 © Ian Mendel |
Peter Key's picture
Freelance Writer, Editor, Consultant, Self-employed

I've been a business journalist since 1985 when I received an MBA from Penn State. I covered energy, technology, and venture capital for The Philadelphia Business Journal from 1998 through 2013....

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  • Jan 13, 2021

A problem with solar power is that, on many days of the year, the amount of it generated begins decreasing just as load is peaking in the late afternoon.

An electric power cooperative on the island of Kaua‘i in the state of Hawai‘i recently announced a project meant to help it overcome that problem.

The West Kaua‘i Energy Project would use solar generation, pumped-storage hydropower and storage batteries to meet 25 percent of Kaua‘i’s total electricity needs, make the power on Kaua‘i’s grid 80 percent renewable and enable the island to run solely on renewable energy for prolonged periods without sunlight.

When operational, the project’s solar generation and pumped-storage hydropower would contribute up to 35 megawatts of power directly to the grid on Kaua‘i and store up to 240 megawatt hours of electricity for dispatch during the evening peak load on the island.

The project would be built and run by The AES Corporation for the Kaua‘i Island Utility Cooperative (KIUC). The Arlington, Va.-based energy giant already has completed two solar + storage projects with KIUC and has more than 200 MW of solar, solar + storage, and wind projects in operation or under development in Hawai‘i.

For the project, three existing reservoirs and their related ditch system infrastructure would be rehabilitated. Additionally, the historic diversion structures in Kokeʻe would be modified to restore and increase flow to the Waimea River (pictured above).

KIUC and AES said environmental studies for the project have been ongoing and a draft environmental assessment is expected to be filed with Hawai‘i's Department of Land and Natural Resources this quarter.




Christian Payerl's picture
Christian Payerl on Jan 13, 2021

Very good initiative from KIUC and AES to increase there way to 100% renewable. Maybe following comment from my side can provide additional edge on their actions towards 100% renewable!

Just now ABB is working together with SEV the local electrical utility at Faero islands to install a power system on the island of Suduroy based on 100% renewable energy (mainly from wind power). The tricky issue with these island networks is to be able to provide a power system which is "stable" enough for modern society. This means that voltage and frequency variations shall be limited even during the event of a failure in the power system and that power quality emissions such as harmonics, flicker and unbalance shall not exceed international standards. In the Faero island case it was shown that the combination of wind turbines and energy storage systems needed also the support from a synchronous condense (SynCon), which is damping the RoCoF (Rate of Change of Frequency) with the inertia delivered by the SynCon. Additionally to that it was easier to handle voltage voltage dips and voltage regulation on SEV´s distribution system, as the SynCon is providing fault current contribution (system strength) and MVAr´s for voltage control. So in this case wind + BESS + SynCon is a perfect match! 


Peter Key's picture
Peter Key on Jan 13, 2021


Thanks for the comment. I don't know what KIUC uses for grid stabilization, but it would be interesting to find out. Hopefully, next winter, when the pandemic is over, someone will pay me to spend a month or two on Kaua‘i to find out.

Also, I couldn't find any stories or write-ups on ABB's work with SEV in the Faroe Islands. Are any in English available?


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