Kauai Island Utility Cooperative, Hawaii’s only member-owned electric utility, is making significant progress toward its goal of using renewable resources to generate 50 percent of Kauai’s power by 2023.
At the end of 2016, 36 percent of the electricity generated on Kauai originates from a mix of renewable resources: solar, hydropower and biomass. That's up from 5 percent in 2009.
On the sunniest days, 90 percent of Kauai’s daytime energy needs are currently met by renewables - primarily solar - which is believed to be the highest percentage of solar on an electrical grid of any utility in the U.S.
Here’s a summary of projects:
- Koloa array: This 12-megawatt project owned by KIUC went online in August 2014. The $40 million array produces nearly 6 percent of Kauai’s energy needs and reduces KIUC’s oil consumption by 1.7 million gallons a year.
- Anahola array: The largest solar project in the state, this 12-megawatt, $54 million solar array came online in October 2015. It reduces KIUC’s carbon dioxide emissions by 18,000 tons per year. The array consists of 59,000 panels.
- Customer solar: Up from a total of 311 systems in 2010 to 3,100 as of October 2015. Rooftop systems are now used by 10 percent of residential customers.
- Green Energy: This 7-megawatt plant just outside Lihue provides 12 percent of Kauai’s power. One of the first plants of its kind in this country, the $90-million project burns wood chips from invasive species and from locally grown trees.
- Five hydroelectric plants, some built more than 100 years ago to provide power to sugar plantations, provide 7.5 percent of Kauai’s electricity. A 6-megawatt project is in the permitting process and is expected to come online by 2019. It would be the first new hydroelectric plant on Kauai in 80 years.
- Batteries: KIUC currently has 10.5 megawatts of battery energy storage on its grid. This includes 6 megawatts of storage with a lithium-ion battery system at the Anahola solar array.
- Dispatchable solar: In September 2015, KIUC signed a power purchase agreement with SolarCity for electricity from the first utility-scale solar array and battery storage system designed to supply power to the grid in the evening, when demand is highest. The proposed SolarCity project is believed to be the first utility-scale system in the U.S. to provide dispatchable solar energy, meaning that the utility can count on electricity being available when it’s needed, even hours after the sun goes down. The 52 MWh battery system will feed up to 13 megawatts of electricity onto the grid to “shave” the amount of conventional power generation needed to meet the evening peak, which lasts from 5 p.m. to 10 p.m. Target date for completion is the first quarter of 2017.
- Pumped storage hydro: The system proposed for Kauai’s west side will use an upper storage pond connected by a five-mile-long buried steel pipeline to a lower pond. During the day, inexpensive solar power would be used to push the water uphill to the storage pond. At night, when demand for electricity is at its peak, the water would be released, flowing downhill through the pipe to turn a turbine and generate electricity.
- KIUC is the first utility in Hawaii to begin using the “smart grid” of the 21st century. With its successful deployment of 28,000 “smart meters” in 2013, customers can go online to track their own energy use and set goals for efficiency. The technology will also enable KIUC to experiment time-of-use rates, pre-pay billing and other service enhancements, including outage maps.