SolarCity wants to prove solar power with battery backups can provide effective, cost-efficient energy for the grid. Earlier this month it signed multiple contracts for energy storage systems paired with solar, but the project on Hawaii’s Kauaʻi Island might be the most ambitious—and least costly—yet. This comes as evidence shows that solar with battery backups may soon start challenging utilities on price.
On Sept. 9 the Kauaʻi Island Utility Cooperative (KIUC) announced it signed a power purchase agreement (PPA) with SolarCity for a solar photovoltaic array and a utility-scale battery storage system that’s designed specifically to supply power to the grid in the evening. The 52 megawatt hour battery system is designed to provide up to 13 megawatts of electricity to the island’s grid between 5 p.m. and 10 p.m.—during the island’s peak use hours.The system will help shave the amount of power required from the island’s other generators. The system is designed to allow the utility to use the stored solar electricity in the batteries instead of relying on the island’s diesel generators.
The project, pending state regulatory approval would be located by KIUC’s Kapaia power plant, a diesel generator. “KIUC has been investigating energy storage options for more than two years and price has always been the biggest challenge,” said David Bissell, President and CEO of KIUC.
Under the proposal the utility would pay SolarCity 14.5 cents/kWh. That’s less than the cost of fossil fuel generation in the state but more than it pays for power directly from its two, 12 megawatt solar farms. “This is a breakthrough project on technology and on price that enables us to move solar energy to the peak demand hours in the evening and reduce the amount of fossil fuel we’re using,” Bissell said.
“SolarCity is excited to bring the first dispatchable solar storage system to the island of Kaua‘i. Hawai‘i has been and continues to be at the forefront of new technology and research for solar and storage,” said Jon Yoshimura, Director of Policy and Electricity Markets for Solar City. “This solution will allow for more efficient load balancing and will reduce dependence on fossil fuel-based power.”
The utility has request an accelerated decision from the utility commission to ensure the project can be completed and online intake to meet the Investment Tax Credit deadline of Dec. 31, 2016. To meet that deadline construction must begin by April 2016, according to the utility.Tweet