ISLAND MAY GET BACKUP

Eversource proposes energy storage site on Martha’s Vineyard

Eversource announced it is “charging forward” with plans to build an energy storage facility on Martha’s Vineyard that will improve reliability for the island’s growing demand for electricity.

On Wednesday night, the utility company, along with the state Department of Public Utilities, held a public hearing in Oak Bluffs about Eversource’s plans to build a lithium-ion, 14.7 megawatt battery system.

Martha’s Vineyard is now served by four underwater cables from Falmouth and in the event of a cable failure, five diesel generators would kick in to provide electricity.

The island draws in more than 63 megawatts of electricity during the summer months when the population swells to more than 120,000 people. The proposed project would pro- vide auxiliary power during peak usage or in the event of an emergency, such as an outage or the failure of an undersea cable.

“Instead of resorting to using diesel generators that are dirty, the lithium battery is safe and provides energy that is cleaner,” said Charlotte Ancel, director of clean energy at Eversource. “Reducing the five diesel generators is the equivalent of taking 5,000 cars off the road.”

The utility said the battery system would reduce greenhouse gas emissions, reduce reliance on the generators, offset high-demand usage during summer months and reduce the need to repair or replace the undersea cables serving the island.

Ancel said lithium-ion battery technology has significantly advanced since the 1990s and is “so good we are now able to store electricity at utility scale and inject it into the grid when needed.”

The 14.7-megawatt battery storage, housed in an existing Eversource facility, could power more than 10,000 homes and would cost approximately $15 million. The utility expects the project would be completed by next year.

Last year, Eversource was the first utility in the Bay State to secure approval for 50 megawatts of grid-scale storage. Eversource delivers electricity and natural gas and supplies water to 4 million customers in Massachusetts, Connecticut and New Hampshire.

“This is just the beginning,” Ancel said of the new, green-friendly battery technology. “It’s the direction the world is going in. The batteries on Martha’s Vineyard will help us support interconnection of more distributed solar on the island.”