After Solar Design Associates Inc. (SDA) developed a microgrid project on Cuttyhunk Island earlier this year, the picturesque Massachusetts island has been getting the majority of its electricity from a solar array that also charges an energy storage system for nighttime power.

Throughout the summer, the microgrid has provided over 50% of the electricity for Cuttyhunk residents and summer boaters visiting its harbor, according to SDA. Furthermore, SDA expects the microgrid will provide more than 80% of off-season electricity as the small island’s summertime population of 300 shrinks to about 50 year-rounders.

The island, which has 174 electric meters, had previously relied solely on diesel-powered generation with fuel delivered by barge for all of its electricity. SDA says the new Cuttyhunk microgrid comprises 1,020 solar panels totaling 351.9 kW, plus 1 MWh of electric storage in a bank of lithium-ion batteries. The project was supported by a U.S. Department of Agriculture rural electrification grant.

Cuttyhunk is the westernmost of the Elizabeth Islands that comprise the town of Gosnold. Paul Elias, a member of the Gosnold Electric Light Commission that oversees the town-owned utility serving the island, says, “We’ve been delighted with the performance of the system.”

“The microgrid’s performance and reliability have exceeded all our expectations, and we are on track to burn 30,000 fewer gallons of diesel fuel this year,” adds Elias. “That is an excellent benefit for the environment of this unique place and major cost savings for the community.”

SDA President Steven J. Strong comments, “Solar-plus-storage is clearly the next frontier for renewable energy, and the Cuttyhunk project validates the extraordinary benefits this innovative approach can deliver for cost, reliability, and sustainability at community scale.”

Based in Harvard, Mass., SDA notes it is is currently developing a solar-plus-storage system for the Isle au Haut Electric Power Co. in Maine that is projected to provide 100% of its year-round electricity and eliminate its dependence on a 35-year-old undersea electric cable. Isle au Haut has 140 year-round and seasonal electric customers.

“While solar-plus-storage is an especially compelling approach for island communities dependent on high-cost diesel generators or costly-to-maintain cables, we’ve developed solar-plus-storage solutions for commercial, industrial, and utility customers as well,” says Strong. “We see enormous potential around the world for this transformational energy technology.’’

On Cuttyhunk, SDA served as engineer-of-record for the project, providing design and engineering, procurement assistance, permitting support, construction management, and full system commissioning.