An Alternative To An Expensive New Undersea Cable

To the editor: The recent article in the Nantucket Current about the potential need for a third undersea electric cable by 2033 highlights a challenge that deserves our attention - and our imagination. While the projected $200 million investment in a new cable may eventually prove necessary, I believe Nantucket could first consider a more flexible, resilient, and sustainable alternative: investing in local solar and battery storage.

For example, with a $120 million budget, we could deploy a hybrid energy system with 15 MW of solar and 35 MW of battery storage. This solution could dramatically reduce our reliance on imported electricity from the mainland, provide over 10 hours of backup power during peak load conditions, and shift solar energy into evening demand periods.

Just as important, this approach could save the community upwards of $80 million when compared to the cost of a third undersea cable. That’s a meaningful difference.

One of Nantucket’s lesser-known challenges is a reverse capacity limit—a restriction on how much renewable energy can be generated locally without risking being “back-fed” to the mainland, could also be solved. By integrating battery storage, we can capture excess solar during the day and discharge it during periods of high local demand.

I recognize that land availability is a real constraint. Large-scale ground-mounted solar may be difficult without creative approaches. Fortunately, there are promising alternatives such as solar carports over parking lots, the airport, and strategic partnerships with the island's larger landowners.

This isn’t about opposing infrastructure. It’s about maximizing the assets we can build right here on-island—keeping investment local, reducing our carbon footprint, and improving grid resiliency in ways that directly benefit Nantucket. As of today, we collectively spend more than $40 million a year on electricity, and those costs are only rising.

I hope this conversation continues—and that we take the time to fully explore all our options before defaulting to a solution that, while technically viable, may not be the most forward-looking or best path forward.

Sincerely,

Tim Carruthers
Executive Director, ACK Smart Energy