National Grid announced this week that its project for a 48 megawatt-hour battery energy storage system on the island of Nantucket has been greenlit and Tesla has been selected to provide the batteries.

Nantucket is a small island of about 10,000 permanent residents about 30 miles off the Massachusetts coast, but it’s also a very popular touristic location.

The island’s electricity is currently supplied via two submarine cables that connect to the mainland transmission system on Cape Cod.

It results in a critical failure point, but the island’s power is still secured with two six-megawatt diesel generators acting as backup power.

Now National Grid explains that those two generators are reaching the end of their useful life and need to be replaced.

The company is looking ahead and sees that the island’s electricity demand is increasing and they would likely need to add a third submarine cable within the next decade or so.

Therefore, they instead suggested the 6 MW/48 MWh battery energy storage system with only one new generator. This way, the battery system can act as backup for short interruptions in power and the generator can kick in to recharge the batteries if needed.

But maybe more importantly, the battery system will also serve to reduce peak demand from the island and stabilize the grid.

With this system, National Grid believes that they can delay adding a third submarine transmission line by at least another decade.

Rudy Wynter, president and COO of National Grid’s FERC-regulated Businesses, commented on the announcement yesterday:

“The BESS provides a very efficient and effective solution to two major energy challenges facing the island. Our customers, communities, and policymakers look to us to deliver innovative solutions like this to help advance our clean energy future.”

Town of Nantucket Energy Coordinator Lauren Sinatra added:

“The Town of Nantucket commends National Grid’s decision to deploy an innovative energy storage solution on the island. We are confident that the proposed project, combined with targeted energy-saving programs and other planned electric infrastructure upgrades, will play a transformational role in meeting Nantucket’s near- and long-term energy needs.”

48 MWh will require over 200 Tesla Powerpacks – making it one of Tesla’s biggest energy storage projects to date.

Tesla’s energy storage division has been ramping up lately with a deployment of 109 MWh last quarter, but they also have a lot of projects in their backlog.

They have been deploying Powerpacks in Puerto Rico to help the power restoration effort and they are still working on their giant 100 MW/129 MWh project in Australia.

But this new project is more reminiscent of Tesla’s remote island projects, like powering an island with a microgrid in North Carolina, a resort in the Fiji Islands, and its bigger Powerpack project on the Island of Kauai.

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