Clean energy journalism for a cooler tomorrow

Newsletter: Vermont’s home batteries take on gas power plants

Vermont utility Green Mountain Power uses Tesla Powerwall batteries for frequency regulation.
By Julian Spector

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Grid futurists anticipate a world where small-scale energy equipment scattered across homes and businesses usurps the fossil-fueled, capital-intensive plants that currently run the grid.

To make this happen, all those devices need to operate as reliably as today’s centralized, utility-run infrastructure. That’s not easy, and not guaranteed. But Vermont utility Green Mountain Power just proved the concept in a new way.

GMP already coordinates Tesla Powerwall batteries in hundreds of customer homes. They serve backup power during outages and deliver electricity to the grid during moments of extreme demand, saving millions of dollars for utility customers overall.

Now, Jeff St. John reports, GMP proved it can harness hundreds of batteries for the grid service of frequency regulation. The batteries, communicating over broadband internet, accurately responded to commands within the tight four-second interval required by the grid operator.

This is just a small first step, but the implication is clear for the transition off fossil fuels:

“We have some legacy peaker facilities that I can’t wait to retire,” said Josh Castonguay, the utility’s chief innovation officer, referring to the natural-gas-fired power plants used to quickly respond to grid-balancing needs.

Jeff’s article delves into the details. But Vermont is well on its way to proving that batteries distributed in people’s homes can take over for the roles played by fossil fuel plants. That’s timely, because the utility has promised to stop burning fossil fuels by 2030.

And the homeowners make money on this.

  • They pay $55 per month for battery backup power. 
  • But if they let GMP use their batteries for frequency regulation, they earn $13.50 a month, effectively lowering the cost of resilience. 
  • The rest of the frequency revenue is split between Tesla and paying down the cost of electricity for all GMP customers.

(Lead image: ​“tesla home battery“by Stratageme.com is licensed under CC BY-NC-SA 2.0)

Julian Spector is a senior reporter at Canary Media. He reports on batteries, long-duration energy storage, low-carbon hydrogen, and clean energy breakthroughs around the world.

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