State regulator lifts cap on home battery storage systems in response to climate change

Good news for Powerwall lovers.

State regulators lifted the enrollment cap for the home battery backup power system last week, following a request from Green Mountain Power in April. The state's largest utility made the request to lift the cap after the third devastating storm in Vermont this year. The Vermont Public Utility Commission agreed, citing the likelihood of more extreme weather to come and growing demand for home batteries to keep the lights on after those storms knock out power.

Removing the cap allows more GMP customers to access the program as Vermont sees increasingly severe weather because of climate change, according to a news release.

"Accelerating storm resiliency is our path forward, especially after what Vermonters have gone through this year," Mari McClure, GMP president and CEO, said in a statement. "We're pleased we can expand access, allowing more customers to enroll in these programs which have a proven track record of keeping customers powered up through extremely tough conditions."

Tesla Powerwall battery backup as seen in a Green Mountain Power customer's home in Colchester.
Tesla Powerwall battery backup as seen in a Green Mountain Power customer's home in Colchester.

Both the Powerwall and Bring Your Own Device programs were capped at 500 customers annually since 2020. The waitlist for the Powerwall program is now 1,200 customers, stretching into 2026. About 300 customers joined the waitlist this summer, according to Green Mountain Power, following historic flooding in Vermont.

People prefer Powerwall

Green Mountain Power customers have two options to get Powerwall batteries, manufactured by Tesla. Customers can pay $55 per month for 10 years, or $5,500 up front, saving $1,100 over the monthly lease option. Tesla covers standard installation costs.

In addition to the Tesla Powerwall batteries, GMP offers the Bring Your Own Device (BYOD) option that allows customers to buy one of six other brands of storage batteries: Emporia, Enphase, Generac PWRcell, Solar Edge or Sonnen. The BYOD batteries have to be purchased and installed at the customer's expense, but GMP offers a rebate of up to $10,500, depending on how much power customers choose to share with GMP during times of peak demand.

Both the Powerwall and BYOD batteries are part of a network of stored energy that GMP can tap into for about 50 megawatts of power when it needs it, during heatwaves, for example. GMP estimates the utility has saved all of its customers up to $3 million per year for the last few years by utilizing this virtual power plant.

Between the two programs, the Tesla Powerwall proved to be the more popular choice, installed in the homes of 2,600 customers as opposed to 313 customers who opted for the BYOD program.

Contact Dan D’Ambrosio at 660-1841 or ddambrosi@gannett.com. Follow him on Twitter @DanDambrosioVT.

This article originally appeared on Burlington Free Press: More Vermonters can access home battery storage; regulator lifts cap