Excerpts from powermag.com/vermont-and-iso-new-england-provide-an-interesting-renewable-energy-transition-case-study/ submitted by Bob M.
About 80% of Vermont’s power comes from renewable energy. Almost no fossil-fueled plants operate in the state, other than a handful of peaker units, many of which are on the short-list for closure.
Distributed Energy Proliferates …
The reason is that rooftop solar has become widespread in the region. According to ISO-New England, Vermont had 434.24 MW of installed solar capacity at the end of 2021. For context, remember, that’s roughly 43% of the state’s peak load demand, and it’s all distributed generation.
“Almost every school in the state of Vermont has solar on it,” Chris Root, COO for Vermont Electric Power Co. in Rutland, Vermon … “But, we don’t have large solar. This isn’t like Arizona, where you go in the desert and put 300 MW. The largest single photovoltaic plant in Vermont is only 20 megawatts. … We’re talking about distributed resources—this is the model of distributed resources. They’re on houses. They’re on fields. They’re on businesses.”
But when the sun goes down …
Then, when the sun goes down, power companies have to make up for the lost generation. … Energy storage is seen as a vital component in managing the swings. Green Mountain Power (GMP), which serves approximately 270,000 residential and business customers in Vermont, implemented a “Home Energy Storage” program that has reportedly been very successful. The program has three options: Bring Your Own Device (BYOD), Enphase IQ Battery, and Tesla Powerwall.
… customers can get up to $10,500 toward a home battery purchase using the BYOD option, or they can lease Enphase IQ or Tesla Powerwall battery systems on a 10-year plan for $65 and $55 a month, respectively. Customers can save money by paying the full lease upfront for $6,500 and $5,500, respectively.
To participate in the program, GMP requires customers “to share access to the batteries to cut power demand during expensive energy peaks when people are using a lot of energy, which helps lower costs for all.” The company said its growing network of shared stored energy reduced about $3 million in costs for all customers in 2021 by cutting power demand during energy peaks.