GMP is “really anxious” to retire tens of megawatts of fossil-fuel powered peaker plants over the next few years, Castonguay said. The utility wants to replace that peaker demand in part with energy storage, Castonguay said.
GMP has 13 to 14 MW of distributed, small-scale residential batteries on its grid, and about 100 MW of peaking facilities, he said. The utility partnered with Tesla nearly five years ago, to unlock the potential of small-scale storage to address energy demand peaks, but discussions with local installers led to the creation of a BYOD pilot and program as well.
The BYOD tariff could add up to 5 MW of stored energy annually. On the Tesla Powerwall partnership, the utility would add up to 1,000 Powerwall batteries per year, totaling 5 MW and just over 13 MWh.
Up to 500 customers will be allowed to enroll each year into GMP’s Powerwall program for a 10-year lease that can be extended to 15 years without additional cost. Customers can pay for the two Powerwall batteries with $5,500 up front or $55 per month for 10 years.
The tariff for a BYOD option, developed with Renewable Energy Vermont and other distributed energy developers, gives up to $10,500 in upfront incentives to at least 500 customers a year that enroll and purchase their own storage systems. Customers can choose their upfront savings by selecting the amount of stored power they enroll with the utility through other local storage providers, which GMP can access during peak demand times.
Renewable Energy Vermont was not available for comment. The group is supportive of both of the programs at this time, according to GMP.
The utility has a checkpoint for the programs in about two years, when regulators will assess the need for tariff adjustments.
Both offerings are intended to lower energy costs overall for customers. GMP is also about to announce a series of smaller green economic recovery programs, Castonguay said, in keeping with the utility’s goals for cleaner, cheaper power and to support customers during a period of economic downturn. The utility also has an electric vehicle charging rate pending approval by the Vermont Public Utility Commission (PUC), under which customers could access a cheaper price for electricity when charging their cars.
The rollout of the programs is attractive during the conditions created by COVID-19 as energy resiliency gains more prominence with people spending time at home, according to Castonguay.
“Given the environment now, a lot of folks around the state working from home, it’s interesting in that it makes the proposition of having solid, reliable electricity with battery backup even more important than it has been in the past,” he said.
The key to GMP’s regulatory success in getting the tariff approved was showing the PUC data analysis of the program pilot, Castonguay said. This is the first program of its kind to get tariff approval in the U.S.,Â according to the utility, and GMP is sharing its lessons with other utilities across the country.
“It’s really hard to gauge [the program’s value] unless you’ve had an actual rollout in a pilot, and proven that everything functions as you expect, produces the value that you expect,” he said.
This post has been updated to clarify Renewable Energy Vermont now supports the BYOD and the GMP energy storage offer.