Startup offers low-cost home batteries to Massachusetts residents

A company called Haven Energy has started offering home batteries on a subscription in four counties in southeastern Massachusetts, starting at $29 a month with a 10-year contract. Haven installs a 15-kilowatt-hour battery and keeps ownership of it, which is what keeps the monthly cost low. That's a big drop from buying a battery outright, where a home system can easily cost more than $15,000. Tesla launched something similar last month in Massachusetts and Connecticut, cutting about $30 a month off its existing battery-leasing program.

The low price works because the companies, not the homeowner, collect payments from a Massachusetts utility program called ConnectedSolutions, which pays battery owners for sending stored power back to the grid during peak demand, like hot summer afternoons. A typical battery can earn over $1,000 a year this way, and a newer version of the program pays even more in areas where the local grid is congested. Under Haven's plan, customers keep at least 20 percent of stored power on reserve, and the batteries switch to a "safety mode" that blocks grid discharge if a storm threatens an outage, so backup power stays available at home. Homeowners with solar panels can also use these batteries to store daytime solar power for use later.

This subscription approach isn't unique to Massachusetts. Vermont's largest utility has offered similar battery leases since 2017, and dozens of states now have programs that pay households for sharing battery power with the grid, a trend that could make backup batteries as easy to sign up for as any other home service.