Tesla’s Powerwall battery will be installed in 500 Vermont homes next year, making Green Mountain Power the first utility in the country to offer a home battery option, SmartGrid News reports.

The 7 kilowatt-hour battery, the smaller of two Powerwall options introduced by Tesla earlier this year, will provide four to six hours of backup power.

Green Mountain plans to begin with ten customers in the Rutland area before offering it to customers in the rest of its service area. The price of the PowerWall battery and the SolarEdge inverter has been set at $6,500 (not including the cost of installation). Green Mountain is offering customers three payment options, including a lease that requires no upfront cost.

In a statement, Green Mountain said the battery would allow utility customers to become more energy independent while allowing the utility to reduce peak demand on the grid.

GMP President and CEO Mary Powell called the program a “game changer” that would move Vermont away from a century-old grid system to a more reliable and economical alternative.

Three ways to pay

A Powerwall can be installed on homes with and without photovoltaic (PV) systems. Green Mountain is giving customers several ways of paying for the system:

• Lease. Customers pay nothing up front for the battery, but pay a monthly fee of $37.50, roughly $1.25 a day.
• Buy outright. Customers would pay the full $6,500 cost.
• Buy but share. Customers who pay the $6,500 purchase cost and share access to the battery would get a monthly credit on their bills of $31.76. That, the utility said, “represents the value of leveraging the battery to help lower peak energy costs.”

The utility said the first batch of batteries would be arriving in January, with the balance to follow over the next several months. More than 500 customers had signed up for the program by Dec. 17, the utility said.

The batteries can be installed indoors or outdoors, although they’re not designed to operate in temperatures below -4°F. The 220-pound batteries come with a 10-year warranty.

Green Mountain has about 265,000 residential and business customers in Vermont. It previously announced plans to run the Emerald Lake State Park entirely on solar electricity with a system combining PV panels and Powerwall batteries. Tesla has announced plans to sell the Powerwall to residential customers in Australia.