Tesla’s new PowerWall batteries have the potential to lower costs for consumers, particularly when paired with solar panels. In years to come, they could help people go off-grid or use substantially less grid power.
But they might well help utilities as well, smoothing out demand peak and reducing the cost of dealing with outages.
That’s why Mary Powell, CEO of Green Mountain Power, in Vermont, says utilities might soon install energy storage as standard in people’s homes. She sees home batteries as tickets to greater resiliency and flexibility in utility operations–products that help all customers, not just those with Powerwalls.
“I could see a day that we’re saying to customers, ‘unless you object, we would like to install these in your house with your meter,'” she says. “Because there could be so much value we could generate, not just with that customer, but for all the other customers that we serve, if they’re in strategic locations.”
Green Mountain Power recently became the first utility in the country to offer the Powerwall, but it’s not simply being Tesla’s dealer. Customers can buy a 7KW system outright. Or, they can also grant GMP access to the battery should the utility need it and have GMP effectively subsidize the cost. The utility is offering to pay Powerwall customers a credit of $37.50 a month on their bill, reflecting the value of the unit to the wider network.
At $6,500 (including installation), Powell says the main benefit to customers at this stage will probably be as a back-up system. Effectively, it is an alternative to getting an oil-powered generator.
“Vermont is a rural state with lots of miles of lines and not that many homes,” Powell says. “There are tree-related outages and animal-related outages. The most important thing you’re getting out-of-the-gate is resiliency.”
Tesla expects its initial customers to come in markets like Hawaii, Germany, and Australia, where electricity is comparatively expensive, or in places like California, where there are incentives for home-generated power.
For its part, GMP plans to install the first Powerwalls in the city of Rutland, where it’s running an experimental micro-grid project, and in extremely rural areas, where keeping up the grid is most challenging. It has 500 units from Tesla and already has orders for most of them.
In the next year, the utility also plans to offer new rates that encourage people to charge up their Powerwalls when power is cheapest (probably in the middle of the night). These won’t help GMP make money selling power–it may make less. But it could lead to a more reliable grid overall.