If what happened on July 29 in California is any indication of the future of the power grid, then there is reason for optimism.

Let’s look at it from the perspective of Tom Weldon, who owns a house on the south end of San Jose and has rooftop solar and a battery system.

Weldon didn’t do anything out of the ordinary on that day. But his batteries, hooked up to software run by the solar company Sunrun, were part of a two-hour test to see the capabilities of home-based batteries when they work together to send power to the grid.