When the sun goes down: Mandalay Homes launches home energy storage project

Your home could be battery operated, especially if you live in New York, California, Massachusetts, Hawaii, Vermont, Arizona or a growing roster of other states and municipalities experimenting with revamping their electrical grids for the 21st century.

Last week, real estate developer Mandalay Homes announced a plan to build up to 4,000 ultra energy-efficient homes —including 2,900 in Prescott, Arizona—that will feature 8 kilowatt-hour batteries from German maker Sonnen, as reported in The Wall Street Journal. Blake Richetta, senior vice president at Sonnen, says it could eventually be the biggest home energy-storage project in the U.S., says

Without batteries and other means of energy storage, the ability of utility companies to deliver power could eventually be threatened.

When the sun goes down

In Arizona, for example, there’s an overabundance of solar power in the middle of the day during cool times of the year, then a sudden crash in the evenings, when people get home and energy use spikes.

For utilities, it’s a headache, Marc Romito, director of customer technology at Arizona Public Service, tells the Journal. The price of electricity on interstate markets can go negative at certain times, forcing them to dump excess electricity or pay others to take it.

The Mandalay homes, which will come with the Sonnen battery preinstalled, will be part of a Sonnen-managed “virtual power plant for demand response” that could allow the houses to stabilize the grid, lower its carbon footprint and decrease peak load, says Mr. Richetta.

While the Mandalay Homes project is still in the blueprint stage, with only one test home built so far, this kind of radical, battery-enabled rethink of the grid is already happening in Vermont, the Journal reports.

The biggest challenge to home battery storage remains economics. Utilities’ current rate structures don’t charge most homeowners for using excess power, nor do they change the price based on time of day. For the overwhelming majority of homeowners, the payback on a solar power system with battery storage could take decades.