During Irma’s Power Outages, Some Houses Kept The Lights On With Solar And Batteries
The ability of some residences and businesses to stay functioning as the power went out around them shows the growing potential of local generation and microgrids. Now those batteries just have to get a lot cheaper.
When Hurricane Irma blew out a transformer on his block in Orlando on the night of September 10, Andy Green–like most of the people on his street, and millions of people throughout Florida–lost power from the grid. But Green, who installed Tesla’s Powerwall home battery storage in early August, kept his lights on.
“We didn’t have full power–we couldn’t have the whole house running–but we cut it down to the bare minimum, like air conditioning, refrigeration, internet, that sort of thing,” says Green. Though power is still out in parts of Orlando, electricity on his block came back from the grid 21 hours later. While it was off, Green’s Powerwall, connected to the solar panels on his roof, kept going. When the clouds parted the next day, the battery started recharging.
Typically, rooftop solar panels send power directly back into the grid. Power customers usually get a discount on their electric bill, but in a disaster, the fact that solar panels keep generating power isn’t useful. The rise of new home battery storage products like the Powerwall is changing that.
Of course, if a storm is strong enough to tear solar panels off a roof and the battery can’t recharge, this type of system wouldn’t work for long. It’s also expensive: A single Powerwall unit, which can store 14 kilowatt-hours of energy, costs $5,500 plus supporting hardware and installation that can cost up to $2,000. A similar battery from Mercedes-Benz ranges from $5,000 to $13,000 for a 20 kilowatt-hour system including installation. In the U.K., where Ikea now sells both solar panels and batteries, its batteries are also nearly $4,000 at current exchange rates. Beyond cost, if someone rents an apartment or house and can’t install solar panels, it’s not an option.
But the cost is likely to drop, and battery storage and solar power could also be used in community solar projects, where customers don’t have solar panels at their own homes, but invest in or buy power from a nearby microgrid. In Orlando, customers can buy solar energy from a 12-megawatt solar farm built on top of a landfill; while the power is currently sent back to the grid, in the future, it’s possible that it and other community solar farms could use batteries to provide local backup power from multiple locations in emergencies.
After Hurricane Sandy, a microgrid at Princeton University–in that case, running on both gas and solar power–kept the power on at the school and turned it into a hub for emergency service workers. After Hurricane Harvey, natural gas-powered microgrids kept some supermarkets running. The falling cost of both solar and batteries is making it more likely that future microgrids will be fully renewably powered.
More people will also likely invest in battery storage for solar panels at home. “At this stage, it’s a luxury,” says Green. “Hopefully, as the price comes down on these things they’ll be a little bit more mainstream . . . if you can shell out the cash for them and have them in your house, they’re absolutely a boon to have. We were able to take warm showers and cook food . . . for a relatively long duration.”
