Hurricane Ian: When the power grid is down will solar and battery be able to power your house?

Hurricane Ian’s destructive winds and floods are likely to cause power outages for a long time across large areas of Florida. The hurricane will be the latest storm in a line of extreme temperatures and cold weather events that have shut off power to millions of Americans in recent times for several days.

In many disaster- and outage-prone regions, people are beginning to ask whether investing in solar panels on rooftops and battery storage systems will ensure that the power is on, and keep the AC in operation even when the power grid isn’t.

When the grid goes down and solar panels do not have batteries will shut down. But with batteries, homes are able to shut off to the grid. Each morning, sun illuminates the home and charges up the batteries, which provide energy throughout the night.

We team at Berkeley Lab examined what it would take for homes and commercial structures to withstand prolonged power outages lasting three or more days by using solar panels and batteries.

How much can solar + storage do?

In a new report we created an unavoidable power outage in every county in the U.S., testing whether a rooftop solar array with a 10- or 30-kilowatt-hour battery is able to provide power to critical loads such as refrigeration, lighting, internet service and well pumps; should it be able to extend the power and also power cooling and heating or even provide power to a complete home.

To put that into perspective, the most popular battery in the market, the Tesla Powerwall, is just 13 kWh of storage.

In general, we discovered that even a small system of solar and one battery can provide power to critical appliances in a house for days, practically anywhere in the country.

However, our maps reveal that providing backup for heating and cooling can be an issue, but not an impossible one. The homes located in the Southeast and Pacific Northwest often have power-hogging electric resistance heaters, exceeding the capability of solar and storage in winter time outages. homes with efficient heat pumps did better. The summer load of air conditioning can be a lot in the Southwest which makes it difficult to meet all cooling needs with solar and storage in an event of a summer blackout.

A larger array of solar and battery systems can assist, but the ability to meet demand during power outages is dependent on the weather conditions, how energy efficient the home is and other factors. For instance, simple adjustments to the thermostat during power outages can reduce the demand for cooling and heating, and allow solar with storage to provide backup power for longer periods.

In the case of solar power and storage, a 10-kWh battery can supply backup power, in various scenarios. Berkeley Lab, CC BY

The capacity to power commercial buildings differs depending on the building type. Schools and big-box retail stores that have enough roof space for solar in relation to demand for power in the building perform better than multistory, energy-intensive buildings like hospitals.

How would solar have dealt with 10 past disasters

We also looked at 10 real-world outage events occurring from 2017 to 2020, such as hurricanes, wildfires and storms, and then simulated the performance of buildings in specific areas and actual weather patterns both during and following the outages.

We found that in seven outages the majority of houses would have been capable of sustaining essential loads, as well as heating and cooling by using solar with 30 kWh of storage, which is about two Powerwalls.

But the weather around the outage can have a big impact in particular for hurricanes. Following Hurricane Florence knocked out power throughout North Carolina in 2018, cloudy skies hung around throughout three consecutive days reducing or stopping the solar panel’s output.

Harvey Harvey On the contrary, hit on the Texas coast during August 2017 but moved on to cause widespread destruction elsewhere in Texas. It was clear skies above Corpus Christi cleared even as it took a several weeks to restore power. Storage and solar power would have been a big assistance in this case and could have provided all the energy requirements for an average single-family house, when clear skies were seen.

What would a typical home have done with solar and 30 kWh of storage following hurricanes Florence as well as Harvey. The light blue line shows the brief periods of “unserved load,’ or gaps in the ability to meet demand for power following the storms. The state of charge shows batteries were able to stretch solar power through the night.  


We also found that solar is able to perform well in less cloudy events, like wildfire prevention shutoffs in California or following the 2020 derecho storm in Iowa.

The source of heat for a home is also an important aspect. In a period of five to 10 days following an ice storm in Oklahoma in 2020 We discovered that solar power and a 30-kWh battery could have provided nearly all the vital power and heat needed for homes equipped with the natural gas heating system or heat pump. However, homes equipped with electrical resistance heating could have come short.

In Texas the majority houses are heated with electricity mostly resistance heaters. Energy Star-rated heat pumps – that provide heating as well as cooling – consume half as much energy for heat production as electrical resistance heaters and can also be more efficient in cooling than the standard air conditioning unit. Converting older resistance heaters to new heat pumps will not only save money and reduce the peak demand, but also boost the resilience of your system during outages.

New backup forms

The installation of storage and solar to provide back-up power for a home or building takes more effort and costs more – just one Powerwall could cost from US$12,000 to $16,500 for a complete installation, including the incentives, and tax. This is the same as a fair-sized solar system. However, an increasing number homes are considering installing solar panels.

Over 90% of solar projects that were built on the island of Hawaii by 2021 had been connected with batteries following a regulation change. The distributed power plants are helping to power the grid since coal power plants are being retired.

California has more than 1.5 million rooftop solar systems. An increasing number of consumers are retrofitting batteries on system, and adding new storage and solar, in part because utilities have been forced to use “public safety power shutoffs” to limit the possibility of wildfires sparked by power lines during the dry, windy weather.

Electric vehicles and automobiles are able to store more batteries than the Powerwall and are a great source of battery storage for future home batteries too. Ford

As well, new types that use backup energy are emerging from electric cars, particularly. Ford is partnering with SunRun to integrate its brand new F150 Lightning electric pickup truck with solar power and a two-way charger that could make use of the truck’s battery to power a home. The standard version of the truck comes with an 98-kWh battery. This is which is equivalent to more than 7 Tesla powerwall batteries for stationary use.

Critical power to support critical services

A fire station located in Puerto Rico offers a glimpse of what storage and solar can accomplish. After Hurricane Maria shut down power for a period of time during 2017, more than 4000 solar panels were put in place on the island, often paired with battery storage. One of these is situated in the town of Guanica, in the town of Guanica that was not able to handle emergency calls in previous outages.

After Hurricane Fiona’s winds and flooding again shut down power to most of Puerto Rico in September 2022 The fire station was still operating.

“The solar system is working beautifully!” Sgt. Luis Saez told Canary Media the day after Fiona knocked out power. “We did not lose power all throughout the hurricane.”

Maps show most parts of the country can run on solar plus storage for 'critical' uses. Still, a large percentage can run air and heat, but few can support an entire home.


Line charts show power potential from storage and demand during two major storms. They start low as the storm hits but then improve quickly.


An electric truck parked in a garage, plugged in, while people remove storm debris from a yard


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