Hurricane Ian: When the power grid goes out can solar and batteries be able to power the home?

The impact of Hurricane Ian’s destructive winds and floods are likely to bring long-lasting power outages to large portions of Florida. This is the latest in a string of extreme heat and cold events that have knocked out power to millions Americans in recent years for days at a.

In many outage-prone and disaster-prone regions, people are beginning to question whether installing solar rooftops or battery storage will ensure that the power is on, and keep the AC on even when the power grid isn’t.

When the grid goes out the majority of solar systems that lack a battery will also be shut down. With batteries, homes are able to disconnect with the grid. Every morning, sun illuminates the home and charges up the batteries, which provide energy throughout the night.

Our Berkeley Lab team Berkeley Lab looked into what it might require for commercial and residential structures to endure long power outages, of three days or more using batteries and solar power.

How much can solar + storage be used to?

For a new study we have created an unavoidable power outage in each county across the U.S., testing whether a rooftop solar system combined with a 10 or 30-kilowatt-hour battery can supply power to vital loads like lighting, refrigeration, internet service and well pumps. It was also determined if it could go further as well as power cooling and heating or even supply power to an entire home.

For a better understanding, the most popular battery on the market The Tesla Powerwall, has just over 13 kWh of capacity.

We found that even a small system of solar and one battery can provide power to critical appliances in a house for days, practically everywhere in the nation.

But our maps reveal that providing backup for cooling and heat can be an issue, but not an insurmountable one. The homes located in the Southeast and Pacific Northwest often have power-hogging electric resistance heaters, which exceed the capability of solar and storage in winter time outages. homes with efficient heat pumps performed better. The summer load of air conditioning is often high in the Southwest which makes it difficult to meet all cooling needs by using solar energy and storage during a summer blackout.

A larger array of batteries and solar systems can aid, however, the amount of power needed during outages still depends on the weather, how energy efficient the home is, and other aspects. For instance, simple thermostat adjustments during power outages reduce heating and cooling needs and permit solar systems with storage to keep backup power for longer periods.

Where solar and storage with batteries of 10 kWh can provide backup power, in various scenarios. Berkeley Lab, CC BY

The capacity to power commercial buildings varies widely, dependent on the type of building. Retail stores and schools with enough roof space for solar in relation to the power requirements of the building, fare much better than large, energy-intensive buildings such as hospitals.

How would solar have dealt with 10 past disasters

We also looked at 10 real-world outage events occurring from 2017 to 2020, including hurricanes as well as wildfires and storms and also modeled the building’s performance for specific locations and real weather patterns during and after the outages.

We observed that during seven outages, most homes would have been capable of sustaining essential loads, as well as heating and cooling by using solar power with 30 kWh of storage, or just over two Powerwalls.

However, the weather surrounding the outage can have a big impact in particular for hurricanes. Following the hurricane Florence destroyed power across North Carolina in 2018, clouds were threatening over three whole days dimming or cutting off solar panels’ power.

The hurricane Harvey On the other hand, slammed the Texas coastline in the month of August of 2017 but moved on to cause widespread damage throughout Texas. The skies over Corpus Christi cleared even as it took a week or more to restore power. Storage and solar would have been a big assistance in this case and could have provided all the power needs for a typical single-family home, once it cleared.

What a typical house would have fared with solar power along with 30 kWh storage after the hurricanes Florence and Harvey. The blue light line indicates the short periods of ‘unserved load’, or gaps in the ability to meet demand for power immediately following the storms. The charge state shows batteries could stretch solar power into the night.  

FIND SOLAR SYSTEMS/BACKUP FOR YOUR HOME

We also found that solar can do well even in cloudy weather like the shutoffs for wildfire prevention in California or following the derecho windstorm of 2020 in Iowa.

The heat source in a home is another important factor. In a five-to-10-day outage following an snowstorm in Oklahoma in 2020, we found that solar plus a 30-kWh battery could have supplied almost all the critical energy and heat required for homes that have the natural gas heating system or heat pump. However, homes that have electronic resistance heating might have been short.

In Texas the majority of homes are heated with electricity mostly resistance heaters. Heat pumps that are Energy Star-certified – that provide heating as well as cooling – consume less power for heat production as electrical resistance heaters. They can also be more efficient in cooling than the average new air conditioning unit. The conversion of older resistance heaters into 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 solar and storage to provide backup power to an apartment or house requires more effort and costs more – just one Powerwall can run between $12,000 and $15,500 for a full system installation, before incentives and taxes. This is about the cost of a fair-sized solar system. However, an increasing number of homeowners are installing both.

Over 90 percent of solar projects that were built on the island of Hawaii by 2021 had been connected with batteries after changes to regulation. These energy plants distributed across the globe are helping to power the grid as coal plants are being retired.

California has over 1.5 million rooftop solar systems. An increasing number of consumers are retrofitting their batteries to their systems, or adding solar plus storage partly because utilities have been forced to use “public safety power shutoffs” to lower the risk of wildfires that are sparked by power lines during dry, windy days.

Electric vehicles and automobiles contain more battery storage than the Powerwall and could be used as the future home batteries. Ford

And new forms of backup power are being developed from electric cars, particularly. Ford has partnered with SunRun to integrate its brand new F150 Lightning electric pickup truck with solar and a two-way charger that could make use of the truck’s battery to power a home. The basic model of this truck comes with one 98-kWh battery. That’s the equivalent of seven Tesla Powerwall stationary batteries.

Critical power to support critical services

A fire station located in Puerto Rico offers a glimpse of what storage and solar could do. After Hurricane Maria interrupted power for a period of time during 2017, more than 40000 solar panels were set up on the island, often combined with batteries for storage. One of those is at the fire station in Guanica, the town. Guanica that was inaccessible to emergencies during previous outages.

The hurricane’s winds and flooding again shut down power to most parts of Puerto Rico in September 2022, the fire station was operating.

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

 

 

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