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(The Conversation) Catastrophic winds and flooding from Hurricane Ian are likely to cause long-term power outages across much of Florida. The storm is the latest in a series of tornadoes and extreme heat and cold spells that have left millions of Americans without power for days at a time in recent years.
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In many areas prone to disasters and power outages, people are beginning to wonder if investing in battery storage and rooftop solar systems can keep the lights and air conditioning on when the grid can't.
When the grid fails, most solar systems without batteries also shut down. But with batteries, the house can be disconnected from the grid. Every day the sun supplies the house and charges the batteries, which provide electricity at night.
Our team at BerkeleyLab investigated what homes and commercial buildings might need to weather long-term power outages of three days or more using solar and battery power.
How much can solar + storage do?
For a new report, we modeled public power outages for every county in the United States and tested whether a rooftop solar system with a 10- or 30-kWh battery could manage critical loads like cooling, lighting, Internet service, and battery life. battery well. sports shoes; if he can go so far as to provide heating and air conditioning; Or even if it can run a full house.
To put this in perspective, the most popular battery on the market, the Tesla Powerwall, has just over 13 kWh of storage.
Overall, we've found that even a modest solar plus battery system can have critical loads on a home for days, almost anywhere in the country.
But our maps show that providing cooling and heating support can be challenging, but not insurmountable. Homes in the Pacific Southeast and Northwest are often equipped with energy-hungry electric resistance heaters, which exceed solar energy and storage capacity during winter power outages. Homes with efficient heat pumps fared better. The summer air conditioning load can be heavy in the Southwest, making it difficult to meet all cooling and solar storage needs in the event of a summer power outage.
Larger solar systems and batteries can help, but meeting demand during outages still depends on the weather, your home's energy efficiency and other factors. For example, simple thermostat adjustments during power outages reduce heating and cooling needs and allow solar with storage to store backup power for longer periods.
The ability to operate commercial buildings varies greatly depending on the type of building. Schools and large retail stores, with sufficient roof space for solar energy relative to the building's energy demand, outperform energy-intensive high-rise buildings such as hospitals.
How solar power can deal with the 10 disasters of the past
We also analyzed 10 actual outages from 2017 to 2020, including hurricanes, wildfires and storms, typical building performance for specific locations, and actual weather conditions during and after outages.
We found that in seven of the outages, most homes could have received critical loads as well as solar heating and cooling with 30 kWh of storage, or just over two energy walls.
But the weather conditions surrounding the outage can have a big impact, especially in the case of hurricanes. After Hurricane Florence knocked out power in North Carolina in 2018, cloudy skies persisted for three days, causing solar panel production to scale back or even shut down.
Meanwhile, Hurricane Harvey hit the Texas coast in August 2017, but continued to wreak havoc in other parts of Texas. The skies over Corpus Christi cleared, although it took a week or more to restore power. Solar power and storage would have been a big help in this case, providing almost all of the energy needs of a typical single-family home once the skies clear.
Similarly, we found that solar power can perform well during less cloudy events, such as power outages caused by wildfires in California or after a windstorm in Iowa in 2020.
The heat source in the home is also a big factor. During an outage of five to 10 days after the 2020 Oklahoma snowstorm, we found that solar power plus a 30 kWh battery could provide almost all of the critical power and heat needed for homes equipped with natural gas radiators or heat pumps. But houses with electrical resistance for heating will not be enough.
In Texas, more than half of the homes are heated with electricity, most of them with resistance heating. Energy Star qualified heat pumps provide both heating and cooling and use half the electricity per unit of heat output than electric resistance heaters and are more efficient at cooling than the average new air conditioner. Converting old resistance heaters to new heat pumps can not only save money and reduce peak demand, but also increase resilience during outages.
Deploying solar and storage to provide backup power for a home or building requires additional work and costs more: A Powerwall alone can cost between $12,000 and $16,500 for a complete solar system installation, before incentives and taxes. This is equal to the size of a good solar system. However, an increasing number of owners are installing both.
More than 90% of new solar installations in Hawaii by 2021 will be integrated with batteries after a regulatory change. Now these distributed power plants help supply the grid as coal power plants are retired.
California has more than 1.5 million rooftop solar systems. A growing number of customers are retrofitting batteries in their systems or adding new solar storage units, in part because utilities have used "public safety outages" to reduce the risk of power line fires on dry days. and windy.
New forms of backup power are emerging, especially from electric vehicles. Ford has partnered with SunRun to equip the new F150 Lightning electric truck with solar power and a two-way charger that can use the truck's battery to power a home. The standard version of the truck comes with a 98 kWh battery, equivalent to more than seven stationary Tesla Powerwall batteries.
Critical power for critical services
A fire station in Puerto Rico offers a glimpse of what solar power and conservation can do. After Hurricane Maria knocked out power for months in 2017, more than 40,000 solar power systems were installed on the island, often combined with storage batteries. One is at the fire station in the city of Guánica, which was unable to receive emergency calls during previous outages.
When winds and flooding from Hurricane Fiona knocked out power to much of Puerto Rico in September 2022, the fire station was still operating.
"The solar system is working fine!" Sergeant Louis Saez told Canary Media the day after Fiona lost power. "We didn't lose steam throughout the hurricane."
This article is republished from The Conversation under a Creative Commons license. Read the original article here: https://theconversation.com/could-solar-and-battery-power-your-home-when-the-electricity-grid-goes-out-191157.
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