Here’s How Home Backup Batteries Could Help the Power Grid
August 4, 2022
Texas could turn homes into power plants. The KVUE Defenders investigated what options are available and what’s standing in the way.
AUSTIN, Texas — “Right here we’re currently producing 7.1 kilowatt-hour kilowatts of power,” Sam Qassom of Pflugerville said.
Keeping kilowatts flowing through his home is of little concern to Sam Qassom.
“The dryer’s running. Obviously, AC is running. I can hear it going on over there,” Qassom said.
The solar panels on his roof collected nearly 10 times the power he needed.
Qassom said he purposefully bought more solar power than he needed. He wanted to make sure he had enough to keep a full backup battery charged.
“Our community is all electric, so we don’t have gas, water heaters or gas heat, gas stove – everything is electric, so we consume a lot of energy,” Qassom said.
In February 2021, Qassom felt the weight of that energy. A deadly winter storm caused blackouts across Texas. Hundreds died. Qassom was without power for days.
He said the temperature inside dropped fast.
“It was 39 degrees inside the house,” Qassom.
On the second day without power, he and his family left to stay with relatives.
Qassom didn’t have his solar panels at the time. It wouldn’t matter anyway.
Power flows from either a power plant, solar farm or wind turbines through high-voltage transmission lines. Then the power gets converted to low-voltage distribution lines, which carry the power to homes and businesses.
In Texas, rooftop solar doesn’t power the home. It goes to the grid. Homes draw off the grid unless they have a backup battery.
If the power goes out, Sam has enough battery storage to power his house.
“I don’t, I don’t worry whatsoever,” Qassom said.
“A year ago it was about a 10% adoption rate of people that buy solar plus batteries. Today that’s up to about 25%,” Bret Biggart, Freedom Solar CEO, said.
Biggart said more homeowners are looking to buy batteries because of the 2021 deadly winter storm. Without power loss, the batteries aren’t needed.
A virtual power plant
Qassom studied how his batteries could help others when he didn’t need it.
“Texas is a big state. There’s bound to be instances where Houston and Dallas are experiencing something and they need to borrow from us and I can provide and get something back out of it without necessarily being affected,” Qassom said.
There is a way.
“They [batteries] are a very fast resource,” Scott Hinson, Pecan Street, Inc. chief technology officer, said.
Pecan Street conducts energy data research for businesses and governments. It also tests products.
Hinson studied how someone like Qassom could use his backup battery to help everyone and get paid for it. It’s called a virtual power plant.
“A virtual power plant is a way to balance the grid,” Hinson said.
If there is a power emergency or strong demand, a homeowner could also sell stored battery power. A company would aggregate power across several devices, creating a virtual power plant.
It’s not widely allowed for residents.
The power grid manager, Electric Reliability Council of Texas (ERCOT), needs the Public Utility Commission of Texas to approve the idea.
“This is incredibly complex. Everything from how does it impact the customer, what are the customer protection rights?” Peter Lake, PUC chairman, said.
In June, Lake and the other PUC commissioners agreed to launch a pilot project.
“There are a lot of questions that need to be answered because we can answer them, but we’re going to be deliberate and be thorough to make sure that we get it right before we plug it in,” Lake said.
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During the first workshop session, energy companies voiced concerns including size of the project. A large project may give the better assessment but may take longer to implement. A small project disincentivizes companies from participating because it may cost more setting up the pilot than what they can get back.
“We’re going to make sure to maximize that potential. But at the same time, always ensure that reliability is our absolute priority,” Lake said.
The idea isn’t new. Green Mountain Power in Vermont started using virtual power plants in 2017. It now expands battery use by leasing backup batteries to homeowners that can’t afford to pay for one.
At home, Austin Energy proved a similar concept nearly a decade ago.
“When you install battery systems like this, you want to make sure you have all the right safety protocols, all the right access points in there,” Cameron Freberg, Austin Energy’s Emerging Technology Program manager, said.
He showed the KVUE Defenders how they use batteries in the Mueller neighborhood.
The project was launched in 2012 with the help from the U.S. Department of Energy and Pecan Street, Inc.
Batteries inside climate-controlled boxes store energy from the rooftop solar on nearby homes. The energy can go back into the neighborhood or through a substation to the power grid.
Austin’s battery is owned and operated by Austin Energy. While the homeowner is credited for their solar power, Austin Energy is paid for what comes out of the City’s battery.
Austin Energy filed comments to PUC showing small personal batteries could overwhelm the system.
“DERs [Distributed Energy Resources] will necessitate improvements to the transmission and distribution system that will impose significant costs, including the installation of dedicated distribution feeders, reconductoring, installation of equipment to mitigate voltage issues, the addition of capacitor banks to maintain the power factor, and system protection upgrades,” the filing shows.
Austin Energy said customers not receiving the benefit should not have to pay for the upgrades.
“Customers realize benefits – lower bills, resiliency, etc. – from DERs and thus should shoulder these costs in most circumstances as to avoid placing burdens on other customers,” the filing shows.
“We expect this solar adoption to be massive, you know, over the coming years. I think the grid will look much different and I think that solar will be a huge part of the solution. It will be much more widely adopted,” Biggart said.
Austin Energy and Pecan Street are now studying how electric vehicles can be used during high energy demand.
“The one I’m most excited about is when we figure out or once as electric vehicles grow and grow and grow, those are just battery systems on wheels,” Freberg said.
For now, the only way Qassom uses his battery to help the grid is when demand peaks. When it is more efficient, Qassom takes himself off the grid and relies on his batteries.
“We all need to do our part when we can do our part,” Qassom said.