Batteries could be key to storing excess electricity

Posted February 13, 2021 1:01 a.m. EST

— So many Decorah residents are putting up solar panels and installing small turbines that Alliant Energy, which serves the city of 7,700 in Winneshiek County, is nearing the limit of how much distributed energy it can host without degrading the quality of electricity in the community.

Rather than say no to more renewable energy, the utility is installing a $2.5 million battery system to store the energy and regulate voltage.

“It can absorb power when there’s too much and then, later in the day, when the sun goes down, we can release that energy and let it flow back onto the system,” said Sarah Martz, manager of distribution engineering at Alliant.

As energy costs rise and climate change causes more extreme weather that can disrupt energy delivery, scientists, entrepreneurs and government leaders are considering the best ways to store energy so it’s there when we need it.

The Cedar Rapids Gazette reports that energy storage is a way for utilities to make money — hopefully sharing the benefits with customers — and increase resilience.

Each year, some share of Iowa’s wind power isn’t delivered to the power grid because demand for power is low at the time. If this energy could be stored and later sold into the grid, Iowa’s wind plant owners could make more than $25 million a year, according to a December report from the Iowa Economic Development Authority.

The report also states that developing Iowa’s battery storage industry could bring 300 to 600 new full-time jobs to Iowa and increase gross domestic product $13 million to $24 million per year.

It’s these potential benefits of battery storage that caused the Economic Development Authority to award a $200,000 grant to Alliant for the battery installation in Decorah.

The U.S. Department of Energy contributed another $250,000.

“This gave us a great opportunity to advance one of the first battery storage project in the state,” said Brian Selinger, team leader of the Iowa Energy Office within the Economic Development Authority.

The pilot project will help show the feasibility of the battery installation and the life span of the battery, Selinger said. These are critical questions because they factor into the cost-benefit analysis of battery storage overall.

“We really need to know the years of battery life,” said Anne Kimber, director of the Electric Power Research Center at Iowa State University.

“The utilities are taking kind of a research-and-development approach to see what makes sense.”

While energy storage through batteries has huge potential, there still are many questions, including whether lithium-ion batteries are the best option and how we should dispose of spent batteries — especially ones the size of shipping containers, Kimber said.

ISU Engineering professor Steve W. Martin has won federal grants to create batteries out of sodium, which is inexpensive, safe and would be easy to dispose of afterward.

Early testing also is being done with zinc batteries, Kimber said.

When the Aug. 10 derecho knocked down scores of power lines in Cedar Rapids, many businesses and not-for-profits bought or rented diesel-powered generators to regain use of lights, refrigeration and electronic systems.

What if users could tap into battery storage instead of using generators?

Moving batteries into place after a storm would be hard, Kimber said, because “lithium-powered batteries are incredibly heavy. You’ve have to have ways to transport these and not destroy the roads.”

But if there’s battery storage connected to a solar project already in the community, you could keep recharging those batteries throughout the days of recovery.

Kimber would like to see the government put a value on keeping continuous power, maintaining safe food storage and keeping people at work and in school.

“If we add all that into the equation into the cost of how valuable a battery is, we might get a different equation,” she said.

“Battery storage is going to play a key role in bringing power back more quickly.”

Steve Falck, senior policy advocate at the Environmental Law and Policy Center, said he’d like to see Iowa make some changes to support further development of energy storage.

First, the state should update its Renewable Portfolio Standard, adopted in 1983, to include energy storage, which would require utilities to deploy storage in the grid.

“There could be incentives to help deploy that market quicker,” Falck said.

Falck added that the Iowa Utilities Board could require utilities to make public data about savings or profits from energy storage so the benefits can be shared by the customers.

As part of the state’s grant with Alliant, the utility will be sharing data from the Decorah installation with Kimber so ISU students can help with analysis.

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