Dominion proposes pilot to test longer-lasting battery storage
A battery system operated by Dominion Energy in Powhatan County, Virginia. (Sarah Vogelsong / Virginia Mercury)
Dominion Energy is seeking regulatory approval for a battery storage pilot that would be capable of discharging stored power over longer periods of time than its current technology allows, a development seen as a key component of the transition to renewable energy.
At its Darbytown Power Station in Henrico County, Dominion wants to try out two batteries: one 5 megawatt iron-air battery from Form Energy that uses a rust oxidation process and another 4 megawatt zinc-hybrid battery from Eos Energy that uses a zinc reaction process.
The two technologies, which are being proposed as part of a portfolio of battery pilots by Dominion, have the ability to dispatch energy for up to 100 hours and 16 hours, respectively. The most common form of battery technology uses lithium, which can dispatch stored energy for up to roughly four hours.
As Virginia utilities increasingly generate power from renewable sources like solar and wind, reliability concerns have put a stronger focus on battery storage as a way to provide power to the grid when weather conditions are poor.
“We want to discharge this energy sometimes when the sun isn’t shining and the wind isn’t blowing,” said Tim Eberly, a Dominion spokesperson. “That’s why these longer-duration batteries are so critical when it comes to this transition to a clean energy grid and renewable energy.”
The two new batteries also have safety and other benefits compared to lithium batteries, the company says.
The non-lithium technologies avoid the risk of “thermal runaway,” which is when one lithium cell in the battery overheats and leaks into another cell, causing a chain reaction.
Furthermore, said Brandon Martin, manager of business development at Dominion, because demand for lithium is so high, the use of other materials for batteries could ease supply worries.
“The electric vehicle market and other sources of demand are expected to be about 90% of the total lithium produced,” he said. “Standalone energy storage is expected to be about 10%. And that’s our utility. … Other utilities across the U.S. … have energy storage goals as well.”
Ram B. Gupta, a professor at Virginia Commonwealth University’s College of Engineering who has studied the mining of minerals for battery storage technology, noted non-lithium batteries may not be as efficient at storing electricity as lithium batteries. But the iron and zinc they rely on is also more prevalent and less toxic than lithium, he said.
“We really need technology that uses elements that are not too toxic and not too expensive,” Gupta said.
Dominion isn’t the only utility experimenting with longer-duration batteries. At a press conference Monday, the U.S. Department of Energy’s Office of Clean Energy Demonstrations detailed nine long-duration energy storage projects around the country, including one in Maryland. Currently, said Juan Alvarez, a program manager for the office, only 2% of the 1,325 energy storage projects in North America have a duration of over 10 hours.
“Cheaper, longer energy storage can support the expansion of renewables like solar and wind by providing stability, flexibility and optionality to the grid,” said Alvarez.
If they receive State Corporation Commission approval, Dominion’s proposed projects would be operational by 2026. They come with an estimated price tag of $70.6 million, but Martin said there would be no change in customer bills since the costs for the projects will be recovered through the current base rates.
Virginia’s 2018 Grid Transformation and Security Act directed the SCC to establish pilot programs for Dominion to test out battery technologies capable of storing up to 30 megawatts of electricity. The utility is already running three lithium battery pilots in Powhatan, Hanover and New Kent counties totaling 16 megawatts and recently broke ground on a 50 megawatt battery storage facility, the company’s largest.
The Virginia Clean Economy Act calls for Dominion to develop 2,700 megawatts of battery storage by 2035.
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