Dominion Tests New Batter Storage Technology

 from a Dominion Energy press release:

To transform our Virginia grid to 100% fossil fuel free, requires long-lasting batteries- lots of them to continue to operate the grid when the wind does not blow and the sun does not shine. Last week, Dominion Energy Virginia proposed to the Virginia State Corporation Commission (SCC) a groundbreaking battery storage pilot project that could significantly increase the length of time batteries can discharge electricity to the grid.

Dominion wants to test two types of batteries that can power its system for up to 100 hours with pilot projects at its Darbytown power station in Henrico County. Both types are batteries are potential alternatives to lithium-ion batteries which are expensive at utility scales. Moreover, lithium-ion batteries are not suitable for long-term storage or staying charged up for prolonged periods of time.

One of the technologies (what is being called the Rust battery) could discharge energy for multiple days, reportedly up to 100 hours. The existing  batteries currently in the Dominion's fleet and across the U.S. have durations that, on average, are limited to four hours or less. So, these test project comes at a critical time as the company develops the largest offshore wind project in the U.S. and continues expanding the second-largest solar fleet in the nation.

"We are making the grid increasingly clean in Virginia with historic investments in offshore wind and solar," said Ed Baine, President of Dominion Energy Virginia. "With longer-duration batteries in the mix, this project could be a transformational step forward, helping us safely discharge stored energy when it is needed most by our customers."

The pilot project, which will be located at the Darbytown Power Station in Henrico County, will test two alternatives to lithium-ion batteries: iron-air batteries (also called Rust batteries) developed by Form Energy and zinc-hybrid batteries developed by Eos Energy Enterprises.

Form Energy's battery are modular units around 5 cubic feet that uses a reversible process to store and release energy. During the charging process, the battery converts iron oxide or rust into metallic iron and releases oxygen as a by-product. When discharging, the oxygen reacts with metallic iron and leads to iron oxide formation, releasing energy. The reaction does not happen instantly like in a lithium-ion battery but at a large enough scale can produce a continuous stream of energy that is sufficient to support the requirements of the grid.

Form Energy's iron-air technology has the potential to discharge energy for up to 100 hours, significantly longer than the batteries available on the market today. Rusting, which is the chemical reaction that creates iron oxide releases energy, which the battery taps to feed an electric current to the grid. Charging them with electricity from the grid removes the rust, allowing the batteries to recharge and the energy releasing reaction to start again.

"We are pleased to partner with Dominion Energy on the innovative Darbytown Storage Pilot Project and look forward to delivering a 100-hour iron-air battery system that will enhance grid reliability and provide Dominion's Virginia customers with access to wind and solar energy when and where it is needed over periods of multiple days," Form Energy's co-founder and CEO Mateo Jaramillo said. This is the second pilot project in development for Form Energy.

"We are proud to have been selected for this critical project. Dominion understands that meeting our future energy needs requires multiple storage technologies," said Joe Mastrangelo, Chief Executive Officer of Eos Energy Enterprises. "We're excited to show Dominion how well our zinc-hybrid batteries perform." The Znyth™ aqueous zinc battery was designed to overcome the limitations of conventional lithium-ion technology. Safe, scalable, efficient, sustainable—and manufactured in the U.S. The company says that it will deliver reliable energy storage alternative for 3- to 12-hour applications. Other pilot projects have been announced in Texas and California.

In addition to SCC approval, the project would require development plan approval from Henrico County. If approved, construction would begin by late 2024, and the project would be operational by late 2026.

The project would add to Dominion Energy Virginia's growing fleet of battery storage facilities, including three in operation in Powhatan, New Kent and Hanover counties. The company has three additional large-scale battery storage facilities under development in Chesterfield County, Sussex County and at Dulles International Airport in Loudoun County. Replacing fossil fuel generation in the grid requires long-lasting batteries- lots of them.