Iron-air batteries to stabilise grid as coal plants shut down
Form Energy is partnering up with a US utility Xcel Energy for commercial deployment of its iron-air battery storage system. The 1GWh multi-day storage system will be used to integrate renewables and maintain grid reliability as retiring coal plants in two US states are shut down.
Form Energy, a US-based tech company developing multi-day energy storage systems is partnering with Xcel Energy to deploy its battery systems at two of Xcel Energy’s retiring coal plant sites.
The storage technology is hoped to allow Xcel Energy to integrate more renewable energy into its system and maintain reliability as it retires the coal plants in the coming years.
Iron-air battery storage systems
10MW/1,000MWh multi-day storage systems will be deployed by Xcel Energy-Minnesota at the Sherburne County Generating Station in Becker, Minnesota, and by Xcel Energy-Colorada at the Comanche Generating Station in Pueblo, Colorado.
Each individual battery module is about the size of a side-by-side washer/dryer set and contains a stack of approximately 50 one-meter-tall cells. The cells include iron and air electrodes, the parts of the battery that enable the electrochemical reactions to store and discharge electricity.
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Each of these cells is filled with water-based, non-flammable electrolyte, like the electrolyte used in AA batteries.
Within the storage system, battery modules are grouped in enclosures; hundreds of these are grouped together in modular megawatt-scale power blocks. Depending on the system size, tens to hundreds of these power blocks will be connected to the electricity grid.
For scale, in its least dense configuration, a one megawatt system comprises half an acre of land, and higher density configurations would achieve over 3MW/acre.
Modeling grid operations
Form Energy and Xcel Energy collaborated on extensive modeling with Formware, Form Energy’s investment and operational modeling tool for power grids.
This modeling helped Xcel Energy validate how Form’s multi-day storage will enhance Xcel Energy’s ability to integrate large amounts of wind energy and other renewable resources on its system.
Additionally, this analysis demonstrated that Form Energy’s 100-hour iron-air battery technology will strengthen the grid against normal day-to-day, week-to-week, and season-to-season weather variability, in addition to extreme weather events including severe winter storms and polar vortex events.
Many types of battery storage technology are being developed – wood, sand and ice among the growing list. And Form’s iron-air, which was unveiled in July 2022, is one of the few with a claim to 100-hour, 1GWh efficiency.
On the project, Mateo Jaramillo, CEO and co-founder of Form Energy, said: “This partnership highlights Xcel Energy’s commitment to ensuring grid resiliency and reliability, energy security, and access to low-cost clean energy when and where it is needed – every day of the year.”
Both projects are expected to come online as early as 2025.
