Grid-scale energy storage developer Form Energy announced it is moving ahead under an agreement with Georgia Power to deploy a 15 MW/1500 MWh iron-air battery system in Georgia. The multi-day battery system could come online as early as 2026 and is subject to regulatory approvals.

Georgia Power first teased the collaboration in its 2022 Integrated Resource Plan as part of an effort to shift to a cleaner resource mix and eventually introduce long-duration or multi-day storage applications.

In its IRP the utility said it planned to evaluate opportunities in the 5-15 MW range to deploy this

technology and it would return to Georgia regulators for project approval once it identified an optimal application.

Form Energy is backed by the Bill Gates-led investment fund Breakthrough Energy Ventures. The company says its first announced commercial product, the iron-air-exchange battery, can deliver 100 hours of electricity at a price of less than $20/kWh.

Form says the technology’s basic principle of operation is reversible rusting. While discharging, the battery breathes in oxygen from the air and converts iron metal to rust. While charging, the application of an electrical current converts the rust back to iron and the battery breathes out oxygen.

The companies will continue to fully evaluate that the 100-hour iron-air battery technology will strengthen Georgia’s electric grid against normal day-to-day, week-to-week, and season-to-season weather variability. This analysis includes modeling by Georgia Power and Form Energy’s operational modeling tool for power grids.