Nine Utilities Put Sodium-Ion Storage to the Test

A Colorado pilot from Peak Energy and utility partners tests whether sodium-ion batteries can compete with lithium in future grid storage projects

4 Oct 2025

A pilot project in Colorado has begun testing sodium-ion batteries on the US power grid, offering utilities an early look at a technology that could broaden options for large-scale energy storage.

Peak Energy said its 3.5MWh system became operational in September 2025 at the SolarTAC testing site, developed in partnership with nine utilities and independent power producers. The project is among the first real-world demonstrations of sodium-ion batteries operating in grid conditions in the US.

The initiative comes as grid-scale storage has largely been dominated by lithium-based systems. Rather than displacing existing technologies, the pilot is intended to test whether sodium-ion batteries can operate reliably at commercial scale.

Utilities involved in the project are collecting operational data while the system runs alongside established grid infrastructure. The partners are examining whether the technology can provide stable output, meet safety requirements and compete on lifecycle cost before considering wider deployment.

Peak Energy argues that sodium-ion chemistry could offer a supply chain advantage. Sodium is widely available and does not rely on the same minerals that underpin lithium battery production, which are often tied to complex global supply chains. Companies and policymakers in the US have increasingly focused on reducing exposure to mineral price volatility and geopolitical risk.

The pilot also allows participating utilities to evaluate the technology without committing to large procurement contracts. Operational data gathered in the coming months will be used to determine whether sodium-ion systems can become commercially bankable assets.

Industry observers say the technology still faces several hurdles. Domestic manufacturing capacity for sodium-ion batteries remains limited, and long-term durability will need to be demonstrated through sustained field operation.

Policy incentives and domestic manufacturing requirements could also shape adoption. With electricity demand rising because of electrification and expanding data centre capacity, utilities are examining a range of storage technologies. Results from the Colorado pilot over the next 12 to 24 months may provide a clearer indication of sodium-ion’s commercial prospects.