Wisconsin Pilots New Sodium Battery That Cuts Costs in Half

Energy storage is about to get a whole lot cheaper, and Wisconsin is leading the charge.

Peak Energy and global power company RWE Americas just launched the Midwest's first sodium-ion battery storage system in eastern Wisconsin. Unlike the lithium-ion batteries most grids rely on, this new technology uses sodium, an abundant element that's far less expensive and doesn't require the complex cooling systems that drive up costs.

The math is compelling. Peak Energy says its sodium-ion system cuts the lifetime cost of stored energy by about $70 per kilowatt-hour, roughly half what conventional battery systems cost today. That savings comes from eliminating energy-hungry air conditioning units, slashing maintenance requirements, and reducing the need to overbuild capacity to compensate for battery wear over time.

The timing couldn't be better. Like most of the country, Wisconsin and the broader Midwest region are seeing electricity demand surge while grid storage remains scarce. That mismatch drives up energy costs for everyone.

Research shows that adding just 10 gigawatt-hours of battery storage across the Midwest over the next decade could save the region $27 billion compared to operating without it. If those batteries use Peak's sodium technology instead of traditional lithium systems, the savings jump by another 25%.

The Ripple Effect

This pilot matters because grid batteries are becoming essential infrastructure as more wind and solar power comes online. They store electricity when production is high and demand is low, then release it during peak hours when prices spike. That helps keep the grid stable and prevents utilities from making expensive emergency power purchases.

The sodium-ion design works because the chemistry is inherently more stable than lithium. The batteries can operate across a wide temperature range without losing performance, which means they can sit outdoors in Wisconsin winters without expensive climate control. That simplicity translates directly into lower costs for utilities and, eventually, for customers paying their power bills.

RWE Americas, which operates 13 gigawatts of energy assets across the US, will test how the technology performs under real grid conditions. "Peak's innovations, enabled by sodium-ion batteries, greatly reduce energy storage costs, enabling lower cost energy delivery to Wisconsin residents," said Peak Energy CEO Landon Mossburg.

If the Wisconsin pilot succeeds, it could open the door to widespread adoption of sodium-ion batteries for large-scale storage nationwide, making clean energy more affordable and reliable for millions of Americans.