A Minnesota battery pack is being built to run nonstop for 100 hours on rusting iron, and that is roughly ten times longer than the lithium batteries that dominate the grid today

A quiet field in rural Minnesota is filling up with steel enclosures the size of shipping containers, wired together and waiting for winter. Inside…

Rows of battery enclosures at a 100-hour battery storage site, minnesota battery
Energy · Hugo Rojas · October 28, 2026
Newsletter

The morning brief

One email each weekday. Energy, technology, and finance, in the time it takes to finish a coffee.