Tenor Energy is developing an entropic energy storage technology that converts molecular entropy changes directly into mechanical work, enabling ultra low-cost, flexible-duration grid storage. Instead of relying on lithium-based electrochemistry or geographically constrained pumped hydro, Tenor engineers a set of molecular interactions to maximize energy density using abundant, cheap, non-toxic raw materials such as limestone. The system charges and discharges through reversible compression and expansion of a working fluid, harnessing vapor pressure without an intermediate heat step and remaining compatible with existing steam turbine technology.

The process integrates off-the-shelf, technology-ready components—charging and discharging equipment, storage tanks, and raw materials are all at TRL 9—while the overall integrated process is at TRL 3 today. Tenor projects capital costs that improve with storage duration and a levelized cost of storage around $40/MWh, significantly below lithium-ion batteries (~$150/MWh) and pumped hydro (~$200/MWh). The initial roadmap is a 100 W garage prototype (already built), followed by a 10 kW pre-commercial unit (~$300k budget by September 2026) and a 1 MW demonstration in 2027, with 10–100 MW projects to follow via technology licensing to independent power producers (IPPs) that are actively building large storage portfolios. Founded by Ameya Rao (PhD Chemical Engineering, MIT; ex–Pure Lithium), Tenor is currently raising ~$300k to build the 10 kW prototype and secure patents, targeting proof of product–market fit with IPPs as the next inflection point.