Long-Duration Storage Is 2028+ at Scale

The long-duration energy storage (LDES) category — broadly defined as >8 hours of discharge — is critical for a fully decarbonized grid but is not yet an investable infrastructure asset class in 2026. Form Energy's iron-air battery, Ambri's liquid metal battery, and various compressed air and gravity storage concepts all have credible physics but none have demonstrated bankable track records sufficient for non-recourse project finance. DOE LDES demonstration programs are the right funding mechanism at this stage. The realistic commercial deployment window is post-2028, dependent on cost reduction to sub-$100/kWh for overnight capacity. Venture exposure to 1–2 technology leaders makes sense; project equity does not yet.