Elestor

Dutch long-duration energy storage (LDES) developer headquartered in Arnhem, Netherlands, commercializing a hydrogen-iron flow battery. The technology stores energy in liquid electrolytes in external tanks, decoupling power and energy so duration can scale from roughly 8 to 150 hours at low marginal cost using abundant materials (hydrogen and iron). Elestor reports >75% system-level round-trip efficiency and a projected 20-25 year operating life. In July 2026 it announced its first large-scale commercial deployment partnership with Windpark Zeewolde.

Raised a EUR 30 million (~US$34 million) Series A led by Equinor Ventures, with participation from Vopak Ventures, Invest-NL, Somerset Capital Partners, EIT InnoEnergy and Enfuro Ventures (per Energy-Storage.news, July 2026).