Epyr, a France based provider of thermal energy storage, has raised 15 million euros, about 17 million dollars, in an oversubscribed Series A round led by SlateVC. Existing investors AENU and Daphni participated, alongside new backers WEPA Ventures, OVNI Capital and Aurum Impact. The round comes 18 months after a 3 million euro pre-seed co-led by AENU and Daphni.
Epyr’s systems use electric resistors to heat air and transfer the energy into firebricks, storing heat at high temperature so industrial sites can draw process heat when they need it, charged at low electricity price periods. The company targets industrial steam, mainly in paper, food and beverage, and chemicals. A unit at WEPA’s hygiene paper plant in Troyes entered operation in early 2026, and Epyr has been selected to deploy a 35 megawatt hour unit at Papeco’s Orval-sur-Sienne site, which it describes as France’s largest thermal storage project, replacing all natural gas consumption at that facility.
SlateVC co-founder Sebastien Leger put the addressable market at about 100 billion euros for industrial heat in Europe and backed Epyr to become a European leader in electrifying it. Mercom’s data show venture funding for energy storage companies totalled 1.6 billion dollars across 51 deals in the first half of 2026, down 6 percent year on year, almost all of it electrochemical.
The gap is the investment case. Batteries monetise electricity in and electricity out; industrial heat storage monetises the spread between cheap electrons and gas priced heat, a larger and less contested market, but one where every deployment is a bespoke industrial integration. The Series A prices that execution risk at venture scale, with a paper industry customer, WEPA, sitting on both sides of the table as user and investor.