Epyr raises €15 million Series A led by SlateVC for industrial heat storage

Epyr, a Paris-based energy technology company founded in 2024, announced on Oct. 13 that it raised €15 million in a Series A round led by SlateVC. Existing investors AENU, Daphni, OVNI, WEPA Ventures and Aurum Impact participated. The announcement converts the round to $16.8 million; ESG Today's headline rounds that to $17 million.

Epyr builds thermal energy storage that lets industrial sites substitute electricity for fossil fuel in high-temperature heat. Electric heating elements run during low-price power hours and heat air, which in turn heats firebricks that hold thermal energy at high temperature; the stored heat is released when a site needs it. The company sells the package as storage hardware, system integration, energy management and financing under a Heat-as-a-Service model. Its founders are Léa Dardenne and Bastien Oggeri.

The first project named is a 35 MWh unit for Papeco, a French hygiene paper manufacturer, at its Orval-sur-Sienne site. Epyr says the installation is designed to replace the site's entire natural gas consumption and is expected to be France's largest thermal energy storage installation.

The economics rest on when power is bought. Epyr said France has already recorded more hours of near-zero or negative power prices this year than in 2025, and called electricity the cheapest, cleanest energy source available to European industry. Industrial heat accounts for roughly 20% of global energy consumption and remains largely dependent on fossil fuels, natural gas in particular in Europe; the EU has made electrifying it a priority for emissions and reduced reliance on imported fossil fuels.

Heat-as-a-Service is what distinguishes this from a hardware sale: the financing sits inside the contract, so the customer buys delivered heat rather than a capital project. The round is small next to other European energy technology financings this year: Munich-based fuel-cell maker Reverion's $175 million Series B, which this publication reported in September, is more than ten times the size.