Epyr Raises €15 Million to Scale Thermal Energy Storage Across European Industry

French energy technology company Epyr has raised €15 million in an oversubscribed Series A to scale thermal energy storage projects for industrial heat across Europe. The round was led by SlateVC, with existing investors AENU, Daphni, WEPA Ventures, OVNI Capital and Aurum Impact also participating. The funding will support a new wave of deployments, including a 35 MWh thermal storage system at French papermaker Papeco, as Epyr expands beyond its first operating installation at WEPA Group’s Troyes paper mill.

Industrial heat accounts for around 20% of global energy consumption and remains heavily dependent on fossil fuels, particularly natural gas in Europe. Epyr is targeting industrial steam applications in sectors such as paper, food and beverage, and chemicals, where switching to electricity depends heavily on whether power can compete with gas on cost.

 

Thermal Storage Makes Low-Cost Electricity Available When Industry Needs Heat

 

Epyr’s system uses electricity during low-cost periods to heat air, which transfers the energy into high-temperature firebricks. The stored heat can then be released later when an industrial process needs steam or thermal energy.

This allows industrial sites to take advantage of periods when renewable generation pushes electricity prices close to zero or below zero, without having to match production schedules directly to those periods. The storage system can also provide flexibility to the electricity grid by shifting demand away from more constrained hours.

"In France, there have already been more hours of near-zero or negative power prices this year than in 2025. That electricity is the cheapest, cleanest energy source European industry has," said Epyr co-founders Léa Dardenne and Bastien Oggeri. "Our mission is to harness it, and this Series A lets us do it at scale."

 

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WEPA Provides the First Industrial Reference

 

Epyr’s first commercial installation was commissioned at WEPA Group’s paper mill in Troyes in May 2026. The company says the system was built and commissioned in less than six months and can now supply up to 25% of the site’s steam requirements.

The operating reference is important because industrial customers typically require evidence that new thermal technologies can integrate with existing processes without affecting reliability. Epyr is using the WEPA project as the basis for expanding into larger systems and additional industrial sectors.

 

Papeco Project Will Test Full Natural Gas Replacement

 

The next major deployment is a 35 MWh thermal energy storage system at Papeco’s Orval-sur-Sienne facility. Epyr says the project will replace all natural gas consumption at the site, making it a more significant test of industrial electrification than the partial steam coverage achieved at WEPA.

Energy Pool is supporting Papeco from project studies through operations, while Epyr will supply the thermal storage solution. Several additional projects are also under evaluation, with further deployments expected to be announced.

 

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Heat-as-a-Service Could Reduce Upfront Barriers

 

Epyr combines the storage technology with system integration, energy management and, where required, third-party financing through a Heat-as-a-Service model. That structure can allow industrial companies to adopt electrified heat without taking responsibility for every element of project financing and operation themselves.

"Together with Epyr, we have shown that innovative energy solutions can be implemented quickly and successfully in an industrial environment," said Andreas Krengel, Member of the Management Board at WEPA. "The first installation has demonstrated the value of both the technology and the partnership."

 

The Economics Will Determine How Quickly Industrial Heat Electrifies

 

Thermal storage could address one of the core difficulties of industrial electrification: renewable electricity can be inexpensive at certain hours, while industrial heat demand is continuous. Storing heat allows industrial sites to separate the timing of electricity purchases from the timing of heat consumption.

Epyr now needs to show that the economics demonstrated at its early sites can be repeated across industries and electricity markets. The 35 MWh Papeco installation will be an important test because replacing an entire natural gas heat requirement would provide stronger evidence that thermal energy storage can move beyond supplementary use and become a primary source of industrial process heat.

 

Source: Epyr