Paper mills run on steam, and for a century, that steam has mostly come from burning gas. The heat is constant, the boilers are expensive, and the carbon footprint is stubborn. In Troyes, France, a WEPA Group paper mill now gets a quarter of its steam from a different source: a large, insulated box of electrically heated bricks [PaperFIRST, Unknown]. It is the first industrial deployment for Epyr, a Paris startup that thinks the easiest way to decarbonize a factory is to sell it heat, not hardware.
Founded in 2024, Epyr combines resistive electric heating, high-temperature thermal storage, and an energy management system into a single package. The idea is straightforward: use cheap, low-carbon electricity, often from overnight wind or midday solar, to heat air that in turn heats a stack of refractory bricks to around 800°C [Perplexity Sonar Pro Brief]. When the mill needs steam, the system pulls that stored heat back out. The technical trick is making it reliable and economical. The commercial trick, which Epyr is betting on, is removing every barrier for the customer. They call it Heat-as-a-Service [Our solution | Epyr, Unknown].
The wedge is financing, not physics
For an industrial plant manager, the problem is rarely a lack of will to decarbonize. It is a spreadsheet full of operational risk and capital expenditure. Retrofitting a gas boiler or installing a new electric heating system is a multi-million euro project that disrupts production and sits on the balance sheet for years. Epyr’s model is designed to make those objections vanish. The company builds, owns, and operates the thermal storage system on the customer’s site. The customer simply pays for the heat delivered, as they would for gas, but from a carbon-free source [News - Serie A | Epyr, Unknown]. It is a capex-to-opex shift that makes the unit economics the entire sales pitch.
The WEPA deployment in Troyes, launched in May 2026, is the proof of concept [IMPERIUM MAGAZINE, Unknown]. Built and commissioned in under six months without stopping the paper machine, the unit now supplies steam covering up to a quarter of the site’s needs [LeSPROM, June 2026]. WEPA Ventures, the paper group’s family venture arm, was also an early investor, creating a tight feedback loop between pilot and product. The Series A round, closed in October 2026, is already earmarked for the next project: a system for French hygiene-paper manufacturer Papeco at its Orval-sur-Sienne site [ESG Today, October 2026].
A team built for industrial scale
The founders bring a complementary mix of deep-tech company building and heavy-industry strategy. Bastien Oggeri is a repeat entrepreneur who co-founded Innovafeed, the insect-protein producer that reached French Tech Next40 status [Maddyness, February 2025]. He knows how to scale a physical process from lab to factory. Co-founder Léa Dardenne is a former Boston Consulting Group partner who focused on energy and climate strategy, the kind of background that helps navigate utility contracts and corporate sustainability mandates [WEPA and Epyr inaugurate thermal energy storage unit at..., Unknown]. As of October 2026, they were leading a team of around fifteen [LeSPROM, June 2026].
The funding history shows a consortium of climate-focused European funds sticking with the company through its early de-risking.
| Date | Round | Amount | Lead Investor(s) |
|---|---|---|---|
| Feb 2025 | Pre-seed | €3.1M | AENU, Daphni [Maddyness, February 2025] |
| Oct 2026 | Series A | €15M | SlateVC [ESG Today, October 2026] |
Prior investors AENU, Daphni, OVNI Capital, and WEPA Ventures all participated in the Series A, joined by new investor Aurum Impact [tech.eu, October 2026]. The €18 million (estimated) total war chest is for scaling manufacturing and signing more multi-year heat supply contracts.
Where the temperature could drop
The bet is elegant, but the path is lined with industrial-grade challenges. The risks are not about the physics of heating bricks, but the commercial and operational realities of being a utility.
- Commodity price risk. Epyr’s model relies on buying electricity at low prices to maintain a heat price competitive with gas. A sustained spike in European power markets, or a collapse in gas prices, could squeeze their margin or force them to raise their heat price, testing customer loyalty.
- Operational burden. Owning and operating hardware inside a customer’s critical infrastructure is a forever commitment. Any unplanned downtime stops a paper machine, transferring a major operational risk onto Epyr’s balance sheet. Their service-level agreements will need to be bulletproof.
- Sales cycle scale. Each deployment is a custom engineering and construction project tied to a single site. While the service model accelerates the yes, the physical nature of the business means growth is measured in bricks and mortar, not software licenses. Scaling to dozens of sites will test their project delivery muscle.
The company’s answer to these risks is embedded in its model. By owning the asset, they capture the upside of smart energy trading to manage price risk. Their six-month deployment at WEPA suggests they can move with the speed industrial partners require. The real test is whether they can replicate that speed at Papeco and beyond.
The next twelve months of steam
The immediate roadmap is about proving the model is repeatable. The Papeco project will be a crucial second data point, showing whether the Troyes deployment was a fortunate one-off or a reproducible blueprint. Expect the company to grow its engineering and project delivery teams significantly with the Series A capital. The goal, as stated, is simple: make industrial heat electrification competitive [Laurent BLAISE - LB Agri E+ C- | LinkedIn, Retrieved 2026].
On the back of an envelope, the unit economics start to make sense. A large paper mill can use several megawatts of thermal energy continuously. If Epyr’s unit displaces a quarter of the gas at such a site, that’s hundreds of tons of CO2 avoided annually, and a multi-year revenue contract locked in. The capital cost of their system is fronted by Epyr, but the lifetime value of the heat contract, plus any associated green certificates or carbon credits, has to cover it with room for profit. Their direct incumbent isn’t another tech startup; it’s the gas boiler,a century-old, depreciated asset that only pays for fuel. To win, Epyr’s cost of delivered heat must undercut gas, after accounting for the capital cost of their box of bricks. That’s the calculation running in every plant manager’s office they walk into.
Sources
- [ESG Today, October 2026] Epyr Raises $17 Million to Scale Industrial Heat Electrification Platform | https://www.esgtoday.com/epyr-raises-17-million-to-scale-industrial-heat-electrification-platform/
- [tech.eu, October 2026] French startup Epyr raises €15M following successful industrial heat storage deployment | https://tech.eu/2026/10/13/french-startup-epyr-raises-eur15m-following-successful-industrial-heat-storage-deployment/
- [Maddyness, February 2025] Le cofondateur d’Innovafeed Bastien Oggeri, aux prémices d’une nouvelle aventure entrepreneuriale | https://www.maddyness.com/2025/02/03/le-cofondateur-dinnovafeed-bastien-oggeri-aux-premices-dune-nouvelle-aventure-entrepreneuriale/
- [LeSPROM, June 2026] WEPA inaugurates thermal storage unit at its Troyes site in France | https://www.lesprom.com/en/news/WEPA_inaugurates_thermal_storage_unit_at_its_Troyes_site_in_France_123608/
- [PaperFIRST, Unknown] WEPA and Epyr inaugurate thermal energy storage unit at the Troyes site | https://www.epyr.co/news-wepa
- [IMPERIUM MAGAZINE, Unknown] Epyr's first industrial thermal energy storage unit launch | https://www.epyr.co/
- [Perplexity Sonar Pro Brief] Product and technology description | Snippet from research
- [Our solution | Epyr, Unknown] Heat-as-a-Service model description | https://www.epyr.co/
- [News - Serie A | Epyr, Unknown] Series A announcement and Papeco project | https://www.epyr.co/news-serie-a
- [WEPA and Epyr inaugurate thermal energy storage unit at..., Unknown] Partnership announcement with team background | Snippet from research
- [Laurent BLAISE - LB Agri E+ C- | LinkedIn, Retrieved 2026] Company objective statement | Snippet from research