Investments · 7

Companies building the next European energy leaders

Seed to Series B+, tickets from €0.3M to €8M.

Europe

5France
1United Kingdom
1Italy

Energy Efficiency & AI is open. We are actively sourcing the next names in the book.

New Nuclear

Stellaria

Fast breeder Molten Salt Reactor

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Europe
France
Location
Grenoble, France
Founded
2023
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New Nuclear

The company

In brief

Stellaria, founded in 2023 in Grenoble, France, is pioneering the development of a compact 4th generation Advanced Modular Reactor (AMR) employing liquid fuel, the Stellarium.

Founders

The people building it

Nicolas Breyton, Guillaume Campioni, Lucas Tardieu, Bruno Desbrière and Antoine Gerschenfeld — five engineers with strong nuclear and industry backgrounds (CEA, ILL, Schneider Electric).

Stellaria team

Technology

Fuel cycle

Stellaria’s Stellarium reactor is designed to renew 100% of its fuel during operation. By using a fast neutron spectrum and liquid fuel salts, the reactor can recycle spent nuclear fuel and consume long-lived radioactive waste. This innovation drastically reduces the need for fresh uranium, minimizes waste output, and contributes to a more sustainable nuclear fuel cycle.

Reactor design

Unlike conventional pressurized-water reactors, Stellarium operates at low pressure using molten salt as both fuel carrier and coolant. This enhances safety, stability, and efficiency. The compact and modular architecture allows for deployment in industrial sites or as part of a flexible energy grid. Producing both electricity and process heat, the reactor is designed to support energy-intensive industries while complementing renewable energy sources with reliable, carbon-free baseload power.

Energy Storage

VoltR

Giving batteries a second life for a circular energy future.

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Europe
France
Location
France
Founded
2023
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Energy Storage

The company

In brief

VoltR is a French manufacturer specialized in battery cells repurposing. The company develops an AI technology for the characterisation and prediction of cells’ future performance, which allows to reassemble cells with the same performance potential to manufacture new battery stacks.

Founders

The people building it

Maxime Bleskine, Alban Regnier, François Mallet and Thibaud Maufront — four engineers with backgrounds in electrochemistry, energy systems, and industrial engineering.

VoltR team

Technology

Innovation

Their patented process combines low-energy, low-emission chemical treatments with advanced material analysis and reconditioning to enable industrial-scale recycling. An integrated AI system assesses and predicts cell degradation, future performance, and the most efficient way to associate the cells. Battery stacks are then tailored to specific applications. VoltR’s approach strengthens Europe’s autonomy over critical resources while advancing truly circular and sustainable electrification.

Energy Storage

Entroview

Redefining battery management for a sustainable future

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Europe
France
Location
Paris, France
Founded
2021
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Energy Storage

The company

In brief

Entroview, founded in 2021 in Paris, develops a battery diagnostic software based on a disruptive method: real-time measurement of entropy variation. The start-up proposes today one product based on its patents.

Founders

The people building it

Sohaïb El Outmani (Telecom Paris) and Gaëtan Depaëpe (cofounder of Runview and Likewatt).

Entroview team

Technology

Three solutions

Entroview’s first product, EntroDiag, assesses batteries health and safety with State Of Health (SOH) diagnostics. The second solution detects defects on gigafactory production lines much faster than current processes, offering a considerable gain in time and storage space. The third product focuses on the precise measurement of battery State of Charge (SOC), a key factor in ensuring vehicle range and extending the lifetime of battery packs.

Entropy-based technology

Through a patented thermodynamical measurement, Entroview can determine what is inside each cell and link the results to chemical composition, particle size or phase transition. In lithium-ion batteries, this relates to the various ways lithium atoms can position themselves within the electrodes — microscopic-level insights that are critical for evaluating SOH and SOC.

New Nuclear

Blue Capsule

Unique nuclear heat and power for industry

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Europe
France
Location
France
Founded
2022
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New Nuclear

The company

In brief

Blue Capsule develops a small modular reactor of 4th generation at the convergence of two known technologies: High Temperature Reactors with classic He/water exchanger and Na/Air heat exchanger used in fast-neutron reactors. The reactor aims to generate heat for industries.

Founders

The people building it

Edouard Hourcade (nuclear engineer), Alexey Lokhov (École Polytechnique) and Alexis Burdeau (École Polytechnique).

Blue Capsule team

Technology

High temperature reactor

Capable of generating heat at up to 750°C, Blue Capsule’s reactor provides a pathway to decarbonize the energy sector by offering a low-carbon alternative for high-temperature industrial heat production. One example is the decarbonization of hydrogen production, as Blue Capsule could allow steam reforming, water electrolysis and methane pyrolysis processes to become emission-free.

The sodium/air heat exchanger

Unlike traditional helium/water systems, Blue Capsule’s sodium/air heat exchanger delivers several key advantages. It offers superior thermal conductivity, enabling up to five times higher power density. The design integrates an additional safety feature linked to the fuel’s degradation point, while reducing external environmental risks by using air as the cooling medium. This approach also provides greater flexibility in reactor siting, since no water source is required.

Energy Storage

TaiSan

Unleash the potential of next-generation mobility with advanced electrolyte technology.

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Europe
United Kingdom
Location
London, United Kingdom
Founded
2023
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Energy Storage

The company

In brief

TaiSan is developing a next-generation sodium-metal quasi solid-state battery, based on a polymer gel electrolyte and a sodium metal anode. Founded in 2023 in London, TaiSan focuses on improving performances of both sodium and quasi solid-state cells (energy density, sustainability, cyclability).

Founders

The people building it

Sanzhar Taizhan (Warwick).

TaiSan team

Technology

Innovative electrolyte and anode

TaiSan’s electrolyte is based on a polymer gel, a hybrid approach between the conventional liquid state and the future solid state. It swells as it absorbs the liquid, forming a gel that can conduct ions between the anode and the cathode. In addition, its sodium-X metal anode contributes to the formation of a protective layer on the anode, which is essential to prevent dendrite growth.

Next-gen anodes

This solution increases the energy density of a sodium-based battery chemistry while enhancing its safety. It also simplifies industrialization. These characteristics enable TaiSan to reduce the cost per kWh as well as the environmental impact of their batteries. Initial markets: micromobility, stationary applications, and consumer electronics.

New Nuclear

Otrera

Next-generation reactors for a sustainable energy future

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Europe
France
Location
France
Founded
2023
Vertical
New Nuclear

The company

In brief

Otrera is a spinoff of the French Alternative Energies and Atomic Energy Commission (CEA) proposing a Sodium Fast Reactor (SFR) with an innovative and modular architecture. The company uses French nuclear expertise to develop a modular reactor for electricity and heat production.

Founders

The people building it

Frédéric Varaine (nuclear engineer) and Jean-Eric Lucas (HEC Paris).

Otrera team

Technology

Disruptive architecture

Otrera’s design is based on an advanced modular loop-type reactor using electromagnetic pumps and incorporating system simplifications to address the key challenges of SFR technology and leverage its strong potential. This design stands out for its capacity of efficient recycling of spent fuel assemblies, its extended operating autonomy and its enhanced safety features.

Factory-prefabricated components

The components planned for the Otrera reactor are based on proven expertise from RNR sector components. Their limited size, due to the reactor’s compactness, allows for factory prefabrication and testing operations to reduce on-site assembly and testing times. Furthermore, the reactor’s design enables a modular approach to offer a wide range of power options for electrical and/or thermal energy production.

Energy Storage

Sinergy Flow

Affordable long-duration energy storage for renewable energy systems

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Europe
Italy
Location
Milan, Italy
Founded
2022
Vertical
Energy Storage

The company

In brief

Sinergy Flow is an Italian energy storage startup founded in 2022 in Milan. The company focuses on developing innovative long-duration energy storage solutions designed to support the large-scale integration of renewable energy sources into modern electricity grids.

Founders

The people building it

Alessandra Accogli, Gabriele Panzeri and Matteo Salerno — engineers specialized in materials science, electrochemistry and energy systems, originating from research at Politecnico di Milano.

Sinergy Flow team

Technology

Redox flow battery technology

Sinergy Flow develops a redox flow battery designed for long-duration energy storage. Unlike lithium-ion batteries, flow batteries store energy in liquid electrolytes that circulate through electrochemical cells. This architecture allows energy capacity and power output to be scaled independently, enabling flexible and modular systems suitable for grid-scale applications.

Abundant and sustainable materials

The company’s technology relies on abundant and low-cost materials such as zinc and sulfur. By avoiding scarce or critical raw materials, Sinergy Flow aims to reduce battery costs while improving supply chain resilience. The use of widely available materials also supports a more sustainable and circular approach to energy storage.

Scalable grid-level storage

Sinergy Flow’s modular systems are designed to provide long-duration storage for renewable energy installations and power grids. By enabling the storage of large amounts of electricity for extended periods, the technology helps manage renewable intermittency and supports the transition toward highly decarbonized energy systems.