Calogena Wins €40M EU Backing for Nuclear District Heating
French startup Calogena announced €40 million in European support toward a first commercial CAL30 reactor in Pierrelatte, designed to feed heat directly into city networks.
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giftdetect· the right gift in minutesCalogena, a subsidiary of French industrial group Gorgé, said on 5 November that it has secured €40 million in European support toward the potential construction of a first commercial installation in Pierrelatte, in the Drôme department. The plan is to supply hot water to urban heating networks serving homes and public buildings.
A reactor that makes heat, not electricity
The CAL30 is a nuclear heating plant. It uses uranium fission to warm water for a district network, whereas a conventional nuclear power station turns heat into steam to drive a turbine. Its rated output is 30 megawatts thermal, meaning 30 MWh of heat per hour at full power.
The fuel is low-enriched uranium, in a shortened version of fuel already used in power reactors. The reactor sits in a water pool, and according to Calogena the reactor water circulates by natural convection, without pumps. Heat passes through exchangers to an intermediate loop and then to the city network, so reactor water never reaches buildings. As a small modular reactor (SMR), it is meant to be built from factory-made components and reproduced across sites. Its safety must still be demonstrated to the competent authority before commissioning.
The backdrop is decarbonisation. According to the European Commission, about two-thirds of the energy used for heating and cooling in the EU still came from fossil fuels in 2025. Cities will compare the reactor with geothermal, biomass and recovered heat.
Two economic tests
The first is cost. The reactor price is only part of the bill: site works, grid connection, equipment, interest before first revenue, operation, fuel and end-of-life obligations all count. Municipalities will need to compare the cost of heat delivered to the network, which differs from subscribers' bills. The EU aid can reduce the amount to be financed, but its effect on price depends on the total budget and how the rest is funded.
The second is volume. Cities use far more heat in winter than in summer, yet fixed annual costs such as repaying the investment must be spread over fewer megawatt-hours when sales fall. The Pierrelatte project targets 131 GWh a year.
Calogena was founded in 2021. Following a capital increase announced in April 2026, Gorgé remains majority shareholder, joined by Snef, Banque des Territoires and the Deep Tech 2030 fund managed by Bpifrance. The project is part of France 2030 support for innovative small reactors.
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