2025 marked a turning point in France's energy transition. On the one hand, the climate emergency continued to intensify and its impacts on communities became increasingly tangible. On the other, the country's strained public finances tightened further. The only way forward, in other words, is to entirely rethink the way decarbonisation is funded. 

Benjamin Fremaux, Thomas Le Beux and Antoine Pellion shared their views on the issue with some 15 journalists this morning, and underlined a point that is sometimes overlooked: despite a degree of ecological backlash in political spheres, the people on the front line remain fully determined to move forward. Our Observatory for the Local Energy Transition survey, which we conducted with Ipsos and Villes de France, confirms that voters and the local officials they elect still rank environmental action high on their list of priorities. 

Heat, a gigantic pillar in the energy transition, is mostly ignored

Turning intention into action inevitably involves financing. And heat is where much of that financing needs to be directed: it accounts for 45% of the energy France consumes and 60% of it is fossil-fuelled. This overlooked fact is holding back climate action. 

As public funding inevitably continues to decline, a new industrial model is gaining traction: third-party investment. It opens the door to turnkey decarbonisation solutions without burdening constrained public budgets. 

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Third-party investment unlocks private capital

The concept isn't new. But it is becoming a cornerstone. In practical terms, Idex invested close to €300 million with its partners – local governments, manufacturers, social landlords – in local, low-carbon energy infrastructure in 2025. That is six times more than in 2018. And the momentum is growing: we plan to invest a further €386 million in 2026.

Bordeaux (€134 million), Brest (€70 million), Saint-Lô (€45 million) and Bourg-Saint-Maurice (€15 million) are examples of cities and towns across France where we financed, built and operate decarbonisation infrastructure designed around local areas' needs. 

The three pillars for local energy sovereignty

Idex no longer positions itself as a technical operator: it now aims to be an architect of local energy sovereignty, following three principles:

A technology-agnostic approach: we choose the best fit, in light of the area's needs and locally available resources, from the full array of options (geothermal heat, biomass, waste heat, solar, etc.). 

Integrated financing: we provide private capital so that local governments can bring ambitious projects to life without waiting for increasingly scarce public subsidies. 

Firm long-term commitments: we guarantee the energy and environmental performance of the infrastructure we develop, as part of long-term partnerships.

Statements of intent won't make energy cleaner: financing will 

Third-party investment is the game changer for communities that refuse to let budget constraints restrict their climate ambitions. It unlocks real financing for the real emergency by turning private-sector players such as Idex into active partners in the energy transition. 

With communities and for communities: that is how decarbonisation is materialising in France.