France: Reflex: Learning New Risks to Connect More Solar Energy, Faster (2/7)

Grid connection remains one of the main bottlenecks in the development of photovoltaics. When a source substation is saturated, the conventional solution often involves waiting for reinforcement works, sometimes for several years – up to 10 years currently in certain departments. Reflex is an initiative launched by Enedis to “overbook” source substations in order to connect more renewable energy sources, and faster.

This approach allows for the provision of connection offers that exceed standard sizing, in exchange for occasional curtailment. Producers thus accept an injectable power that is sometimes lower than their installed capacity, but obtain a faster connection. The derogation for the tests (conducted in the Landes and Picardy regions, on eleven source substations) was granted by the DGEC in 2021.

Since then, the approach has been generalized, turning Reflex from an experiment into a standard method. By the end of 2025, more than 40 medium-voltage (MV) projects and 180 low-voltage (LV) projects, representing 210 MW, had already received offers utilizing this additional capacity. By 2028, Enedis plans to make 600 to 800 MW of additional capacity available across approximately fifty source substations. Progress is being made: nearly 190 MW of additional capacity had been unlocked on 31 transformers by March 2026.

“The second phase of generalization (starting in 2028) will extend to all relevant source substations, thanks to the industrial tools and methods developed by that time,” the CRE specifies in its report.

Incorporating curtailment into the risk

Accepting an injectable power level lower than the installed capacity can enable grid connection to be secured several years earlier. However, this risk must be properly integrated into the economic model. To date, connected assets have only experienced a few sporadic curtailments in 2025, largely due to their small scale, which remains below 9.2 MWc. The higher the plant’s output, the more likely it is to be targeted by Enedis, which specifies: “The grid connections expected in 2026 and 2027 will progressively lead to a more significant need for flexibility, or, failing that, to injection curtailments.”

In 2025, the Reflex mechanism resulted in 671 MWh of non-injected energy, with an average compensation of €74/MWh. This compensates for part of the revenue loss associated with injection curtailments, without constituting additional income for the producer.

The arbitrage therefore depends closely on the price at which the producer would have sold that energy. For a project backed by a power purchase agreement, the risk is easily measurable. For a valuation on the markets, the reading becomes more nuanced. When solar production hours coincide with low or negative prices, curtailment can even limit a loss. The real issue for the developer is therefore not only the volume of curtailment, but its hourly profile.

For project developers, this requires integrating a detailed analysis from the development phase: production profile, expected price curves, indemnification clauses, the possibility of coupling PV with storage, and the cost of control. The calculation is no longer just “how many MWh do I lose,” but “which MWh do I lose, at what price, and what flexibility services can I monetize in return.”

Consequently, Enedis’s reference technical documentation must evolve to incorporate the remote control criteria applicable to future low-voltage renewable energy production projects. This is not necessarily straightforward, given the history of this network, which is less technologically advanced than the high-voltage network, particularly in terms of real-time sensors. “For projects that have already received a connection proposal or are already connected at low voltage in constrained areas, the installation of these devices is the only identified lever to avoid stressing the infrastructure when the volumes injected into the transmission network exceed the evacuation thresholds of high-voltage lines, or when the amount of production exceeds the capacity of the distribution network infrastructure, thereby compromising the operational safety of the networks. It must therefore be implemented by Enedis in the affected areas.” It is not so simple…