In France, a 100% renewable energy scenario is technically possible

This report was highly anticipated. The RTE electricity transmission network and the International Energy Agency (IEA) presented a study to the press this Wednesday morning according to which it is technically possible for France, by 2050, to draw much, if not all, of its electricity comes from variable renewables, i.e. photovoltaic panels and wind turbines. A far from trivial conclusion in the midst of a debate on the launch, or not, of a new nuclear program which would result in the construction of six new EPRs.

The fact remains that a strong, or even very strong, integration of renewable energies into the French electricity system is only feasible if four technical conditions are met. They concern compensation for the variability of renewable energies, maintaining the frequency at 50 hertz at all times, reserves and margins to manage the network in real time and, finally, a major reconfiguration of the transmission network.

A purely technical assessment

This report, commissioned by the government in 2019, focuses on the debate on the technical feasibility of an electricity system tending towards 100% renewable energy, whereas today he solar and wind power now represent less than 20% of the French electricity mix and nuclear more than 70%. In other words, it does not look at the economic, environmental and societal aspects of such a scenario. "It's a progress report and a global study will be published next fall," said Xavier Piechaczyk.

"A Copernican moment"

Barbara Pompili, the Minister for the Ecological Transition, welcomed the publication of this report, which she learned about at the start of the week.

For its part, Greenpeace also welcomes this report in a very positive way, "even if we think that it arrives late", comments Cécile Génot, communication officer at Greenpeace France. It comes "to confirm what so many environmental organizations and experts in the energy sector have been carrying for years: yes, in France, renewable energies are solid alternatives to fossil fuels and nuclear", points out the NGO anti-nuclear. "What is interesting is that the IEA is carrying this report even though it is a pro-nuclear organization. The fact that it is able to make this scenario public is very positive", notes Cécile Genot.

Industrialising technologies

The fact remains that such a scenario is technically only possible if France gives itself the means to overcome the technical and industrial challenges.

"All the technical solutions already exist one by one, at least at the theoretical or demonstrator stage", explained the president of RTE, while underlining the major challenge of the industrialization of these technologies.

One of the great complexities associated with renewable energies is their intermittency. In the evening, for example, photovoltaic production decreases significantly even though the demand for electricity is not weakening. Conversely, in the spring, wind farms can produce more electricity than necessary. However, RTE must permanently guarantee a balance between the demand and the production of electricity. This is the sine qua non condition for each consumer to have electricity by pressing the switch. In a configuration where renewable energies are largely dominant, the tools to manage this variability, such as storage, are essential. We then speak of controllable capacities.

Massively increase control capacities

According to RTE, 40 to 60 GW of controllable capacities will be necessary in addition to the current 30 GW, supplied in particular by hydraulic dams, in order to cover peak consumption. It would then be necessary to add 3 to 4 GW of additional capacity each year between 2035 and 2050.

As for the stability of the network, France and Europe will have to set up an experimental roadmap if the instantaneous share (i.e. the peak of production) of renewable energies exceeds 80 %.

Develop new electric highways

The transmission network will have to be reinforced to ensure exchanges of much greater volumes of electricity between different parts of the territory. Indeed, in summer, most of the electricity production could come from the south of France. Electricity that will then have to be routed to other regions. On this point, RTE does not mention technical or even economic issues, but that of acceptability because of the large high-voltage lines that would have to be drawn on virgin spaces.

Today, the number one in the integration of renewable energies is Denmark, with 60% in annual share. A configuration made possible in particular thanks to the numerous interconnections with its neighboring countries. In France, the multiannual energy program provides for renewable energies to reach 40% by 2030.

The authorities will then have to arbitrate between several scenarios when most nuclear reactors will reach the end of their life by 2050. Two options are emerging: replacing old reactors with new ones or completely replacing nuclear production with alternative energies. renewable. In both cases, renewable energies will occupy a prominent place in our electricity system.

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