France moves towards more flexible electricity system


This article is part of our special report Renewables’ integration in the electricity grid.

Author: Nelly Moussu /

Content of this article does not reflect the positions or opinions of the EU-SysFlex project or its partners. EU-SysFlex is not responsible for the information or opinions included in this article.


Energy professionals working on better integrating the growing number of renewable energies into the French energy mix are finding the varying number of renewable energies challenging EURACTIV France reports.

Despite the challenges, aggregating multiple decentralised sources, using so-called “smart grids” and goodwill could help with better integration.

French electricity is currently mostly made up of nuclear energy, representing 69% of the mix. However, what has been termed a “controllable” energy source should decrease in the coming years and replace solar and wind energy – both intermittent by nature.

At the same time, the EU has also set its target for 2030 to increase the share of renewables across the bloc to 40%, according to the new targets put forward by the European Commission to meet the climate objectives of the Paris Agreement.

In Denmark, solar and wind power already represent more than 50% of the electricity mix, while in Spain, Ireland, Portugal and Germany, the rate is around 30%.

But integrating the various and intermittent renewable energies into the energy mixes will gradually become more complex.

Hydropower is currently the primary renewable energy source in France, accounting for 13% of the mix, followed by wind power, representing 7.9%.

“In the future, what will develop more rapidly are wind and photovoltaic energy,” Marie-Ann Evans Calmels, technical director of the EU-SysFlex project at EDF, has said.

But for each type of energy, integration problems into the electricity grid are not the same.

Although it is seasonal, hydroelectricity can be controlled, whereas solar and wind power are highly dependent on weather conditions and are constrained by their intermittence.

“Variations in hydraulic production are much slower than variations in wind and photovoltaic production; the latter is highly variable,” Yves Barlier, the smart grids director at Enedis, has confirmed.

The overall challenge is to balance electricity production and demand in real-time. But there are other issues to consider, such as voltage control.

This is the purpose of the Horizon 2020 research project called EU-SysFlex.

From November 2017 to February 2022, seven industrial demonstrators – including one in France – tested several solutions for integrating renewable energy sources into the electricity grid; more precisely, the integration of at least 50% renewable energy sources.

Nuclear power, a flexible energy

The first solution is to aggregate multiple decentralised resources. This makes it possible to balance supply and demand by relying on wind farms, solar farms, energy storage systems, electric vehicles and heat pumps.

And the larger the grid, the simpler it is. While a gust of wind in France’s north-western city of Brest may have no impact on a national scale, it would complicate the electricity network management at the city level.

This makes production more flexible, adapting particular energy according to climate or demand fluctuations.

For France’s energy mix, nuclear can also be flexible. “The share of nuclear power can go up or down; it is a flexible energy source, just like a gas or coal-fired power station,” Barlier also said.

“Today, we still rely heavily on the flexibilities provided by the existing energy mix, namely nuclear and hydro,” said Calmels. “We, therefore, need to imagine how to rely on the flexibilities of tomorrow, provided by the fleet that will be in place by 2030 and then by 2050,” she added.

‘Smart’ grids and goodwill

Another way to integrate more renewables into the grid is to work on demand. “Part of the consumption will have to adapt to the production,” said Barlier.

Cold rooms in shopping centres could, for example, be used flexibly and not powered when there is neither wind nor sun. “A cold room can be kept at minus 20°C for several hours without electricity if it is well insulated,” explained Barlier.

Flexible consumption, at first with large industrial companies, could thus be developed. Several technologies would even allow such a system to be controlled in real-time, using smart grids or connected objects like the Linky meter.

However, there is also a need for goodwill.

Under French law, for instance, flexibility cannot be imposed on consumption, meaning compensation is the only way to convince energy consumers. “Flexibility in production is well controlled. But flexibility in consumption is a little bit new,” said Barlier.

Although the technologies already exist, goodwill appears to be the most uncertain parameter for developing flexibility in consumption.

In France, electricity suppliers like Engie already offer ways to control and modulate consumption remotely.

“Thanks to occasional cuts in the supply of heating and electric hot water of 15 to 20 minutes per hour, it would be possible to achieve average savings of around 5-8% of daily electricity consumption on days when the system is switched off,” Engie explains on its website.

This all poses a series of significant challenges in scaling within the EU, data interoperability, coordination between players, organisation of the energy market, and many other issues that the EU is currently looking into.

In the meantime, the flexibility of production should be put to the test after French President Emmanuel Macron announced increasing nuclear, wind and solar in the country’s energy mix.


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