[Decoding] What Role for Nuclear Energy in France by 2035? (RTE Report)

On September 20 2023, France Transmission System Operator (RTE) presented its Generation Adequacy Report for 2023-2035. RTE explores the levers available over this period to achieve France’s decarbonisation and reindustrialisation objectives. Among these levers, nuclear plays a pivotal role in energy supply and peak power requirements in all scenarios considered.

As the Ministry of Ecological Transition draws conclusions from working groups dedicated to the reflections on the future French energy and climate strategy (SFEC), RTE is publishing a new forecast on the transformation of the electricity system between now and 2035. This medium-term horizon includes two significant milestones in terms of energy and climate policy: firstly, a 55% reduction in net emissions as part of the European “Fit for 55” plan; secondly, a reindustrialisation plan for France. RTE explores three sets of scenarios that offer insights into the trajectories for achieving climate objectives and ensuring the security of supply for the French electricity system:

  1. the reference scenarios (A – “Successful acceleration”) describe a favourable macroeconomic environment (financing available, successful reindustrialisation, etc.) in which all the levers that can be used for the transition are combined;
  2. the scenarios in which France lags more or less behind on a combination of these levers (B – “Partial achievement”);
  3. the scenarios in which the macroeconomic context is deteriorating (C – “Globalization thwarted”).
Rising electricity consumption: a solidly established result

RTE’s Energy Pathways 2050, published in September 2021, has already contributed to a broad understanding of the determinants of electricity consumption trends in France. There is now a consensus, backed up by numerous technical and economic results: achieving climate objectives will require an increase in electricity consumption driven by the electrification of uses (heating, transport) and the relocation of industries that need to be decarbonised (via electrolytic hydrogen or the electrification of processes). This is essential to achieve the desired reduction in fossil fuels, which weigh on France’s trade balance[1]. Such objectives “place electricity consumption trajectories up to 2035 among the highest in the Energy Pathways 2050”, explain the report’s authors.

Four levers are needed to respond to this rise in electricity consumption. On the demand side: efficiency and sobriety. On the supply side: renewables and nuclear power. RTE is clear about the contribution of this pairing: “there is no doubt that the French electricity mix will continue to be made up of nuclear reactors and renewable installations”, the report goes on to explain, adding that there is still room for political discussion, albeit constrained by technical fundamentals.

Nuclear generation is unavoidable in the short and medium-term

In its assumptions on nuclear production, RTE is in line with the Government’s guidelines for the sector, namely, for existing nuclear power plants, continued operation beyond 50 years, subject to safety conditions, and the launch of studies for its continuation beyond 60 years. Therefore, The aim is to reverse the current multi-annual energy programme (PPE), which calls for the closure of 12 nuclear reactors and a cap on the fleet’s capacity.

In terms of production, in line with EDF’s contribution to the LPEC law consultation process, RTE assumes that the fleet will operate conservatively “post-stress corrosion”. In total, RTE assumes an average volume of around 350 TWh for the existing fleet, plus 10 TWh from the Flamanville EPR, which will be commissioned in 2024 and gradually ramped up.

A low variant (330 TWh) and a high variant (400 TWh) are also studied, corresponding to pre-crisis availability rates. This latter variant accounts for the potential positive effects of a program to increase the power of existing reactors and the additional benefits of the Start 2025 program on operational performance. As Luc Rémont presented this project to the National Assembly on July 19, 2023: “We are going to build an investment plan to get as close as possible to 400 TWh, which will take a few more years. This is an ambitious plan […] aiming for 400 TWh on a fleet that will be 20 years older than the year in question is a colossal industrial challenge.”

“Ambitious” and “colossal” – these terms measure up to the transition’s stakes and the tremendous project in which the sector is embarking. Especially since “maximising the annual production of the existing nuclear fleet” is, as RTE assures, “an essential element to achieve decarbonisation in the next decade”. Thus, two timeframes coexist for the sector: the medium/short term, with the performance of the existing fleet and the commissioning of Flamanville, and post-2035, with the commissioning of the first EPR2 reactors.

Security of supply: the pivotal role of nuclear in moving away from coal

According to RTE, supply security is expected to strengthen in the short term, as “the French electricity system has now passed its most delicate period”. In this context, the closure of the last two coal-fired power plants is made possible “under strict conditions”:

  • The closure of the Saint-Avold plant (coal) will depend on a high availability of nuclear power in winter (to meet peak demand) of at least 55 GW;
  • Given the constraints on the Brittany grid, until the Flamanville EPR is fully operational, it will be necessary to maintain the Cordemais power station (coal).

Beyond the closure of Saint-Avold, the high availability of the nuclear fleet in winter would avoid the construction of new gas-fired power plants, whose conversion (to hydrogen or biomass, for example) would not be immediate. Thus, in a context[2] where peak demand will become crucial, moving away from fossil fuels – coal and gas – depends on the existing fleet’s good performance.

Modulating the nuclear fleet

Today, modulation of the nuclear fleet offers solutions for real-time balancing and economic optimisation of fuel management according to market prices. On a much more marginal scale, modulation also responds to a lack of economic outlets when prices are low or negative. In total, this modulation represents an annual volume of 30 TWh. However, the rise in renewable energies has been accompanied by a fall in market prices, affecting the profitability of capital-intensive conventional production facilities that do not benefit from off-market remuneration. This has led RTE to be cautious about maintaining all reactors (beyond the safety-related authorisations) and is helping to draw up the low variant (330 TWh) in which 0 to 6 reactor closures are considered. At the European level, renewable production’s impact on French nuclear modulation remains limited. ■

By Ilyas Hanine (Sfen)

Photo: Xavier Piechaczyk, Chairman of RTE’s Executive Board, and Thomas Veyrenc, Director of RTE’s Strategy, Forecasting and Evaluation Division, at the presentation of the 2023-2035 Generation Adequacy Report on September 20 – ©RTE

[1] This is a key issue to understand: if the transition costs a lot of money, it is important to compare this cost with the expected gains from moving away from fossil fuels.

[2] First-order electrification of heating.