Global connections

Energy, climate: the essential contribution of nuclear power

Awareness of climate change is leading to a gradual shift away from carbon-based energy. In this context, nuclear power should be able to find renewed interest. However, this is not the case. France has decided to reduce the share of this decarbonised energy to 50% of the electricity mix by 2035, leading to the closure of 14 nuclear reactors. However, at the global level, the International Energy Agency supports nuclear energy. In his interview with REE, André Merlin, a leading figure in French and European electricity networks, considers that to make a success of its energy transition, France must rely on a mix combining nuclear power and renewables. France must support its nuclear industry by renewing its power plants and continue to export its nuclear expertise around the world.

Interview with André Merlin, Honorary Chairman of RTE, Former President of CIGRE
By Bruno Meyer and Gérald Sanchis

REE: The French High Commissioner for the Plan expressed his support for nuclear energy in a report entitled "electricity: the duty of lucidity" submitted in March 1st, 2021. What is your opinion on the place of nuclear power in the French energy mix?

André Merlin: Energy accounts for 70% of greenhouse gas emissions, both at national and European level. If we want to reduce these emissions, we must first reduce the share due to energy. The most appropriate way is to use carbon-free electricity. Electricity should be used in areas such as space heating and mobility. This implies the implementation of public policies leading to effective incentives for the thermal insulation of buildings and housing, but also the installation of heat pumps in both new and existing buildings. With regard to mobility, the use of electric cars, or rechargeable hybrids, should be encouraged.

Thus the share of electricity in the French energy mix is expected to increase significantly. It is currently 25% and the PPE (Multiannual Energy Programme) forecasts 50% by 2050, or even 66% according to certain scenarios. This would correspond to an electricity generation of between 650 and 700 TWh, compared to a generation of 538 TWh in 2019.

In France, to generate this amount of low-carbon electricity, we can rely on hydropower generation (60 TWh), with little room for growth. The PPE focuses on the growth of new and renewable energy sources (RES), such as wind, solar and biomass with a target of 125 TWh in 2028 compared to 54 TWh in 2019. Wind and solar photovoltaic pose problems, particularly due to their intermittency. As a result, the contribution of nuclear power (378 TWh in 2019) seems increasingly essential, both in France and in Europe and elsewhere in the world, with regard to future efforts resulting from the Paris climate agreements.

China, which produced 350 TWh of nuclear electricity in 2019, aims to produce 1000 TWh by 2035 with a fleet of reactors with a capacity of 150 GW, i.e. a construction rate of eight 1000 MW reactors per year. It should be noted that the first Chinese nuclear reactors were based on French pressurised water technology (900 MW level), and that China has now developed its own industry.

Other countries are in favour of nuclear power. These include India, the United Kingdom, Russia and the United States. However, the United States have shale gas, which partly explains the current lack of nuclear projects in development.

REE: The reduction of greenhouse gas emissions is an important issue for the European Union. Quantitative targets have been set for 2020 and 2030. How do you see these targets being met?

A.M.: In France, the quantity of greenhouse gases in CO2 equivalent emitted each year is 450 million tonnes, 70% of which is due to energy, i.e. 320 million tonnes.

In Germany, where electricity consumption was 600 TWh in 2019, i.e. 25% higher than in France, the total annual CO2 equivalent emissions are 900 million tonnes, i.e. twice as much as in France. The energy sector's share is 740 million tonnes. There is therefore a gap of 420 million tonnes between Germany's and France's CO2 emissions in the energy sector, mainly due to electricity generation: 70% nuclear in France and 28% coal, 15% gas and a weaker penetration of electricity in the domestic sector than in Germany.

In order to achieve the European targets of a 50-55% reduction in emissions by 2030 compared to 1990, it will be necessary to eradicate coal-fired power generation. This is the big challenge facing Germany.

In Europe, greenhouse gas emissions fell until 2014. They then stagnated from 2014 to 2018. The 2020 targets are therefore unlikely to be met, although they are less ambitious than those for 2030.

Type of energy Amount of CO2 per kWh


1 kg


500 g


85 g *


26 g


29 g

Amount of CO2 produced for 1 kWh of electricity produced - source: European Joint Research Center (JRC).

(*) Mainly due to the manufacture of the panels with carbon energy.

In 2008, the European Commission proposed to each Member State to set three binding targets:

  • A target for reducing greenhouse gas emissions;
  • A target for increasing the share of renewable energy in the energy mix;
  • A target on improving energy efficiency.

It might have been preferable to set only one binding target, that of reducing greenhouse gas emissions, the other two being left to the discretion of each Member State. 

REE: What is your perception of the development of nuclear power in France?

A.M.: The choice of pressurised water nuclear power was made in 1968 by General Charles de Gaulle on the proposal of EDF's General Director, Marcel Boiteux. The main objective at the time was to ensure France's security of electricity supply, so as not to be dependent on imported oil and coal. It was also to offer our fellow citizens electricity at an affordable price.

The first oil crisis in 1973 accelerated the deployment of the planned programme. The government of Pierre Mesmer decided to build this pressurised water nuclear power plant in series. EDF's equipment department was appointed industrial architect and Framatome the builder of the nuclear boiler. Michel Hug was in charge of this programme from 1974 to 1987, which will mark the history of the nuclear power industry. A total of 58 reactors were built in 15 years in three successive stages: 900 MW, 1300 MW and 1450 MW, this last stage being equipped with a totally digital control system.

The choice of the EPR (European Pressurized Reactor) dates back to the 1980s, under the presidency of François Mitterrand. At the time, the idea was to build a "nuclear Airbus". But after many wonderings, it was not possible to reconcile two different conceptions: the French one, inherited from the Westinghouse company, and the German Siemens company. The EPR project was therefore pursued by France alone.

The French nuclear programme as it was conceived and implemented was admired by several countries, in particular the United States. In China in 1982, the Minister of Energy at the time, Li Peng, seeing what France had done, decided to build two 900 MW nuclear units, same as those built at Gravelines, on the Daya Bay site. This was the beginning of cooperation between France and China in the nuclear field.  Then Li Peng, who became Prime Minister, expanded this cooperation, which is still going on today.

REE: The use of nuclear energy requires the availability of an efficient industry. However, the last French nuclear power plant was commissioned 19 years ago. Do we now have the capacity to maintain or develop this skill-intensive technology?

A.M.: Civil nuclear power is an area where France has excelled and continues to excel, even if the completion of the Flamanville EPR remains laborious. In the meantime, China has been able to commission two EPRs at the Taishan and Fuqing sites.

The construction of the EPR in France, which began in 2005, should have been started in the period 1995-2000. The choice of this delay made by the public authorities and the management of EDF has certainly led to a loss of competence, which should however be able to be made up for fairly quickly.

Nuclear skills have been partly safeguarded through the maintenance of the 58 reactors in service. Following the Fukushima incident, the recommendations of the French Nuclear Safety Authority (ASN) led to the implementation of measures to further reduce the risk of core meltdown. EDF's major refurbishment project, which incorporates these new devices, aims to increase the operating safety of the current fleet. If the ASN gives its approval, it is in France's interest to extend the operating life of current reactors to 60 years, instead of the 40 years initially planned.   

Collaboration in nuclear research should continue between France, the UK and China. It is thanks to the pooling of resources that we will manage to make optimal progress. Moreover, it is regrettable that France has stopped the Astrid project, a fourth generation nuclear power plant. One of the aims of this breeder reactor was to produce more electricity from the same amount of uranium.

REE: The European Commission has just published the delegated act on the energies that can be included in the European taxonomy on green finance. For the moment, nuclear energy is not included. What do you think about this?

A.M.: The choice of the energy mix of each State does not belong to the European Union, it is the responsibility of each State. The European Union's responsibility in the energy field is the implementation of rules on competition and environmental protection.

Ongoing discussions at European level on the taxonomy, and more particularly on whether or not to include nuclear energy in the category of decarbonised energy, have shown that some Member States are in favour. The countries that are opposed justify their position by using the DNSH (Do Not Significantly Harm) criterion. This criterion corresponds to health risks. This is not the opinion of the United Nations. Through the United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR), the UN considers that, apart from Chernobyl, there has been no nuclear accident or incident with a significant impact on the environment, including Fukushima.

Within the European Union, the 10 states that are in favour of including nuclear in the taxonomy are France, Finland, the Netherlands, Poland, Slovakia, the Czech Republic, Hungary, Romania, Bulgaria and Slovenia. The United Kingdom was also included in this group before Brexit. Given their population, these 10 European countries have a blocking minority. Under these circumstances, the taxonomy cannot be adopted according to the current EC proposal, which excludes nuclear power for the time being. A reflection group has been set up to look into this issue. For its part, Germany considers that it cannot do without gas. A possible compromise could be to include nuclear and gas in the taxonomy.

REE: The low-carbon objective condemns the use of gas in the long term. What role do you see for this energy?

A.M.: In France, the temperature gradient is currently 2400 MW per degree C. This means that in winter a drop in outside temperature of one degree Celsius leads to an increase in electrical power of 2400 MW. If heat pumps are widely used in buildings and homes as a replacement for oil-fired boilers, it is to be feared that this gradient will increase, making it more difficult to provide electricity in winter. The gas industry offers a hybrid heat pump. When it is cold, gas heating, biogas or, failing that, natural gas, replaces the electric heat pump.

Germany, like Poland, needs gas to ensure its energy transition away from coal for electricity generation. The share of electricity generated from gas in Germany has already increased by almost 50% from 60 to 90 TWh between 2015 and 2019. The development of intermittent RES requires controllable means of generation.

REE: The PPE sets the share of nuclear power in the electricity mix at 50% by 2035. This implies the replacement of reactors by wind and solar energy.  What do you think about this?

A. M.: With the replacement of conventional units of production by renewable energies, wind or solar, the electromechanical inertia of electrical systems will be reduced. This reduction can be detrimental to the restoration of the frequency in the event of an electrical incident (see recent blackouts in Australia, Taiwan, the United Kingdom, etc.). It is therefore necessary to have a proportional amount of controllable production means, either nuclear or gas.  This leads to an increase in the overall cost of renewable energies. When we say that we are at parity of cost between nuclear and wind energy, it is not exact. What we need to compare is the full cost of wind power with the cost of nuclear fuel, or add the cost of controllable means (e.g. gas power stations) to wind power and compare it with the full cost of nuclear power.

Another point to consider is the acceptance of wind power by local residents, which is becoming increasingly problematic as it is generating more and more opposition. The objectives that have been set in the 2028 PPE, for example, and which foresee more than a doubling of the number of onshore wind turbines, will be difficult to achieve.

Knowing that 1 MW of photovoltaic solar energy requires one hectare of land, the objective of 30 GW of additional photovoltaic power in 2028 compared to 2019 therefore implies the use of 30,000 hectares of land throughout the country, which seems excessive from the point of view of the agricultural world.

Also, before shutting down 12,600 MW of nuclear reactors in 2035 as planned by the public authorities, it is important to see if it is possible to implement all these intermittent renewable energies on our territory. There are of course offshore wind projects, but they have yet to show their feasibility in terms of cost, and they too are generating a lot of opposition from our fellow citizens.

In 2028, 3% of electricity is expected to be generated from offshore wind. However, it is not specified what level of electricity consumption in France is expected at that time. Assuming a consumption of 600 TWh, 3% would correspond to 18 TWh, with an offshore wind power plant operating for about 3000 hours per year, which leads to 6000 MW of installed capacity. It is therefore a real challenge to build all these wind turbines and the associated electricity network in such a short time.  

REE: What developments do you see for nuclear power? 

A. M.: For the second part of the 21st century, it is hoped that nuclear fusion will be a new means of generating electricity under more acceptable conditions than nuclear fission. Nuclear fusion produces less radioactive wastes than fission with shorter lifetimes. Today, there is an international demonstrator, the ITER project, under construction in Cadarache (France). This demonstrator should be operational in 2040. If successful, many countries could commit to industrial prototypes. China, in particular, is planning to build an industrial prototype from 2040. In 1970, Francis Perrin, High Commissioner for Atomic Energy, announced that the nuclear fusion reactor would be available perhaps around 2020. We are no longer very far away.

In addition, small nuclear reactor projects are being developed in several countries (Small Modular Reactors). For the French electricity network, given its configuration, it will probably be more economical to replace existing reactors with reactors of comparable size on the same sites, rather than installing these small reactors scattered over the territory. In other countries, why not, but it is a question of economic efficiency.

REE: In conclusion, what advice would you give for the future based on your experience?

A. M.: As the report by the French High Commissioner for the Plan points out, at the end of 2018 the share of renewables in the French energy mix was 16.6%, far from the 23% target set by the European Commission for 2020. The 2030 targets will be even more difficult to reach (32%), especially as there is increasing opposition to onshore wind turbines or ground-based solar power plants. Also, in order to fight global warming, the contribution of electro-nuclear energy is unavoidable.

It is to be welcomed that political figures are taking up sensitive issues such as the place of nuclear energy in the energy mix. This is the case of François Bayrou in his capacity as High Commissioner for the Plan. He also speaks of a duty of lucidity. I would also like to quote the former French President of the National Assembly, Bernard Accoyer, who took the initiative of creating an association called "patrimoine nucléaire climat France" (nuclear heritage and climate France), which aims to support nuclear energy in electricity generation.

At the time of the construction of the nuclear fleet in France, the concern was not global warming. It was not pointed out that one of the advantages of nuclear power is that it does not emit CO2. A large proportion of French citizens are still convinced that nuclear power emits as much greenhouse gas as fossil fuel power plants.

It would therefore be useful to conduct a wide-ranging democratic debate to highlight the advantages and disadvantages of each form of non-carbon energy, including nuclear power.

About André Merlin

André Merlin is the founder and first Chairman of the Executive Board of RTE, of which he is now Honorary Chairman. He was co-founder of ETSO, the European association of electric transmission system operators, special advisor to the European Commissioner for Energy, and Chairman of CIGRE and Medgrid.

Banner and thumbnail credit: Photo by Mick Truyts on Unsplash


Global Connections

Global Connections Section includes invited articles and interviews along with CIGRE articles to broaden global power system expertise. Invited authors and interviews approved by the Electra Editorial Board may express opinions solely their own.

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