Is Nuclear Energy Good for the Environment?
Published on 02.06.201910 min read

Valérie Faudon
Nuclear: A Low-Carbon Energy to Address the Climate Emergency
The debate on the ecological transition in France has once again placed the spotlight on the question of reducing the use of energies that emit carbon dioxide ( ), namely fossil fuels. While it does not count as a renewable in the current state of its development, is nonetheless a carbon-free energy that helps reduce emissions. In this article, Valérie Faudon, General Delegate of the French Nuclear Energy Society (SFEN), offers her analysis.
The climate emergency, in other words the imperative need to fight , is increasingly seen by public opinion as the foremost environmental challenge, in France and worldwide. The fight involves reducing greenhouse gas emissions, in particular CO2, and therefore what is known as the “decarbonization” of the various energies we use.
Nuclear energy is a decarbonized energy – that is, it does not emit CO2 in the actual generation process. For a comprehensive comparison of energies, experts have developed lifecycle assessments. In the case of nuclear , the process involves calculating the emissions resulting from the construction of a reactor, its operation for several decades and its dismantling, as well as the production of enriched , the reprocessing of fuel and the management of waste. On this basis, the production of 1 kilowatt-hour (kWh) of nuclear electricity anywhere in the world releases on average 12 grams of CO2 (and even less in France), going by the findings of widely accepted IPCC1 studies. This is roughly equivalent to a kilowatt-hour of wind power and lower than a kilowatt-hour of photovoltaic power (around 50 g). And it is naturally without comparison with the readings for natural gas (around 500 g) or (around 1,000 g).
Nuclear-Renewable Complementarity
Let’s first look at the situation on a global scale. A first challenge is to decarbonize the electricity sector, which alone represents 40% of global emissions. Fossil fuels still account for more than 65% of power generation, with coal alone representing 40%. A second challenge is to meet growing demand. Most studies estimate that consumption will double by 2050, due to growth in the global population, the rise of emerging countries and the electrification of needs, with growing use of electric cars for instance. And let’s not forget that there are still 1 billion people who do not have access to electricity!
This dual challenge – decarbonize power generation and meet electricity demand – is immense: three years after the Paris Agreement, CO2 emissions, instead of decreasing, are still increasing. Nuclear energy will be essential, along with renewables, in achieving the goal of decarbonization. This does not mean that the share of nuclear in the power generation mix will soar. Depending on the scenario, it will remain at the same level, just above 10%.
Now let’s look at some examples in Europe. Countries that have combined nuclear power and hydropower, such as Sweden and Switzerland, have rapidly reduced their emissions. By contrast, Germany will not achieve its climate goals. Despite massive investments in renewable energies, France’s neighbor across the Rhine has not been able, due to the premature closure of its nuclear power plants, to reduce the share of coal, which is stable at close to 40%. The phase-out of coal, so necessary in the struggle for the climate and against air pollution, will be a very long process.
In France, the large share of nuclear power in the mix (nearly 75%), combined with renewables (particularly hydropower), gives the country the lowest emissions per capita of the seven most developed powers. Substituting low-carbon for low-carbon nuclear power in the electricity sector will not further reduce emissions. At worst, it could result in an increase in emissions, because the intermittent nature of wind and solar energy makes it necessary to maintain sufficient production resources available 24 hours a day. So the forecast scenario of bringing nuclear power down to 50% of the overall mix by 2025 (the original target) would have required keeping four coal-fired power plants and building 20 new gas-fired plants, all of them emitting large amounts of CO2. It is to avoid this risk that the target has been pushed back to 2035.
Admittedly, nuclear energy raises concerns. Major accidents have marked public opinion, which is also impacted by concerns about how nuclear waste can be managed. However, solutions exist, ranging from geological storage to control by an independent safety authority.
Nuclear energy has the potential to decarbonize the electricity sector more – and more quickly. Its flexibility, namely its capacity to increase or reduce output, would allow solar and wind power to develop while ensuring the security of supply. All low-carbon technologies (renewable, nuclear as well as carbon capture and storage) must be harnessed to respond to the climate emergency.
Valérie Faudon is General Delegate of the French Nuclear Energy Society (SFEN) and Vice President of the European Nuclear Society (ENS). She also teaches at the Public School of International Affairs at Sciences Po. After holding various management positions in groups in the United States and France, she served as Marketing Director of Areva from 2009 to 2012. Valérie is a graduate of École Polytechnique, École Nationale des Ponts et Chaussées, and the Institut d’Études Politiques in Paris. She also holds a Master of Science degree from Stanford University in California.
Sources :
- Intergovernmental Panel on Climate Change.

Jean-Guy Devezeaux de Lavergne
The Nuclear Industry Out to 2030 and 2050
The various “scenarios” that have been put forward for 2030, 2050 and 2100 are shaping the work of energy producers and climatologists the world over. Nuclear energy’s place in these visions of the future is the topic of often heated debate. In this article, Jean-Guy Devezeaux de Lavergne, head of the I-tésé Institute at the French Alternative Energies and Atomic Energy Commission (CEA), provides his view on these issues.
It’s important to first understand what an “energy scenario” is. It does not involve predicting or forecasting what will happen in the future! Its role is to illustrate possible – and even desirable – future scenarios and to build solutions to obtain them. Put simply, the goal is to set end-points and map out action plans to achieve them.
These end-points can be staggered over different periods. Energy producers generally work toward 2050, but sometimes to 2035 or 2040, as opposed to climatologists who look further out to 2100. Analysts take into account the economic constraints and public policy that will obviously impact the strategies used in achieving the objective. They often use a benchmark such as “business as usual”, which means what will happen if we don’t act.
Thousands of energy and climate scenarios have been devised worldwide. Those prepared by the , the and European organizations are often cited. But each country also produces many too1.
As far as the is concerned and, in particular, the place of nuclear power, two horizons clearly have to be distinguished. The first is 2030-2035, for which targets have already been set and current techniques will still be able to be used in optimized form. This contrasts with the second half of the century in which we will have to undertake what is called “deep decarbonization”, involving a much wider range of technologies that are capable of turning the energy industry upside down.
Out to 2030-2035
Let’s take a look at the first period. The target is chiefly to decarbonize electricity by reducing the use of coal and natural gas, which still dominate the world’s energy production, and improving . From this standpoint, nuclear power, as a carbon-free energy source, has a role to play alongside renewables, such as wind and solar. Moreover, all of the IPCC scenarios include it at various levels.
Asia has started building third-generation reactors, and Europe has committed to doing so too. To curtail costs, industrial output will have to be scaled up significantly – a key challenge for France, it should be noted. The other challenge is R&D, particularly to operate existing nuclear power plants as efficiently as possible, monitor the aging process and renovate when necessary, in addition to checking that the installations meet stricter safety regulations.
Deep Decarbonization in the Second Half of the Century
But this first period will reach its limits when we approach 2050. Then, we will have to set a target of “zero emissions” of if we want to keep global warming to between 1.5°C and 2°C by 2100. The IPCC has unequivocally illustrated the damage we face if we exceed this threshold. But successfully pulling off “deep decarbonization” will require a shift in gears.
A raft of innovations will change the game provided we prepare them far enough in advance. The CEA is working on the , batteries and photovoltaic technologies of the future, for example. Specialists are also developing “electrofuels”, whereby electrical energy from renewable and nuclear energy sources are stored in fuels. CO2 is also an option. What efficient technologies will emerge in this new landscape and what will the relative costs of the different energy sources be? It’s still anyone’s game…
We will therefore have to ensure we have the necessary leeway. Nuclear energy can provide this as its output can be flexibly adjusted, making it possible to integrate renewables into the mix. The costs associated with nuclear power are also known. Eliminating the energy source would entail a risk, namely of having an energy mix that is too expensive, emits too much CO2 or is not sufficiently secure or even unstable. Nuclear energy of the future, out to 2050, may still be more of an open playing field than it is today, with the possible advent of new reactors such as small modular reactors (SMRs), heat-generating reactors (which operate at different temperature levels) and reactors that enable new forms of combustible fuel recycling. By 2100, the future of may take shape.
However, as with other innovations, we will have to develop this new technological cycle through appropriate nuclear research, which is going to be quite a feat in a world where energy research investment has become stagnant, despite the urgency.
Jean-Guy Devezeaux de Lavergne is head of the I-tésé Institute, a unit within the French Alternative Energies and Atomic Energy Commission (CEA) that studies the technical and economic aspects of energy systems. An engineer graduate from École Nationale Supérieure de l'Électricité (Sup’Élec), he has a Ph.D. in Economic Sciences and is an expert in the economics of energy and particularly long-term research. He co-heads the “Scenarios” work group at ANCRE, France’s national alliance for energy research. He is also Vice President of the Nuclear Development Committee of the OECD Nuclear Energy Agency
Sources :
- In France alone, scenarios have been penned by the country’s transmission system operator RTE, the Environment and Energy Management Agency (ADEME) and the government as well as professional associations, NGOs and industry alliances such as energy research body ANCRE.