François VALLET
Abonné·e de Mediapart

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Billet de blog 11 nov. 2021


Any use of non-renewable energy, or combustion of biomass, turns into heat that accumulates in the air, soil and water. Several scientific publications show that heat emissions are a major cause of global warming. Nuclear power plants, which emit a lot of heat per kWh produced, warm the climate.

François VALLET
Abonné·e de Mediapart

Ce blog est personnel, la rédaction n’est pas à l’origine de ses contenus.


Any non-renewable energy consumption, or biomass combustion, ultimately turns, and irreversibly, into heat.

This heat accumulates in the air, in the soil and in the water (in solid, liquid or vapor form), which leads to an increase in the temperature of these environments but also to disturbances in oceanic circulation, wind conditions, cloud cover, etc.

Several publications by Swedish, French, American, Chinese, Canadian, etc. researchers deal with these subjects.

The production of electricity, from non-renewable energies (including nuclear energy) and biomass combustion, by converting heat into motion (alternator), leads to significant heat losses and the need for a "cold source" (water or air) to cool the thermodynamic machine.

Nuclear power plants, which are one of the least efficient technologies for converting heat to electricity, emit more heat directly and immediately than most other techniques for converting heat to electricity (coal, oil and gas plants). Nuclear reactors were not originally designed to generate electricity but to produce the plutonium needed to make atomic weapons and to power nuclear submarines.

The concentration of this mode of electricity production in high-power plants, neither too far away nor too close to large cities for obvious reasons of acceptability and safety, has the following consequences:

- highly concentrated thermal pollution with significant warming of the "cold source" (water and air), disruption of the local meteorology and increase in global warming,

- the practical impossibility of "recovering" the waste heat both because of the distances from the places of heat consumption and because of the degradation of the efficiency of conversion of heat into electricity that would result in the recovery of heat at a usable temperature level,

- strong competition with other uses of water (agricultural, drinking water, other industries), which are also threatened by radioactive and chemical pollution specific to the nuclear industry.

Fortunately, this mode of electricity production is very rare and only constitutes a very small part of the global energy supply, which makes its effect on the global climate very little noticeable until now. But in countries heavily equipped with nuclear reactors, for their electricity production (France, Sweden, etc.) and for the production of atomic weapons, the effect of heat emissions on the regional climate is significant and measurable.

The desire of some countries to increase nuclear electricity production over and over again, if implemented, could only lead to an aggravation of global warming.


The French nuclear industry is in dire straits. EDF and Orano are embroiled in industrial and financial fiascos (EPR construction site in Flamanville, reprocessing plant in La Hague, MOx fuel fabrication plant in Marcoule, etc.). These companies need colossal funding to be able to continue to operate their existing facilities at the end of their rope. The Areva bankruptcy has not served as a lesson for French leaders. The cornered government is trying to create a diversion by putting forward, at the same time, a new concept of a small modular reactor adorned with all the virtues and a project to build 6 new EPR mega-reactors while that of Flamanville is still not in service. Public deficits have never been so high but the headlong rush continues "whatever the cost". To wrap this "poisoned radioactive gift" and silence opponents, the low CO2 emissions of nuclear power are systematically highlighted. Bad luck for French leaders, nuclear energy is heating up the planet and the climate, wherever it is used. But since it is very little, because of its prohibitive cost and unacceptable risks for populations, it is not evident on a global scale.

Indeed, the electricity production of all the nuclear reactors in operation in the world is of the order of 10% of the total world electricity production. This corresponds to around 2% of all energy consumed, since on the world average electricity constitutes 20% of total energy consumption.

In France, on the other hand, with nearly 70% of the electricity produced by nuclear energy, which corresponds to nearly 20% of all the energy consumed, the global warming caused by nuclear power plants is quite visible. if we want to take the trouble to look at what is happening in real life and not in the virtual world of climate simulations or government visions of energy futures.

A large part of the French population seems to have understood this well and does not trust the allegations of the nuclearists who assert that nuclear power does not warm the planet. A survey carried out by BVA in 2019 for the company Orano (formerly Areva) clearly indicates: "The fact that nuclear energy emits little CO2 is little known to the French, who on the contrary consider very largely (69%) that nuclear contributes to climate change.”[1]

It is surely not the ignorance of the French which is the cause of the result indicated by BVA but quite simply the fact that they understand very well that nuclear power heats the planet in a consequent way when it is used on a large scale for the production of electricity.

Because nuclear reactors are one of the least efficient technologies for transforming primary energy into electricity, that is, one of the technologies that warms the environment the most per unit of electricity produced. The French Ministry of Ecology indicates this very clearly in a publication of July 2017[2], "Energy efficiency in France - Evolution between 2000 and 2016 and international comparison.

Primary energy intensity, which includes energy losses during its transformation or transport, is, for its part, higher in France (101 toe per M $ 2011 of GDP) than in Germany (86 toe per M $ 2011 of GDP). This is largely explained by the greater weight of electricity in the final energy mix as well as by the greater use of nuclear power to produce this electricity in France. Indeed, on the one hand, the production of electricity is generally accompanied by significant heat losses and, on the other hand, these losses are on average relatively higher in nuclear power plants than in those using fossil fuels and in particular those of cogeneration, more developed in Germany than in France. "

Per unit of GDP, France heats up the portion of the planet it constitutes, directly and immediately, than Germany. And nuclear power plants are the cause, not only because of their "heat loss" but also because of the total heat emission they produce.

  1. What are the “nuclear” processes that are warming the planet and the climate?

The reactions of fission or fusion of atomic nuclei, causing a chain reaction, controlled or uncontrolled, produce a strong release of heat and radioactivity which did not exist before these reactions.

- The thermo-nuclear fusion process is that which occurs in the sun.

- The process of uncontrolled fission (explosion) is that which occurs in atomic bombs with highly enriched uranium or in atomic bombs with plutonium.

- The controlled fission process is that which occurs in nuclear reactors for the production of plutonium and the production of electricity.

- Controlled fusion is a chimera pursued by nuclearists, for example with the Iter project in Cadarache.[3]

These processes, apart from the fusion that occurs within the Sun, can only exist through the functioning of a set of activities in nuclear research and industry. These make it possible to manufacture, operate, maintain and dismantle "at the end of their life", atomic weapons, reactors for military use (propulsion of ships, submarines, missiles, etc.), power generation reactors and medical and imaging facilities.

The industries mobilized are mining, uranium transformation and enrichment (chemistry), the manufacture of "fuels" for military or civilian use, the construction of military and civilian reactors, the operation and the maintenance of reactors, the treatment of spent fuel with a view to extracting plutonium, the transport and storage of waste and radioactive materials, but also the financing of projects and the communication that accompanies them. And these industries cannot exist without strong political support and substantial public funding.

All of these activities consume energy, release heat and warm the climate.

 2. What do we call climate?

According to the Larousse of the French language:

  • Set of meteorological phenomena that characterize the average state of the atmosphere in a given location.
  • But also all the living conditions, the circumstances that affect someone; environment, atmosphere, context: the political, social climate.

According to the Robert:

  • Set of atmospheric and meteorological circumstances (humidity, pressures, temperatures, etc.) specific to a region (also microclimate). Equatorial, tropical, desert, temperate climate.
  • Moral atmosphere. Climate of hostility.

According to these definitions, the notion of global climate or global climate change does not really have a physical meaning since there is no such thing as a global place or a global region. It is just an abstract concept used by climatologists to characterize the evolution of the global average temperature (another abstract concept) and other climatic parameters, observed for about forty years.

Caring for the global climate is important, but what matters most to the people of the planet is the climate of where they live. It is therefore necessary to examine the impact of human activities on climate change at different scales.

 3. How and to what extent does nuclear power heat up our living environments?

 3.1. General approach and scope of the problem posed by nuclear power

Several recent or somewhat older scientific publications show that all heat emissions of anthropogenic origin (that is to say linked to human activities), including from nuclear fission, accumulate in the air, water and soil. The heat accumulated in these environments leads to not only local but also regional and global warming.

At the scale of France, for example, the heat rejected by all the nuclear reactors in operation in 2017 (828 TWh)[4] corresponds to more than 2.3 times the final energy consumption for heating and domestic hot water for all homes (357 TWh)[5]. If we add to the heat emissions the electricity produced which ultimately degrades into heat, in 2017, all French nuclear reactors emitted 3.3 times the heat released for heating and domestic hot water of all the accommodation. And this value does not take into account heat emissions from industry and transport upstream and downstream of nuclear power plants (mines, uranium processing and enrichment, waste reprocessing and storage).

These heat emissions are anything but anecdotal. They obviously have an important role in the global warming caused by France.

3.2. Effects of heat emissions from nuclear power plants, at the local and river scales

One of the questions raised during the construction of the first high-power nuclear power plants was the impact of their heat releases on aquatic life.

A study by CEMAGREF (center for the study of agricultural machinery), relating to the Bugey nuclear power plant and published in 1991, examines this subject in detail[6].

Here is an excerpt from the study summary:

“The hot water discharges from the Bugey Nuclear Production Center lead to an average rise of 6°C in the temperature of the Rhône waters up to 5 km downstream from the plant. The heating of the water is still noticeable at the level of the confluence with the Ain. …. At the heated station level, in 1988-89 a significant reduction in the taxonomic richness of invertebrates was observed, notably with the disappearance of Potamanthus luteus (mayfly) and Propappus volki (oligochaete). There is also a decrease in the density of Chironomidae and oligochaetes, the latter, as well as the Gammaridae, disappearing during the hottest period (August, September). "

For the microorganisms living in the waters of the Rhône, the Bugey nuclear power plant has indeed caused very significant localized climate change and even fatal for certain species.

A more recent study, carried out by EDF and published in May 2016[7], examines the effect of nuclear power stations cooled by water from the Rhône on the temperature increase in the river.

In the summary of this "thermal study of the Rhône" we can read that the heat emissions from the power plants located between Saint-Vulbas (upstream of the Bugey nuclear power plant) and Aramon (downstream of the Tricastin power plant) ) caused an annual average increase in the temperature of the Rhône waters of 1.2 °C out of a total increase of 1.4 °C (comparison between the period 1988-2010 and the period 1920-1977).

In hot weather, and no longer on an annual average, the "contribution" of the Nuclear Power Generation Plants (NPPs) was 1.6 °C.

This river-wide warming is quite significant compared to the global warming of land surfaces across the planet, of the order of 0.7 ° C between the same two periods.

It only represents part of the problem because 6 of the 14 nuclear reactors, located on the banks of the Rhône, are equipped with cooling towers which evacuate part of the heat in the waters of the river and another part in the air as evaporated water.

Finally, many studies are interested in the heat island effect caused by highly concentrated heat emissions from densely populated urban areas. The local climate is affected very significantly.

3.3. Effects of heat emissions, including those from nuclear power plants, on a regional and global scale

Several scientists have demonstrated that the heat emissions corresponding to the use of non-renewable and stock energies (fossils, fuelwood, waste from petroleum, nuclear energy, etc.) warm the planet with large-scale effects and in proportions that are not negligible.

 Bo Nordell and Bruno Gervet, Department of Civil and Environmental Engineering, Luleå University of Technology in Sweden, published in 2009 a very interesting study on this subject[8]. Here is the abstract :

« The increase in the global air temperature is an inadequate measure of global warming, which should rather be considered in terms of energy. The ongoing global warming means that heat has been accumulating since 1880 in

the air, ground and water. Before explaining this warming by external heat sources, the net heat emissions on Earth must be considered. Such emissions from, e.g., the global use of fossil fuels and nuclear power, must contribute to global warming. The aim of this study is to compare globally accumulated and emitted heat. The heat accumulated in the air corresponds to 6.6% of global warming, while the remaining heat is stored in the ground (31.5%), melting of ice (33.4%) and sea water (28.5%). It was found that the net heat emissions from 1880–2000 correspond to 74% of the accumulated heat, i.e., global warming, during the same period. The missing heat (26%) must have other causes, e.g., the greenhouse effect, the natural variations in the climate and/or the underestimation of net heat emissions. Most measures that have already been taken to combat global warming are also beneficial for the current explanation, though nuclear power is not a solution to (but part of) the problem. »

Another study, published in February 2016 in the International Journal of Climatology[9], examines the possible effect of anthropogenic heat release from global energy use on the global climate. Here is the abstract:

« The high-resolution global distribution of anthropogenic heat release (AHR), which is generated by human energy consumption, is estimated by means of applying satellite remote sensing. Additionally, it was considered into a global climate model and the possible climatic effect of AHR is examined in this study. AHR is geographically concentrated and fundamentally correlates with economic activity in global scale. The current mean AHR flux on the global scale is approximately 0.03 Wm−2; however, the flux reaches a level high enough to influence the regional climate in concentrated urban areas. Global climate model results indicate that AHR may disrupt the normal atmospheric circulation and could have an obvious effect on the surface temperature at middle and high latitudes in summer and winter over the Northern Hemisphere. The climatic effect of AHR differs in various seasons: the global mean surface temperature could increase by approximately 0.02 K in boreal summer and by 0.10 K in boreal winter. With the continued development of the global economy and urbanization, the climatic effect of AHR will become increasingly pronounced. The climatic effect of AHR should not be merely confined to the regional climate, AHR is a tiny but essential factor in global climate and long-term climate change that should not be ignored. »

Finally, a study published in April 2021 examines the “impact of anthropogenic heat emissions on global atmospheric temperature”[10]. Here is the abstract :

« The use of different primary energy sources in human society has led to two major polluting emissions in the environment: energy (mostly heat), and chemical substances (mostly carbon dioxide). In this paper, the total global anthropogenic emissions of heat to the atmosphere during the industrial era (years 1850-2018) were determined and their effect on the change of global atmospheric temperature was calculated. The concept of a theoretical three-phase Earth reactor was introduced to estimate global atmospheric temperature increase caused by anthro-pogenic heat emissions. The resulting calculations closely approximated the actual atmospheric temperature change recorded during the last 170-year period. These results suggest that the temperature change of the atmosphere (global warming) is entirely due to anthropogenic heat emissions. »


Resorting to lies is a systematic and recurring practice of the nuclear industry, which allows it to hide its wrongdoing. Orano, for example, broadcast at the end of 2019, through the regional daily press and a weekly supplement, an advertisement whose main message, "Nuclear: no, we are not warming the planet", was clearly false. The Jury of Advertising Ethics (JDP) ruled that this advertising did not comply with the rules of ethics[11] and in particular the "sustainable development" recommendations of the French Professional Advertising Regulatory Authority (ARPP).

This judgment did not prevent this company from persevering in the lies.

It also did not dissuade EDF from taking up the torch of lies with a new advertisement pinned by « Le Canard Enchaîné » on October 20, 2021 (article "Asterisk among the hucksters").

But these deceptive advertisements only deceive those who want to be deceived. Global warming by nuclear power is very real and has been confirmed by several scientific publications, in particular the thermal study of the Rhône carried out by EDF, which the advertisers of this company must not have consulted.

As they should not have consulted the publications, recent or older, of several researchers for whom heat emissions are a major or even unique cause of global warming. These publications are completely ignored by the IPCC, even though they reach the same types of conclusions with different methods.

Under these conditions, claiming that nuclear power is an acceptable solution to mitigate global warming, as the governments of nuclear states, the nuclear industry, the International Energy Agency (IEA) and even the IPCC are doing, is at stake better an error the worse a deception.

The only way not to worsen global warming, through human activities using energy, would be to use only renewable energies (excluding biomass combustion).

While waiting for these energies to be sufficiently developed, it is urgent, among the various ways to less aggravate global warming, to stop the production of nuclear electricity. This can be easily replaced by other techniques that emit less heat, using existing installations that are much less dangerous, much less expensive and that do not emit radioactivity into the environment.

Shutting down all the nuclear reactors currently in service in the world does not pose a global energy supply problem and makes it possible to immediately mitigate global warming, particularly that caused by highly nuclear countries such as France, whose share of nuclear power in production electricity is the highest in the world. At the scale of Europe, its interconnected electricity grids and its electricity market, shutting down all nuclear reactors in service would obviously be very good for the climate and for our common security. This does not pose a problem of energy supply, nor an economic problem: nuclear power supplies barely 6% of all the energy consumed in Europe (25% of consumption is in the form of electricity and 25% of electricity is produced by nuclear power plants).

François VALLET - Engineer in climatic, energy and environmental engineering



[3] On this subject, see the « Canard Enchaîné » article of 27/10/2021 "Iter, an experimental reactor at the‘ com "

[4] This value is obtained by subtracting from the primary energy consumption for the production of nuclear electricity (1,207 TWh) the production of nuclear electricity (379 TWh according to the indications on page 21 of the annual balance sheet established by RTE).

[5] The energy consumption of all homes in France in 2017 was 307.6 TWh for heating and 49 TWh for the production of domestic hot water, for a total of nearly 357 TWh. These values come from the publications of the French Ministry of "Ecological Transition" :







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