13. May 2007

CO2 Emissions of Nuclear Energy Generation

Nuclear Energy

The discussion about the benefit of nuclear power for the global climate is kinda broken on both sides. Supporters keep claiming that nuclear power is “free of CO2”. The other side brings up claims like “nuclear power has a higher CO2 output than coal powered plants”. Both arguments are nonsense.

Emissions before and after power generation

You can’t just count the CO2 produced during the actual power generation. To generate nuclear power, the nuclear fuel (uranium) has to be mined and purified. Then, it has to be pressed into fuel rods and transported to the power plant. When it reaches the end of its lifetime, it has to be stored somewhere (indefinitely). There is also a lot of machinery involved which needs to be built and maintained. All this consumes energy and releases CO2 into the atmosphere – directly or indirectly.

Unfortunately, it is hard to find some solid assumption about the overall CO2 output of nuclear power plants. They range from 8 to 65 grams per kilowatt hour produced electricity. The storage of the nuclear waste isn’t even included in these assumptions.

For comparison: According to the same sources, fossile energy production release at best 370g/kWh (natural gas CCPP).


A new study by Jan Willem Storm van Leeuwen and Philip Smith says that nuclear power produces 90 to 140 grams CO2 per kilowatt hour. I took these numbers from secondary sources, though, since I couldn’t locate a clear statement about that in the original study.

Long term perspectives

CO2 emissions of nuclear energy depend primarily on the fuel production. The future production of uranium is controversially disputed.

The “Deutsche Physikalische Gesellschaft” (DPG) sees no problems in future nuclear fuel production. According to them, only a small part of the global uranium deposits have been discovered yet.

An intensive prospection happened only between 1970 and 1985. The yearly effort was minimal compared to the investments into the search for other energy sources like oil.
(translated from Klimaschutz und Energieversorgung in Deutschland 1990 – 2020, S. 68)

Critical voices see that a little less optimistic. They predict a declining uranium concentration, which increases the CO2 output during enrichment. In the worst case the energy required to enrich the uranium could even exceed the amount of energy that can be retrieved in the nuclear power plants.


This article is not meant as a statement for or against nuclear energy. It is only meant to bring some facts into the discussion about nuclear energy in context of the climate crisis. Additional facts are very much welcome, because they are hard to find.

Also don’t forget that despite the current discussion about change of climate, there are other factors that need to be put into consideration when discussing nuclear energy. There is not just CO2 emissions, but also security, nuclear waste which has to be stored over countless generations, etc…


Serik.de: Schont Atomenergie das Klima?
Dr. Ludwig Lindner: CO2-Bilanz von Stromerzeugunsanlagen im Lebenszyklus
Deutsche Physikalische Gesellschaft (DPG): Klimaschutz und Energieversorgung in Deutschland 1990 – 2020
Ulf Bossel: Das Märchen vom CO2-freien Atomstrom
ISA, The University of Sydney: Life-Cycle Energy Balance and Greenhouse Gas Emissions of Nuclear Energy in Australia
Nuclear power the energy balance by Jan Willem Storm van Leeuwen and Philip Smith

(This article is also available in German)

Topics: climateCO2energynuclearpower


  1. yes but the CO2 emissions you speak of before and after are as a result of electricity. Why does the electricity used in the production of nuclear plants have to cause co2 if it comes from renewable or nuclear sources? When the uranium is mined it will leave a negative space which can be filled with the waste. The power stations themselves can be encased in lead and/or buried underground rendering meltdowns (however unlikely) as relatively harmless

    Comment by charlie — 13. May 2007 @ 19:15

  2. There really is no need for nuclear power in Europe because there is a simple mature technology available that can deliver huge amounts of clean energy without any of the headaches of nuclear power.

    I refer to ‘concentrating solar power’ (CSP), the technique of concentrating sunlight using mirrors to create heat, and then using the heat to raise steam and drive turbines and generators, just like a conventional power station. It is possible to store solar heat in melted salts so that electricity generation may continue through the night or on cloudy days. This technology has been generating electricity successfully in California since 1985 and currently provides power for about 100,000 Californian homes. CSP plants are now being planned or built in many parts of the world.

    CSP works best in hot deserts and, of course, there are not many of these in Europe! But it is feasible and economic to transmit solar electricity over very long distances using highly-efficient ‘HVDC’ transmission lines. With transmission losses at about 3% per 1000 km, solar electricity may, for example, be transmitted from North Africa to London with only about 10% loss of power. A large-scale HVDC transmission grid has also been proposed by the wind energy company Airtricity as a means of optimising the use of wind power throughout Europe.

    In the ‘TRANS-CSP’ report commissioned by the German government, it is estimated that CSP electricity, imported from North Africa and the Middle East, could become one of the cheapest sources of electricity in Europe, including the cost of transmission. That report shows in great detail how Europe can meet all its needs for electricity, make deep cuts in CO2 emissions, and phase out nuclear power at the same time.

    Further information about CSP may be found at http://www.trec-uk.org.uk and http://www.trecers.net . Copies of the TRANS-CSP report may be downloaded from http://www.trec-uk.org.uk/reports.htm . The many problems associated with nuclear power are summarised at http://www.mng.org.uk/green_house/no_nukes.htm .

    Comment by Robert Palgrave — 14. May 2007 @ 7:49

  3. charlie: Not all emission originate from electricity. For example, you need to transport the uranium which uses fuel. I also don’t know the inner workings of the enrichment process… does it purely rely on electricity? Anyway, these numbers try to reflect the current state… in which there is no “green energy” used to generate nuclear energy.

    You can’t just put the nuclear waste in the empty space of uranium mines. It has to be stored savely for millennia, so the storage room has to be geologically über-stable. As far as I know, there is not one final storage place in Germany, yet.

    Robert: Thanks for the extensive info. :) Sounds like an interesting project, I hope it’ll get its chance…

    Comment by Flo — 14. May 2007 @ 9:33

  4. As i am studying renewable energy at the moment i feel a little more well informed,than the average lay man, Concentrating solar is a very viable answer, so is The hydrogen economy, it is just a case of timing and money and urgency, if oil rises to 200 $ a barrel then alternatives will become available sooner rather than later.

    Comment by Jason — 21. December 2007 @ 16:13

  5. There is a relatively new study to this topic: A life cycle analysis (LCA) carried out by Jan Willem Storm van Leeuwen and Philip Smith came to the following result: Electricity from atomic energy emits between 90 and 140 g CO2 per kWh of electricity produced.

    The study is available at http://www.stormsmith.nl/

    Comment by Juerg — 28. May 2008 @ 12:28

  6. Great Post , good i stumbled on this ! I think ill dig this :)

    Comment by Home Wind Power — 23. February 2009 @ 22:58

  7. in your last paragraph you should also not neglect the problems of mining. the olympic dam mine in south australia for instance, uses 42 million litres of water a day (rare fossilised desert water) and leaves giant lakes of poisoned water. also cancers and birth defects amoungst workers is quite high…etc…

    then there is insitu leech mining, another huge problem..

    Comment by karen eliot — 25. October 2009 @ 12:36

  8. Thanks for the interesting post about CO2 emissions. I look forward to reading more from you in the future.

    Comment by charles @ build solar panels — 28. October 2009 @ 19:01

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