Nuclear and renewables – mutually exclusive: renewables better for climate action

Comparative impact of nuclear and renewables on CO2 emissions, By Philippe Gauthier, Resilience.org October 9, 2020 Countries which are heavily invested in nuclear energy remain higher CO2 emitters, on average, than countries which have invested at the same level in renewable energy. This is the main finding of a study recently published in the journal Nature Energy. The results also tend to confirm the hypothesis that it is difficult to commit both to nuclear and renewables due to a systemic incompatibility between these two approaches.

The study, led by Benjamin K. Sovacool of the University of Sussex, England, is not based on simply on an analysis of various national case studies, but on a database encompassing 123 countries over 25 years (30 favouring nuclear and 117 renewables, with some overlap between the two). The information spans two periods, 1990 to 2004 and 2000 to 2014, which makes it easier to better track the impact of the emergence of renewables in the 21st century. The data was used to verify the existence of correlations, which often turned out to be very strong (a p value of less than 0.05, or even 0.001). The results of these regressions are presented in the form of rather dry tables.

The work aimed to assess three hypotheses. The first is that the greater a country’s nuclear power generation capabilities, the lower its greenhouse gas emissions are. The second is that the greater a country’s renewable energy generation capabilities, the lower its emissions are. The third is that nuclear and renewables coexist uneasily within a national energy system and that the dominance of either delays or prevents the adoption of the other………….

Explanatory factors

What explains these rather unfavorable results for nuclear power? Data collected by the researchers shows that, on average, the delivery time is 90 months for nuclear projects, compared to 40 months for solar and wind projects. Only hydropower has longer lead times. Nuclear and hydropower projects are more prone to delays and cost overruns than smaller-scale renewable projects, which yield low carbon energy more quickly.

Renewables are also associated with a positive learning curve whereby each completed project decreases the costs and increases the performance of subsequent projects. In comparison, nuclear power exhibits a negative learning curve. The study specifically cites the case of France, where each new generation of reactors has involved increased costs or lower performance. The tightening of safety measures after each major accident (Three Mile Island, Chernobyl, Fukushima) has greatly contributed to these increased costs in every country.

The study concludes that renewables have a demonstrable record of reducing greenhouse gas emissions. Nuclear power has a more mixed record, due to the different nature of the energy systems in which it operates. Finally, the results tend to confirm the hypothesis of mutual exclusion already widely noted in the scientific literature. According to the researchers, countries that think they can obtain emission reductions by investing in nuclear energy may actually be forgoing even greater reductions that could be achieved by renewables.

Source:

Benjamin K. Sovacool et al. Differences in carbon emissions reduction between countries pursuing renewable electricity versus nuclear power, in Nature Energy, October 5, 2020 https://www.nature.com/articles/s41560-020-00696-3.epdf?

https://www.resilience.org/stories/2020-10-09/comparative-impact-of-nuclear-and-renewables-on-co2-emissions/