A landmark study has put the figure of 1.84 million on the number of lives saved by the worldwide use of nuclear power instead of fossil fuels. The report co-authored by former NASA scientist James Hansen presents a dramatic new case for nuclear energy.
It begins by taking historic generation data from the nuclear sector and estimating emissions from fossil fuels that would likely have met the same generation role if nuclear had not been used. Nuclear plants with poorer performance below 65% capacity factor were swapped for gas generation while higher performers were swapped for coal, which worked out as a mix of 95% coal and 5% gas replacing nuclear.
"In Germany, which has announced plans to shut down all reactors by 2022, we calculate that nuclear power has prevented an average of over 117,000 deaths from 1971-2009"
James Hansen and Pushker Kharecha
The results are projected total emissions that would have probably led to the deaths of 1.84 million people between 1971 and 2009 based on average mortality estimates from fossil combustion pollution. This is probably an underestimate, said Hansen and co-author Pushker Kharecha, noting that the life-cycle mortality estimates are the biggest source of uncertainty in the report: Some coal units produce three times more dangerous pollution than the average they have used. The higher estimate for lives saved by nuclear energy was over 7.5 million - and these figures do not count a range of serious respiratory illnesses, cancers, hereditary effects and heart problems.
In the recent time period of 2000-9 nuclear power plants avoided pollution which would otherwise have caused around 76,000 deaths per year, said the report. Entitled Prevented mortality and greenhouse gas emissions from historical and projected nuclear power, it was published as a 'just accepted' peer-reviewed paper in Environmental Science & Technology on 15 March.
Lifecycles and beyond
The report takes a figure of 4900 as the potential deaths caused by the use of nuclear energy in the period 1971-2009, explaining at length that this "could be a major overestimate relative to empirical value (by two orders of magnitude)." The figure is based mainly on presumed "air pollution-related effects" and only 25% on documented cases of occupational accidents and their effects on the public, notably the Chernobyl accident.
The report states: "The absence of evidence of large mortality from past nuclear accidents is consistent with recent findings that the 'linear no-threshold' model used to derive the nuclear mortality factor might not be valid for the relatively low radiation doses that the public was exposed to from nuclear power plant accidents."
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Until his retirement this week, Hansen had been head of the NASA Goddard Institute for Space Studies and a leading climate change scientist. That topic featured in the report: "It is important to bear in mind that our results for prevented mortality are likely conservative, because the mortality factors... do not incorporate impacts of ongoing or future anthropogenic climate change. These impacts are likely to become devastating for both human health and ecosystems if recent global greenhouse gas emission trends continue."
Nuclear power has served to buy time and make climate mitigation far more feasible. The emission of some 64 billion tonnes of carbon dioxide equivalent have been avoided by nuclear power - almost two years' emissions at today's rate of around 34 billion tonnes per year. Considering a goal to limit carbon dioxide concentrations to 350 parts per billion by the end of this century, the report said that only 500 billion tonnes of carbon dioxide would be 'allowable'. If the nuclear sector performs to the expectations of the International Atomic Energy Agency (IAEA), it stands to avoid the emission of between 80 and 240 billion tonnes (based on IAEA's low and high nuclear scenarios and whether this replaces gas or coal). This future contribution from nuclear could instead come from other low-carbon sources. Nevertheless, the report concludes, "achieving these [climate] targets emphasizes the importance of retaining and expanding nuclear power, as well as carbon-free renewables, in the near-term global energy supply."
Researched and written
by World Nuclear News