Nuclear power must be rejected as a climate change abatement strategy for three major reasons: a doubling of nuclear power would reduce global greenhouse emissions by no more than about 5%. A much larger expansion of nuclear power would deplete conventional uranium reserves in a few decades.
In addition, there are the serious hazards of nuclear power, in particular the contribution of "civil" nuclear programs to the proliferation of nuclear weapons — the most destructive weapons ever devised.
Third, the availability of a plethora of clean energy options — renewable energy sources plus energy efficiency and conservation measures — means that we can meet energy demand and sharply reduce greenhouse emissions and therefore obviate any "need" for nuclear power.
This article addresses the first of those arguments — the limitations of nuclear power as a climate change abatement strategy. (The second and third arguments are explored in papers on the Friends of the Earth website <www.foe.org.au> and the EnergyScience Coalition website <www.energyscience.org.au>.)
Electricity is responsible for less than one third of global greenhouse gas emissions. According to the Uranium Institute, the figure is "about 30%". A detailed paper prepared for the Pew Center on Climate Change puts the figure at just 16%.
The simplistic view that nuclear power alone can "solve" climate change is already out the window. Nuclear power is used almost exclusively for electricity generation (a very small number of reactors are used for heat co-generation and desalination), and electricity generation accounts for just 16-30% of global greenhouse emissions.
This is not to dismiss, or trivialise, the importance of reducing emissions from the electricity sector, not least because there are projections that emissions from electricity generation will increase in overall terms and that the percentage of overall emissions from the electricity sector will increase.
Emissions reduced?
Ian Hore-Lacy from the industry-funded Uranium Information Centre (UIC) claims that a doubling of nuclear power would reduce greenhouse emissions in the power sector by 25%. But the power sector accounts for just 16-30% of greenhouse emissions, so Hore-Lacy's figure of 25% falls to just 4-7.5% if the impact on overall emissions rather than just the power sector is considered.
The figure needs to be further reduced because the UIC makes no allowance for the considerable time that would be required to double nuclear output.
It is unlikely that nuclear output could be doubled before the middle of the century. A fixed additional input of nuclear power will have a relatively smaller impact if measured against increased overall greenhouse emissions. Under a business-as-usual scenario, overall emissions could be expected to double by the middle of the century, so the estimated emissions reduction of 4-7.5% would be halved.
Notwithstanding the assumptions and uncertainties built into the above calculations, it can be concluded that it is unlikely that a doubling of global nuclear power would reduce emissions by more than 5%.
Doubling nuclear output by the middle of the century would require the construction of 800-900 reactors to replace most of the existing cohort of reactors and to build as many again. The capital cost would be several trillion dollars and the 800-900 reactors would produce more than 1 million tonnes of nuclear waste (in the form of spent fuel) and enough plutonium to build more than 1 million nuclear weapons.
Clearly, a doubling of nuclear power would come at considerable expense and risk yet the greenhouse benefits would be small.
One important assumption has not yet been mentioned. The above calculations assume that nuclear power displaces coal. But, compared to most renewable energy sources, nuclear power produces more greenhouse emissions per unit energy produced.
For example, the 2006 Switkowski nuclear report states that nuclear power is three times more greenhouse intensive than wind power. As high-grade uranium ores give way to low-grade ores, nuclear power may become six times more greenhouse intensive than wind power. Nuclear power is vastly more greenhouse intensive than energy efficiency measures and will become even more so as high-grade reserves are depleted.
A temporary response
A very large expansion of nuclear power could make a significant dent in greenhouse emissions. A ten-fold expansion might reduce overall greenhouse emissions by about 20%. But the proliferation risks would be horrendous.
Harold Feiveson, writing in a 2001 issue of the Journal of the Federation of American Scientists, calculates that with a ten-fold increase in nuclear output, 700 tonnes of plutonium would be produced annually. Assuming 10 kilograms of "reactor grade" plutonium is required for one nuclear weapon, 700 tonnes would suffice to produce 70,000 nuclear weapons annually, or 3.5 million weapons over a 50-year reactor lifespan.
In addition to the proliferation risks, a very large increase in nuclear output would run up against the problem of limited conventional uranium reserves.
According to the Nuclear Energy Agency and the International Atomic Energy Agency (IAEA), the total known recoverable uranium reserves — reasonably assured reserves and estimated additional reserves which can be extracted at a cost of less than US$80/kg — amount to 3.5 million tonnes. At the current rate of usage — 67,000 tonnes per year — these reserves will last for just over 50 years.
Of course, the nuclear power industry will not come to an immediate halt once the known low-cost reserves have been exhausted. Other relatively high-grade, low-cost ores will be discovered, and lower-grade ores can be used. A number of studies estimate the reasonably-assured, reasonable-cost conventional uranium reserves in the range of 14-16 million tonnes, enough for about 200 years at the current rate of consumption.
But if nuclear power increased ten-fold, these reserves would be depleted in a few decades, leaving us with the fanciful and/or highly-problematic options of extensive reprocessing to recycle uranium, fusion, thorium, or the use of plutonium in fast neutron (breeder) reactors.
Large amounts of uranium are also contained in "unconventional sources" such as granite (4 parts per million), sedimentary rock (2 ppm) and seawater (up to four billion tonnes at 0.003 ppm).
It is doubtful whether uranium could be economically recovered from unconventional sources, and the extraction of uranium from such ultra-low-grade ores raises further concerns in relation to the amount of energy required to extract the uranium and the greenhouse emissions expended.
[Jim Green is the national nuclear campaigner with Friends of the Earth, Australia An earlier, referenced version of this paper was published as EnergyScience Briefing Paper #3, <www.energyscience.org.au>.]