Most environmentalists agree that nuclear energy is not the answer to our clean energy needs. The risks it poses, the role nuclear energy plays in weapons proliferation and the storage of nuclear waste all play a part in that assessment. Still, the nuclear industry touts nuclear energy as “clean” energy, i.e. free of greenhouse gas emissions. But is it?
To get some answers, I asked Jan Willem Storm van Leeuwen from Ceedata Consultancy, author of the paper “Nuclear Power – the Energy Balance, Energy Insecurity and Greenhouse Gases”. The research on the paper began in 2000, with several subsequent updates, when Jan was asked by Green parties of the European Parliament to prepare a background document for the UN Climate Conference.
Leslie Berliant: What is the ‘energy cliff’ and why do you say that beyond it, nuclear cannot generate net useful energy?
Jan Willem Storm van Leeuwen: The energy cliff is the relationship between the amount of net energy extractable from uranium ore and the grade (uranium content) of the ore used to get it.
Figure 1
 Jan Willem Storm van Leeuwen |
An LWR nuclear power plant of new design can generate some 160 TJ/Mg natural uranium (= 160 GJ/kg). If only the processes of the nuclear fuel chain are accounted for (see upper curve) the net energy (= useful energy) from the nuclear system is slightly more than 120 GJ/kg. This value declines with decreasing ore grade. Below a grade of some 0.02% no net energy is possible: the nuclear system falls off the energy cliff.
The lower curve refers to the complete system, including construction, decommissioning and dismantling.
Today the world nuclear capacity is around 370 GW, providing 2.1% of the world energy supply (see Part A - PDF).
Scenario 1: the world capacity remains at today’s level.
Scenario 2: the nuclear contribution remains constant at 2.1%. This implies a growth of 2-3% a year to maintain a constant percentage share.
Based on these two simple scenarios the depletion of the world’s recoverable uranium resources looks like Figure 2. Figure 3 illustrates the energy cliff over time, in both scenarios.
Figure 2
Figure 3
LB: Most people refer to nuclear as ‘clean’ energy - meaning carbon neutral - but you posit that nuclear energy produces more CO2 than a fossil-fueled power station. How does nuclear energy produce carbon dioxide emissions, how much and at what points in the process?
JWSvL: All processes of the nuclear system (see Parts C, D and E - PDFs), except the reactor itself, consume fossil fuels and consequently emit CO2. The nuclear CO2 emission depends on the ore grade, as is explained in Part D. With decreasing ore grade, the CO2 emission increases: see Figure 4. The world average ore grade today is about 0.15% U3O8. and the world average CO2 emission is around 120 g/kWh (with a large spread). When poorer ores are to be mined, the specific CO2 emissions increase steeply with decreasing ore grade.
Figure 4
The consequences over time are given in Figure 5, in the same two scenarios as above.
Within several decades nuclear CO2 emissions will rise steeply and surpass that of gas-fired and essentially any fossil-generated electricity.
Figure 5
LB: What is the energy input for cleaning up nuclear waste?
JWSvL: Cleaning up nuclear waste only consumes energy and materials, see Part E. Handling, conditioning and final disposal of spent fuel alone may consume some 80 PJ during the operational lifetime of a Nuclear Power Plant.
LB: What is the energy input for constructing, operating and dismantling nuclear reactors?
JWSvL: The energy input of construction, decommissioning and dismantling will take some 120 PJ (see Part F). Operation, maintenance and refurbishments during the operational lifetime consume 2.82 PJ/year, see Part F.
LB: Why should we worry about the amount of uranium ore that has to be processed for nuclear power plants?
JWSvL: The Uranium resources with a net energy content are limited: see above and Part D.
In addition, Uranium mining has a very large environmental impact.
LB: You mention that processes to convert uranium ore are a well kept secret and therefore one can’t assume that those processes do not include emissions of greenhouse gases. Do you have any suspicions as to whether there are emissions and what those emissions may be?
JWSvL: The processes required to convert uranium ore into nuclear fuel are known in general outline, but the emissions of these processes are a well-kept secret. See Part C. Surely these processes do emit gaseous effluents, as does any other chemical process. We can only guess which gases and in what amounts. One thing is certain: the nuclear industry cannot claim GHG free energy (apart from CO2) without an independent investigation and publication of the emissions of all processes of the nuclear chain. No reported data in no way means no emissions.
LB: Have there been any outcomes from your findings in terms of actions taken by European or other governments?
JWSvL: In Europe no open actions have been taken, to my knowledge. Australia ordered a review of our report, done by ISA of the University of Sydney.
LB: What do you think should be done with nuclear plants that are currently operational?
JWSvL: They should be shut down as soon as possible, to limit the generation of more radioactive waste and energy debts. In my view the society, or economy, has only a limited room (energy, materials, human skills for activities which are not directy needed to maintain the infrastructure (e.g. roads, energy supply, water supply, education, buildings, food production, care) and to secure its future existence. If this free room or ability to cope with large-scale developments threatening the infrastructure (e.g. climate change, energy shortage, wars on oil or minerals) is used for a dead-end technology like nuclear, there remains no or too liitle room to work on sustainable solutions of the new problems. Going nuclear means opening a bottomless sink, due to the energy debt and the uncontrollable costs, and wasting our ability to cope with challenges ahead. Nuclear power badly delays a necessary transition.
Further Reading:
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December 11th, 2007
My colleague David Bradish, among others, has spent a considerable amount of time debunking the claims of Storm van Leeuwen. Click here for a complete archive of those posts, or here for the first in the series.
Finally, for references to independent third parties who have come to significantly different conclusions than Storm van Leeuwen, click here.