GREENHOUSE EMISSIONS FROM NUCLEAR POWER AND URANIUM MINING

“If one takes into consideration the mining of resources, the transportation, the building and maintaining of nuclear power plants, the distribution of the electricity and the necessary additional production of heat, then nuclear power does often look worse for climate protection than other forms of energy production. A modern gas-fired power station in connection with heat production [co-generation] can be more favourable for the climate. Even better for the climate are renewable energies and most of all the efficient use of energy.”
— German Environmental Ministry, March 2006, ‘Atomkraft: Ein teurer Irrweg. Die Mythen der Atomwirtschaft’.

Summary: Claims that nuclear power is ‘greenhouse free’ are false. Nuclear power is more greenhouse intensive than some renewable energy sources and most energy efficiency measures. Life-cycle greenhouse emissions from nuclear power will increase as relatively high-grade uranium ores are mined out and gradually give way to the mining of lower-grade ores.

The following table is taken from the Switkowski report (2006, p.93), based on commissioned research:

TECHNOLOGY EMISSIONS INTENSITY g CO2-e/kWh

BEST ESTIMATE RANGE
Brown coal (subcritical) 1175 1011–1506
Black coal (subcritical) 941 843–1171
Natural gas (open cycle) 751 627–891
Natural gas (combined cycle) 577 491–655
Solar photovoltaics 106 53c217
Nuclear (light water reactor) 60 10–130
Wind turbines 21 13–40
Hydro (run-of-river) 15 6.5–44

Greenhouse emissions arise across the nuclear fuel cycle – uranium mining, milling, conversion, and enrichment; reactor construction, refurbishment and decommissioning; and waste management (e.g. reprocessing, and/or encasement in glass or cement). In addition, transportation is extensive – for example, Australian uranium may be converted to uranium hexafluoride in Canada, then enriched in France, then fabricated into fuel rods in Japan, and the spent fuel may be reprocessed in the UK or France resulting in plutonium, uranium and waste streams which may be subject to further international transportation.

Academic Benjamin Sovacool (2008) states that the front end of the nuclear fuel cycle (uranium mining, milling, and enrichment) is responsible for 38% of the emissions of the entire nuclear fuel cycle; plant construction is responsible for 12%; decommissioning and plant operation, including the use of fossil-fueled generators to backup nuclear plants when they offline for servicing, account for 35%; and the back end of the fuel cycle, which includes storing spent fuel and fuel conditioning, accounts for 15%.

Sovacool (2008) states: “To provide just a rough estimate of how much equivalent carbon dioxide nuclear plants emit over the course of their lifecycle, a 1,000 MW reactor operating at a 90 percent capacity factor will emit the equivalent of 1,427 tons of carbon dioxide every day, or 522,323 metric tons of carbon dioxide every year. Nuclear facilities were responsible for emitting the equivalent of some 183 million metric tons of carbon dioxide in 2005. Assuming a carbon tax of $24 per ton − nothing too extreme − and that 1,000 MW nuclear plant would have to pay almost $12.6 million per year for its carbon-equivalent emissions. For the global nuclear power industry, this equates to approximately $4.4 billion in carbon taxes per year.”

Life-cycle greenhouse emissions from nuclear power will increase as relatively high-grade uranium ores are mined out and gradually give way to the mining of lower-grade ores. Metals and mining consultancy firm CRU Group (2009) calculates that the average grade of uranium projects at the feasibility study stage around the world is 35% lower than the grades of current mines, and that exploration projects have average grades 60% below existing operations.

The extent of the increase in the greenhouse intensity of uranium mining is the subject of debate and considerable uncertainty. It depends not only on declining ore grades but also on other variables such as the choice of tailings management options at uranium mines. Nuclear power is already more greenhouse intensive than some renewable energy sources (wind, hydro) and is likely to become more greenhouse intensive than solar PV (indeed it already is according to some studies − see Sovacool 2008b). Emissions from nuclear power could possibly rise to the extent that they would be equivalent with those from an efficient gas-fired plant.

In a paper prepared for the Australian Uranium Association, Sydney University academic Manfred Lenzen (2009) concludes that life-cycle greenhouse gas emissions for nuclear power range from 10−130 g/kWh with the main variables being ore grades, enrichment technology (gaseous diffusion is highly greenhouse intensive, centrifuge enrichment less so), reactor fuel re-load frequency and burn-up, and to a lesser extent enrichment level, plant lifetime, load factors, and enrichment tails assay. Lenzen calculates a “worst case” – 0.01% ore grade, 75% load factor, 25 year lifetime, only diffusion enrichment, and a carbon-intensive background economy – resulting in emissions of 248 g/kWh.

Others calculate still higher values, for example by assuming energy- and emissions-intensive burial of large volumes of low-level ore, waste rock, and mill tailings, rather than the current practice of surface storage.

Dr Mark Diesendorf from the University of NSW argues: “In the case where high-grade uranium ore is used, CO2 emissions from the nuclear fuel cycle are much less than those of an equivalent gas-fired power station. But the world’s reserves of high-grade uranium are very limited and may only last a few decades. The vast majority of the world’s uranium is low-grade. CO2 emissions from mining, milling and enrichment of low-grade uranium are substantial, and so total CO2 emissions from the nuclear fuel cycle become greater than or equal to those of a gas-fired power station.”

GREENHOUSE EMISSIONS AND URANIUM MINING

“So the real choice is between nuclear power and a mix of renewable energy technologies combined with efficiency measures. If that is the choice, it would take creative arithmetic to make a case that our uranium is doing anything at all to save the world from climate change. I would be more impressed by the integrity of those arguing for us to export uranium to slow global warming if they were also calling for us to reduce our coal exports. Australia could do much more to help the global atmosphere by cutting our coal exports than we could by the most fanciful estimate of the potential benefits from our uranium. Of course, many of those urging uranium exports are also in the vanguard of calls to export even more coal than we do today. This shows that they are actually more interested in the short-term economic benefits of mineral exports than in any effect on the global environment.”
— Prof. Ian Lowe, September 7, 2007, ‘Heeding the warning signs’, Sydney Morning Herald, http://www.smh.com.au/news/national/heeding-the-warning-signs/2007/09/06/1188783415604.html?page=fullpage

The uranium industry and its supporters often claim that Australia’s uranium exports are responsible for large reductions in greenhouse emissions. To give one example, the Australian Uranium Association (2010) claims that current annual exports of around 10,000 tonnes “help avoid around 400 million tonnes of greenhouse gases that would otherwise be emitted each year by fossil-fuelled power stations.”

However that argument assumes that uranium and nuclear power displaces coal-fired plants – an arbitrary and unlikely assumption and one which is too infrequently made explicit. Australia’s uranium exports are not responsible for any reduction of greenhouse emissions if simply displacing uranium from other sources (ignoring marginal variations in the emissions intensity of different mines). Moreover, uranium mining companies want to take credit for the alleged greenhouse benefits of uranium exports but not for the WMD proliferation risks or the high-level nuclear waste legacy.

Emissions (or alleged emissions savings) from the end use of Australia’s energy exports are not counted in Australia’s greenhouse emissions figures. If they were, the accounting would include emissions-intensive fossil fuel exports as well as uranium. Companies such as BHP Billiton want to take credit for the alleged emissions ‘savings’ from their uranium exports but accept no responsibility for emissions from the burning of their fossil fuel exports.

Some companies with financial interests in both uranium and fossil fuels have been vocal climate change sceptics and have used political donations, corporate front groups and a myriad of other tactics to prevent action being taken to address climate change by reducing fossil fuel usage. WMC Ltd., the former owner of the Olympic Dam mine, is one notorious example (Green, 2002).

While indirect or end-use emissions from energy exports are not factored into Australia’s greenhouse accounts, the direct emissions associated with uranium mining do count in Australia’s emissions accounting. For the proposed Olympic Dam mine expansion, BHP Billiton (2009) projects that emissions will increase from 1.14 million tonnes (Mt) annually to at least 5.24–5.84 Mt annually by 2020. An independent assessment by Dr Gavin Mudd (2009) from Monash University estimates emissions of 4.5–6.6 Mt. Thus the mine expansion will make it all but impossible for South Australia to reach its legislated target of 13 Mt of greenhouse emissions annually by 2050 as Olympic Dam alone will account for one-third to one-half of the target.

References:

* Australian Uranium Association, 2010, ‘Facts about the uranium industry’, <www.aua.org.au/Content/Keyindustryfacts.aspx>, accessed 27 February 2010.
* BHP Billiton, 2009, Draft Environmental Impact Statement, <www.bhpbilliton.com/bb/odxEis.jsp>.
* CRU Group, 2009, ‘Next generation uranium – at what cost?’, <http://crugroup.com/Documents/UraniumPressRelease2009Sep23.pdf>.
* Diesendorf, Mark, ABC ‘Ask an Expert’, <www.abc.net.au/science/expert/realexpert/nuclearpower/03.htm>.
* Green, Jim, 2002, ‘WMC Ltd.: corporate greenhouse gangster’, <http://pandora.nla.gov.au/pan/30410/20090218-0153/www.geocities.com/jimgreen3/wmc.html>
* Lenzen, Manfred, 2009, ‘Current state of development of electricity-generating technologies – a literature review’, <www.aua.org.au/Content/Lenzenreport.aspx> or direct download <www.aua.org.au/DisplayFile.aspx?FileID=36>
* Mudd, Gavin, 2009, ‘Prediction of Greenhouse Gas Emissions for the Olympic Dam Mega-Expansion’, <www.foe.org.au/anti-nuclear/issues/oz/u/roxby>.
* Sovacool, Benjamin, 2008, ‘Nuclear power: False climate change prophet?’, <http://scitizen.com/future-energies/nuclear-power-false-climate-change-prophet-_a-14-2136.html>
* Sovacool, Benjamin, 2008b, ‘Valuing the greenhouse gas emissions from nuclear power: A critical survey’, Energy Policy, vol.36, pp.2940– 2953, <http://linkinghub.elsevier.com/retrieve/pii/S0301421508001997>
* Switkowski Report, 2006, <http://nla.gov.au/nla.arc-66043>.


More information:

* Gavin M. Mudd and Mark Diesendorf, 2008, ‘Sustainability of Uranium Mining and Milling: Toward Quantifying Resources and Eco-Efficiency’, Environ. Sci. Technol., 42 (7), 2624–2630, http://pubs.acs.org/cgi-bin/sample.cgi/esthag/2008/42/i07/html/es702249v.html