Enrich, baby, enrich

If we focus only on what comes out of a smokestack we’re missing a key part of the supply chain for electric power.  Whether the upstream activities involve oil drilling or uranium enrichment, individuals that set our energy policies should consider them.

With the recent announcement by the Obama administration to provide loan guarantees for new nuclear power plants, I thought I’d apply some life cycle thinking to energy production and test the claims on greenhouse gas emissions from nuclear power.  Researchers use a life cycle approach called a full energy chain analysis (or FENCH) to quantify the impacts of the entire energy chain.

A group of Swiss researchers used the FENCH approach to model the main types of electricity production in the US (supplied by coal, natural gas and nuclear), and compared them to renewable energy production (from photovoltaic, hydropower, biomass, wind, and geothermal).  Including the entire nuclear energy chain (from uranium ore extraction to radioactive waste repositories) revealed that uranium enrichment and its electricity supply is an important contributor to energy expenditures.  They estimated that nuclear power in the US emits 13 g CO2-eq/kWh compared to about 1200 g CO2-eq/kWh for coal [1].  The Öko-Institute estimated 33 g CO2-eq/kWh for nuclear power in Germany [2] and an earlier study in a bulletin from the International Atomic Energy Agency found a range of 2.5-5.7 CO2-eq/kWh [3].

Clearly, nuclear power dramatically reduces CO2-equivalent emissions when compared to coal-fired power plants, but what about energy from renewable sources?  Let’s consider wind power.  In another study by Dones, they found that the majority of the emissions from wind power arise from the production of the materials that go into the turbine, tower and foundation – upstream activities that must be accounted for in the full energy chain.  Under average European conditions, onshore wind (with a 20% capacity factor) and offshore wind (with a 30% capacity factor) emits 14 g CO2-eq/kWh.  Under optimal wind conditions, an estimated 10 g CO2-eq/kWh are released.  The same paper found a range of 6-12 g CO2-eq/kWh for nuclear power in Europe. [4]

Under favorable wind conditions, the studies show that wind and nuclear power emit about the same amount of greenhouse gases per kilowatt hour over the entire energy chain.  Our policymakers should begin to factor in these findings before labeling nuclear power as a ‘carbon free’ energy source, and using it to advance climate change legislation.  What about the price tag for this policy?

An article in Mother Jones describes some of the costs we can expect with the new plan to underwrite nuclear power.  Long-term storage solutions for nuclear waste have so far escaped us, and some states are getting anxious about temporary storage.

In future posts, I’ll look into costs and the FENCH studies in more detail, and share some more findings on renewable energy.

Image: Available at: http://www.flickr.com/photos/vattenfall (Creative Commons license)

[1] Dones R., Bauer C., Heck T. (2007) LCA of current coal, gas and nuclear electricity systems and electricity mix in the USA. Proceedings of the 14th SETAC Europe LCA Case Studies Symposium, December 3-4, 2007, Gothenburg, Sweden.
[2] Fritsche UR, Lim S-S. (2006) Comparison of Greenhouse-Gas Emissions and Abatement Costs of Nuclear and Alternative Energy Options from a Life-Cycle Perspective (updated version). Öko-Institute. Available at: http://www.oeko.de/service/gemis/files/doku/nuclear_co2paper_update2006.pdf.
[3] Spadaro, J.V., Langlois, L., and Hamilton, B. (2000) “Greenhouse Gas Emissions of Different Electricity Generating Chains”, IAEA Bulletin, 42 (2).
[4] Dones R., Heck T., Hirschberg S. (2004) “Greenhouse Gas Emissions from Energy Systems, Comparison and Overview.” In: Encyclopedia of Energy (Ed. Cleveland C.), Vol. 3, pp. 77-95. Academic Press/Elsevier, San Diego, USA.