Solar dead last (oops, my bad...wind is worse).
"The 2001 and 2002 Storm van Leeuwen & Smith papers and Background Information represent an interesting attempt to grapple with a complex subject but depend on many essentially speculative figures to put the case that nuclear energy incurs substantial energy debts and gives rise to minimal net energy outputs considered on a lifetime basis. Recent life cycle assessment (LCA) studies such as Vattenfall's show figures around ten times lower for key capital and waste-related energy demands. The Vattenfall life cycle study gives a bottom line of 1.35% of lifetime energy output being required for all inputs, and only a tiny fraction of this being in the nature of energy debts.
Finally, it should be pointed out that, even on the basis of their assumptions and using their inaccurate figures, Storm van Leeuwen & Smith still are forced to conclude that nuclear power plants produce less CO2 than fossil-fuelled plants, although in their view "the difference is not large". Others might see a 20 to 50-fold difference (between nuclear and gas or coal) as significant. The audited Vattenfall figure for CO2 emission on lifecycle basis is 3.10 g/kWh, less than one percent of the best fossil fuel figure. This could approximately double if nuclear power inputs to enrichment were replaced by fossil fuel ones, but it is still very low.
It is clear, then that the concerns related to energy costs at the heart of the Storm van Leeuwen & Smith paper can be dismissed. The authors' other point, that nuclear energy is not sustainable, is addressed in the Sustainable Energy and Supply of Uranium papers in this series."
http://www.world-nuclear.org/info/Energy-and-Environment/Energy-Analysis-of-Power-Systems/#.UWLqOxma3nA
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