Nuclear Energy: too little too late?

by Andrew Teller

Even a cursory glance through the international press is sufficient to notice two highly correlated types of articles. The first type is about decision-makers thinking of reviving the nuclear option to combat climate change. The second type reports pronouncements of skeptics claiming that nuclear energy is not the answer to the climate change problem. Under various guises, the arguments of the opponents boil down to two basic statements:

• the share of nuclear energy in the global primary energy supply is too small to make any noticeable difference to the actual amount of carbon dioxide emissions;

• it would take so much time launching a large-scale nuclear programme that it would start to kick in too late to achieve any useful purpose.

Let us examine these claims in turn. The first one is usually supported by a figure: nuclear energy amounts to 6% only of the total primary energy supply. So the argument goes: if nuclear energy helps to the tune of 6% only, we do not change the magnitude of the global warming challenge in any noticeable way if we renounce to nuclear power plants. This piece of reasoning is very clear, very simple to understand and all too easy to accept. A moment of reflection shows however that it takes two conditions for granted: a) the world’s total energy production is the right yardstick for measuring the contribution of nuclear energy and b) there are carbon-free solutions available in sufficient supply to permit avoiding (or replacing) NPPs at no extra cost. Unsurprisingly, neither condition is fulfilled. The contribution of nuclear energy must be assessed with respect to the objective to be reached, which definitely not the same as achieving zero CO₂ emissions.

Two scientists from Princeton University have come up with what is generally regarded as a realistic objective. They show how world CO₂ emissions could be stabilized to the current level of 7GtC (yes, 7 billion tonnes of carbon!) over the next fifty years despite an expected steep increase in energy consumption . This objective translates into avoiding the generation of 175 GtC during the said time span. On the other hand, phasing nuclear energy out would add about 20 GtC to that burden. I conclude from this that nuclear energy’s contribution to the fight against climate change is equal to 20/175, i.e. 11.4%, and not 6%. Of course, one might easily argue that 11.4% is still not a lot. The picture will however be further altered if we shift our attention to the financial aspect of the matter. Carbon-free substitutes to nuclear power plants that would be equally cost-effective are not available in large quantities. Some wind farms might nowadays be competitive with NPPs as long as their overall contribution remains marginal. Pushing the share of wind energy beyond, say, 20% will leave the existing base-load generating capacity (all fossil-fuelled and nuclear) unable to compensate the intermittency of wind. This will require energy storage devices and push the cost of wind electricity to levels noticeably higher than those experienced so far. Other production means, such as off-shore wind and solar electricity will be even more expensive. We can therefore expect the cost of each additional tonne of carbon avoided to become dearer and dearer, as depicted in figure 1. The total cost of avoiding a certain amount of carbon emissions is numerically equal to the area under the curve. So, the cost of avoiding 175 GtC will be represented by area OAB. If we must make up for the phase-out of nuclear energy, we’ll have to avoid 195 GtC and add to OAB a cost represented by area ABCD. Therefore, the relative contribution of nuclear energy is equal to the ratio ABCD/OAB. It is difficult to put precise figures on the curve in figure 1. Just to give an order of magnitude of the outcome that can be expected, it can be noted that, using the curve below, a nuclear phase-out would increase the bill by about 34%. One can assert that 34% is still not a lot. Should anybody do so, I would then suggest looking at the absolute figures lurking behind the percentages. According to an assessment made at the Massachusetts Institute of Technology , the cost of avoiding emissions of carbon in the (A-C) part of the curve in figure 1 could exceed 400 USD/tC for the United States. With a curve such as the one depicted below, this would yield an average cost of 185 USD/tC. Let us not go to such extremes and assume conservatively – and somewhat arbitrarily – an average cost of only 40 €/tC. Avoiding 175 GtC would then entail a cost of the order of 7 000 billions €. I do not see how anybody could possibly state that 34% of this amount is not a lot.

Figure 1

So much for the “too little” argument. What can we say about the “too late” one? Opponents of nuclear energy are quick to point out that the deployment of a sizeable fleet of new reactors would take decades and would consequently come after the death of the patient. I agree with the premise but not with the conclusion. Scaling up the current industrial capacity to meet increased demand will take time, but so will the implementation of additional gas transport capacity, or of wind farms capable of storing energy to be released when the wind does not blow. So will also achieving meaningful energy savings through better thermal efficiency in buildings or improved transport habits. Clearly, this argument sounds more like a lame excuse for dodging the nuclear option: lead time problems are not insuperable. Furthermore, while it is reasonable to start working on the problem now, it would be unreasonable to demand tangible results tomorrow. The article mentioned above under reference 1 confirms that 50 years is an appropriate time span for planning our actions and reaping the benefits thereof. This leaves nuclear energy ample time to provide an orderly and not-to-be-dismissed contribution to the fight against global warming.

¹ S. Pacala & R. Socolow Stabilization Wedges: Solving the Climate Problem for the Next 50 Years with Current Technologies, Science, vol 305, 13 August 2004.

² MIT Joint Program on the Science and Policy of Global Change, April 2000 (reprinted from Making Technology Work (p 105) by John M. Deutch & Richard K. Lester, Cambridge University Press, 2004)