Future without Nuclear Energy; is it Feasible, is it Sensible?

Considering the necessity and future role of nuclear energy as relevant to the climate problem, we have focused on the period to the year 2065. For quantification of the required emission reduction we have used IEA WEO 2009 and WEO 2011 data as presented in their Reference strategies predicting emissions with business as usual practices, and WEO 450 Energy strategies which show the time development of allowed emissions consistent with a limit on the global temperature increase of 2 ºC and the peak CO2 concentration of 450 ppm. By extrapolating these data to the year 2065 we obtain 77.4 GtCO2-eq for Reference emission and 10 GtCO2-eq for WEO 450 strategy allowing emission, resulting in 67.4 GtCO2-eq reduction required to come down to sustainable WEO 450 trajectory. The large contributions to emission reduction from fusion energy and fossil fuel with carbon separation and storage are not likely. Main carbon non-emitting sources assumed in the years up to 2065 are proven technology nuclear fission and renewable sources. In our specified strategy aimed to achieve WEO 450 target we assumed an energy mix including nuclear power build-up in the period 2025-2065 to the level of 3300 GW in 2065. With the resulting nuclear contribution of 25.2 GtCO2 to the total required emission reduction of 67.4 GtCO2, what remains for renewable sources, energy saving and increased efficiency of energy use to contribute are prodigious 42.2 GtCO2-eq. Assuming that energy saving and more efficient energy use will by 2065 effect an annual reduction between 10 to 16 GtCO2-eq, remaining 26.2 to 32.2 GtCO2, respectively 27290 and 33540 TWh would be the task for renewable energy sources. Our estimates about contribution of renewable sources going as far as 2065 are based on EREC prediction for EU and on our extension to world total with EREC and GWEC prediction as a guide. Our high, but still credible estimates of predicted world renewable energy contribution by 2065 come to the similar figures between 29260 and 36180 TWh. However, without nuclear contribution in 2065, renewable energy contribution would have to be doubled, practically impossible task in the time period in consideration. Resulting contributions by renewable sources, probably their upper limits, allow some conclusions about the role of nuclear energy in future decades. By combining highest contributions from energy saving, efficiency increase and other measures to reduce emission, apart from energy production, with highest prediction for renewable sources contribution, we obtain the minimum nuclear energy requirement of about 2190 GW in 2065. This minimum nuclear strategy should be planned and prepared for, unless there is strong evidence that other carbon free energy sources (CCS or fusion) could be developed in time. Expansion of nuclear power by about 1800 GW by 2065 would come from different and already developed industrial sector, which can give its contribution to the energy mix, without obstructing the build-up of renewable sources. It would not be wise to forfeit nuclear contribution at least in the period to 2065, critical for the control of climate change