The growing concern about the negative effects of fossil fuels on the environment, and the limited resources of them have forced more intensive use of other energy sources. In absence of sufficient economically feasible renewable energies, nuclear power may play essential role in this field. Recently, the advantages and disadvantages of nuclear power and fossil fuels regarding their efficiencies have been attracted researchers' interest. This paper discusses on the findings from "A Grammar for assessing the performance of power supply systems: comparing nuclear energy to fossil energy" (Diaz-Maurin F, Giampietro M. 2013). Although the "Grammar" is a very valuable approach, it can be accomplished by using helpful quantitative methods. In this discussion, we apply quantitative decision-making approaches to compare the same fossil fuel (coal) power plants with nuclear power plants. Economic variables are also taken into consideration. The DEA (data envelopment analysis) and SAW (simple additive weighting) are the methods applied. Results confirm the results of the reference paper in most cases and show that the fossil fuel power plants with CCS (carbon capture and storage) are slightly more efficient than nuclear power plants. However, selection of input and output variables is disputable. Assuming job creation as a desired output can change the ranking results. (C) 2013 Elsevier Ltd. All rights reserved.