of air pollutants that can be reasonably anticipated to endanger public health or welfare to below the volume or rate required by the Clean Air Act, in the case of a type of facility which has significant emission of air pollutants, or (II) yields at least a 50 percent improvement in energy efficiency, as compared to existing fuel-based electric generating commercial technology, and (ii) which operates with a capacity factor of at least 50 percent, (B) any new or improved reactor design licensed by the Nuclear Regulatory Commission which produces electricity through nuclear fission or a fusion chain reaction and which (when compared to existing nuclear commercial technologies)— (i) reduces the high-level radioactive waste or spent nuclear fuel per unit of energy yield, (ii) improves fuel utilization, (iii) decreases core damage frequency or large early release frequency by at least a factor of 10, or (iv) increases thermal efficiency, (C) any new technology or new improvement to technology which generates electricity from renewable energy (as defined in section 203(b)(2) of the Energy Policy Act of 2005) and which generates at least a 25 percent increase in the conversion efficiency of the facility as compared with the commercial technology of the same type as such technology which is considered to be the best of its type in commercial use, or (D) technology which the Secretary, in consultation with the Secretary of Energy, determines would improve energy efficiency or conversion efficiency of electric generating commercial technology by not less than 15 percent. (2) Conversion efficiency The term conversion efficiency means the fraction— (A) the numerator of which is the total useful electrical or thermal power produced by an electric generating facility at normal operating rates, and expected to be consumed in its normal application, and (B) the denominator of which is the incident energy, whether mechanical, radiation, or thermal energy, which is measurable at the input of the electric generating facility.