In this paper, the strategic technology options, especially the potential role of natural gas combined cycle and nuclear power plants, in mitigation of CO2 emission in electricity sector in China are assessed. We analyse the influence of different power generation technologies on CO2 emission volume and abatement cost based on energy market and electricity demand prospects, and least-cost expansion of electricity generating system. In the latter model, we take into account electricity supply quality and CO2 emission. The CO2 abatement cost is estimated in a period of time rather than the traditional abatement cost estimation performed for a target year. The proposed model is applied to the case of Shanghai Municipality in China to assess potential role of natural gas combined cycle and nuclear power plants in mitigation of CO2 emission. Impact of the baseline technology choice on CO2 abatement cost is analysed through the formulation of three scenarios. For the first one (“Baseline” scenario), it is assumed that expansion of the electricity supply system is based only on coal-fired power plants; for the second scenario, it is supposed that the decision makers have already envisaged the use of natural gas combined cycle power plants (CCPP) in addition to coal fired ones; the third scenario mixes coal-fired, natural gas CCPP and nuclear power plants. It is found that on the horizon of the study (2020), maximum CO2 emission mitigation potential of natural gas CCPPs can reach 42.4 million tons (MtCO2), whereas maximum CO2 emission reduction potential of nuclear power plants can be 298.2 MtCO2. The CO2 abatement cost estimation falls into the range from US$19/tCO2 to US$51/tCO2 depending on the level of imposed CO2 penalty, volume of carbon emission reduction and baseline technology choice.