Clean production pathways for regional power-generation system under emission constraints: A case study of Shanghai, China

China is now facing pressures of emission reduction both from greenhouse gases (GHGs) and local air pollutants (LAPs). Considering power generation system contributes a great share of CO2 and PM2.5 emissions, a regional power generation system modelling and optimization framework using Long-range Energy Alternatives Planning System (LEAP) is conducted in order to explore the cost-effective cleaner capacity expansion pathways under various emissions constraints. A case study of Shanghai follows, focusing on analysis of capacity additions for different power generation technologies, as well as energy inputs, reduction co-benefits and system costs. The results indicate that: i) the clean production pathways differentiate along with stricter CO2 constraints; ii) Ultra-supercritical coal-fired units have significant advantage under no emission constraint, which are substitute by cleaner power generation units such as wind power, solar power and Integrated Gasification Combined Cycle (IGCC) under the CO2 constrained scenario and the combined CO2-PM2.5 constrained scenario; iii) CO2 constraint displays stronger reduction co-benefits than that of PM2.5; iv) Emission constraints are conductive to energy savings that will increase system cost. Finally, policy recommendations are made through sensitivity analysis that only when the price of natural gas declines sharply can natural gas units become one of the alternatives that reduce coal consumption and the related CO2 emissions.