The role of dispatchability in China's power system decarbonization

As the decarbonization of the electric power sector gathers pace, electric power systems will need to evolve in multiple ways: larger amounts of intermittent renewables will need to be deployed, as will dispatchable power generators, transmission lines, and energy storage solutions. Some of these resources could provide the electric power system with much-needed dispatchability, but the value of each will evolve over time and space, as will the impact of their deployment on economic costs and carbon emissions. This study systematically compares the roles that different sources of dispatchability could play in a power system's decarbonization and the evolution of its topology over the period from 2020 to 2060, with China as a case study. Results show that adding these resources to a system's operation yields multiple benefits for decarbonization. These include higher levels of renewables integration (+46 000 TWh, +19%), cost reductions (−5800 billion RMB, −13%), and lower GHG emissions (−23 billion tonnes, −23%). The role of different resources changes throughout the transition: transmission always plays the dominant role; dispatchable coal and nuclear generation reduces renewable curtailment up to 2030; pumped-hydro storage reduces curtailment from 2030 to 2040; and battery storage and concentrating solar power become critical after 2040. This evolution could redraw the economic and environmental maps of China by redistributing infrastructure, renewables integration and carbon emissions to less-developed, remote areas. These results help prioritize efforts to facilitate power system decarbonization over several decades; they also yield insights regarding the regional and sustainable development impact of the low-carbon transition.