Power system transition pathways in mega-cities under the “Dual Carbon” targets: A multi-temporal case study of Beijing in China

As carbon neutrality goals accelerate, the interplay between urban carbon reduction planning and power system transition is growing increasingly synergistic. Beijing, as China's capital with substantial power consumption and carbon emissions, presents a critical case for studying power transition. Using the LEAP-PYPSA-BJ model, this study analyzes Beijing's power system transition pathways under the carbon-neutral objective, considering renewable energy output characteristics and power grid constrains. Results indicate that achieving natural carbon neutrality in Beijing by 2060 remains challenging. To sustain a downward trajectory in emissions and address potential extreme weather events, electrification must be planned prudently in light of low-carbon power availability. On the supply side, wind and solar power are set to become key pillars of Beijing's electricity mix by 2060, with projected installed capacity ranging from 26.02 to 33.13 GW for wind and 60.97–83.15 GW for solar PV. However, the expansion of local renewable capacity must be coupled with enhanced development of imported green electricity and the corresponding transmission lines, with projections indicating that the actual capacity requirement for these imported power transmission lines could reach up to 35 GW by 2060. In addition, power planning must consider the spatial and temporal distribution of local power sources in Beijing, as well as ensuring sufficient local grid capacity is available. As load growth continues and the power supply becomes increasingly decarbonized, there is a pressing need for capacity expansion in much of the local transmission lines. During extreme weather events, specific local transmission lines may require capacity upgrades of up to 4.52 GW. A strategic focus will be essential in key load centers such as Haidian, Chaoyang, Lize, CBD, and Yizhuang. Based on these findings, policy recommendations are proposed.