The role of renewables in achieving net-zero in China's electricity sector: An environmental assessment from a life cycle perspective

As the biggest greenhouse gas (GHG) emitter globally, China has pledged to achieve carbon neutrality by 2060. However, the environmental sustainability of this goal has not been assessed comprehensively on a life cycle basis. Focusing on the electricity sector, which contributes >40% to China's GHG emissions, this study evaluates the role and the potential of renewables for achieving net-zero by estimating their life cycle impacts across 31 provinces in China. A future (2050) renewable electricity grid is designed considering daily demand and generation curves, as well as resource potential and future technological advancements. Most of the electricity is generated by solar and wind (70%), followed by hydro (9%), biomass with and without carbon capture and storage (6%), and energy storage (14%). This mix achieves a net-negative climate change impact of −12 kg CO 2 eq./MWh electricity generated (compared to the current 877 kg CO 2 eq./MWh). The net negative impact is found in 18 provinces (−2.1 to −166.1 kg CO 2 eq. per MWh) owing to the biomass energy with carbon capture and storage (BECCS). The rest of the provinces have a net-positive but still relatively low impact (0–42 kg CO 2 eq./MWh) because of the high share of renewables. The majority of the remaining 17 impacts are also significantly lower (5.5–96%) than the impacts of the current grid, except for metal depletion, water consumption and freshwater and marine ecotoxicity. The minimum requirements for achieving the net-zero target for the electricity sector are either the utilisation of 55% of the total estimated biomass energy potential of 22 EJ, or BECCS share of 46% in the total capacity of biomass plants, equivalent to 2.25% of electricity generation. These results help to identify the environmental trade-offs in meeting the decarbonisation targets and to guide a future deployment of net-zero electricity in China.