Synergetic pathways of water-energy-carbon in ecologically vulnerable regions aiming for carbon neutrality: a case study of Shaanxi, China

Synergetic energy-water-carbon pathways are key issues to be tackled under carbon-neutral target and high-quality development worldwide, especially in ecologically vulnerable regions (EVRs). In this study, to explore the synergistic pathways in an EVR, a water-energy-carbon assessment (WECA) model was built, and the synergistic effects of water-energy-carbon were comprehensively and quantitatively analyzed under various scenarios of regional transition. Shaanxi Province was chosen as the representative EVR, and Lower challenge (LEC) and Greater challenge (GER) scenarios of zero-carbon transition were set considering the technological maturity and regional energy characteristics. The results showed that there were limited effects under the zero-carbon transition of the entire region on reducing water withdrawals and improving the water quality. In the LEC scenario, the energy demand and CO₂ emissions of Shaanxi in 2060 will decrease by 70.9% and 99.4%, respectively, whereas the water withdrawal and freshwater aquatic ecotoxicity potential (FAETP) will only decrease by 8.9% and 1.6%, respectively. This could be attributed to the stronger demand for electricity in the energy demand sector caused by industrial transition measures. The GER scenario showed significant growth in water withdrawals (16.0%) and FAETP (36.0%) because of additional biomass demand. To promote the synergetic development of regional transition, EVRs should urgently promote zero-carbon technologies (especially solar and wind power technologies) between 2020 and 2060 and dry cooling technology for power generation before 2030. In particular, a cautious attitude toward the biomass energy with carbon capture and storage technology in EVRs is strongly recommended.