From wind-solar accommodation to potential coal-generation displacement: spatial coordination and operational CO2 mitigation in China’s power system

Wind-solar accommodation does not necessarily yield equivalent reductions in coal generation or emissions. Using 2022 hourly output for 2880 county-level units, 8760-h loads for 31 provinces and data for 2985 coal units or project phases, we compare provincial self-accommodation, neighboring-province pairing, nationwide pairing and national aggregation. Absolute coal-generation displacement is measured against a constructed common reference excluding studied wind-solar generation under unchanged demand and resources: a model counterfactual, not observed 2022 dispatch. Under the benchmark assumptions, nationwide pairing increases direct accommodation by 310.59 TWh (39.04%), coal-generation displacement by 285.98 TWh (47.61%) and operational CO₂ mitigation by 250.36 Mt (41.29%) relative to provincial self-accommodation. Renewable supply, coal conversion and displaced emission intensity contribute 191.39, 90.66 and − 31.69 Mt, respectively. Although nationwide pairing and national aggregation both directly accommodate approximately 1106.15 TWh, aggregation displaces another 144.58 TWh of coal generation and avoids another 127.79 Mt of CO 2 . Additional sensitivity tests retain positive coordination benefits but show substantial dependence on matching assumptions, annual reduction allowances and eligible provincial connections. These estimates describe conditional coordination potential under fixed unit emission intensities and unrestricted transfers within coordinated domains. Renewable planning should jointly assess accommodation, access to reducible coal generation and unit-level emission differences.