Can Solar Photovoltaic Poverty Alleviation Policies Reduce Carbon Emissions and Increase Income in China?

China implemented a solar photovoltaic (PV) poverty alleviation (PVPA) policy of building nearly 0.24 million PVPA power plants in 2014-2020 to fight poverty. However, our current knowledge of its effects, encompassing not only primary poverty alleviation but also secondary objectives such as carbon emission-reduction, remains comparatively constrained. Here, we present a comprehensive assessment of the emission-reducing and income-increasing effects of the PVPA policy using estimated carbon emission factors and a staggered difference-in-difference model based on integrated data from almost all actual PVPA plants in China. Our analysis revealed the co-benefits of emission-reduction and poverty alleviation, with PVPA policy boosting villagers' per capita net income by 2-3% in villages with PV plants. A nonlinear, inverted U-shaped relationship between income and PVPA plant investment was identified with a $2.21 million inflection point. Spatial heterogeneity was observed in the income-increasing effect, with centralized village-level plants proving more effective than rooftop household plants. China's PVPA plants reduced carbon emissions by nearly 3% in 2020 and are projected to generate 774 billion kW h of electricity by 2045, mitigating 715.75 million tons of carbon emissions. The findings from this research offer insights for optimizing antipoverty and climate change policies to facilitate sustainable development goal achievement in China and other developing nations.