Vehicle or power grid? Subsidy policy performance evaluation of China's plug in hybrid electric vehicles promotion and power grid cleaning construction.

China has implemented strong incentives to promote the market of plug-in hybrid electric vehicles (PHEVs). The increase of PHEV will lead to an increase in electricity consumption, and more power generation will also lead to more carbon dioxide emissions. Therefore, it is necessary to evaluate the environmental benefits of the subsidy policy. In this study, we calculated the CO emission reduction and the increase of grid power generation and the CO emission from the investment and construction of clean energy power generation facilities caused by the subsidy of PHEV from 2016 to 2020, and evaluated the effect of PHEV subsidy through the multi-period DID model. The results show that replacing ICEV with a PHEV will reduce CO emissions by 12.38 kg per 100 km. Under the existing grid structure and power generation conditions, the promotion of PHEV will have a positive impact on CO emissions, but the effect is short-lived. Without considering other costs, the investment in clean energy power generation facilities at this stage will achieve better CO emission reduction effect than the promotion of PHEV.