Research About Green Electricity and Zero-Carbon Fuel on Reduction of CO2 Emissions for Commercial Vehicles Under "Dual-Carbon" Target

China's CO2 emissions from commercial vehicles have an important impact on global climate change. However, a systematic research analysis, especially from new energy in the "dual-carbon" time is still insufficient. Thus, based on zero-carbon energy (green electricity, green hydrogen, and green ammonia), this paper carries out the research about CO2 emissions prediction between zero-carbon energy and diesel in light-duty trucks and different sales fraction projects of zero-carbon energy from 2020 to 2060, and the changes in the quantity of light-duty trucks (including stock, increment, scrap and total amount). The calculation results show that CO2 emissions from diesel is the largest, a gradual upward trend in general, and reaches peak value in 2055 (1.793 billion tons). Based on different sales fraction projects for green electricity trucks, CO2 emissions of peak in 2035. As penetration increases, CO2 emissions gradually decline. Reduction of CO2 emissions of Project_1 is 19.94% and will stabilize after 2055. However, CO2 emissions of Project_4 stabilize after 2040 and 15 years earlier than Project_4's, and CO2 emissions are nearly zero. The change rule of CO2 emissions from "Diesel + Green Hydrogen" and "Diesel + Green Ammonia" is similar, and CO2 emissions from "Diesel + Green Ammonia" is higher than that of "Diesel + Green Hydrogen". The permeability of Project_4 changes greatly, and the results are a large reduction. Based on 2020's data, and as gray ammonia is fuel, the results show that the current overall emission level can be reduced only when the CO2 emissions level for the production of gray ammonia reduces by less than 30% of the current level. These results obviously have guiding significance to low CO2 emissions from commercial vehicles.