Approximately 42% of the carbon burden associated with electric vehicle charging in China’s largest cities occurs in less developed regions where the electricity needed to power the vehicles is generated. Such was the conclusion made by scientists from Tianjin University and Peking University based on an analysis of data on more than 245 million vehicles in 285 cities across the country. The biggest environmental benefits from electric transport are enjoyed by China’s largest metropolitan areas: the Jing-Jin-Ji cluster (Beijing, Tianjin and Hebei), the Yangtze Delta and the Pearl River Delta. A significant portion of the associated CO₂ emissions is concentrated in northern and northeastern regions with a high share of coal-fired power generation.
Electric vehicles are rightfully considered a more eco-friendly alternative to vehicles with internal combustion engines. They emit virtually no CO₂ while driving. However, their batteries need to be charged with electricity, and when this electricity is produced by coal-fired power plants, emissions occur not on the road but during power generation.
In order to gain an understanding of where these emissions are generated, the researchers compared data on electric vehicles with information on the power grid and specific power plants. This allowed them to track which regions generate electricity for charging vehicles and where the associated emissions actually occur.
The analysis showed that, starting from 2020, economically developed cities in eastern China, including Beijing, Shanghai, Shenzhen and Guangzhou, where most of the country’s electric vehicles are concentrated, have been consuming electricity in such a way that 41.8% of the CO₂ emissions associated with charging them is generated in less developed regions. This effect is especially evident in northern and northeastern China, where a large number of coal-fired power plants are located, supplying these megacities with electricity via the national grid.
To put that into perspective, the scientists compared two scenarios. In the first scenario, each city supplied electric vehicles solely with its own electricity. The second scenario took into account actual power supplies between regions. This made it possible to see how often electricity for charging vehicles is generated far away from the cities where they are used.
The comparison revealed how unevenly the environmental benefits of electric vehicles are distributed. In China’s biggest and wealthiest cities, electric vehicles helped reduce CO₂ emissions by 38–63% compared to internal-combustion engine vehicles. However, the electricity for charging these vehicles was often generated by coal-fired power plants in other regions of the country. As a result, some of the emissions related to electric vehicles were essentially transferred there. In a few energy-supplying regions, these emissions turned out to be 16.9–52% higher than those from comparable gasoline-powered vehicles.
To assess future developments, the scientists simulated three scenarios for the development of China’s energy sector through 2060. The first one envisaged a continuation of current trends, the second one had carbon neutrality achieved by 2060, and the third one included deeper emissions reductions. Their calculations suggest that regional differences will persist until at least 2030, as the number of electric vehicles in major cities continues to soar. After 2040, this gap will gradually begin to narrow. The speed of changes will depend primarily on the pace of replacement of coal-fired power generation by low-carbon energy sources.
The redistribution of emissions will have not only environmental but also economic implications. The researchers estimate that regions supplying large cities with electricity will account for an additional 78.8–92.1 million tons of CO₂ by 2040. If these emissions were to be covered by climate regulations or carbon pricing, the pressure on these areas could be quite substantial. In the most ambitious development scenario, the associated climate costs could reach $4.77 billion per year by 2055. As a point of comparison, this corresponds to about 6.2% of China’s total environmental spending in 2024.
The scientists believe that the results of their study reaffirm the urgent need for low-carbon power generation. As long as coal-fired power plants play a major role in the energy balance of countries, the spread of electric transport will not always lead to an even reduction in CO₂ emissions. Under these conditions, some environmental benefits of electric vehicles are achieved via the usual redistribution of the carbon burden within countries.
