Can electric vehicles help China improve air? US media: these two conditions must be satisfied.
According to Daily Science website May 1, researchers from Harvard University and Tsinghua University have found that if the government encourages car owners to charge their cars slowly during off-peak hours, private electric vehicles in China can play a positive role in reducing carbon dioxide emissions and making wind power generation more effective. Use. On the other hand, if the "fast charging mode" is used to charge the electric vehicle quickly, it may have the opposite effect.
At the same time, buses and taxis in China have also contributed significantly to the emission of nitrogen oxides, which is a major precursor of air pollution, the report said. The team found that replacing buses and taxis with electric cars was the most effective way to improve air quality. The research is published in the journal Nature energy.
One of the authors of the study, John Paulson School of Engineering and Applied Sciences (SEAS) of Harvard University and Michael McClelloy, professor of Environmental Sciences at the Department of Earth and Planetary Sciences, said: "This study provides a more subtle strategy for reducing carbon dioxide emissions and improving air quality in China."
Chen Xinyu, co-author of the report and assistant researcher of SEAS Environmental Science and Engineering, said: "It is very important to properly manage the charging of electric vehicles in order to maximize the advantages of renewable energy sources."
Researchers use real-time electricity demand data and driving patterns in Beijing and suburbs to build integrated models of energy systems, the report said. They found that the charging mode of electric vehicles, whether in low-energy slow charging mode or high-energy fast charging mode, plays an important role in wind energy integration. Generally speaking, the fast charging mode with 30 minutes or less is mainly in the peak period of power demand. As a result, higher demand for electricity at peak hours has led to more coal-fired generators on the line. As these generators run at night, the opportunity to make full use of available wind power is reduced.
Chris Nelson, one of the authors of the study and executive director of Harvard's China Project, said: "If the government encourages car owners to wait until evening to recharge their electric cars in slow charging mode (which takes several hours), then they can make full use of the non-peak wind energy."
In terms of reducing air pollution, the researchers found that public transport fueled by gasoline or diesel, i.e., about 30,000 buses and 66,000 taxis, accounted for nearly 20% of the total emissions of nitrogen oxides, equivalent to 8.2 million private cars. Changing Beijing's buses and taxis into electric vehicles will greatly reduce the total amount of nitrogen oxide emissions and help improve air quality.
"Changing public transport to electric vehicles and encouraging private car owners to charge electric vehicles during off-peak hours are the most effective strategies to reduce Beijing's emissions of nitrogen oxides and carbon dioxide," said Michael Roy. He added: "this strategy is also applicable to other cities in the world that use large amounts of coal-fired power generation."
Source: Reference News Network