Electric vehicles are considered a more environmentally sensitive alternative to motor vehicles running on fossil fuels. With increasing global focus on the environment, China is relying on electric vehicles to improve air quality and reduce CO2 emissions. However, a major share of China's electricity is generated by coal-fired power plants, raising questions on the effectiveness of the electric vehicle (EV) strategy.
A research collaboration between Harvard University and Tsinghua University in Beijing has recommended that EV owners should be encouraged to ‘slowly charge’ their vehicles during off-peak hours, maximising the effective use of wind-generated power.
Additionally, buses and taxis contribute to most of the NOX emissions in the country. The study found that public vehicles consisting of about 30,000 buses and 66,000 taxis, and running on gas or diesel accounted for nearly 20 percent of total NOX emissions, equivalent to 8.2 million private vehicles. Changing them to electrical operation will contribute significantly to improving air quality.
The study was based on real-time power demand data and driving patterns in Beijing and suburban areas. The researchers found how charging electric vehicles in low-energy slow mode or high-energy fast mode played a significant role in the integration of wind energy. Vehicle charging in the fast mode typically occurred during peak hours, increasing peak power demand and triggering additional coal generators to come online.
However, when people are incentivised to charge their vehicles in the slow-charge mode later in the evening, the power load could take advantage of wind energy available during off-peak hours.
This strategy could be applied across the world, especially in cities dependent on coal-generated electricity.