Researchers at Michigan State University (MSU) and China’s Hunan University have found that electric vehicles (EV) emit significantly less heat than autos with combustion engines and believe that adopting EVs could help cool major urban areas such as Beijing that suffer from the urban heat island effect, which can raise temperatures within cities as much as 5o C (41o F) higher than the surrounding countryside.That in turn could result in city residents needing less air conditioning and by extension, power.
The study’s co-author Jianguo “Jack” Liu, MSU’s Rachel Carson Chair in Sustainability and director of the Center for Systems Integration and Sustainability (CSIS), says “It’s easy not to see the big picture on issues like electric cars and global warming, but when we look with a holistic approach, we find these unexpected connections. Heat waves kill, and in terms of climate change, even one degree can make a difference.”
The research, led by Professor Canbing Li of Hunan University, was prompted by the argument that EVs environmental benefits are offset by the expense and pollution from manufacturing the vehicles. Li and his team took a broader view of the issue and in the study note that conventional vehicles and air conditioners are the two biggest contributors to the heat island intensity (the difference between urban temperatures and the cooler temperatures of rural areas.) EV’s emit approximately 80 percent less heat than a gas-powered vehicle.
According to the “Hidden Benefits of Electric Vehicles for Addressing Climate Change” paper, the researchers used Beijing in summer of 2012 to calculate that switching vehicles from gas to electricity could reduce the heat island intensity by nearly 1 degree Celsius. That would have saved Beijing 14.4 million kilowatt hours and slashed carbon dioxide emissions by 11,779 tons per day.
The authors also note that other factors that can influence the urban heat island effect may need to be considered when weighing the benefits and disadvantages of replacing conventional vehicles with electric vehicles.