Tuesday 29 March 2016

Electric vehicles are even more environmentally friendly than you thought – update


You’re probably aware of many of the environmental advantages of electric vehicles (EVs) – reduced carbon footprint, reduced air pollution etc.

But you may not have heard of their reduced heat island effect.

Heat island effect? – human activities are concentrated in urban areas. Almost all human activities produce heat – some obviously – such as household heating, some less obviously – such as household cooling. (Have you ever walked past the outside outlet of an air conditioner?) Heat released by human activity in an urban area raises the local temperature – creating a heat island.

NASA explains the heat island effect


Heat island effect leads to more air-conditioner use in hot weather – which further contributes to the heat island effect.

What internal combustion engines do best, is make heat. In practice, only about 20% of the energy in fossil fuel powers the vehicle. The remaining 80% escapes directly as heat – in urban areas, contributing to the heat island effect.

Electric motors are many times more efficient than internal combustion engines, releasing only 20% of the heat energy.

Canbing Li et. al. have shown that in Beijing, “The replacement of CVs [conventional vehicles] by EVs in 2012 could have mitigated the summer heat island intensity (HII) by about 0.94°C, reduced the amount of electricity consumed daily by air conditioners in buildings by 14.44 million kilowatt-hours (kWh), & reduced daily CO2 emissions by 10,686 tonnes.”1

Obviously, the same principle applies to other cities too.

https://research.msu.edu/electric-vehicles-emit-significantly-less-heat/
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1 Canbing Li et. al: “Hidden Benefits of Electric Vehicles for Addressing Climate Change”, published in Nature, https://www.nature.com/articles/srep09213

/ electric cars electric vehicle EV environmentally friendly benefits electric vehicle EV diminished carbon footprint less air pollution more subtle benefits as well new research Michigan State University research EVs emit less heat urban heat island effect reduced large-scale adoption of EVs phasing out heat-spewing gas-powered vehicles hot cities summer hotter global warming reduced improving livability reducing cooling bills energy use petrol gas powered vehicles switch to electrics big picture electric cars global warming study Jianguo Liu Rachel Carson Chair Sustainability Michigan State University director Center for Systems Integration and Sustainability heat waves kill climate change one degree research Professor Canbing Li Hunan University Changsha China visiting scholar conventional vehicles air conditioners biggest contributors heat island effect intensity difference between urban temperatures cooler temperatures rural areas electric vehicles are cooler 20% of the heat a gas vehicle emits researchers Beijing summer of 2012 calculate switching vehicles gas electricity reduce heat island intensity 1 degree Celsius saved Beijing 14.4 million kilowatt hours slashed carbon dioxide emissions 11,779 tons per day paper Hidden Benefits of Electric Vehicles for Addressing Climate Change effects aerosol pollution heat island intensity potential factor research new findings recently published journal Scientific Reports /