MIT Ends the EV Versus ICE Sustainability Argument

­Anyone who has a Facebook account has likely come across at least one post that describes how electric vehicles are unsustainable, usually followed by a bullet list of points that are supposed to prove the argument. It has previously been difficult to find actual data to either support or counter this claim. Most research has been limited to single factors and not the overall level of sustainability. However, recent research form MIT has done just that, and it is unsurprising to find out that EVs are considerably greener than ICE powered vehicles in all scenarios.

The researchers used data from every US zip code and analysed many factors that could affect emissions or costs. These include typical drive cycles, the amount of traffic, local gas and electricity prices, makeup of the regional electricity mix, meteorological profiles, and more. In every case, the EV proved more environmentally friendly over the entire lifetime, even though it was ‘dirtier’ to originally produce. The findings held out, even in areas where the energy mix came mainly from coal, and in colder regions. 

“There are a lot of statements being thrown around, like that electric vehicles don’t reduce emissions very much in cool climates, and we wanted to analyze these factors systematically and evaluate these statements against one another simultaneously. Rather than simply asking, ‘Are EVs better?’, this paper helps answer ‘better for whom, and under what conditions?’. If someone wants to buy a car and have a better understanding of the factors that affect emissions and costs, this holistic approach is important,” explained Marco Miotti PhD ’20, a senior researcher at ETH Zurich who completed this research while a graduate student in the Institute for Data, Systems, and Society (IDSS) at MIT.

The researchers used statistical approaches to amalgamate different types of data and then designed their analysis to focus on the spatial picture of emissions and costs, based on U.S. zip codes, while simultaneously considering the impact of the size and features of each specific vehicle model.

The areas that EVs proved most sustainable had a cleaner electricity mix, denser traffic, higher annual travel distances, and a mild climate, in decreasing order of importance. In each area, emission reductions increase for drivers who drive more often, drive larger vehicles, and are more frequently stuck in traffic. In a colder area like North Dakota, fuel economy of battery-electric vehicles might be reduced by as much as 50 percent on a particularly frigid night, but the effect on annual emission benefits was minimal.

On the cost side, the models show that, in most places across the US, EVs are competitive with comparable combustion-engine vehicles in terms of lifetime ownership cost, even without clean vehicle tax credits. And in areas where electricity is relatively affordable, battery-electric vehicles tend to cost less than their plug-in hybrid or combustion-engine counterparts.