Enrique Dans
Published in

Enrique Dans

IMAGE: Ryan Mirjanic (CC BY SA)

Myths and shibboleths about electric vehicles: the long tailpipe theory

One of the most frequent comments spouted by critics of electric vehicles is, “the electricity they use is produced by fossil fuels, so actually they’re more polluting than petrol or diesel vehicles.” The long tailpipe theory, repeatedly rubbished by science, is still the fallback argument for the ill-informed.

Where does it come from? The two main sources of air pollution are vehicles with diesel or gasoline engines and electricity generated by coal or diesel oil. Since many countries still generate electricity in this way, the argument goes that electric vehicles are simply transferring the pollution from our exhaust pipe to the chimney of a power station.

Is that true? No. The first reason is obvious: not all electricity is produced by coal and diesel power plants. More and more countries are using sustainable generation such as hydroelectric, wind, solar or other renewables, while at the same time, we are seeing an increase in distributed generation infrastructures such as solar panels in homes. Therefore, even if all we were doing was transferring pollution from one point to another, in the vast majority of countries a certain part of that electricity would come from clean sources. In fossil fuel vehicles, this is not the case: everything it produces comes from where it comes from, and anybody with a minimum of environmental awareness should be ashamed every time they get behind the wheel.

A recent study of electric buses, but applicable to any type of vehicle, shows that electric vehicles are less contaminating than their internal combustion equivalents, regardless of the source of the electricity, and even in places where most power plants are coal fired. The reason is as simple as it is obvious: energy produced in a power plant is much more efficient than in the small engine of a vehicle, no matter how much technology has improved the efficiency of these vehicles. The average coal, diesel or natural gas power plant is 60% efficient, which implies that 40% of the energy obtained from the fuel used is lost in the process of producing electricity. An internal combustion engine is at best 25%, efficient, with most energy simply lost as heat. In a large power plant, the possibilities of reusing that heat are obviously much greater than in the small engine of a vehicle. When measuring so-called well-to-wheel emissions, in the case of the United States, the efficiency of electric vehicles is consistently well above that obtained even by the best and most modern internal combustion vehicles, regardless of how the electricity is obtained.

In short, the long exhaust pipe theory is a myth used by those who, for whatever reason, oppose change. It joins other myths, such as the supposed difficulties involved in recycling batteries or generating the electricity required to recharge electric vehicles. Little wonder that those in the oil and car industries, who have a vested interest in maintaining the status quo trot out these shibboleths, but there is no excuse for anybody else. Instead, let’s get the full facts and bear them in mind when deciding our transport options.

This article was previously published on Forbes.

(En español, aquí)



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