Electric Cars Only as Green as the Electricity Powering Them, Another Study Says

Maarten Takens/CC BY-ND 2.0

A new report on electric cars' environmental impact from the Norwegian University of Science and Technology, highlighted by BBC News, reiterates much of what's been long said:

  1. If you power electric cars with dirty electricity the environmental benefits over internal combustion vehicles drops considerably.
  2. The longer you keep an electric vehicle, a function of battery life and the cost to replace old batteries, the greater the environmental benefits over gasoline or diesel vehicles.

That noted, the new report does offer some interesting latest stats on the life-cycle environmental impact of electric cars versus diesel and gasoline-powered cars that are worth committing to memory.

  • In terms of production, the report found, electric vehicles actually are about twice as harmful as internal combustion vehicles, due to the materials used in batteries and electric motors.
  • As far as greenhouse gas emissions when in use, based on the current European electricity mix (which actually varies widely depending on the country, but probably not much more than the differences between that in various US states), electric vehicles offer only a 10-24% reduction compared to gasoline or diesel vehicles.Perhaps obviously, if you're charging your car with electricity produced entirely from coal or fracked shale gas, both of which have much higher emissions than other fossil fuels, the resultant emissions of the car are higher—even if nothing is directly being emitted when motoring. Conversely, if your electricity is entirely from wind power, for example, you've eliminated the emissions from use nearly entirely.In areas where coal dominates, the authors note that it's actually counterproductive to promote electric car use.
  • Regarding the increasing benefits of keeping an electric car a while: With a 200,000km (124,000 miles) lifetime, electric vehicles have a climate change benefit of 27-29% compared with gasoline vehicles, and 17-20% compared to diesel. If an electric vehicle only lasts half that range though the benefit is much less: A 9-14% improvement over gasoline-powered vehicles and no real benefit at all over diesel.

While all of this certainly pours a bit of cold water on the touted benefits of electric vehicles—unless you're powering your electric car with renewable energy, you're probably not treading as lighting on the planet as you think you are—at the same time, for me, it all really highlights the interconnectedness of various green efforts and the need for green changes across the full spectrum of modern life.

You can't just change what cars use for power; you have to also change how that power is generated, as well as improving manufacturing processes to reduce impact.

The takeaway shouldn't be, as the BBC headline attempts to convey, that electric cars pose an environmental risk. Rather, under current circumstances, the benefits don't fully live up to the potential benefits if the electricity mix was all renewables (or more renewables even), the direction we have to be moving. The two parts, changing vehicles and changing electricity mix, have to change together—changing only one won't work.

Worth noting, analysis earlier this year on the benefits of electric vehicles in the US came down on the side of electric cars being a good choice everywhere in the nation.

Tags: Coal | Electric Cars | Electricity

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