Life Cycle Analysis Compares Footprint of Gas and Electric Passenger Cars


Image: david megginson, Flickr

Electric cars are the darlings of the green technology futurists. But wait, cries a receding voice, "what about the environmental impact of all those batteries?" Until recently, that lurking uncertainty shadowed the celebration of a substitute for our mobility needs. A study by EMPA, the Swiss Federal Laboratories for Materials Science and Technology, casts light on the question: when is an electric car better than a gas-powered vehicle? The EMPA team compared an electric vehicle in the VW Golf class using Li-ion baterries with a vehicle meeting the highest emissions standards in Europe (known as Euro-5), with fuel consumption of 5.2 L/100km (45.2 mpg). Their report was published in Environmental Science and Technology.

EMPA calculates that the contribution of the battery manufacture, use, and disposal contributed a mere 15% to the life cycle impact of the electric vehicle over a 150,000 km (93,000 mile) life span. Half of this is due to refining the copper and aluminum used in the batteries; the lithium contributes only 2.3 percent.

As one would expect, the lifetime fuel use of the vehicle dominates the footprint. EMPA evaluated several sources for the power used to recharge the electric vehicle, and reports the results in a user-friendly comparison to the equivalent fuel efficiency of a gas-powered vehicle. Their findings prove that electric vehicles offer a better lifetime impact than currently available combustion engine technology, but perhaps by a smaller margin than one would like to think:

  • An electric car charged with power from a coal-fired plant is roughly equivalent to a gas powered vehicle that gets 5.2L/100 km (45.2 mpg).
  • If charged on the typical mix of European power, derived from renewables and nuclear power as well as combustion platns, the gas-powered vehicle needs to achive a fuel consumption of 3-4 L/100 km (78.4 to 58.8 mpg) to compete with electric.
  • An electric car charged solely by renewable energy competes with a fuel efficiency of 2L/100 km (117.6 mpg).

So it appears that electric cars perform much better than vehicles representing the average fuel efficieny on the road. But with the so-called 3-L car already on the market, and 1-L cars on the concept board, the electric car may not be the only answer for personal mobility with lower eco-impact. However, the electric car in this comparison offers substantially more passenger and cargo capacity than a typical 3-L, much less 1-L, car can provide...a strong factor in the vehicle choice of most people.

More on Electric Cars:
Electric Cars to be Competitive with Gas Cars in About 5 Years, Says Steven Chu
Hybrid-Electric Cars: How They Work, Battery Technology and More
Here's What Happens to a Tesla Electric Car Battery at the End of its Life
More from EMPA:
Using Life Cycle Analysis to Reduce Emissions and Encourage Video Conferencing
E-Waste in India To Rise 500% by 2020
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Tags: Batteries | Electric Cars | Electric Vehicles | Life Cycle Analysis

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