The Grade 7 class at the American School of Barcelona is studying alternative energies as part of their most recent social studies unit. When I was asked to talk to them about life cycles and LCA, I foolishly thought that what I said would be all news to them. Their teacher told me that during previous discussions about electric cars one inquisitive young student asked if they were really much better than gasoline cars given the energy needed to create the battery. I was impressed by her innate life cycle thinking, and immediately set-off to answer her doubts. So after only a quick search on the Web I came across a short review of an LCA from Seikei University, Tokyo written by the Institute for Life Cycle Environmental Assessment. The study compares the CO2 emissions from the manufacture and use phases of petroleum, electric and hybrid cars. The petroleum car uses less CO2 during manufacture, followed by the hybrid and then the electric, most likely due to the production of the electric battery. Check out the graph above of the results.

Total carbon dioxide emissions over the lifetimes of gasoline, hybrid, and electric cars. The electric car is shown three times, with differing use energies depending on the method of generating electricity: coal, liquefied natural gas, or hydroelectric.

The electric car is shown three times with different electricity generation options – coal, liquefied natural gas (common in Japan and similar to natural gas in the U.S.) and hydroelectric power. You can see that the electric car comes out on top when natural gas and hydroelectric power are the electricity sources, but is almost the same as a regular gas powered car if the electricity comes from coal. As they say, certainly the most important lesson learned from this LCA is the importance of the source of electricity used for an electric car. If you want to make an impact on CO2 emissions with your next car purchase, you need to know how the electricity in your region is generated before making your choice. Read more about electric car efficiency here.