Tuesday, June 21, 2011

Electric Cars Not So Green After All

An Un-Green "Leaf"

The Electricity-Hogging Chevy Volt

Nissan and General Motors are touting electric cars, like the Nissan Leaf, pictured above, as "green" alternatives to traditional gasoline-powered automobiles. At the same time, the National Government is subsidizing the sale of such automobiles, providing a $7,500 tax credit to individuals who purchase such automobiles. Moreover, as previously reported on this blog, President Obama justified the money-losing bailout of General Motors in part by claiming that the government would, as the owner of GM, encourage the firm to produce "green" automobiles like the $40,000 (minimum) Chevy Volt, also pictured above.

Just last week the Australian newspaper reported on the findings of a British study that suggests that electric cars are actually less "green" than their gasoline-powered counterparts. As summarized by this story, the study found that "[a]n electric car owner would have to drive at least 129,000 km before producing a net savings of CO2" compared to a similar gasoline-power automobile. Why? Because the production and disposal of batteries employed in electric automobiles consumes significant amounts of electricity, with the result that the production of an electric automobile consumes at least 50 percent more carbon than the production of a similar gasoline-powered automobile. Thus, while electric cars emit less carbon per mile than their gasoline-powered counterparts, their lifetime carbon footprint exceeds that of gasoline-powered cars unless driven at least 129,000 km. The authors of the study also suggest that electric automobiles will rarely reach the 129,000 km mark, "because they typically have a range of less than 145km on a single charge and are unsuitable for long trips."

Taken at face value, this study, if accurate, would seem to undermine the case for encouraging the production of electric automobiles. Perhaps the Federal Trade Commission or Environmental Protection Agency will require Nissan and General Motors to disclose to consumers the actual carbon footprint of their vehicles.

Still, there are two caveats.

First, some electricity generation is carbon-free. Hence, the results of the study are presumably sensitive to assumptions about the method of generating the electricity employed to manufacture electric cars and their batteries and to charge such cars. Thus, an electric car manufactured in France, where nuclear power provides 75 percent of the nation's electricity, would have a smaller lifetime carbon footprint than an electric car manufactured in the United States, where coal provides 56 percent of the nation's electricity, and nuclear energy provides a mere 20 percent , or China, where coal provides 80 percent of the nation's electricity and nuclear power provides only 3-4 percent.

Second, it's conceivable that, over time, the energy-intensity of battery production will fall, thereby reducing the carbon footprint of electric automobiles. For instance, as the output of electric cars rises, manufacturers of batteries may be able to realize economies of scale and thus reduce production costs, including electricty consumption. This is sheer speculation, however. Indeed, the overall cost of producing an electric car could fall, without impacting the amount of electricity consumed per automobile produced.