Navigant Research Blog

Criticism of EV Battery Environmental Impacts Misses the Point

Ryan Citron — April 2, 2014

The environmental impact of electric vehicles (EVs) remains the subject of debate, with Tesla Motors becoming the latest scapegoat for allegedly contributing to acid rain in China.  Bloomberg News points out that EV batteries require the use of graphite, which is mostly mined and processed in China.  Graphite mining pollutes the air and water and harms agricultural crops.  The average electric car contains about 110 lbs of graphite, and Tesla’s proposed Gigafactory is expected to single-handedly double the demand for graphite in batteries.

While these are valid concerns, they ignore a few larger facts: the oil industry has far greater overall environmental impact; the production of electricity is much cleaner than refining and burning gasoline; and recycling and reuse techniques are revolutionizing the battery industry.  Tesla, meanwhile, has responded to the graphite concerns. The recent 25th anniversary of the Exxon Valdez Oil Spill reminds us of one of the worst environmental disasters in U.S. history, in which 10.8 million gallons of crude oil was spilled into Prince William Sound, off the coast of Alaska.  Ironically, the congested Houston Ship Channel (one of the world’s busiest waterways) was partially closed over the Valdez anniversary because of a weekend oil spill of nearly 170,000 gallons of tar-like crude.

Compared to Gas

Overall, the equivalent lifecycle environmental impact of electricity is much less harmful than gasoline – assuming it isn’t entirely generated by coal.  According to the U.S. Environmental Protection Agency (EPA), a gallon of gasoline produces 8,887 grams (g) of carbon dioxide (CO2) when burned in a vehicle.  An equivalent 10 kilowatt-hours (kWh) of electricity emits about 9,750g of CO2 when generated in a coal-fired power plant, 6,000g when generated in a natural gas plant, 900g from a hydroelectric plant, 550g from solar, and 150g each from wind and nuclear.  These figures include the entire lifecycle analysis, including mining, construction, transportation, and the burning of fuel.  Since 63% of the 2012 electricity mix in the United States was derived from non-coal energy sources, it has been estimated that EVs emit about half the amount of carbon pollution per mile as the average conventional vehicle.

At the same time, innovative recycling and reuse techniques are significantly increasing the sustainability of EV batteries.  In the United States and Europe, all automotive batteries are required by law to be recycled.  This has made the lead-acid battery industry one of the most sustainable industries in the world, with nearly 99% recycling rates of all the batteries’ components.  Additionally, the world’s first large-scale power storage system made from reused EV batteries was recently completed in Japan.

Second Lives for Batteries

While these approaches do not fully solve the problems associated with graphite mining, the environmental impact created by the manufacturing, transportation, and disposal of batteries is significantly lowered for each additional cycle a battery supplies.  If battery lifetimes can be doubled, the negative environmental impact is cut in half.  Navigant Research’s report, Second-Life Batteries: From PEVs to Stationary Applications, also points out that a global second-life battery market will create new businesses and jobs in addition to improving sustainability.  The global second-life battery business is expected to be worth near $100 million by 2020.

Even with the negative externalities associated with graphite production, EVs still offer an improved overall environmental picture than traditional internal combustion engine (ICE) vehicles.  And Tesla, perhaps in response to pollution criticisms, has announced that it will source the raw materials for the proposed Gigafactory exclusively from North American supply chains. Producing graphite in North America is a much cleaner process than in China.

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