How Clean Are EVs?

Because electric vehicles have no tailpipe emissions, they are often marketed as "clean" cars.  EVs certainly are cleaner than traditional gasoline-powered cars during operation, but how "clean" are they really?  To be accurate, we need to look at the vehicle through the life cycle assessment, covering everything from material extraction, manufacturing, packaging, transportation, use, and end of life.

All vehicle manufacturing takes an incredible toll on the environment and releases tons of greenhouse gas emissions every year.  When it comes to manufacturing alone, EVs are actually worse for the planet than a conventional car.  When a new EV appears in the showroom, it has already caused 30,000 pounds of carbon-dioxide emission.  The equivalent amount for manufacturing an internal combustion engine car is 14,000 pounds.

In addition to the carbon emissions from the manufacturing process, raw materials needed to make EV lithium-ion batteries (cobalt, lithium, graphite, and nickel) require fossil fuels to mine and to heat them to high temperatures.  Extracting the metals from their ores requires a process called smelting, which can emit sulfur oxide and other chemicals that are harmful to air pollution. 

Acquiring cobalt is a problematic process.  As much as 70% of the world's cobalt supply is mined in the Democratic Republic of Congo.  A substantial portion of this mining is done in unregulated "artisanal" mines where workers, including many children, dig the metal from the earth using only hand tools.  Many of the cobalt mining operations have been linked to human rights violations.  When mining cobalt, hazardous tailings and slags are produced that can leach into the surrounding environment.  Studies have found high exposure of these waste materials in nearby communities.  

The world's lithium is mined either in Australia or from salt flats in the Andean regions of Argentina, Bolivia, and Chile.  These operations use large amounts of groundwater to pump out the brines, which draws down the water available to indigenous farmers and herders.  This production process makes manufacturing EVs about 50% more water intensive than traditional gasoline-powered cars.

It is also important to consider the source of electricity used to charge EV batteries.  If the electricity used to charge an EV comes from renewable sources like wind or solar, then the vehicle can be considered clean in terms of emissions.  However, if the electricity comes from fossil fuels like coal or natural gas, then the emissions associated with generating that electricity must be taken into account.  Electric grids still need to get much, much cleaner before electric vehicles are truly emissions free.  "Coal tends to be the critical factor," said Jeremy Michalek, a professor of engineering at Carnegie Mellon University. "If you've got electric cars - that are being plugged in at night and leading nearby coal plants to burn more coal to charge them, then the climate benefits won't be as great, and you can even get more air pollution."

While 99% of lead-acid batteries are recycled in the United Stations, estimated recycling rates for lithium-ion batteries are about 5%.  "The percentage of lithium batteries being recycled is very low, but with time and innovation, that's going to increase," said Radenka Maric, a professor at the University of Connecticut's Department of Chemical and Biomolecular Engineering.  Experts point out that spent batteries contain valuable metals and other materials that can be recovered and reused. Depending on the process used, battery recycling can also use large amounts of water or emit air pollutants.  Recently, researchers from MIT found that, if done properly, used car batteries could be used for a decade or more as backup storage for solar power.  Various automakers, including Nissan and BMW, have piloted the use of old electric vehicle batteries for grid storage. 

An International Council on Clean Transportation (ICCT) study says that the gap between EVs and gas cars will only get larger because EVs fuel from the grid and the electricity supply is rapidly "greening" with the addition of more solar and wind power every year.  There is no way to completely eliminate carbon emissions from personal vehicle use, not even with fully electric vehicles.  But when it comes to protecting our planet, we don't need to be perfect; we need to be better.