Aug. 22, 2020

The other side of the electric-vehicle debate

A lithium EV battery weighs about 1,000 pounds. While there are dozens of variations, such a battery typically contains about 25 pounds of lithium, 30 pounds of cobalt, 60 pounds of nickel, 110 pounds of graphite, 90 pounds of copper, about 400 pounds of steel, aluminum, and various plastic components. 

Looking upstream at the ore grades, one can estimate the typical quantity of rock that must be extracted from the earth and processed to yield the pure minerals needed to fabricate that single battery:

  • Lithium brines typically contain less than 0.1% lithium, so that entails some 25,000 pounds of brines to get the 25 pounds of pure lithium.
  •  Cobalt ore grades average about 0.1%, thus nearly 30,000 pounds of ore.
  •  Nickel ore grades average about 1%, thus about 6,000 pounds of ore. 
  •  Graphite ore is typically 10%, thus about 1,000 pounds per battery.
  •  Copper at about 0.6% in the ore, thus about 25,000 pounds of ore per battery.
  • In total then, acquiring just these five elements to produce the 1,000-pound EV battery requires mining about 90,000 pounds of ore. To properly account for all of the earth moved though –which is relevant to the overall environmental footprint, and mining machinery energy use – one needs to estimate the overburden, or the materials first dug up to get to the ore. Depending on ore type and location, overburden ranges from about 3 to 20 tons of earth removed to access each ton of ore.

This means that accessing about 90,000 pounds of ore requires digging and moving between 200,000 and more than 1,500,000 pounds of earth – a rough average of more than 500,000 pounds per battery. The precise number will vary for different battery chemistry formulations, and because different regions have widely variable ore grades. 

It bears noting that this total material footprint does not include the large quantities of materials and chemicals used to process and refine all the various ores. Nor have we counted other materials used when compared with a conventional car, such as replacing steel with aluminum to offset the weight penalty of the battery, or the supply chain for rare earth elements used in electric motors (e.g., neodymium, dysprosium). Also excluded from this tally: the related, but non-battery, electrical systems in an EV use some 300% more overall copper used compared with a conventional automobile.

And a lot of the cobalt mining is slave labour in the Republic of the Congo with poor to non existent environmental conditions. 

And that’s a little part of the other side of the story.