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Copper and Green Energy

July 1, 2024

As I wrote in a recent article (Critical Materials, April 22, 2024), the United States Department of Energy has updated its list of critically important materials.[1-2] The list of 54 materials includes elements that are presently critical to a transition to green energy, such as the rare earth elements important to turbine generators, and electric vehicle motors; and, lithium for storage batteries. Also included on the list is copper, an element historically so inexpensive and plentiful that it was used as the material for the United States penny, formally known as the cent, or one cent piece.[3]

1943 Steel Cent

1943 United States Steel Cent.

Copper was a critical material during World War II, and the United States mint used steel instead of copper for coining cents. They were low-grade steel plated with zinc for protection from rusting.

The steel cent was magnetic, and it was rejected as a "slug" by vending machines.

The Manhattan Project needed huge quantities of wire for its electromagnetic isotope separation process. Instead of using copper, the United States Department of War borrowed 14,000 tons of silver from the United States Department of the Treasury.[4]

(Wikimedia Commons image.)

There was a United States half-cent coin before 1857. After that, the cent has been the lowest face-value coin. However copper's price had increased to the point at which the material composition of a penny was changed in 1982 from being 95% copper to copper-plated zinc with just 2.5% copper. It's been more than forty years since that change, and the cost to manufacture and ship a zinc penny is now about three cents. As the figure shows, the price of copper has skyrocketed in the 21st century.

Copper relative price 1960-2023

Relative price of copper from 1960 to 2023 (1960 = 100%).

One principal lesson from economics is the law of supply and demand. Copper has increased in price from present demands of "green energy" technologies, such as electric vehicles and wind turbine generators.

(Created using Gnumeric with data from several Internet sources. Click for larger image.)

Such a high copper price is a huge incentive for copper ore extraction. but a recent report by Lawrence M. Cathles, professor emeritus of Earth and atmospheric sciences at Cornell University (Ithaca, New York), and Adam C. Simon, professor of Earth and environmental sciences at the University of Michigan (Ann Arbor, Michigan) concludes that copper can't be mined fast enough to satisfy market demand for green energy technology.[5-6]

The Chino open-pit copper mine near Silver City, New Mexico

The Chino open-pit copper mine near Silver City, New Mexico.

The area was historically known for copper mining, but the town's founding came shortly after the discovery of silver ore deposits in the area.

The copper ore is a porphyry copper deposit. Such deposits are the largest source of copper ore, and they are also a source of molybdenum

(Wikimedia Commons image by Eric Guinther. Click for larger image.)

The 2022 Inflation Reduction Act requires that all cars manufactured by 2035 will be electric vehicles.[6] An electric vehicle needs three to five times the quantity of copper of an internal combustion engine vehicle, and more copper is required for upgrades to the electrical grid to supply energy to all those vehicles.[6] Study co-author, Adam C. Simon, remarks that a standard Honda Accord needs about 40 pounds of copper, but a fully electric version of that same car needs nearly 200 pounds of copper. As for the needed upgrades to the electric grid infrastructure, an onshore wind turbine has about 10 tons of copper, and offshore wind turbines need more than twice that amount.[6] The study authors call into question the presumption that the copper needed for the green energy transition will somehow be available.[5]

To assess future copper availability, the report investigates needed copper supply and demand from 2018 to 2050 and how this could match the historical record of copper mine output.[5] More than 100 companies operate copper mines on six continents, and this mining provided an historical record of copper mining from 1900 to the present day.[6] The researchers then modeled how much copper would be needed in the United States for a complete shift to electric vehicles.[6] It was found that copper can't be mined rapidly enough to satisfy the government roadmap for green energy.[6] As Simon summarized,
"We show in the paper that the amount of copper needed is essentially impossible for mining companies to produce."[6]

required annual copper production for a transition to green energy

This graph shows the required annual copper production for three scenarios. The black line gives the trend without an energy transition. The green line shows the production needed just for electric vehicles. The red line is for a full transition to electric energy (wind and solar rather than fossil fuels) by 2050. The authors of ref. 5 argue that the red line trend is unobtainable. (Created using Gnumeric from data in ref 5.[5] Click for larger image.)

According to the study, in a business as usual model 115% more copper will need to be mined through 2050 than has been mined in all of history up to 2018 just to meet current copper needs, here and in the developing world, even without a green energy transition.[5-6] For complete electrification of the world's vehicle fleet, 55% additional mines will need to start copper production than otherwise needed.[5] That's about six new large copper mines starting production annually through 2050.[6] Electric grid upgrades would account for about 40% of the needed production from these new mines.[6] The authors state that a move to hybrid electric vehicles instead of fully electric vehicles would require negligible extra copper mining, and they recommend a focus on manufacturing hybrid vehicles.[5-6] According to Simon, the rate-limiting step to bringing new mines into production is the permitting process with an average time between discovery of a new copper mineral deposit and getting a permit to mine is about 20 years.[6]


  1. What Are Critical Materials and Critical Minerals?, Critical Minerals & Materials Program, United States Department of Energy.
  2. Diana J. Bauer, Ruby T. Nguyen, Braeton J. Smith, et al., "Critical Materials Assessment," U.S. Department of Energy, July 2023.
  3. Coin Specifications, United States Mint.
  4. Bruce Cameron Reed, "From Treasury Vault to the Manhattan Project," American Scientist, vol. 99, no. 1 (January-February, 2011), pp. 40ff., DOI: 10.1511/2011.88.40.
  5. Lawrence M. Cathles, and Adam C. Simon, "Copper Mining and Vehicle Electrification," International Energy Forum, April, 2024.
  6. Morgan Sherburne, "Copper can't be mined fast enough to electrify the US," University of Michigan Press Release, May 15, 2024.

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