Demand for electric vehicle cable and wire is outstripping copper supply, according to a recent study conducted by the University of Michigan. The shortfall could have serious consequences for the U.S. auto industry’s ability to electrify.

“Copper cannot be mined quickly enough to keep up with current U.S. policy guidelines to transition the country’s electricity and vehicle infrastructure to renewable energy,” warns Adam Simon, Ph.D., a professor of earth and environmental sciences at the University of Michigan who conducted the study algong with Lawrence Cathles, Ph.D., professor emeritus of earth and atmospheric sciences at Cornell University.

According to Simon, current EV projections are unrealistic. He says that’s because battery-powered cars require three to five times as much copper as an internal combustion engine (ICE) vehicle—not to mention the copper required for upgrades to the electric grid.

“A normal Honda Accord needs about 40 pounds of copper,” says Simon, who specializes in how copper deposites form and how to find replacements. “The same battery electric Honda Accord needs almost 200 pounds of copper. The amount of copper needed is essentially impossible for mining companies to produce.”

The study examined 120 years of global data from copper mining companies, and calculated how much copper the U.S. fleet of cars would need to upgrade to renewable energy. It found that renewable energy’s copper needs would outstrip what copper mines can produce at the current rate.

“Mining companies will not provide the amount of copper necessary to achieve vehicle electrification goals,” warns Simon.

The shortfall is in part because of the permitting process for mining companies. The average time between discovering a new copper mineral deposit and getting a permit to build a mine is about 20 years.

“Mining companies have to fully characterize the local environment and ecosystem around any proposed mine,” says Simon. “They have to describe how mning activities could potentially impact the local ecosystem and have mitigation strategies in place in case something goes wrong. And, in the U.S., the National Enivironmental Policy Act allows any person to sue to prevent a mining operation from starting.”

Copper is mined by more than 100 companies operating mines on six continents. Cathles and Simon examined data for global copper production back to the year 1900, which told them the global amount of copper mining companies had produced over 120 years. They then modeled how much copper mining companies are likely to produce for the rest of this century.

Between now and 2050, the world will need to mine 115 percent more copper than has been mined in all of human history up until 2018 just to meet “business as usual,” claims Simon. “This would meet our current copper needs and support the developing world without considering the green energy transition.’

To meet the copper needs of electrifying the global vehicle fleet, Simon says as many as six new large copper mines must be brought online annually over the next several decades. About 40 percent of the production from new mines will be required for electric vehicle-related grid upgrades.

To address this future shortfall, Simon believes the auto industry should focus it attention on producing hybrid vehicles.

“The amount of copper required for EVs is significantly greater than hybrids,” notes Simon. “The average ICE vehicle contains an average of 53 pounds of copper vs. 64 pounds for a hybrid vehicle and 132 pounds for an EV.

“A global fleet of hybrid vehicles woulds require mining 275 million tons of copper from now to 2050 vs. 404 million tons for EVs,” explains Simon.

“Policymakers should consider copper as the limiting factor for the energy transition, and think about how copper is allocated,” Simon points out. “We know, for example, that a Toyota Prius actually has a slightly better impact on climate than a Tesla. Instead of producing 20 million electric vehicles in the United States and globally, 100 million battery electric vehicles each year, [it might be] more feasible to focus on building 20 million hybrid vehicles.

“We think our study highlights that significant progress can be made to reduce emissions in the United States,” says Simon. “However, the current—almost singular—emphasis on downstream manufacture of renewable energy technologies cannot be met by upstream mine production of copper and other metals without a complete mindset change about mining among environmental groups and policymakers.”