These Materials Are Making EVs Three Times As Wasteful As Gas Cars
Many companies are racing to become carbon neutral. With their near-zero operational emissions, electric vehicles promise a cleaner, quieter future than their gasoline-guzzling predecessors. Nations, led by giants like China (the world's largest producer and consumer of electric vehicles), are pouring investment into this 'e-mobility transition.
Researchers at the College of Urban and Environmental Sciences, Peking University developed a global mine-site-specific database and a supply-chain-based framework to quantify the total material requirement (TMR) of passenger car supply chain. They were looking for hidden flows in the critical minerals used in electric vehicles. These are the materials dug up during mining that don't make it into the final product—the overburden, waste rock, and tailings—and they are far exceeding the useful materials.
They found that an new electric vehicle generates over three times the hidden flows of a conventional vehicle. These hidden flows exceed the eventual used resources by 35 times, with only 3% of the extracted materials entering the car sector. Notably, 48% of these hidden flows occur outside manufacturing countries, highlighting the global environmental burden of China’s e-mobility transition.
What Exactly Are "Hidden Flows"?
When we talk about an electric car, we usually focus on the valuable, critical minerals inside: lithium, cobalt, nickel, and copper. These are the "useful resources" that power the batteries and motors, but we know that there are many problems with these minerals leading to increased crime and limited attention to human rights in financing.
"Hidden flows," on the other hand, are the colossal volumes of unused material that must be removed just to reach those valuable resources. They are the dirt, rock, and residue—literally the waste—generated by mining. They are tracked using an indicator called the Total Material Requirement (TMR), which accounts for everything extracted from the Earth to create a product, both the useful part and the associated waste.
Historically, these hidden flows have been vastly overlooked compared to the critical battery materials, yet their environmental impact is staggering and global.
Massive Land Disruption: Waste rock and tailings already cover an area of the Earth's surface roughly equal to one million square kilometers.
Toxic Exposure: This waste has exposed an estimated 23.48 million people and 5.72 million livestock to toxic pollutants.
Climate & Deforestation: Soil removal, a key hidden flow, has released at least 50 gigatons (Gt) of carbon since the industrial revolution, an amount comparable to all global greenhouse-gas emissions in 2022. Furthermore, mining has driven 46.5% of tropical forest loss between 2000 and 2019, leading to a massive loss of carbon sequestration.
The problem is compounded by a simple geological reality: declining ore grades. The easier-to-reach, high-concentration ores have already been mined. To extract the same amount of a mineral today, miners must dig up more rock, resulting in more waste and higher energy consumption. As the world demands more minerals for the e-mobility transition, the volume of hidden flows is projected to rise dramatically.
NEVs vs. Conventional Cars
The study's most immediate and shocking finding is the direct comparison between a standard Internal Combustion Engine Vehicle (ICEV) and a New Energy Vehicle (NEV).
An NEV generates over three times the hidden flows of a conventional vehicle.
To put this into context, consider the average material extraction required for one vehicle unit:
A conventional vehicle requires about 48 tonnes (t) of material from the lithosphere.
A Battery Electric Vehicle with a high-capacity NMC111 battery requires nearly 159 tonnes (t) of material from the lithosphere—a massive increase.
While an electric vehicle's direct material inputs (the parts that end up in the car) are only slightly higher (93-104% of a gas vehicle), the associated mining waste—the hidden flows—skyrockets.
The culprits are the critical minerals needed for batteries and fuel cells: Lithium (Li), Cobalt (Co), Nickel (Ni), and Platinum (Pt). These minerals are used in relatively small quantities—they make up only 0.4% to 9.5% of the direct material flows in an electric vehicle. However, extracting them is incredibly resource-intensive, meaning they account for a huge chunk of the waste, contributing 6% to 41% of the hidden flows per vehicle.
This is due to abysmal material efficiency in their mining:
Platinum (Pt): Exhibits the lowest average material efficiency in the passenger car sector at only 0.0002%. This means for every million tonnes of earth dug up, only two tonnes of Pt makes it into a final product.
Cobalt (Co): Material efficiency is around 0.1%.
Copper (Cu): Material efficiency is around 0.2%.
The high demand for these materials, coupled with low ore grades (e.g., Pt ore grades range from a minuscule 0.0001% to 0.0007%), forces miners to dig up enormous amounts of waste material. In fact, batteries alone account for 26-28% of the Total Material Requirement for an electric vehicle.
A Focus On China’s EV Supply Chain
By using China's supply chain—the world's most critical—as its focus, the study was able to map the global reach of these invisible environmental impacts.
In 2019, the entire Chinese passenger car production system triggered the extraction of a staggering 1,163 Million tonnes (Mt) of materials from the Earth. But, only 3% of all extracted materials entered China's car sector.
So, out of 1,163 Mt extracted, 1,106 Mt were hidden flows, resulting in the astonishing statistic that hidden flows exceeded the eventual useful resources by a factor of 35 times. The material efficiency of the industry is a meager 3%.
The environmental damage isn't confined to China, the manufacturing country, either. It is exported to the nations that supply the raw minerals. This is because 48% of these hidden flows occur outside China. The environmental burden is shouldered by resource-supplying countries like:
Chile (10% of the TMR).
Australia (7% of the TMR).
Peru (6% of the TMR).
South Africa (5% of the TMR).
China heavily relies on imports—iron (Fe) from Australia, copper (Cu) from Chile and Peru, and platinum (Pt) from South Africa40. The high TMR coefficients of Cu and Pt, in particular, contribute to remarkable hidden flows beyond China’s borders, highlighting an unequal distribution of the environmental burden of e-mobility.
Hidden Polluters
Which materials and processes drive this massive waste stream?
Copper (Cu): Copper production is the single largest contributor to the overall TMR, driving 37% of the sector's total hidden flows. Despite only accounting for 2% of direct material inputs in a passenger car, its high TMR coefficient means mining Cu generates disproportionately huge amounts of waste.
Iron (Fe) and Aluminum (Al): Followed by Cu, Iron accounted for 28% of the TMR, and Aluminum accounted for 16%.
Coal & Energy: The refining and smelting process is highly energy-intensive. When this process relies on coal power, the coal extraction itself generates its own massive hidden flows. Domestic TMR in China was driven primarily by coal production (49%) for energy generation.
Overall, two processes—beneficiation (removing waste from raw ore to make a concentrate, accounting for 36% of total mining waste) and smelting and refining (the energy-intensive process, accounting for 34% of total mining waste)—generate the bulk of the waste streams.
The study estimates that the extraction of 1,163 Mt of materials for China's car production in 2019 could have released approximately 53 Mt of carbon dioxide from soil carbon oxidation alone. These previously unreported emissions are comparable to the total annual emissions of an upper-middle-income country like Peru. The electric car's invisible footprint is not just a waste problem; it's a significant climate contributor, before the car even hits the road.
Battery Type Matters
Not all EVs are created equal when it comes to material burden. The type of battery used makes a significant difference in the magnitude of hidden flows.
The researchers found that NMC-series (Lithium Nickel Manganese Cobalt Oxide) and NCA (Lithium Nickel Cobalt Aluminum Oxide) batteries generate 40% to 101% more hidden flows than LFP (Lithium Iron Phosphate) batteries.
This difference is critical for policymakers and manufacturers. An NMC-series battery relies heavily on nickel and cobalt, minerals with notoriously low material efficiencies. LFP, on the other hand, relies on more abundant and less waste-intensive materials like iron. This high-resolution difference provides a tangible path for immediate mitigation.
Potential Solutions
The good news is that by quantifying and mapping the hidden flows, the study offers clear, targeted strategies for mitigating the environmental impact and improving material efficiency. The transition can still be green, but it requires addressing the problem at its source: the mine and the factory.
Massive Scale-up of Recycling (Targeting Copper): Since Copper is the single largest contributor to hidden flows (37%), focusing on it yields the greatest benefit. Replacing primary (newly mined) copper with secondary (recycled) copper could reduce the total hidden flows from China’s car production by a substantial 35%.
Intelligent Battery Substitution: A shift towards battery types with lower material requirements is an immediate solution. By replacing NMC/NCA batteries with LFP batteries, hidden flows could be reduced by an estimated 12% by 2050 as the e-mobility transition accelerates.
Decarbonizing Energy-Intensive Processes: The energy used for smelting and refining—processes that contribute over one-third of total hidden flows—must be cleaned up. Transitioning these energy-intensive steps to clean energy sources could reduce hidden flows by 13-14%.
Responsible Global Sourcing: Resource-supplying nations should prioritize data transparency and shift production away from "high-TMR mines" toward low-TMR, high-reserve mines. Furthermore, manufacturers in countries like China should consider sourcing minerals from countries with naturally higher material efficiencies (e.g., bauxite extracted in Indonesia has a TMR coefficient that is only 20% of that for Chinese bauxite). This, however, must be balanced with geopolitical and resource security concerns.
