Report: Clean tech mining is getting less extractive as efficiency improves

Clean energy technologies often receive flak because of the mining for critical minerals and other materials necessary to power them, which can come with environmental as well as social harms.

However, new research suggests that the mining toll of fossil fuels is even higher.

• The top line: In terms of how much mining is required, clean energy has a smaller material footprint than fossil fuels, according to a recent report from the Breakthrough Institute. And as material use efficiency increases, mining for materials needed for clean energy — solar, wind, storage, as well as nuclear — is expected to shrink further. 
• The market grounding: On a global scale, mining and processing capacities are growing quickly in anticipation of the needs of the renewables sector — in 2023, for instance, global lithium production grew 31.3% in 2023 compared to 2022. Accordingly, last year critical material prices largely normalized, belying pandemic-era concern that they would be an ongoing drag on the energy transition. However, prices are getting so low that certain planned-for mines in the United States are on hold because they no longer pencil out. 

Cleantech mining’s environmental footprints can be as little as half the size of that of a conventional gas plant, the report found, and up to 20 times smaller than that of a coal plant — even when accounting for the material needs of battery storage.Of the clean technologies analyzed in the study, onshore wind clocked in with the highest mining intensity.

Nuclear has the smallest extractive footprint per gigawatt-hour of electricity produced. Only 30% as much rock and metal are required for a GWh of nuclear power as for a utility-scale solar project, and 23% as much as for onshore wind. 

Indeed, the report found that compared to solar, wind, or batteries, “nuclear power plants consume just 11% to 38% the mass of critical minerals per GWh,” noting that this could help safeguard decarbonization efforts against volatile supply chains. 

(Breakthrough Institute spearheads the Build Nuclear Now coalition, and has tended to take a bullish stance on especially advanced nuclear power in the past.)

From a raw material standpoint, nuclear once again comes out on top, the report found. Per GWh, the average nuclear plant needs between 0.6-1.4 tons of materials, as compared with the 1.8 tons required by utility-scale solar. Wind projects are more materials-hungry, with offshore wind requiring two tons and onshore requiring a whopping 7.1 tons of raw materials per GWh of electricity — almost four times as much as a solar farm. 

This is projected to change, though. As solar and offshore wind technology has continued to improve, so has their material usage. Many solar and wind projects are now on track to catch up with some nuclear plants, the study found.

And, when material demand is viewed from a nameplate capacity standpoint, nuclear, onshore, and offshore wind have comparable material footprints that hover between 300,000 and 600,000 tons of infrastructure material per gigawatt. Solar is significantly lower, with just over 100,000 tons per GW required. 

The report noted that bulk materials like steel and "mundane" materials like plastic are unlikely to pose supply problems. Critical minerals, however, are another story. Copper, for instance, has a particularly large role for solar, requiring over 23 tons of rock to be mined per GWh of solar electricity produced. 

As such, the authors suggest that treating copper, nickel, and other critical minerals as key areas of impact is the most effective way to cut down mining impacts of clean energy, adding that “improved mining approaches, greater use of recycled inputs, increased technology lifetimes and efficiencies, and reductions in the quantities” of required minerals can also help decrease the footprint and cut down costs. 

The report also recommends increasing recycled raw material usage and prioritizing research and development of “unconventional resources” like direct lithium brine extraction and seafloor nodule collection, as well as relying on nuclear power as a way to avoid commodity risks or trade disruptions.

The report draws upon data from the National Renewable Energy Laboratory, the Massachusetts Institute of Technology, and the U.S. Geological Survey.