Clean energy supports a sustainable lifestyle because it is produced from renewable sources like the sun and the wind. However, that energy is not entirely clean due to its reliance on critical minerals.

According to the U.S. Geological Survey, “critical minerals” are vital to American economic or national security and possess a vulnerable supply chain. A subset of critical minerals are “rare earth elements,” which share chemical properties and are intermixed within mineral deposits. Rare earth elements exist in most massive rock formations, but their typically low concentrations make them “rare.”

Possessing a striking range of applications in modern technology, critical minerals enable green energy. For example, lithium is a key component of rechargeable batteries for electric cars and solar panels while gallium is used in LEDs. Alloys made with neodymium and
samarium make super strong magnets for wind turbines, and thin-film solar cells incorporate dysprosium and cerium.

Unfortunately, critical minerals are normally produced by mining. Extracting and refining raw minerals usually require much energy, emit significant amounts of greenhouse gases, degrade the land, pollute and deplete water supplies, cause biodiversity loss, and leave behind hazardous tailings. Because rare earth elements in particular occur together in nature, they must be separated; often this is done through an energy-intensive process called solvent extraction, which can involve toxic acids.

Recycling from e-waste and tailings can mitigate the potential environmental harm of critical minerals. Recycling rates are rising, but in general — and particularly for rare earth elements — the infrastructure of this nascent industry is underdeveloped, collection is inefficient and costly, and the recycling process itself can be resource-intensive and dirty.

Technological progress provides another way forward. Battery production can become cleaner with electrodialysis and other new, direct lithium extraction processes, and it has been shown that the magnets needed for wind turbines and electric vehicles can be made with fewer rare earth elements. Finally, we can improve older, noncritical minerals technologies, such as generators and motors based on electromagnetic induction rather than magnets.

We should celebrate the growing demand for renewable energy worldwide but fear the consequent environmental risks of increased mining of critical minerals. Since turning away from clean energy is not an option, let’s make it cleaner.

David Conwell belongs to the nationwide advocacy organization Citizens’ Climate Lobby and is a former member of the Brunswick Sustainability Committee.