Coal Ash Could Yield Nearly $100 Billion in Rare Earths

A team of geoscientists led by Bridget Scanlon estimates that coal ash from US power plants may hold a large domestic supply of rare earth elements (REEs).

Using data on ash composition from 1985–2021, researchers estimate roughly 11 million tons of REEs could be present in accessible coal-ash deposits. Concentrations in ash are reported to be four to ten times higher than in the parent coal, because combustion concentrates many noncombustible minerals.

REEs — the lanthanides plus yttrium and scandium — are critical to batteries, electric vehicles, wind turbines and electronics. The US currently imports about 70% of its REE supply, much of it from China, creating strategic vulnerabilities.

Economic valuations in the study range from about $56 billion for the 15 lanthanides alone to $165 billion when yttrium and scandium are included; an estimated $97 billion might be recoverable under optimistic assumptions. These figures depend on developing scalable, cost-effective extraction methods.

Researchers say recovering REEs from coal ash could be less invasive than primary mining and could also help remediate unlined landfills and ponds. However, extraction technologies remain nascent, and commercial viability will require pilot projects, environmental safeguards, and further R&D. Alternative unconventional sources such as volcanic deposits and phytomining are also under investigation.