The inconsistency of some renewable energy sources, such as solar and wind, presents a significant challenge to their universal adoption. Strategies to efficiently store the electricity generated when sources are abundant are thus necessary. Currently, lithium-ion batteries are a common storage technology. They power electric vehicles and can be used in conjunction with solar panels to ensure electricity availability, day or night. Most lithium is mined outside the United States. To ensure a consistent supply chain and support U.S. clean energy goals, additional domestic mining is being pursued. This is controversial; despite the economic and supply chain benefits, mining can generate significant pollution (mining operations are generally powered by fossil fuels and generate waste), is water-intensive, and can disrupt existing ecosystems and valued lands.
Biomining has been used in the extraction of copper, gold, and other metals,1Schippers, A., Hedrich, S., Vasters, J., Drobe, M., Sand, W., & Willscher, S. (2014). Biomining: Metal recovery from ores with microorganisms. Advances in Biochemical Engineering/Biotechnology, 141, 1–47. View Publication. but there has been limited research toward biomining lithium. Bioleaching lithium from lithium ion secondary batteries by Acidithiobacillus ferrooxidans has been demonstrated, though recovery was low.2Mishra, D., Kim, D.-J., Ralph, D. E., Ahn, J.-G., & Rhee, Y.-H. (2008). Bioleaching of metals from spent lithium ion secondary batteries using Acidithiobacillus ferrooxidans. Waste Management, 28(2), 333–338. View Publication. Microbes could potentially be engineered to more efficiently extract lithium from open pits, brines, and/or from recycled materials, thereby reducing the use of land, water, and energy. For example, a common mechanism of lithium mining is to inject water underground, where lithium and other salts are dissolved, then pump it back to the surface into lithium brine ponds and wait months to years for the water to evaporate, leaving the lithium behind. Using engineered microbes to recover the lithium from the brine could decrease land use and water lost from these typically arid environments.
Nontechnical considerations and social dimensions
- Ethical / societal – Could efforts be better spent focused on alternatives to lithium mining, such as alternative battery systems (e.g., microbial fuel cell technologies)?
- Economic – Can lithium mining microbes be produced cost effectively at large enough scale for use?
Benefits and consequences:
- Ethical / societal – Is there an environmental benefit to biomining as compared to traditional lithium mining? Is there an environmental harm? How can different perspectives on this be heard and taken into account?
- Ethical / societal, Economic – What are the benefits and consequences of biomining lithium in different environments/from different sources (i.e., brines, spent lithium batteries, ore)?
- Economic – Would this enable platform development for biomining other metals, e.g., rare-earth metals?
- Policy / regulatory – How would this interact with the existing federal land leasing or other forms of mineral acquisition rights?
- Ethical / societal – How does biomining lithium impact miners and local communities in terms of, for example, health, economic opportunity, environmental integrity, and changes to tourism and outdoor recreation?
- Security – Could engineered microbes for lithium mining be used intentionally or accidentally to destroy lithium batteries?
- Policy / regulatory – Could this technology make illegal lithium mining in protected environments easier?
Competing values and priorities:
- Ethical / societal – Lithium batteries enable the storage of renewable electricity, but lithium mining disrupts land and ecosystems (although there are efforts to minimize impacts and rehabilitate land). How can the disruption to an area of land and the micro- and macro-organisms that inhabit it be weighed against enabling a more consistent renewable energy supply?
- Whose voices are heard and most valued? How might those voices weigh the value of the land compared to the value of mining lithium?
- Can any benefits be disproportionately directed toward the people and lands that are disrupted?
- Schippers, A., Hedrich, S., Vasters, J., Drobe, M., Sand, W., & Willscher, S. (2014). Biomining: Metal recovery from ores with microorganisms. Advances in Biochemical Engineering/Biotechnology, 141, 1–47. https://doi.org/10.1007/10_2013_216
- Mishra, D., Kim, D.-J., Ralph, D. E., Ahn, J.-G., & Rhee, Y.-H. (2008). Bioleaching of metals from spent lithium ion secondary batteries using Acidithiobacillus ferrooxidans. Waste Management, 28(2), 333–338. https://doi.org/10.1016/j.wasman.2007.01.010