Life Cycle Assessment and Techno-Economic Assessment of Lithium Recovery from Geothermal Brine

Lithium-ion batteries (LIB) play an essential role in the electrification of the transportation sector, and battery demand for lithium compounds will see a significant increase in the coming decades. This has raised concerns on the supply of lithium, and as a result, technologies are being developed to process unconventional lithium sources. One promising technology is to extract lithium from geothermal brine using lithium-aluminum-layered double hydroxide chloride (LDH) sorbent and forward osmosis. A combined life cycle assessment (LCA) and techno-economic assessment (TEA) is conducted to evaluate the environmental and economic performance of this technology. It is assumed that the lithium extraction unit is an add-on to a 50 MW geothermal power plant located in California. The analysis is based on lab-scale experimental data and stoichiometry while considering the economy of scale for an industrial system. LCA results suggest that, compared with conventional LiOH and Li2CO3 production pathways, the new technology achieves 1-95% reduction in environmental impacts. Even higher reduction can be achieved for LiOH produced via electrolysis. This add-on unit for lithium extraction could achieve a payback period of less than 1 year and reach net present values of $454M and $315M and internal rates of return of 792 and 1130% for LiOH and Li2CO3 production pathways, respectively. The favorable environmental and economic performance suggests that LDH sorption coupled with forward osmosis has great potential to enable the domestic production of battery lithium compounds and that further development should be carried out.