With the rising demand for electric vehicles (EVs), there is a parallel surge in the need for essential resources like nickel. Traditional mining methods, notorious for their environmental toll driven by carbon-intensive operations, have prompted innovative alternatives to meet this demand sustainably.
A tonne of nickel, crucial for clean-energy EV batteries, can come with a heavy environmental cost: up to 59 tonnes of carbon dioxide emissions from mining and processing alone. In response, emerging enterprises are exploring phytomining as a greener approach. This method harnesses plants capable of extracting and concentrating metals, including nickel, from soils where traditional mining would be impractical or economically unfeasible due to low metal concentrations.
The process involves cultivating specific plant species that absorb nickel from the soil during growth. Once matured, these plants are harvested, dried, and incinerated to extract the metal from the resulting ash. This technique has also been successfully adapted using microorganisms and other plant species to remediate contaminated soils.
Startups such as Metalplant and Econik have embraced phytomining on a significant scale, utilizing hundreds of hectares to sustainably source nickel. Viridian, another innovative firm, has patented technology boasting plants engineered to hyperaccumulate nickel from soil, potentially revolutionizing the industry.
For instance, Odontarrhena decipiens, a notable nickel accumulator, can concentrate up to 2 percent of its biomass with the metal. According to estimates from Viridian, a 1,000-hectare phytomining farm could yield between 250 to 550 metric tons of nickel, valued at US$3 to 7 million.
Moreover, Metalplant has integrated enhanced rock weathering into its operations, utilizing olivine dust to absorb CO2 from the atmosphere. As the rock dust dissolves over time, it forms bicarbonate and simultaneously captures carbon dioxide. This innovative approach not only promises to sequester carbon but also enhances soil fertility while potentially yielding up to 400 kg of nickel per hectare.
The convergence of phytomining and enhanced rock weathering represents a promising step towards sustainable resource extraction for EV batteries. These advancements not only mitigate the environmental impact associated with traditional mining but also offer a pathway to carbon-negative nickel sourcing. Such innovations are pivotal as the automotive industry strives to offset the environmental footprint of EV production, ensuring cleaner and more sustainable mobility solutions for the future.
