Flower farm could supply nickel for electric vehicle batteries

The increasing demand for metals such as nickel for use in batteries has led to the development of new more sustainable methods for extracting resources that do not involve mining, says Interesting Engineering.

This new method essentially uses farming in order to address an industrial need that traditionally involved destructive methods.

Since the Industrial Age, humanity has known only one way of meeting the demand for more metals—mining. The trend has followed until today, and even as the world is looking to adopt electric vehicles to reduce emissions, mining of lithium, nickel, and cobalt is at an all-time high to meet the production demand. 

Mining is energy-intensive and powered by carbon-emitting fossil fuels. This only leads to more emissions. Mining for a tonne of nickel to be used in a non-polluting EV can generate up to 59 tonnes of carbon dioxide. 

So, startups are now turning to plants that can concentrate nickel from the soil. Scientifically, this is referred to as phytomining. It has the dual benefit of preventing mining while still extracting the metal of interest. 

What is phytomining? 

Phytomining uses specific species of plants to concentrate metals of interest from the soil. The farming is done on soils where the metal is already present, but the concentration is not high enough to warrant mining.

Once the plants reach maturity, they are dried on the field and then heated to break down the organic material. Later, the ash can be used to extract the metal of interest. 

The concept isn't entirely new and has been attempted in other forms, such as using microorganisms to concentrate the metal instead or certain species of plants to clear soil of certain contaminants. In recent years, though, startups such as Metalplant and Econik have undertaken phytomining in hundreds of hectares to sustainably source nickel. Another startup, Viridian, has also patented technology for its plants that it claims hyperaccumulates nickel from the soil. 

Plant species such as Odontarrhena decipiens, which has distinct yellow flowers, can accumulate nickel to up to 2 percent of their biomass. According to Viridian's website, a 1,000-hectare farm could capture between 250-550 metric tons of nickel. This could be worth US$3-7 million. 

Cleaning up carbon

Metalplant has taken its phytomining a step further by using its farms to sequester carbon. The startup uses another technique called enhanced rock weathering, where large volumes of rock dust are applied to the farms.

As the rock dust dissolves, it absorbs CO2 from the atmosphere and makes bicarbonate, which can store the gas for many millennia. 

Metalplant's co-founder Sahit Muja is a mining billionaire using olivine, a magnesium iron silicate from his nearby stone quarry, in the phytomining setup at Tropojë in Albania. In June, the company used a few dozen tonnes of olivine dust on its nickel-concentrating farms. 

Olivine is also rich in nickel, and the company hopes it will improve the yield of the plants. Metaplants expects its farms to yield up to 400 kg of nickel per hectare, and this yield is expected to improve in the future. 

More importantly, it also fixes about 200 tonnes of CO2 in the process. This could lead to a carbon-negative way to source the nickel, which EV makers can use to offset the total impact of their production process.