Sustainable phytoextraction of metal-polluted agricultural land used for commercial photovoltaic power generation

Metal pollution of agricultural soils is currently an issue of major concern in China and many soils require remediation. Photovoltaic (PV) power generation is a useful source of renewable energy but solar power plants often require large areas of land. Combining PV power generation with phytoextraction on contaminated arable land is therefore a novel and potential option if these processes can work effectively together. A three-year-long continuous field study was conducted to test the feasibility of phytoextraction using a metal hyperaccumulator species growing under arrays of PV panels. Meteorological data were collected and the growth and cadmium (Cd) and zinc (Zn) uptake of the Cd/Zn hyperaccumulator Sedum plumbizincicola were determined. Shading by the PV panels reduced the annual solar irradiance by 58.4% but this showed no inhibitory effect on plant growth or metal uptake by S. plumbizincicola. Phytoextraction under the PV panels gave high removal efficiencies of Cd and Zn and the hyperaccumulator took up Cd and Zn at rates of 3.40 and 96.2 kg ha−1, respectively, for three seasons. It is concluded that soil phytoextraction and PV electricity generation can be combined to realize soil remediation and energy production.