Implementing a Storage Infrastructure in a Phyto-remediated Biomass-to-biofuels Value Chain: Analysis of Benefits and Costs

Soil pollution, particularly by heavy metals, poses a significant threat in Europe, often rendering traditional remediation methods unfeasible due to the sheer volume of contaminated soil. Phytoremediation, or phytostabilization, offers an effective alternative for low-to-moderate pollution levels. The GOLD project aims to enhance this by cultivating high-yielding lignocellulosic energy crops on such soils, using the harvested biomass as feedstock for a two-step conversion pathway to produce biofuels and alcohol-based coproducts, while also collecting densified heavy metal pollutants in ashes and slags. A key challenge is securing constant feedstock for conversion plants, especially given the variable availability of polluted biomass. This study modelled the impact of a storage infrastructure on value chain logistics, examining scenarios with and without a long-term storage capacity. Results from the Italian case study demonstrated that storage significantly increases the utilization of polluted biomass and enables four times increase in pollutant recovery (from 2.24 t/yr to 8.9 t/yr). However, storage facility deployment comes at a substantial additional cost of 22-24 EUR/t of biomass. Despite these costs, the broader social and environmental benefits of phytoremediation, highlight the need for targeted policy measures like capital support or subsidies to enhance economic feasibility.