Synergy between industry and agriculture: Techno-economic and life cycle assessments of waste recovery for crop growth in glasshouses
Lewis J. McDonald, Ariane S.S. Pinto, Muhammad Naveed Arshad, Rebecca Rowe, Iain Donnison, Marcelle McManus
Abstract
Controlled-environment agriculture in agro-industrial systems, where carbon dioxide, heat, and other wastes are recovered or recycled, has potential to be an environmentally friendly approach with economic feasibility. However, such approaches need careful exploration to ensure that environmental and economic benefits are maximised. Techno-economic, and life cycle assessment were applied to evaluate the synergy of producing crops (tomato and hemp) and recovering industrial wastes (e.g., heat and carbon dioxide) in glasshouses with robust uncertainty and sensitivity analyses. For each crop two scenarios were compared, a linear scenario evaluated the use of raw materials with no waste recovery whereas the circular scenarios captured industry flows and reused or recycled them in the glasshouse, avoiding raw materials consumption. Circular practices had a net benefit on the global warming potential for both crops, capturing up to 50,000 kg/y of CO2 in crops biomass and providing competitive product prices. The analysis shows that circular operational conditions can reduce, by almost half, the break-even product selling prices and sequester up to, approximately, 500 kg CO2eq./m2 of glasshouse compared to linear systems. Future investments in this outstanding strategy to supply the United Kingdom's market demand of tomatoes could lead to a low-cost product and negative CO2eq. emissions by mitigating the importation of these products. Alongside, other impact categories scores may not be as favourable as the global warming potential, due to high impact of the waste management phase, chemical fertilisers, and pesticides utilisation.