S08 - Session O4 - Pathways to Net-Zero farming: a carbon footprint comparison of vertical vs. traditional agriculture

Authors: Francis Baumont de Oliveira, Sam Bannon, Luke Evans, Paul Myers, Laurence Anderson, Iain Young, Jens Thomas *

Agriculture is one of the leading causes of climate change, contributing nearly a quarter of global greenhouse gas emissions. Net-zero carbon goals require a shift in agricultural methods. Indoor vertical farming is a novel form of agriculture that offers space savings, water efficiency, and hyper-local production. However, a significant caveat is the associated greenhouse gas emissions with the energy consumption from artificial lighting. We conduct a carbon life-cycle costing of lettuce production comparing imports from a field-based farm and local food from a vertical farm in a UK context. We aim to answer whether vertical farming is a pathway to net-zero carbon agriculture by examining energy source trade-offs and land conversion diverted to rewilding. To overcome the sparsity of data within the literature and validate carbon emissions, we set up an experimental vertical farm powered by a hydrogen fuel cell. The experimental data using blue hydrogen energy shows emissions as 4.39kg CO2e/kg without deforestation and 5.04kg CO2e/kg with deforestation. The associated emissions for imported lettuce is 1.14kg CO2e/kg and 5.05kg CO2e/kg without and with deforestation considered, respectively. Sensitivity analysis of energy sources in vertical farming shows wind reduces the VF emissions to 1.28kg CO2e/kg with deforestation considered, reducing emissions by a factor of nearly four compared with conventional agriculture. Tidal, nuclear and geothermal energies also show promise for low carbon footprints. The results show that vertical farming could run with a lower carbon footprint when compared to imported lettuce from the field-based farm with renewably sourced energy. Further transparency around embodied carbon of farm equipment would enable complete life cycle analysis. The powering of vertical farms with renewable energy sources whilst returning equivalent land to nature could be a viable pathway to net-zero carbon lettuce production.