How crop breeding programs can improve plant factories' business and environmental sustainability: Insights from a farm level analysis

Plant factories, being more weather independent, can potentially contribute to global food security under climate change scenarios, but their profitability and environmental sustainability are debatable. This study quantitatively assessed the business sustainability and life-cycle-based carbon footprint of a hypothetical plant factory. A system dynamic model was constructed to simulate yearly profit and global warming potential (GWP) of a 2-ha hypothetical farm over 20 years using experimental data from growing 397 Brassica oleracea and 204 Eruca sativa accessions in a prototype plant factory in Singapore. Experimentally derived parameters include resource use data, maximum potential yield improvement, and the effect of increasing planting density on yield. Model simulations predicted that with accession-wide average yield (status quo), the hypothetical plant factory would meet 0.8 % of the leafy vegetable requirement of the population but earn negative profit. The estimated carbon footprint at the end of the simulation period was approximately 21 kg CO2-eq per kg of vegetables with lighting operations being the major contributor. A univariate-sensitivity analysis was conducted to understand how model parameters could affect the plant factory's profit represented by net present value (NPV) and environmental sustainability represented by GWP. Yield improvement was identified as the strongest influencer of NPV followed by price elasticity and annual fluctuations in vegetable price. Yield improvement was also the strongest influencer of GWP followed by planting density and unit light use. This study acknowledged the importance of crop breeding in plant factories' profit and environmental sustainability. The results indicated breeding high-quality unique varieties with improved yield and light use efficiency can potentially benefit plant factories' business and environmental sustainability.