Herb production in plant factories: Environmental impacts, cost-effectiveness, and sustainable potential

Plant factories with artificial lighting (PFALs) offer a sustainable solution to meet growing food demands in urban areas. However, this energy-intensive emerging industry urgently requires the expansion of crop production models (beyond lettuce) and the demonstration of their environmental and economic sustainability. To investigate the performance of herb production in PFALs and the key influences of lighting management, LED efficiency, electricity mix, and facility scale, this study evaluated the environmental performance and economic viability of nasturtium production. The production was assessed across three lighting schemes in various scenarios, analyzing environmental performance across nine categories, and evaluating the benefit-to-cost ratio and potential for commercial-scale production. The highest productivity (17.3 kg/m²/year) was achieved under maximum daily light integral treatment (CL-400), which was associated with increased electricity consumption (0.45 MWh/m²/year) and relatively low global warming potential (17.94 kg CO₂ eq per kg of fresh leaves). Technological advancements in light emitting diode (LED) efficiency could reduce the impact on global warming potential by 29.58%, and the transition to renewable energy sources could decrease the impact on fossil fuel consumption by ˃50%. Moreover, based on economic feasibility analysis, the high lighting input offers the most profitable scenario, with a net margin of 49.6%. The transition to renewable energy is fundamental to achieving environmental sustainability. Productivity gains achieved through effective environmental control can translate high energy use into lower per-unit environmental impacts.