Energy and fertigation consumption and economic viability of a light blocking film in greenhouse lettuce production

High-technology greenhouses offer a promising avenue for enhancing global food security, yet their high operational energy costs, associated with cooling, remain a significant barrier to extensive utilisation in crop production, particularly in warm regions. This study evaluates the impact of Light Blocking Film (LBF) and different cooling technologies on lettuce production in high-technology greenhouses in Australia. The effect of LBF on cooling energy reduction and crop yield variation was evaluated over three lettuce trials, and the results were used to assess the commercial feasibility. LBF was found to slightly reduce average cooling energy expenditure and the average fertigation use by 24.2%. Despite these savings, LBF led to decreased crop yields of 6.2%-14% across three seasons and three different cultivars, highlighting a trade-off between resource use efficiency and productivity. Economic modelling indicates that integrating LBF with fan-pad systems could achieve a net present value of $1013 per m2, and a benefit-cost ratio of 2.11 through the lifespan. Conversely, the system combining LBF with fan-coil units showed a longer payback period of more than 17 years, emphasizing the importance of system compatibility. The study highlights the necessity for precision in the choice of greenhouse technologies to balance energy and resource sustainability with crop productivity. These findings serve as a guide for optimizing technology deployment in protected cropping systems to maximize agricultural, environmental and economic benefits.