Optimal Energy Management in Indoor Farming Using Lighting Flexibility and Intelligent Model Predictive Control

Abstract

Indoor farming enables year-round food production but its reliance on artificial lighting significantly increases energy consumption, peak load charges, and energy costs for growers. Recent studies indicate that plants are able to tolerate interruptions in light, enabling the design of 24-hour lighting schedules (or "recipes") with strategic light modulation in alignment with day-ahead pricing. Thus, we propose an optimal lighting control strategy for indoor farming that modulates light intensity and photoperiod to reduce energy costs. The control strategy is implemented within a model predictive control framework and augmented with transformer-based neural networks to forecast 24-hour ahead solar radiation and electricity prices to improve energy cost reduction. The control strategy is informed by real-world experimentation on lettuce crops to discover minimum light exposure and appropriate dark-light intervals, which are mathematically formulated as constraints to maintain plant health. Simulations for a one-hectare greenhouse, based on real electricity market data from Ontario, demonstrate an annual cost reduction of $318,400 (20.9%), a peak load decrease of 1.6 MW (33.32%), and total energy savings of 1890 MWh (20.2%) against a baseline recipe. These findings highlight the potential of intelligent lighting control to improve the sustainability and economic feasibility of indoor farming.