According to a recently published study in ‘Plants’, a predictive lighting control system could optimize lighting for plants by predicting sunlight and only running the lights when needed. The data showed that farmers could reduce their greenhouse electrical costs by as much as 33% by optimizing their lights.

Detailing on the issue, *Marc Van Iersel, a Professor in the College of Agricultural and Environmental Sciences, University of Georgia, said, “When LED lights first came to market, they gave us an opportunity to control greenhouse lighting on a level that was not possible before. At the time, a lot of research was happening to optimize the lights themselves, but almost no one was working on smart control of the lighting system.”

He further added, “The electricity used for the lights is anywhere from 10% to 30% of the cost of running a greenhouse. Our research began with the idea that, if we can reduce this cost, we can very quickly have an impact on the efficiency and sustainability of greenhouses.”

Marc Van Iersel among turnip plants in a grow room at his greenhouses…
Photo by Andrew Davis Tucker/UGA

The research

A team of University of Georgia researchers designed a new lighting system that could reduce a greenhouse’s electrical demand without hurting the plants.

Electrical engineering Master’s Student Shirin Afazli built a control system that uses sensors to measure current weather conditions, and Ph.D. Student Sahand Mosharafian and Associate Professor Javad Mohammadpour Velni developed light-predicting algorithms in their laboratories. In combination, the system can predict the amount of sunlight in the future. This allows it to optimize the lights inside the greenhouse and give plants the correct amount of light.

(L) Eric Mattos, and (R) Marc van Iersel, Co-founders of Candidus, are adjusting plant growth lamps in a horticulture greenhouse, where they were testing their lighting technology on various crops.
Photo by Dorothy Kozlowski/UGA

Testing the combination

Greenhouses are predominantly used during the winter and spring, so the team tested their system during both growing seasons. While both experiments showed reduced costs while maintaining plant growth, the new system made a bigger impact during the spring. It reduced costs by 33% in the spring but only 4% in the winter. The system generates the most savings while the sun is shining. Because winter months have shorter days, the lights are required to be on more often.

Cost saving  

According to the researchers, the actual cost savings could be even higher. Their experiments assumed a fixed cost for electricity, but in the real world, farms are subject to variable pricing. The team has already programed the system to account for this variable and plans to publish future research that shows higher savings rates. As the planet’s population continues to rise, finding ways to produce more food with less resources becomes increasingly important.

*In 2017 Van Iersel co-founded a startup company, Candidus, based on his research into efficient greenhouse lighting. The company builds better lighting control systems for greenhouses.

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