It’s no news that vertical farms are highly energy-intensive operations that need substantial amounts of electricity to power. High energy demand is therefore one of the main challenges facing the sector.
Using renewable energy can offer vertical farms potential cost savings and protection against energy price volatility.
Nuclear energy is another option for powering vertical farming facilities that require a continuous supply of energy.
US vertical farmer Square Roots, meanwhile, has developed an innovative approach to indoor vertical farming that aims to significantly reduce energy consumption by growing crops in the dark.
Scientists are now suggesting that manipulating light according to the needs of specific crops could make them grow stronger and healthier in an indoor setting while minimising energy use.
“The biggest benefit of vertical farming systems is that healthy food can be grown much more closely to consumers in places where this is impossible otherwise: in mega-cities, in deserts, and in places that are cold and dark during large parts of the year,” said Dr Elias Kaiser, Assistant Professor at Wageningen University and Research in the Netherlands and first author of the study published in Frontiers in Science.
“The biggest challenge is the costs associated with electricity use.”
Dynamic environmental control could 'transform' vertical farming systems
The researchers got round the issue of costly electricity by using dynamic environmental control, which they suggest can help vertical farming become cost-effective and raise healthier plants.
Dynamic environmental control in vertical farming refers to the adaptive management of growing conditions in controlled environment agriculture systems.
This approach involves adjusting various environmental parameters in real-time to optimise plant growth, resource efficiency, and energy costs.
One of the key aspects of dynamic control is adjusting light conditions so that light intensity and duration are modified based on plant needs and electricity prices. Farmers can therefore reduce energy costs by dynamically adjusting light levels in response to fluctuating electricity rates without compromising plant growth.
Prof Leo Marcelis of Wageningen University, the senior author, says the study outlines a strategy that makes use of plant physiology knowledge, novel sensing and modelling techniques, and novel varieties specifically bred for vertical farming systems.
Because plants’ biological functions are heavily influenced by environmental conditions like temperature changes, light wavelengths, and the amount of CO₂ in the atmosphere, manipulating the environment allows a vertical farming system to manipulate plant development, the study says.
The authors created a model for testing smart lighting that aims to keep plants’ ability to photosynthesize steady over the course of a day, while still lowering electricity costs. They found an algorithm could cut electricity costs by 12% without compromising plants’ carbon fixation, just by varying the intensity of the light.
They then tested whether varying light intensity affected the growth of leafy plants like spinach which are often grown in vertical farms, and found that there was no negative effect. This remained true even when the plants were subject to irregularly changing light intensity, rather than a predictable, regular pattern.
Farmers will need suitable sensors and models to help them monitor and adjust the environment, as well as new cultivars bred for vertical farming. These cultivars could take advantage of the potential for local production in sheltered conditions to focus on better nutrition and sensory qualities, rather than robustness or shelf-life.
Larger scale testing is needed
Dynamically adjusting air flow rates, temperature, and CO₂ according to plants’ needs could potentially offer opportunities to minimise electricity costs, the study concludes. But more research is required to calibrate all these variables and strike the right balance between high-quality and high-yield crops.
“Many of the proposed solutions have not been tested at the larger scales that vertical farms represent—they may have been shown at the single-plant level, but not yet at the whole crop stand level,” cautions Kaiser.
“In a vertical farm all growth conditions can be exactly controlled, which is very important to optimize yield, quality, and resource use efficiency,” adds Prof Leo Marcelis of Wageningen University, senior author.
“However, the technical possibility of keeping them constant does not mean that keeping them constant is the best solution. Once dynamic environmental control has become established, both the energy use and costs of the used energy can be substantially reduced, increasing the profitability and sustainability of vertical farms.”
