Minimal environmental impact with indoor cultivation and innovative technology: improving productivity with food gases

Just as the tractor once revolutionized agriculture, the next technology shift is coming – indoor cultivation. With indoor cultivation (hydroponic cultivation) it is possible to grow crops anywhere and at any time, such as close to the consumer and even in winter. The result: fewer transports and fresher vegetables to the customer – all year round. In addition, the environmental impact of the process is low and the flavor is even better.

A large proportion of the fruit and vegetables we consume have often traveled a long way before they are packed and sent to our stores. During the time from harvest to consumer, vegetables often lose part of their nutritional value.

With indoor cultivation, you can grow crops all year round and anywhere, allowing it to move closer to the consumer both geographically and in time. This is good news for the environment, the nutritional content and the sustainability of the vegetables.

Ljusgårda is a proactive player in indoor cultivation and an innovative lettuce factory. The company grows lettuce vertically hydroponically – in water instead of in soil. By adding CO2, it has managed to increase the volume significantly.

Learn more about our offering for the food industry.

In Ljusgårdas cultivation, the plants grow vertically, planted in cultivation tubes that are optimized to keep the roots in place and deliver nutrients efficiently. Irrigation takes place from above and with circular water systems – in other words, the water is recovered and reused. As a result, water consumption is significantly lower than in traditional cultivation. Extra nutrients are added to the water to make the plants grow even better.

Since the cultivation is indoors in a controlled environment where there are no insects or vermin, no pesticides are needed in the cultivation. Ljusgårdas cultivation is also powered by 100% green electricity.

“We are proud to be climate certified and optimize our energy use, which comes from 100% renewable energy sources,” says Maria Hillerström, Marketing Manager at Ljusgårda. “Our water system monitors the mix of minerals, nutrients and PH value, adapted to the needs of the plants. This enables us to grow different types of lettuce, which are also healthy.”

Instead of sunlight, which is required by plants that grow outdoors for their photosynthesis, Ljusgårda uses LED lighting. Sensors constantly measure what each plant needs at different stages to grow and be healthy, and LED technology available on each lettuce stand adapts the light spectrum and amount of light to create the optimal light conditions for each plant.

“Different lights – red, blue or white, affect the plant in different ways and can make it long, spread out or more brittle, for example. The system controls the light and gives each plant what it needs when it needs it,” says Maria.

For some time now, Ljusgårda has been collaborating with Linde to increase productivity. Gases can have a major impact on healthy, vigorous plants.

In order for the plants to grow extra well, CO2 is now added to the room. One might say that CO2 fertilizes the plants. In addition, extra oxygen is added to the water. Oxygen provides extra nutrition. But oxygen is also secreted from the plants themselves.

Robert Glanberg, Process Sales Food at Linde, is the customer manager for Ljusgårda.

“Ljusgårda contacted us because they wanted to test CO2 to increase productivity. The results exceeded expectations and the growth almost doubled. Therefore, Ljusgårda wanted to scale up projects fairly quickly,” says Robert. “Now they have gone ahead and set up a CO2 tank with CO2 fertilization for the entire system.”

Natural gases make a strong positive contribution to cultivation

Facts about usage areas for Carbon dioxide

In many Linde applications, carbon dioxide replaces substances which have a negative impact on the environment. Read more about Carbon dioxide.

For example, it replaces halons in fire extinguishers and freons (CFCs) in the production of polystyrene and polyurethane foams. In dry-ice cleaning processes, carbon dioxide works without any further cleaning solvents, which are often harmful or contaminate the surface being cleaned. Automobile air conditioning systems, which use CO2 as refrigerant instead of HFCs, are not only environmentally sound but also more economical (lower petrol consumption) than systems using fluorinated greenhouse gases.

Carbon dioxide has properties that can be used in many different ways without harming the atmospheric cycle. It is therefore not surprising that carbon dioxide is used in products and processes we encounter every day:

  • In carbonated drinks: improving their lifetime and adding the fresh and sharp taste
  • Cooling or freezing of foodstuffs
  • Cleaning of drinking water: making it less corrosive
  • In greenhouses: increasing growth rates of vegetables
  • Neutralization of wastewater before it is released to the environment
  • Carbon dioxide as dry ice pellets is a highly efficient and flexible chilling agent: no additional energy is required for keeping goods cool and fresh
  • Shielding gas for welding of steel and in laser cutting processes
  • In industrial processes for cooling

How carbon dioxide becomes carbonic acid

Fermentation to produce ethanol releases carbon dioxide. Our main source of carbon dioxide is Lantmännen Agroetanol’s refinery in Norrköping, where approximately 600,000 tons of grain is fermented each year. This also releases carbon dioxide. We collect the carbon dioxide and deliver it to our facility next door, where we convert it to liquid carbon dioxide. Carbon dioxide from nature’s own cycle becomes green CO2.

Carbon dioxide in water is more commonly known as carbonic acid or carbonation. Carbonic acid is a chemical compound that contains carbon dioxide gas. Carbonic acid is formed when carbon dioxide reacts with an aqueous solution. When you make carbonated drinks such as soft drinks, you press carbon dioxide into the aqueous solution under high pressure. The aqueous solution then binds the carbon dioxide which causes the bubbles to remain in the liquid. In short, the gas molecules dissolve and interpose between the water molecules. A very small number of the carbon dioxide molecules also react with a water molecule and become the carbonic bubbles themselves. Imagine that a carbon dioxide molecule (CO2) takes OH from the water molecule (H2O). The second H of the water molecule settles to an O and then a carbonic acid molecule is formed (H2CO3).

Text: Carina Aspenberg

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