Greenhouse growing is an important part of the economy for Nordic countries, where the climate is less than optimal for growing food. It’s therefore natural to expect much of the innovation in greenhouse production to come from the Nordic countries. This is certainly true for Denmark.

Denmark grows its own produce as much as possible. Doing so not only reduces the country’s dependency on imports, but it also minimises CO2 emissions incurred in transportation.  

However, greenhouse farming consumes more energy than traditional farming. Because the country is intent on growing as much as possible locally, Denmark has been investing in new technologies to bring down energy consumption in greenhouse production. 

What’s more, two recent developments have upped the ante – an increase in the use of vertical farming and a new business around locally grown cannabis.

The Danish company Nordic Harvest runs Europe’s biggest vertical farm in Denmark. Vertical farming is either the worst method of farming in terms of CO2 emissions, or it’s the best. That all depends on the type of energy used to power the farm – and on the technology used to run it.

Nordic Harvest uses wind power and a lot of technology, which makes production eco-friendly. However, it needs further innovations to expand, and wants to grow more than just salad greens, herbs and kale – as well as to operate in other countries.  

As for cannabis, it’s a well-kept secret that Denmark is on track for becoming one of the world’s largest producers of medical cannabis, with 200,000 square meters being set aside for this purpose. This success is largely due to the pilot programme for growing the substance, which started in 2018. Cannabis is grown in greenhouses in Denmark.

New tools needed

To help the new productions save energy – and to continue saving even more energy in traditional production – the country needs new tools. Government agencies and research organisations have already helped develop some new technology to support greenhouse growing in becoming more eco-friendly – and those efforts have paid off.  

“Danish greenhouse growers have cut their energy use by about 50% over the past 15 years,” says Jesper Mazanti Aaslyng, consultant with HortiAdvice. “This is in large part thanks to investment in new technologies, and in a new way of controlling the climate in greenhouses.”

Aaslyng is more than just a consultant with HortiAdvice. He has also been in charge of several Danish and international scientific projects on greenhouse production and sustainability, using digital tools for decision support in the greenhouse industry. Ever since 1985, he has been conducting research on horticultural crops, heading the research school for horticultural science at University of Copenhagen until 2007, and serving as department manager for plant technology at Danish Technological Institute (DTI) from 2007 until 2022. 

Denmark sees greenhouse production as a big part of its future. Not only can it feed its own population at less cost and in a more energy-efficient manner, but it can also export some of the technology and know-how. 

A project, called Greenhouse Industry 4.0, was established to bring in some of the latest technology already used in other industries and apply it to greenhouse production.

The project, which began in 2018 and comes to an end in March 2023, promises to make the Danish greenhouse agriculture industry energy-efficient and environmentally sustainable through the use of these new digital offerings. The project is funded by the Danish Energy Agency in the context of EUDP, the Danish Energy Technology Development and Demonstration Programme.  

Applying Industry 4.0 technologies to agriculture 

The goal is to use Industry 4.0 technologies – specifically internet of things (IoT), artificial intelligence (AI), big data, cloud computing and digital twins (DT) – as part of greenhouse production systems. The expectation is that this will be a disruptive approach for vertical integration and optimisation of the greenhouse production processes to improve energy efficiency, production throughput and productivity without compromising product quality or sustainability.

Applying the Industry 4.0 Digital Twin concept to the Danish horticulture greenhouse industry results in a new set of tools that can be used to simulate a physical greenhouse facility to test different scenarios. The tools can also be used to evaluate greenhouse performance. Digital twins use traditional sensor data from production, along with cloud-based data to predict how a physical system will perform under varying operational conditions. They combine modelling, statistics and big data analytics to perform the analyses. 

The digital twins help to optimise along several dimensions – including production schedule, energy consumption and labour cost. They do this by considering all the key factors – including production deadlines, quality grading, heating, artificial lighting, energy prices and weather forecasts. Digital twins can be combined to form an ecosystem of models that simulate an entire production facility. 

An ecosystem of specialised digital twins is linked together to describe and simulate all aspects of the production chain, such as overall production capacity, energy consumption, delivery dates and supply processes. The goal of Greenhouse Industry 4.0 is to develop an ecosystem of digital twins that collectively captures the behaviour of an industrial greenhouse facility. 

Greenhouse Industry 4.0 will use three different types of digital twins. One will cover the greenhouse climate compartments, another will model the production flow, and the third will represent the energy system. The last two are mainly to help researchers develop optimal designs. The first one, used to model the climate compartments, has immediate practical value. 

“The main aim of the climate twin is to optimise plant production, while minimising the use of energy,” says Aaslyng. “We use the climate computer already installed in most greenhouses, which measures the climate both inside and outside the greenhouse and controls the climate inside the greenhouse. We use those data in our software to model what is happening in the production. Photosynthesis, energy use and climate conditions are all modelled.

“The software we developed in the context of Greenhouse Industry 4.0 was acquired by HortiAdvice,” he says. “We are now continuing to develop InfoGrow 2.0 and Virtual Greenhouse in collaboration with the University of Aarhus and the University of Southern Denmark.

“InfoGrow 2.0 provides online analysis of production and the use of energy, along with risk management which takes into account disease risk for plants. Users can adjust set-points for climate parameters to optimise plant growth on a daily basis. The software produces a log, which can be used for further analysis.

“Virtual Greenhouse simulates and analyses the grower’s climate strategy,” says Aaslyng. “It also simulates the effects of adding new hardware to the greenhouse. We developed the digital twin to run simulations that help us understand and optimise production. It models leaf and canopy photosynthesis, climate in the green house, climate in the plant canopy, and use of energy for heating, cooling and artificial lighting.”

Based on the climate conditions, the system uses modelling to estimate the effects on the greenhouse, including evaporation, heat transfer and condensation – and how much photosynthesis will take place for a given type of plant. The system can even make adjustments on the fly to optimise growth. 

Challenges 

Innovation is only part of the game. The other part is convincing growers to use the new technology, and many growers are simply averse to change. 

“The new software pushes the growers to look at their production differently,” says Aaslyng. “They must think in new ways, and they need to use new kinds of setpoints for their production. Many growers are used to a more traditional approach and are reluctant to try new things.”

But Aaslyng is hopeful. Recent events may have changed the attitudes of farmers. “The war in Ukraine and higher energy prices have forced growers to think in new ways,” he says. 

Another reason growers are slow to adopt the new technology is that, just like for any new technology, few people want to be the first to try it out. Most growers prefer to wait until they see their peers using it successfully. 

Part of what HortiAdvice does is to help growers understand new technologies and what it can do for their business. HortiAdvice consults with growers on all aspects of crop production, including finance, management, technology and subsidy schemes. 

A third challenge is getting the manufacturers of different systems to cooperate. The new services depend on data exchange, but not all climate computers are compatible, and suppliers aren’t always willing to modify their own systems. 

The future Greenhouse 

“Greenhouse Industry 4.0 builds on several years of energy research,” says Aaslyng. “The aim is to deliver digital solutions that ensure even greater Danish exports of both food and the technology that can be used in other countries for optimal production in the future.”

Companies that build and operate vertical farms have already made great strides, but more progress is needed before they can produce a larger variety of crops efficiently. They are certainly interested in new technologies. 

Anders Riemann, founder and director of Nordic Harvest, says in a company blog post that the only reason they haven’t moved beyond production of just lettuce, herbs and cabbage is that these are the only plants that are profitable to grow with vertical farming.  

It is not economically feasible to use vertical farming to grow tomatoes, for example, because it takes too much time and effort for the plant to grow leaves and stems, which cannot be sold. Only after a long period of photosynthesis can tomato plants start bearing the fruit that can be sold. 

It’s not only technological development that will determine what makes sense to produce in the future. A whole new ecosystem needs to develop around new methods of farming. For example, seeds will be bred so they are suitable for vertical farming. 

A very ambitious company, Nordic Harvest hopes that once vertical farming is established, they will be able to launch a project of reforestation. Farmland that is no longer needed can be bought and turned back into forest. 

In any case, Denmark is on the right track, supporting a strategic industry with technology projects. The country may be just a few innovations away from becoming a major global player in food production. 

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