innovation
Sundrop Farms most inspirational tomato grower of 2016
Sundrop Farms from Australia was elected most inspirational tomato grower of 2016 during the Tomato Inspiration Event held in Berlin on 4 February. The 100 most innovative tomato growers in the world gathered in Berlin for the third edition of this event. This year it was up to the guests to elect the inspirational winner.
The Tomato Inspiration Award was presented to Philipp Saumweber of Sundrop Farms at the Puro Skybar in Berlin. As there were no specific themes associated with this year’s event, there was no call for the appointment of an international jury. Instead, the participants themselves were invited to cast their votes for the grower who inspires them more than any other.
Previous winners Windset Farms (2014) and Duijvestijn Tomaten (2015) contributed to the event alongside the organisers of the event in the compilation of a long list of the most inspirational producers and product organisations. This resulted in four nominations: APS Salads from Cheshire (UK), the Flandria label of the joint Belgian auctions (LAVA) from Leuven (Belgium), Sundrop Farms from Adelaide (Australia) and Zeiler Gemüsevertrieb from Münchendorf (Austria). Sundrop Farms ultimately won the most votes and was acclaimed the winner.
High-tech in the desert
This year, Sundrop Farms will be opening a state-of-the-art production facility in Port Augusta, in the southern part of Australia. The site will feature four controlled greenhouses (each covering five hectares of land), a desalination system and a field of solar panels that consists of a tower 115 metres high and over 23,000 mirrors to capture the sun’s energy. The new site is unique in the world and will offer employment to some 175 workers and produce over 17,000 tonnes of tomatoes annually. The facility will make use of solar energy, seawater and natural crop protection agents. You can follow the construction of Sundrop Farms from close by on YouTube.
The Tomato Inspiration Event is organised by KAS Tuinbouwcommunicatie and HortiBiz, and sponsored by Bayer, Delphy, Koppert Biological Systems, Oerlemans Plastics, Priva, Saint-Gobain Cultilene and Svensson.
Source: Tomato Inspiration Event. Photo: Sundrop Farms.
‘Production results are satisfactory but we need to raise the bar each year.’
Although their revolutionary greenhouse has had a superb first year, the brothers Duijvestijn see room for improvement. Technically there are still gains to be made. And, although the goal to save 50% on energy by using low-grade heat was achieved in the first year, the businessmen take little pleasure from that. The system’s partners watch and learn. Where can they still make improvements?
The ID greenhouse that Duijvestijn Tomatoes of Pijnacker, the Netherlands, started running in December 2013 is performing well. In the first quarter, the crop was mostly grown in the conventional way in order to eliminate any technical teething troubles without taking any major risks. Then in the very light and closed greenhouse, step by step, they switched to the Next Generation Growing. This greenhouse concept, jointly developed by Technokas, Boal and Scheuten Glass, lends itself excellently to this purpose.
Noteworthy features of the new greenhouse are: A double glazed roof with large format glass (2x3m); insulation glass with four anti-reflective coatings and a structured layer to scatter the incoming light; air conditioning using air drawn in from outside; heating with low grade (primary) and high grade heat (secondary); continuous ridge ventilation with the opening on the top side; and a construction without any light-intercepting trellises. Instead it uses relatively heavy columns and angled sidewalls to support the greenhouse. The screens are tucked under the gutters.
Special year
Ted Duijvestijn calls 2014 a peculiar year, because the reference crop of plum tomato Prunus, performed exceptionally well. “As a result we weren’t able to achieve any extra yield in the new greenhouse,” he said. “If all the components had immediately performed as we wanted them to, we certainly could have got more out of it.”
Apart from the later planting date and the conventional start to the crop, a few other factors contributed to the setback. One of these was the CO2-supply in the new greenhouse. “We had a central control for the CO2 in which a two way valve distributed the CO2 between the conventional greenhouse and ID greenhouse,” explains Duijvestijn. “Measurements inside the greenhouse showed that sometimes too little CO2 entered the new greenhouse so that the concentration measured next to the closed windows was sometimes under the level outside. Then you know you are missing your chance regarding kilos. This year the new greenhouse had its own CO2-control system.”
Insect mesh removed
Another disappointment was that on warm days there was a shortfall in the ventilation capacity. That was directly related to the insect mesh in the ridge ventilation, which the growers had chosen to install at the last minute. “The mesh had a big impact on the ventilation capacity,” says the grower. “On very warm days, which were quite often last year, the plants were sometimes exposed to stress.”
Therefore, the mesh was removed during the crop changeover. Duijvestijn says that it is now more difficult to manage the secondary goal, which is emission-free production, but the ridge ventilation can now very quickly and in line with the original calculations achieve the desired level of cooling.
“The vents open from the top side to obtain the maximum chimney effect,” he explains. When the windows are fully open it’s possible to refresh about 150 m3 air per m2. Due to the diffuse glass that doesn’t have to happen very often but it is good to have such a fast and powerful system available. The capacity to draw in outside air is 10 m3/m2 per hour and is used mostly for the fine-tuning.
Double glass
The advanced and expensive double glazed roof largely meets expectations although Duijvestijn would like to see less condensation.
“That certainly has our attention,” says product manager horticulture Laurens Vlaar, of Scheuten Glass. “We are all convinced that double glazing adds value, but we also know that glass is extremely differentiated and complex. Together with the users and research institutions we want to initiate improvements where possible and offer tailor-made solutions. These could include different structural treatments that you can apply in order to achieve the desired scattering of light. Every type of structure has its advantages and disadvantages. With hindsight we can see that the pyramid structure in this greenhouse roof is a little too coarse. A finer structure would probably lead to fewer problems with condensation.”
Peter Zwinkels, of Technokas, adds: “This has also opened my eyes. In the past condensation was often seen as an inevitable side-effect but in recent years it has started to receive the attention it deserves. Nowadays we always test glass samples that are wet and the differences can be amazingly large. Wageningen has a great setup for taking measurements which we thankfully can use.”
One thing that Zwinkels would like to do differently in this context is take measurements when the glass is at an angle, just like when it is on the greenhouse roof. Currently glass samples are only measured when they are horizontal and that, certainly with respect to condensation, can give a distorted picture.
Potential
Glass producer Scheuten, as a project partner, is closely involved in several new greenhouse concepts in the Netherlands. Despite the still relatively high cost, Vlaar sees a lot of potential for well-insulated, double glazed greenhouse roofs using diffuse tempered glass with AR-coatings.
“The projects which we have been able to achieve so far are fairly small scale and therefore relatively expensive,” he says. “Before there’s a further roll-out, the project volumes need to increase to enable a serious decrease in price. For projects of several hectares that is feasible, certainly now that we are better able to deal with the particular nature of horticultural projects.”
Wageningen UR Greenhouse Horticulture was not only consulted for determining the glass specifications, it also provides the monitoring program. “That’s very valuable,” says Duijvestijn. “Before we invested in this greenhouse I was intensively involved in all kinds of trials for three years. However, I’ve actually learned the most from using it, not least, thanks to the monitoring by the researcher.”
Invest in research
Together with Zwinkels and Vlaar he stresses that the sector and the government should keep up their joint investment in research. The relative reticence that has occurred over the last few years gives him reason for concern. “There have been many cut backs and in my opinion potential financial partners sometimes say no too easily to subsidy applications for research,” according to Zwinkels. “That is partly due to a lack of strategic focus and expertise."
The greenhouse builder cites Next Generation Growing as an example. “I have already seen several requests fail because they were not thought innovative enough. However, many variations are being designed. Growers must be able to make informed choices and that requires comprehensive research and testing. Growers also want to pay but it makes a difference if other parties continue to make a contribution and thereby reduce the business risk to an acceptable level. That is what happened here. Without external help this greenhouse may never have been built."
Summary
The energy target (50% energy savings) was achieved in the first year of production, but by a combination of circumstances no extra yield was achieved in the ID Greenhouse. Now the greenhouse has its own CO2 control system and the insect mesh over the ridge ventilation has been removed, so that may now be possible. The well insulated, double glazed roof made of diffuse glass has excellent transmission properties. The condensation behaviour, in relation to the treatments used to make the glass diffuse, deserves extra attention in future projects.
Text/photos: Jan van Staalduinen
‘Horticultural businesses are becoming software companies.’
Yuri van Geest wrote the bestseller Exponential Organisations together with Salim Ismail and Mike Malone, in which they expose the power of fast-growing organisations like Uber, Airbnb and Netflix. He will be the keynote speaker on the theme ‘the power to change’ at the Westland Event on 15 October. ‘The Netherlands will have to embrace new technology within the next five years, if we aim to remain on the driver’s seat in the global food producing industry.’
Yuri van Geest is a specialist in ‘singularity’ and a key figure behind Singularity University Nederland, which will be opening in Eindhoven this December with strong ties to Rotterdam, Amsterdam, Delft and Nijmegen.
Can you explain your personal interest in horticulture?
‘Food is one of the topics I’m currently rather engrossed in. I have also entered into some partnerships in the horticulture sector; so of course, I take an avid interest in it.’ Van Geest has joined forces with the consultancy firm Hillenraad Partners to set up a five-day training course for entrepreneurs in the horticulture sector, in which they aim to show the participants the many opportunities offered by exponential organisation.
How do you retain a competitive edge in a world in which everything is open source?
Can you briefly explain what exponential organisation is?
‘Every business can become an exponential organisation, from a start-up to a family business that’s been around for a century and a half. Basically, it comes down to the way in which the building blocks of a business are organised. A different organisation, a different structure, culture, strategy and critical performance indicators. New technology, such as nanotechnology, 3D printing and robotics - and additionally communities and big data - has to become engrained, as it were, into the DNA of an organisation. As if the organisation is being turned inside out. Business enterprises are doing less and less independently and are outsourcing expertise and technology on an increasingly larger scale. One of the core questions of the book is: how do you retain control in a world where you have less personal property such as talent, personal and resources? How do you retain a competitive edge in a world in which everything is open source? A business enterprise that is capable of applying this organisational change successfully will be able to perform ten times better and faster than one that maintains a linear growth curve. Exponentially. We have divided this process into four steps, which we are implementing at a global scale at companies such as Procter & Gamble and Huawei.’
What will you be speaking about at the Westland Event?
‘You may not be aware of it completely, but the world has entered into a slipstream of technological advancement. Within five to ten years everything will be controlled by software. Biology and technology are becoming more and more closely intertwined. Food is also becoming software. This means that the food producing industry, including the horticulture sector, will become a software industry. Currently, there are numerous developments in the food producing industry that are founded on technology. Take 3D printed food, for example. You can already get several ingredients in a 3D print. In the future we will be able to print out entire hors d’oeuvres, more hygienically and perhaps even tastier than they could be made by a good restaurant. Or consider nano refrigerators with advanced water, nutrient and LED lighting systems, in which people can grow their own food from seeds. Haier, in collaboration with Syngenta (among others) is already taking serious steps in this direction. In just a few years it will be completely normal to walk into a gym, have your DNA or neuroprofile read and be given a personalised shake containing all the nutrients you need at that moment.’
An essential first step is to make leadership facilitating, instead of top-down.
What can horticulturists learn from exponential organisations?
‘Curiosity, creativity. To dare to open all the blinds, to listen to young employees in particular, to embrace new technology. An essential first step is to make leadership facilitating, instead of top-down. People are becoming increasingly older while the world population is continuously growing. Food production worldwide will have to be increased twofold, perhaps even threefold. The way things are going right now, that would be impossible. If we aim to achieve this, we will need technology based on software. The Netherlands will have to embrace new technology within the next five years, if we aim to remain on the driver’s seat in the global food production industry. Horticulturists can also learn not to assume that everything is the truth. To understand that what you are currently thinking and consider to be true is an assumption. The formula behind the coffee shop we’re sitting in right now is functioning perfectly. At present, it has a functional value. However, developments are following upon one another at an accelerated pace. How long will this coffee shop be able to function as its functioning today? If you do not constantly doubt your assumptions and convictions, are no longer curious, your concept or business will have become obsolete before you know it.’
What is your vision of the future of the Dutch horticulture sector?
‘I feel rather optimistic about it, but we will have to take action now. The pace of innovation is much higher in China and the Silicon Valley. They are also growing food, which is coming our way. Like I said: food is software. The horticulture sector - and even broader, the food producing industry - will have to inject itself with new technology to retain its relevance. A business cannot pick up all this new technology on its own, but it can if it joins forces with others as a group. Together with government agencies, for example, or market parties. We in the Netherlands excel in agriculture and food production. At Singularity University Nederland, which is to become a think-tank for Western Europe, AgriFood will be one of our priority subjects. We could achieve tremendous steps in AgriFood. After all, the Netherlands already have many start-ups and knowledge centres in that field.’
The pace of innovation is much higher in China and the Silicon Valley. They are also growing food, which is coming our way.
Why would you advise students to keep a close eye on the horticulture sector?
‘Horticulture is exciting, because of the many opportunities for growth. As I mentioned before, a myriad of new technologies such as biotechnology, nano technology, robotics, drones and 3D printing are all converging in the horticulture sector. I would advise students to invest in all the information currently available online, in addition to what they’re learning at school. Almost everything you want to know and learn is already available on the internet via open source software. You could watch TED talks, or read blogs and news items on websites such as Edge.org, SingularityHUB or MIT Technology review. I learn something new every day through all this media. This is one of the reasons I prefer to travel by train. You can’t read while driving a car, after all. My advice: you have to get going if you want to participate in today’s changing world.’
The Westland Event will be held on Thursday, 15 October 2015, from 3 to 8 pm. Watch the event in livestream on HortiValley.nl (Dutch spoken). Marco van Zijverden, CEO of the Dutch Flower Group, will be introducing Yuri van Geest at 6.45 pm. View the full programme of the Westland Event.
Text: Stijlmeesters.nl/Nicole Carlier. Photo: Flickr/Sebastiaan ter Burg.
‘I’m not such a big fan of spreadsheets.’
‘Internationalisation is crucial to us’, explains Meiny Prins, CEO and co-owner of Priva, and Businesswoman of the Year 2009.
‘Priva is a family-owned and operated company that supplies climate control products and services. We serve two markets: the built-up environment and production horticulture. We offer measuring and control equipment that will enable its users to achieve the highest possible returns with the least amount of energy possible, and while using the greatest amount of recycled water possible. Our knowledge in the field of horticulture is based on two components: our expertise in the field of measuring and regulation, on the one hand, and our knowledge of plants, on the other. We know precisely what each plant needs and are able to coordinate our parameters to these requirements. This is also the difference between the two markets. There are a lot of variables in greenhouse horticulture, but a greenhouse is also a kind of intensive care unit. If something goes wrong, all the plants in it could die within an hour. This process is not as critical when it comes to buildings; we usually don’t complain unless it’s too hot.
'To keep a leading edge with regard to technology, over 150 of our 450 employees focus on product development, which is an aspect in which we invest a quarter of our revenue.'
‘Our exporting activities are also crucial. To keep a leading edge with regard to technology, over 150 of our 450 employees focus on product development, which is an aspect in which we invest a quarter of our revenue. The Dutch market is too small to bear these costs, let alone the risks of a possible crisis on the market. A workable distribution of risks is, in any case, important. We have to offer our employees a solid foundation. It takes three years to train a salesperson to be sufficiently knowledgeable with regard to our technology, for example. Training a service engineer takes five years, and the training programme for a project engineer takes a full decade to complete. When you invest as heavily as this in people, you can’t suddenly cut costs and then decide to expand immediately after. We sell our products for the horticulture industry in over 100 countries, we have 10 branch offices and supply our products to 140 specialised installation professionals worldwide. Our dedicated consultancy services, however, are still offered only from our head office in De Lier.'
‘As I mentioned previously, our exporting activities were relatively easy to get off the ground, as we are active within two sectors in the horticultural industry. It comes down to simply travelling along with your customers. In the course of time, Dutch growers have been relocating to all corners of the globe. I could even go so far as to say that every greenhouse horticulture project launched today, no matter where in the world, has a Dutch person or firm somehow connected to it. Growers become used to working with specific equipment when they were still in the Netherlands, and want to continue using it at their new location.'
‘The situation is entirely different in the building and construction industry. In this case, we moved from country to country, conquering our niche in the market as we went along. The first country we established a new branch in was Germany. This was not the easiest place to begin, as it was also the home base of many of our competitors in the building management system sector. It may not have been the best choice at the time. We currently have ten offices in such countries as Canada, the UK, Belgium and China.'
'Our new strategy focuses more on “verticals”, specific groups of customers.'
‘We are, however, planning to adjust our strategy, because this approach simply takes too long. It takes five to seven years for a newly established branch to start generating a steady profit. This procedure is too expensive, and too slow for building up a global network. Our new strategy focuses more on “verticals”, specific groups of customers, with scalable solutions that we can develop for specific segments and can subsequently roll out on a global scale. Examples include climate control in supermarkets, or operation rooms.’
Many business enterprises with a focus on exporting activities employ stringent selection criteria from the very start. All applications that do not immediately fall within a specific niche are not followed up on. What is Priva’s strategy in this?
‘Of course, we will look into the application, and do follow up on practically every lead except for in specific cases. What is an important point for consideration is that we are the absolute market leader in our segment. What we want to prevent under all circumstances is getting the reputation of being slow - or, even worse, arrogant.’
Are you personally still active in the market?
‘Certainly! My portfolio within our three-headed management team is commerce. I undertake a long journey twice a year, during which I concentrate on business development, in addition to customer relations management. My position as a CEO opens quite a few doors, and gives me opportunities to set my foot on hitherto unpaved roads. What I specifically aim to do, is to launch pilots in collaboration with businesses that play an exemplary role in the market. By using our equipment and accurately calculating the results and, above all, communicating clearly, we are able to convince other companies of the advantages of our technology much faster.'
You are unlike many other CEOs because you are actively engaged in marketing your firm’s products. Many companies these days are led by spreadsheet experts, and not by people who still play an active role in the market. What’s your opinion of this?
‘I’m not such a big fan of spreadsheets. If you start making calculations, you have to use them sooner or later and most often that will mean cutting costs. After that, it takes about a year to straighten out the consequential damage. What’s more important is that, if I were to start working that way, the rest of my business would be prone to following my example. Before you know it, everything will be directed at internal operations, and that’s not what I want at all. I - and the same goes for the rest of my company - prefer to direct my energy outwards.’
'“Adding value” is our motto, and if I succeed in doing this for another decade, I’m satisfied and will take it from there.'
Meiny Prins is a fervent supporter of the circular economy. She launched the ‘Sustainable Urban Delta’ initiative, a string of pearls in the field of water, food, energy and knowledge.
Is this a personal hobby, or does this tie in with your company somewhere?
‘Sustainability is never a mere hobby; it is a significant theme that deserves the same status as quality. I firmly believe that whoever can offer integrated solutions will have a leading edge on the competition. And that it is important to have a vision for the future. More and more people are drawn to living in a cosmopolitan environment, to urbanisation. This means that the waste water produced by these people will have to be used for the production of food. Waste derived from food will, in turn, be used as biofuel, and residual heat derived from greenhouses to warm residential areas. All of these systems will be scaled downwards, and inter-coordinated. As control is our business, we’re already engaged in developing the next generation of control equipment, in which we don’t take only the greenhouse or building into consideration, but also look into how we can coordinate our system to the processes going on in the direct environment.’
You are the co-owner of a successful business. What are your plans for Priva in the next 50 years?
‘I can’t think that far ahead! My motivation stems from the ability to provide added value. Following in the footsteps of my father, money is not a goal onto itself. Every euro is reinvested in the company. “Adding value” is our motto, and if I succeed in doing this for another decade, I’m satisfied and will take it from there.'
‘It’s not without a reason that I say a decade: these days innovations come and go at such a rapid pace and have such a gigantic impact that added value is the key to survival. Even stronger, everything that is not capable of contributing some sort of added value is disappearing or will be disappearing. This shift is more far-reaching and faster than gradual technical developments. In our niche of the business, we are already referring to what we call “disruptive innovations”, and “game-changing inventions”.'
'It is far better to develop your own Uber Taxi and retain control over it than to relinquish it to the competition.’
‘Within Priva we have already developed all the knowledge we need to cannibalise our own products. If we were to introduce our new concepts on the market, our own sales figures would drop by half. But that’s not what it’s all about; you can also think in terms of possibilities. By considering new markets to tap into, for example. Of course, you don’t really have a choice: if you don’t jump on an initiative, someone else will. It is far better to develop your own Uber Taxi and retain control over it than to relinquish it to the competition.’
This interview was made possible by Tuinbouwvertalingen.nl. Photo: Priva.
‘The focus points of our brainstorming sessions are sustainability, sustainability and sustainability.’
Duijvestijn Tomaten in Pijnacker was elected ‘world’s best tomato grower’ in the Crop & Process Technology category in 2015. Ted Duijvestijn explains the innovative projects his firm is currently working on and what prompted their development. An interview with a passionate entrepreneur.
We are speaking to Ted Duijvestijn in his company’s Innovation Center.
Why do you have an Innovation Center?
‘When we switched from natural gas to geothermal heat we got a lot of interested visitors. And when we built the ID Greenhouse® in 2013, we realised that we needed a solution to be able to continue receiving visitors on this scale. This gave birth to the idea of the Innovation Center, with a big reception area and a balcony with a view over the entire ID Greenhouse®.
‘We attach great value to hygiene and safety. We can now receive visitors and show them what we do without any concessions to either hygiene or safety. Apart from that, we can now receive our customers in a pleasant environment while our day-to-day operations can be carried out without any disturbance.’
What prompted you to choose that name?
‘Our firm has grown step-by-step to 14.5 hectares. After the last expansion we asked ourselves: “How shall we continue: will we try to cut as many costs as possible or are there other opportunities for growth?” We decided that our greatest affinity lay in the field of innovation and that this is precisely where new opportunities can be found. This is our Innovation Center. We regularly hold brainstorming sessions here. This is where we discuss how to respond to changes and what is really important to us. These discussions have generated several innovative projects, such as the ID Greenhouse®. The focus points of our brainstorming sessions are sustainability, sustainability and sustainability. And of course, we always ask ourselves when we come up with a new idea: is it commercially viable, what will it bring us?’
Did you decide to switch to geothermal heat because it is sustainable?
‘Sustainability was a key issue when we made this choice, but our investment had to be profitable, too. We made the switch in 2011. This summer we even had a heat surplus on account of the warm weather. Due to the EHEC crisis we also had a tomatoes surplus, so we came up with the idea of producing oven-dried tomatoes. This is responding to long-term developments and seeing if you obtain a position in a new market. Of course, there is also the financial aspect to consider: can you get funding and develop more know-how? What happens is that you learn new things that take you another step further. We designed a machine dries tomatoes using geothermal heat. We conducted tests on content, taste, temperature, time, varieties - we tested everything we could possibly think of.’
Duijvestijn shows the result with due pride: wedges of dried tomato, in small round containers and in different flavours. The tomatoes were grown on the Duijvestijn premises and are marketed as “Frezta, oven-dried Dutch tomatoes”.’
Isn’t ‘oven-dried’ misleading? They aren’t dried through and through. like most dried tomatoes.
‘They are semi-dried and we add seasoning plus a little oil. You do have to store them in the refrigerator.’
Was it difficult to find distributors?
‘We are still working on it. It is a question of getting distributors interested and gradually building up a market. We can now count several supermarkets, restaurants and delicatessen shops among our customers. In addition to the tomatoes, we also developed a tapenade that market under the name “Tomade”.’
The next innovative product you came up with was the ID Greenhouse®.
‘Looking at new greenhouse systems, we didn’t see many developments that would actually take you a lot further. The frames became higher, that was all. What’s really important is light. Another key topic is energy consumption, even if you have geothermal heat. We wondered how you can combine the two and further optimize your use of energy and hit upon the idea of double glazing. The K factor (thermal conductivity coefficient) of double glazing is twice that of regular single glazing. So we launched a pilot, in collaboration with the Wageningen University Research Centre, based on the VenlowEnergy Greenhouse study that was being conducted at that time. This resulted in the ID Greenhouse®, with a surface area of one hectare. This lets you perform tests on a substantial scale, without being too small to get genuine results.’
How does the ID Greenhouse® distinguish itself from other greenhouses?
‘The ID Greenhouse® has diffuse double glazing with panes measuring 3x2 metres; twice as big as conventional panes. The greenhouse is tilted, so that the rows are at right angles to the cover. We chose this construction because it lets you get as much light as possible to the crop. This construction consolidates the power where it needs to be in the greenhouse. As the screen runs from gutter to gutter, the screen package closes beneath the gutter and barely takes any light away. A tiny grille at the top edge of the ridge vent prevents rain from coming in when the ventilation grid is left slightly open. The exterior has a sloped wall to reinforce the frame. Besides that, you can mount equipment onto it, such as air handling units.’
Does the greenhouse meet your expectations?
‘We chose this greenhouse to grow tomatoes with smallest energy input possible. The first year we used it we received some guidance from Wageningen University Research Centre and were able to achieve energy savings of 60 per cent, by using only low-quality heat. The water from the geothermal well is 75°C. In the standard greenhouse this is cooled to 45°C - depending on the return flow rate - and is then transported to the ID Greenhouse®. The challenge is to cool the water in the ID Greenhouse® down to 25°C, which means that you’re making optimum use of the geothermal energy. After using it in the standard greenhouse you get your heating water practically for free, but in the first year we unfortunately had to make some concessions to quality.’
So the greenhouse isn’t performing satisfactorily?
‘The level of quality rises every year, as is already apparent in the second year. During the first year it is particularly important to ensure that all your equipment is functioning properly. At this stage, it doesn’t pay to spend a lot of time making all sorts minute adjustments to your climate settings in an attempt to take things to the next level. Now that we’re in the second year we aim to achieve savings of 50 per cent, in combination with a higher production at the right level of quality. In first year we achieved our goal of 50 per cent, but not the production level we were after. The biggest problem was related to light loss on account of condensed moisture on the glass. Both the interior and exterior glazing had been provided with an HR coating to prevent light reflection, because you want to get the same amount of light inside the greenhouse that you would with conventional glazing. This coating creates tiny pyramids on the glass, as it were, onto which droplets of condensed moisture cling. We have since removed the coating on the inside. Now the moisture can flow away more easily. A small percentage of light is still lost in comparison to single glazing, but compared to last year we have gained 5 per cent more light.’
So the greenhouse is performing satisfactorily after all?
‘It’s too early to really say anything about it. We aim to compensate for the loss of light through the frame. You can come up with the best ideas on the drawing board, but you never know how well something is going to work until you’ve put it into practice. Only then can a product be truly tested and will you learn more. The CO2 supply - from Ocap - was adjusted in this second year, for example. It failed to produce the correct values from time to time. Instead of the extension of the CO2 supply in the other greenhouses we managed to put together provisionally there is now a direct supply.
‘We achieved the envisioned energy savings, and now we’re working on raising our production level, step by step. After only one year you can’t rightly draw any conclusions; only after about three years can you truly say anything. In the meantime you identify the challenges, look for improvements and learn from your experiences.’
Is such a small ridge vent enough to meet for ventilation needs?
‘The air vents in the greenhouse had been fitted with mesh. As a result, insects could not enter the greenhouse, which means that we can achieve an even lower maximum residue level in our tomatoes. You could then get even more out of using natural enemies. However, the fine mesh obstructed the flow of air; particularly on days with little wind and warm, humid air. Weather conditions like that put a lot of stress on the plants. We therefore abandoned that idea, since stress has a negative impact on quality and production. Now that the mesh has been removed we are able to control the climate, in combination with the AHUs, more accurately.’
Do you expect more greenhouses to be built with double-glazing on the roof?
‘Taking into account the energy savings, our expectations are high. Economically speaking, however, there is still a way to go. Double glazing is still rather expensive.’
Duijvestijn Tomaten in Pijnacker was elected ‘the world’s best tomato grower’ in the Crop & Process Technology category in 2015 by a jury who also presented the accompanying Tomato Inspiration Award. The jury was composed of experts Gene Giacomelli (University of Arizona, USA), Ep Heuvelink (Wageningen University, the Netherlands), Stefanie de Pascale (University of Naples, Italy) and Tadahisa Higashide (NARO Institute, Japan). Duijvestijn Tomaten grows 14.5 hectares of primarily round and plum tomatoes. Besides these tomatoes, they also grow Silky Pink, an exclusive new variety of pink tomato with an exceptionally fruity flavour.
Visit the website Duijvestijn Tomaten.
Would you like to know more? Download the complete interview with Ted Duijvestijn on innovative projects such as geothermal energy, the ID Greenhouse®, CHP units, LEDs, geothermal energy-dried tomatoes and packaging made from waste foliage (login required).
Copy/photo: Tuinbouwteksten.nl/Theo Brakeboer.