energy savings

In part 2 of this interview, tomato grower Ted Duijvestijn speaks about how he aims to operate his business without any need for fossil fuels, reduce environmental pollution caused by packaging waste and grow even healthier tomatoes using LED lighting.

Would combining a CHP unit with geothermal heat be viable?

‘We only use them as a back-up for geothermal heat. Our tomatoes aren’t grown with assimilation lighting, so we don’t need the CHP units for that. We do have one CHP unit that’s constantly in operation. It runs on gas from the heat well. The water from the geothermal well apparently contained methane gas. An old 0.9 kWh CHP unit was used to assess the possibility of using this by-product. As soon as it became apparent that we could, we bought a new CHP unit with a little more capacity that could be run at full capacity on the by-product. With this CHP unit in addition to the geothermal heat we have exactly as much energy as we need. We can independently provide in 100% of our energy need.’

Do you really need that back-up?

‘The geothermal heat well initially met all our expectations, but we experienced a problem in March 2015 when the pump got disconnected. It was anticipated that this pump was located 400 meters below the surface and we had to “fishing” for it. We were able to retrieve the motor, but the pump had sunk to a depth of 2,400 metres. We tried to get it our using a cable with a grapnel. After fourteen attempts we decided to give it one last try and were successful.

‘That’s the problem with new technology; you simply don’t have everything fully under control. Initially everything was running smoothly, with a flow rate of 90 up to 185m3/hr. After some time, the return water was no longer absorbed as easily into the ground; the rate dropped to 60m3/hr. We then discovered that it contained gas. The deeper you get, the warmer the gas becomes and it expands, which makes pumping more and more difficult. We then halted operations. Some relief was brought by a separator, which is now being used to retrieve the gas from the supply pipe that fuels the CHP unit. All of this caused us quite a headache. We had to adjust the process three times before it finally worked properly.’

Were you taking too big a risk when you switched to geothermal energy?

‘Innovation is always paired with risks. You could just as easily say: “I prefer not to take that risk”, but that only leads to stagnation. Fortunately, the government can lend a helping hand by supporting, stimulating and acting as a safety net. Ultimately, all the risks such a business case entails are covered sufficiently. It is very important that innovative projects are backed by the government, because they serve a higher purpose, after all. The entire sector can benefit from the know-how thus gained. Besides that, you can use geothermal energy for a multitude of purposes. Look at our oven-dried tomatoes, for example.’

What else can you do with geothermal energy?

‘Numerous conventional uses come to mind: supplying energy to third parties, such as nearby residences. What will the distribution of geothermal energy be like five, or even ten years from now? The real estate market is continually evolving. It is becoming energy neutral, and as a result discussions are taking a completely new turn. If you enter the market for residential energy supply, you may notice that the situation has changed entirely within the space of five or ten years. You have to calculate that into your plan, too.’

Your geothermal energy project got a lot of attention.

‘That was unprecedented. The first year alone drew over 4,000 visitors from all wakes of life: from ministers to students and from colleagues to interested parties from numerous branches of industry, all with a common interest: sustainable cultivation. From this, you notice that sustainability is becoming increasingly important. These visitors are very important to our firm. The discussions you have with them often lead to unexpected and new insights. They ask smart questions, which forces you to come up with smart answers!’

You are participating in a project for wind turbines. Why? You’re already growing tomatoes on an energy-neutral basis.

‘We aim to become even more sustainable. We want to be entirely fossil fuel-neutral; and that extends to our electricity consumption. We brainstormed on this topic, too: how can this be achieved? We came to the conclusion that you should investigate wind energy, specifically. We learned about a wind turbine initiative in the direct vicinity and decided to participate. This project met with some resistance, so the outcome is still rather uncertain.’

Duijvestijn Tomaten also collaborated on a project that makes cardboard packaging from waste foliage, joining forces with other growers as well as the Smurfit Kappa cardboard factory and the Van Vliet waste treatment company.

Why make packaging from your own waste foliage?

‘It creates residual value. We recently designed packaging to our innovative “Silky Pink” cocktail tomatoes, in collaboration with Rijk Zwaan and The Greenery. I always consider waste a thorn in my side. I like to prevent waste, and so we hit upon the idea of a box made from waste foliage. Nevertheless, the challenges you meet with are becoming more and more complex. You need a different perspective and a different approach. And you need to look at things from a different angle: not from an economical point of view, but by thinking about sustainability. You are doing something society believes in: the bio-based economy, sustainability. These are demands you can respond to wholeheartedly.’

To you, sustainability is not simply a catchword.

‘Absolutely not. There is nothing I hate more than wasting food. You have put everything you have into your product: time, energy, labour, nutrients, attention, love - and that’s being thrown away as if it were nothing! I therefore wholeheartedly support the “Kromkommer” Project (ed. Kromkommer is a contraction of ‘crooked’ and ‘cucumber’), in which odd-looking vegetables and fruit are put to use instead of thrown away. Why throw them away? There’s nothing wrong with them. Supermarkets only want perfect products, and that’s only becoming worse. Many products are therefore not suited for sale to supermarkets, while consumers actually couldn’t care less how straight or crooked their cucumbers actually are.

Do you derive inspiration from this for your own firm?

‘Kromkommer is endeavouring to create a more honest chain to alleviate strain on the environment. From the same perspective we also develop products, test them and assess their market potential. Consider our oven-dried tomatoes. You could fill a container of these only halfway, fill the rest with oil, and offer it at a cheaper price. That puts you in a more competitive position, but we’re convinced that this approach is not viable in the long run. Our preferred target audience is composed of conscious consumers. This group may not be large now, but it is growing. Even senior citizens are becoming more quality-conscious and can afford luxury products. And health freaks may be willing to pay a good price for a good product, but the information you present alongside your products has to appeal to them.’

Is this why you produce extra healthy tomatoes?

‘We are investigating this. Wageningen University Research Centre discovered that LED lighting on sprouting tomato bunches produces fruit with a higher vitamin content. We are now trying this out in the ID Greenhouse®. We are testing the effect of LED lighting on the fruit and expect this to bring us even farther in the future. We have also launched a photosynthesis study among LEDs with a view to further optimising our production. However, if all you are taking into consideration is the cost price, this won’t bring you a step further.’

You regularly mention Wageningen University Research Centre.

‘We have a joint venture with the research centre and with various schools. Many of our visitors are students. I like that fact that they don’t pass instantaneous judgement; they never say: “that’s impossible”. An attitude like that allows you to transcend borders. If you promote that, you will go far. You can build on that. And it’s good training for them. Training and education are becoming increasingly important.’

Can you, as a business, keep abreast of all the new developments?

‘Developments come and go at a rapid pace. This puts a lot of pressure on you. However, you can never keep up with all the developments. You simply have to let go. You shouldn’t let this take the upper hand. You may think you can take control of all the developments, but if you’re not careful they will be taking control of you. The dividing line is very thin: innovation is fun, but it brings a lot of risks with it. On the other hand: if you don’t jump aboard the bandwagon, you won’t be able to travel far.’

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 of Duijvestijn Tomaten-Nursery.

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.