Marcel Dries has been an Energy Advisor at AAB for over ten years. But his career in energy goes back further and includes a long tenure at Westland Energie Services. At AAB, he guides and advises companies on contracting, futures trading, energy analyzes and budgets. Marcel specializes in technology, maintenance, lease and purchase contracts for energy installations, such as CHP. Drawing up feasibility studies for residual heat, steam supply, sustainable energy (such as geothermal heat and solar), calculation concepts for horticultural and industrial clusters are also among his areas of expertise. He does all this with enthusiasm and conviction.

“How can greenhouse horticulture become more sustainable and circular more quickly, what opportunities do you see with regard to sustainable solutions to realize this?”

Marcel: “I agree with the vision that we can achieve a lot of profit by linking greenhouse horticulture clusters to large-scale residual heat sources. The combination with CO₂ supply is essential , otherwise it will not work. Plants not only need heat, but also CO₂. If you get rid of the gas completely, you will no longer have any CO₂. That combination is therefore essential. I strongly believe that we, as a country, need to invest in an infrastructure for heat and CO₂. A kind of highway with which we connect industry, greenhouse horticulture and housing.”

“Other ways to accelerate sustainability are to continue and scale up geothermal heat, to focus on the large-scale reuse of biogenic CO₂, heat pumps for companies for which geothermal heat or residual heat is not a solution and even more LED lighting. Geothermal energy is in its infancy, but is now stalling due to a mismatch in the subsidy scheme. This is a task for the government. Just like making heat pumps affordable, by lifting the exclusion of greenhouse horticulture from subsidies. As for LED lighting, I think more research is needed to roll this out on a large scale. What are the effects specific to each crop? We know the main features, but if we know more about the plant behavior per crop, LED can be used more quickly on a large scale. This large-scale electrification does of course have an effect on the electricity grid in the Netherlands, which is already beginning to crack. Once again a task for the government, if you ask me, to solve the restrictions in the grid.”

How important are CHPs for greenhouse horticulture in the future?

Marcel: “Very important. Essential even for the next 10 to 15 years, I think. For a number of reasons. The investments in the solutions I mentioned earlier to make greenhouse horticulture more sustainable are high, with low variable costs. This allows you to absorb the base load of energy, but not the peak load. That is still much too expensive. CHPs are the most efficient way to deal with peaks in energy consumption. On the other hand, greenhouse horticulture can also play an important role for the Netherlands, by supplying energy when there is no wind or sun.”

“So yes, I think that CHP will certainly be of great importance until 2040, but in a different role than now. In the long term, CHPs also run on hydrogen or green gas.”

Statement: Greenhouse horticulture in the Netherlands is scaling down and is increasingly moving to Southern Europe, because less greenhouse heating is needed there and therefore CO₂ emissions will be lower. Agree or disagree?

Marcel: “My answer is nuanced. I partly agree when it comes to the winter production of some vegetables. You can already see a shift in that. More and more companies are collaborating with companies in Spain and Morocco, for example. In winter, the climate in these countries is perfect for growing fruit vegetables. Not in the summer, then it is too hot. The quality is usually lower. So the question is: what does the consumer want? I therefore do not believe that the Dutch market for these vegetables will disappear completely, but shrink. There will always be consumers who want a high-quality summer product in winter and are willing to pay more for it.”

“I don't believe in it for floriculture. The supply in the winter will fall and the price will rise, it will become a luxury item for consumers who will pay a lot of money for it in the winter.”

Sustainability goes beyond reducing CO₂ emissions. In which area of ​​greenhouse horticulture do you think more can be achieved by making it more sustainable?

Marcel: “I have six points: recyclable packaging, reuse of plant residues, 100% recirculation watering (optimization of disinfection), biological crop protection, increasing water storage (under greenhouse, larger basins) and linking to residential areas/industrial estates that become more sustainable via external heat. All these things are already happening, but I think there is still more to be gained here.”

Proposition: The ambition of Greenhouse Horticulture Netherlands is that by 2040, CO₂-neutral cultivation of the entire greenhouse horticulture sector is feasible. Agree or disagree?

Marcel: “That is feasible, but under a number of conditions. Then I come back to my answer to the first question, that I believe that our country needs a heat infrastructure. It must come; someone has to take the initiative in this. In my opinion, this should be the government. Just as the country built gas pipelines within a few years in the 1950s and 1960s, the same should be the case with the heat network. After all, we have to get off the gas at some point. And no one is just going to build a heat infrastructure on their own - the government should facilitate this.”

“Other important conditions for achieving this ambition are: SDE on geothermal heat, residual heat and CCU CO₂; bottlenecks in the electricity grids must be removed so that solitary (clusters of) companies can switch from gas to full lighting with LED from the electricity grid and electrical heating with heat pumps; SDE geothermal heat/residual heat price reference on CHP (spark spread coupling) instead of 90% of boiler heat costs. The latter is necessary because CHP will remain essential for the energy supply of greenhouse horticulture as the most efficient fossil energy source for the next 10 to 15 years and will provide flexible electricity in the absence of solar and wind energy. That is why, in my view, CHP heat will remain the market price-determining factor for the next 10 to 15 years.”