Nitrogen Emissions and Graphite Rain
Over the past few days, we have been able to read in the news that there are advanced plans for the expropriation of land in order to comply with nitrogen emission standards. I also read that there is no room for Tata Steel if pollution remains at its current levels.
When I read this kind of news, I always ask myself whether this could also become a likely scenario for our sector, greenhouse horticulture, and if so, for what reason.
It is fair to say that greenhouse horticulture as we know it today can be characterized as an industrial activity in which raw materials are used, gas for heat and CO₂, electricity for lighting, water and artificial fertilizers for nutrition. All of these inputs are necessary to supply Europe and the world with healthy food.
On one hand, our sector has the wind in its sails, as there is a strong shift towards a more plant-based lifestyle and high-quality greenhouse horticulture has much to offer in terms of circular cultivation. However, there are also a number of areas where the sector can pay closer attention and demonstrate to society that it is serious about transitioning to a circular business model.
Greenhouse horticulture has an ambitious goal of moving towards fossil-free cultivation, but this immediately raises the challenge of CO₂ supply, because current high production levels are partly the result of CO₂ enrichment inside greenhouses. Most of that CO₂ ultimately escapes through the ventilation windows, and the question arises as to how long society will accept this, as it cannot in itself be called sustainable. This argues in favor of more closed greenhouse systems in which CO₂ is better retained, and where outside air with a higher CO₂ concentration than inside the greenhouse is forced in via air handling units, or even via dedicated installations that extract CO₂ from the outside air and blow it in concentrated form into the greenhouse.
Anyone who has ever witnessed the mining of certain artificial fertilizers firsthand knows that it often involves high fossil energy consumption and a significant impact on the surrounding environment. So when it comes to artificial fertilizers, the greenhouse sector should explore whether the required nutrients could be obtained in a more circular manner.
Fortunately, clean water is sufficiently available in the Netherlands and does not appear to be a problem here, but in other parts of the world this is very much an issue, and for that reason serious efforts must be made to meet part of the water demand (for example for greenhouse cooling) through the use of (treated) salt water.
Regarding the use of assimilation lighting, it is important that the energy required comes from sustainable sources, and in the Netherlands this remains a major challenge at present, one where the sector certainly needs the support of the government.
If the sector continues to make serious progress in developing techniques in the areas outlined above, it can look to the future with confidence.
