Energy transition in greenhouses
Dutch horticultural sector is already circular: more and more energy is renewable, there are many savings, rainwater is collected to be used for production purposes. Less water, less pesticides is good for the environment, but also good for the business.
Also in Poland this trend is visible. But considering the fact that many Polish greenhouses are heated with coal and coal will be sooner or later phased out, it is the right moment to think and implement circular solutions on energy in the greenhouse production.
Greenhouse and energy
‘Kas als energiebron’ is a programme of the Dutch government made together with growers and researchers in order to work on innovations and implement best results of diverse reaserch on energy in greenhouses. The whole programme is financed both by the Dutch government and the sector itself. At this moment 70% of greenhouse owners are member of the platform and almost 10% of the energy they use for greenhouse production is already completely renewable. The results of those research projects are public and every grower can check the announced solutions of the programme to improve own production.
The programme of ‘Greenhouse as energy source’ is made with growers and for growers. The focus lies on implementation, it has to be as practical as possible. On the moment growers are interested and involved at the very beginning of every project, they will also be interested in the whole process and results. In this way projects realized by the Programme perform better as they are oriented on practice, not theory. With this approach however more options are possible. Therefore every project has to be flexible and open to conduct it in multiple options.
Energy costs in Netherlands are high. In a greenhouse even 20% of the total production costs is caused by energy. Therefore it is an important factor for every grower in the Netherlands. But also consumers ask questions on renewable energy, climate change and sustainability. Therefore also from consumers there is a pressure to improve energy balance in a greenhouse. There are loads of reasons for grower to be interested in energy.
Already now there is the possibility to lower the energy usage around by 1/3 with the current technology and energy savings. The other 67% has to be done by new implementations. In the Netherlands thermal heat plays a major role. Other possibilities to change energy system are: green electricity, waste heat etc.
At this stage it is still impossible for the Dutch growers to run a greenhouse fully on renewable energy. But many of them follow (and this is a very good advice for every greenhouse grower) to follow the latest R&D on heating and on LED lighting solutions. Energy will be only more expensive, therefore it is good to think ahead.
One of the easiest ways to increase energy savings in a greenhouse is to use thermal screens, covers that isolate the production from outside. It doesn’t have to be an expensive material like glass. For plants less vulnerable for light artificial bubbles can also be a solution. Another way is to put an extra layer diffuse sheets, that will take care for extra isolation but won’t affect light transmition to the greenhouse.
The transition is on the way to achieve goal. Research and technical developments will only improve and even if not everything goes smoothly, it is never a reason to stop trying.
Savings made by isolation can lead potentially up to 70% of the total energy consumption in a greenhouse. Choices on energy implementation should be considered based on local circumstances and possibilities but there are always ways to improve energy balance in a greenhouse.
The whole production is connected with each other. With intense crop production cycles more intensively artificial light will be used. For sure this will cause energy increase. Old HPS lamps produce heat as well, so together with switch towards LED lightning also heating in a greenhouse will probably increase.
Also in the Netherlands it is not always possible to use thermal heat which is popular energy source in the Netherlands. But there is no one general solution. In such cases many producers decide to install heat pump and combine it with underground storage. A biomass boiler is also a solution that can be used in a greenhouse. The solution is always local available, the owner should look for possibilities locally.
This article was made based on a webinar on circular energy in greenhouses. The whole webinar can be seen here.
TerLaak greenhouse- one of the kind
One of the nicests examples of the modern energy technology is the TerLaak Orchids greenhouse. With its investments the owners of the greenhouse managed energy savings of 40-50%. It is remarkable considering the fact that at the same time, they increased their production and quality of sold products (potted Phalenopsis plants). From the very beginning TerLaak worked closely with the platform ‘Kas als energiebron’. They started small- with 1m2 greenhouse only. Two years later the company built a greenhouse of 400m2 to run tests together with Wageningen University. TerLaak put there also Phalenopsis plants of own production to look for the results of the new technology. It was satisfayng in such a way that couple year later the company decided to build a completely new object in Wateringen. On the surface of 5ha only Phalenopsis plants are being grown. The greenhouse is equipped with so called ‘following sun system’ where black pipes with water are heated by the sun rays and where the point for heating is the best during the day.
TerLaak Orchids thinks holistic and sees savings also on other fields: the greenhouse works on rainwater that is stored in a big pool and in a tank in the ground. Water is cleaned with reverse osmosis and used in the greenhouse. The resting water after production cycle is cleaned again and comes back to the system. The water that cannot get the right production parameters is also cleaned and oxygenated and only then utilized.
Also CO2 that is needed for plant production is received from a petrochemical industry, therefore the gas emission is going down.