ProfiNRG enables large-scale deployment of solar panels on greenhouses
Solar energy is the most popular source of renewable energy among Dutch greenhouse farmers. However, mass installation of solar panels on greenhouses is not yet a reality. 'It is therefore new and there are many complicating factors,' says Cees van de Werken of ProfiNRG. 'Nevertheless, the opportunities are great. We proved that in Luttelgeest, where we installed an 8.2 megawatt peak solar system on a 4-hectare greenhouse complex using our special mounting system. In our pipeline are dozens more such projects.'
The realisation of large solar fields is usually done on agricultural land. That zoning is then exchanged for renewable energy production. With Agri PV, things are different. There are various types of mounting systems that make it possible to combine both functions. Laying solar panels on greenhouses can also be seen in this perspective; a form of dual use is created. And this is increasingly interesting for greenhouse farmers, according to Cees van der Werken.
Wonderful solution
'1 in 3 Dutch greenhouse farmers have solar panels. 20 per cent of them are considering investing in them, AgriDirect's latest survey showed. This is not surprising. Those active in that sector are also keen to become more sustainable to contribute to the energy transition. Moreover, with the astronomical energy prices at the moment, there is a real problem. Costs are spiralling out of control, many companies are struggling. This also leads to an increasing intrinsic need for more autonomy in energy supply. Putting solar panels on greenhouses on a large scale is a wonderful solution. But it is not without its challenges; in a technical sense and because it interferes with a greenhouse farmer's business operations.'
Huge size
ProfiNRG was in the news in mid-2021. The PV installation it realised in Luttelgeest for developer Zonnewijzer went online. The solar power system has as many as 20,000 solar panels good for a peak production of 8.2 megawatts of green power. That is enough to supply 2,200 households with their electricity needs. What makes the project really special, however, is that the system covers 4 hectares of a greenhouse complex; it was the first time that solar panels were laid on greenhouses in this huge scale as standard in the Netherlands. This was partly made possible by the special mounting system developed by ProfiNRG for this application.
Big advantages
The construction of greenhouses is usually not designed to support the weight of solar panels, which is not what they are intended for. Placing solar panels above the existing glass is therefore generally not possible due to the limited load-bearing capacity of the greenhouse construction. If you replace the glass with solar panels, you run into dimensional problems, at least if you don't use standard solar panels. The mounting system we developed offers the solution. We remove the glass from the roof of the greenhouse. Then we mount our profile system on the rods. We slide solar panels into them. This has several advantages, first of all structural. A PV installation must run smoothly for 25 years and also remain in place in heavy weather. Our mounting system provides the necessary robustness. It is also waterproof while facilitating natural ventilation. This is very important as it can get well over 40 degrees in a closed greenhouse. This reduces the efficiency of the panels. In addition, it is a cost-efficient system because we work with standard solar panels available on the market and the construction costs are almost equal to those of an average solar field.
Positive business case
The greenhouse complex in Luttelgeest will get a second life as a green power plant with the installation of solar panels. At the same time, the greenhouse will remain available for growing crops. What these will eventually be and how this will be done is still unclear. Time is needed to experiment; after all, the microclimate in the greenhouses is changing substantially.
'With our greenhouse PV system, solar panels can be seamlessly joined together,' says Van de Werken. 'This allows for maximum solar power generation. This contributes to a positive business case of this type of SDE++ projects. But every advantage has its disadvantage. If you place a large-scale solar energy system on a greenhouse, it will inevitably affect the incidence of light and temperature management. You can play with that, for instance by using solar panels on one side only - with our solution, the solar panel can be arranged freely. Still, switching to a more low-value crop will not infrequently be necessary, and that is of course exciting for an entrepreneur.'
Optimal balance
Van de Werken was one of the Dutch pioneers in PV. He started his first solar energy company in 2009. Three years later, he entered the business market for solar power with ProfiNRG. With this, he initially focused mainly on the agricultural sector under the motto 'Farmer's understanding of solar panels'. In this way, he followed not only his mind, but also his heart.
'I am a horticulturist's son and not the only one in our company. We have a great affinity with greenhouse farming, know the challenges and know what's going on. At a time when energy costs weigh so heavily on operations, PV is a great way to generate extra income. It is then a matter of finding the optimal balance between the two functions and that is where ProfiNRG is happy to help. There are also many greenhouse growers who are considering quitting, or have already done so. Realising a solar energy system on a greenhouse is also worthwhile in those cases. With our system, there can be a good earning model from as little as 1 hectare. We now have dozens of such projects in the pipeline, some in early and others in advanced stages. We currently visit greenhouse growers with an interest in such a system on a weekly basis, which is particularly pleasing because in many cases we can help them on their way to an additional or alternative source of income.'
Read here. The article of the PV installation in Luttelgeest.
