CULTIVATION AND TECHNOLOGY Solar panels on the potato storehouse is an excellent investment A large sign at the beginning of the road to the De Bruijne Agro crop farm and contracting firm reveals the presence of solar panels before you arrive at the farm. The sign tells that the alternative source of energy was installed with a subsidy from the European Agricultural Fund for the Rural Development (EAFRD). The subsidy for the project has to be displayed for five years, says Marco de Bruijne a little later. The Dutch growers organisation ZLTO and the Province of Zeeland applied for subsidy for the instalment of solar panels for interested members in Zeeland two years ago. One of them was the General Partnership of the two brothers Marco and Meeuw de Bruijne. ‘The subsidy application came at exactly the right moment for us’, says Marco, who is doing the talking. ‘Up to 2012, we didn’t have enough storage space at the farm to store all our potatoes and onions, which is why we leased a storage elsewhere, but that was quite far out. We really wanted to have a good overview of all our stored products, which is why we decided to build a new storehouse on our own farm two years ago. De Bruijne Agro’s idea was to build a twin next to an already existing, yet relatively new storehouse (1994) with an identical layout and design. A storehouse constructed in the same way as the already existing storehouse. The new storehouse is also insulated and can hold 1,000 tons of produce, it is divided into two compartments, both provided with above-ground ventilation ducts and related equipment. The storage of potatoes requires the most electricity Just as the brothers started preparations for the construction of the new storage, ZLTO asked if they wanted to take part in a joint subsidy project for the instalment of solar panels. ‘We’d placed the order for the construction of the new storehouse with Hanse-Staalbouw in Nieuwerkerk and this company had been working closely together for some years with the Saman Group in Zierikzee, an installation company that’s specialised in the installation of solar panels. That was a happy coincidence because, together with these two parties, we started to examine the best possible ways to install as many solar panels as we could on the most favourable terms. De Bruijne explains that the storage of potatoes and all the activities around it require the most electricity on the farm. In total, a quarter of the overall acreage of 100 hectares is used by the General Partnership to grow consumption potatoes (Agria, Victoria and Markies). The potatoes require around 75 percent of the total storage capacity of 2,000 tons, the remainder is being used for seed onions. ‘You barely get back one-third of the current electricity rate (VAT included) for your over-capacity.’ Always a bit below the annual requirement De Bruijne can’t say exactly how much energy the potato uses of the total energy consumption. He does know the total annual usage on his crop farm, which is approx. 35,000 kWh. Daniël Lodders, Director of the Saman Group, explains that in this case, he recommended an installation of approx. 30,000 kWh. ‘It’s advisable to stay a little bit below the annual energy requirement. When the solar panels provide more energy than you use yourself, the extra capacity will go to the electricity company. The statutory netting scheme, recently extended until the year 2020, stipulates that you may offset your own electricity use against the over-capacity that was returned. However, you barely get back one-third of the current electricity rate (VAT included) for your over-capacity. That price is too low to make any extra investment in solar panels profitable in the short term’, Lodders explains. According to the factory information, the 132 solar panels installed on De Bruijne’s roofs supply 240 kWh per panel, which adds up to a total of 31,680 kWh. They placed a few extra panels on the roof in order to fully utilise its width, so that exactly four rows of panels could be installed over the full width of the roof. In the storehouse itself, two current transformers were installed, which convert the direct-current of the solar panels into the alternating current of the existing electricity network. A large sign at the beginning of the road to the De Bruijne Agro crop farm and contracting firm reveals the presence of solar panels before you arrive at the farm. More energy through more Zeeland sun So far, De Bruijne is very enthusiastic about how his solar panels function. They even yield 5 percent more energy than promised, he shows us on his computer. He can show the generated electricity with a special programme, which was part of the installation with which he can read out all the details of the solar panels on his computer, smart phone, or tablet. The fitter, Lodders, can fully endorse that De Bruijne’s panels yield more energy than expected. ‘In the province of Zeeland, the number of sun hours is higher in many places than the national average. This means that the installation yields 5 percent more after the first years of installation than what the leaflets say. However, over the years, the electricity yield decreases by about 0.7 percent a year. This isn’t much, which means that 16 Potato World 2015 • number 1 Pagina 15
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