Green Energy Through and Through

Hannes Kuhnwald has been an operations manager for six years. He manages a farm, an agricultural contracting company and a biogas plant with an annual output of 550 kilowatts – at 24 years of age. You can see that he enjoys the work. The native of Friedland took over the operation from his parents, who laid the foundation stone for the company in 1990. Kuhnwald's hobby horse is the biogas plant biogas plant , which is in an easily visible position in front of the gates of the small town in Mecklenburg-Western Pomerania. To make the processes as optimal as possible, he likes devising innovative concepts, and is constantly thinking about new possibilities and methods.

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Hannes Kuhwald (left) and Philipp Brandt of Raiffeisen Uckermark inspect the processed silage from the hammer mill together.Green Energy Through and Through
Hannes Kuhwald (left) and Philipp Brandt of Raiffeisen Uckermark inspect the processed silage from the hammer mill together.

"Originally, our plant was designed for maize and manure", Kuhnwald remembers. Until recently, his family still owned 400 fattening bulls. Additionally, therefore, further sensible use of the liquid manure was a key issue. However, 400 hectares of grassland also belong to the farm. As the bulls have since been sold, there are no consumers for the grassland fodder. Due to its actual design, Kuhnwald continues, the biogas plant is able to process dry and long substrates. The 24-year-old therefore switched and now feeds the plant a daily mixture consisting largely of grass and supplemented by manure and maize. One problem with the plan, however, was that grass, in particular, has very different dry matter (DM) content.

The DM content currently stands at just under 50 percent. That is too much for Hannes Kuhnwald: "The wetter the silage is, the better". He added that 30 to 35 percent was perfect. To achieve these values, he said, he could mix different cuts. But Kuhnwald wants to avoid this intermediate step. He has therefore acquired a hammer mill, which further shreds and defibres the grass that has already been cut. This enabled feeding of the biogas plant to increase from between six and seven tonnes of grass a day to around ten tonnes – albeit not without its problems. Although the silage was wetter, it often proved to be stodgy and tough during the stirring process in the fermenter. The risk of floating layers also increased.

The operations manager therefore contacted his former fellow student, Phillipp Brandt, Agricultural Trade Sales Consultant atRaiffeisen Uckermark. Raiffeisen Uckermark. Together with Dr Andreas Milimonka, AGRAVIS Raiffeisen AG expert in biogas biogas and ensiling ensiling , Brandt took the product Methaferm Grass with him to Friedland. "Methaferm Grass contains a specially selected enzyme mixture, which has been designed specifically for grass-based feeding. Splitting of the cellulose and hemicellulose is accelerated and the biogas process thereby aided", Brandt explains. The advantages of the enzyme are a faster throughput with the same or improved substrate utilization, optimized flow properties due to reduced viscosity, a much lower risk of floating layers, better digester utilization, a more stable biogas process and increased gas yields.

Everything was confirmed with regard to Hannes Kuhnwald's plant: "One test, one hit." Kuhnwald spreads 100 grams of the enzyme per tonne of dry matter over the grass silage, before adding it to the hammer mill. He now feeds up to 13 tonnes of grass a day and has one percent more methane in terms of gas yield.

The collaboration between Kuhnwald and Brandt began with the sale of fertilizers fertilizers and the purchase of grain. Now, a very close collaborative partnership has developed, also due to the enzyme use. It ranges from seed consultancy seed consultancy to the biogas process. The two partners also wanted to improve storage of the silage and grassland management grassland management . Philipp Brandt recommended a special mixture from the Plantinum programme Plantinum programme , which takes account of the fact that Kuhnwald has many bog sites. Furthermore, he is advising him with regard to ensiling. "By using ProFerm, we intend to minimize the ensiling losses and produce more grass per hectare", Bandt explains.

You can find out more about the subject of grass silage for biogas plants from Phillip Brandt, Raiffeisen Uckermark, Tel. 0152 . 64960740, p.brandt@raiffeisen-um.de or from Dr Andreas Milimonka, Tel. 0172 . 5303182, andreas.milimonka@agravis.de.

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