Building on the existing 800 kilowatt biogas site which went live in 2014, the plant has been expanded further and focuses predominantly on a mix of cattle slurry and energy crops. The raw biogas is converted into bio-natural gas using physio-organic washing processes and then fed into the regional natural gas network of the Brandenburg utility company, E.ON-E.DIS.
All in all, the expanded plant now processes approximately 70,000 tonnes of slurry, 50,000 tonnes of maize silage, and 7,000 tonnes of solid manure. In turn, around 75 million kilowatt-hours of gas and heat are generated from these materials. In real terms, this volume supplies heat and electricity to approximately 16,000 households.
To this end, three fermenters and two secondary fermenters with a fermenting volume of around 23,000 cubic metres in total have been installed at the biogas plant as well as six digestate storage tanks with a holding capacity of around 42,000 cubic metres. A pump line measuring approx. two kilometres in length ensures the efficient and ecological transportation of substrates, the slurry is delivered by a dairy farm directly to the biogas plant.
“With this layout, this biogas plant ranks among the largest in Germany in tank volume and gas production, particularly setting functional and operational benchmarks,” emphasises Greenline Managing Director, Frank Nielsen.
“High quality, low production and operational costs, and a high degree of automation in new construction and flexibilisation projects are all helping to establish biogas production as the standard energy alternative in the market of regenerative energy sources going forward,” adds Nielsen. In particular, thanks to the latest EEG amendment and the modified framework conditions for approval, efficient planning concepts and low building costs are fundamental to the chances of executing biogas projects. Furthermore, waste plants for foreign markets with CO2 certificates are becoming increasingly more important. Here too, competitive kWh generation throughout the operational period plays a decisive role.
The biogas plant was built according to industry standards and went into operation in June 2016. The location is the industrial district Lenzen in Brandenburg. Greenline was the general planner of the biogas plant, which uses the substrate compound of sugar beet, grass silage and maize.
Plant operator is Biogas Osters & Voß GmbH & Co. KG with its head office in Groß Gottschow.
During the construction of the plant, great importance was attached to a quality-oriented selection of components and material as well as to functionality that is operator and safety-oriented. Despite high standards, the customary manufacturing costs have been clearly undercut.
A total of about 56,000 tonnes of maize, grass silage and sugar beet are fermented annually in the plant and about 12 million standard cubic metres of biogas are processed. The concept envisages a combination of steel enamel containers for the fermentation and concrete containers for the post-fermentation or digestate storage. Due to the structural height, high-rise steel fermenters feature a high vertical natural convection and therefore low energy consumption. In combination with a central agitator, even problematic substrates can be processed economically. The concrete containers as finishing components are very suitable as a combination for cost reasons.
In a newly constructed ready-mix concrete mobile silo, about 30,000 tonnes of substrates are stored. Vertical walls with U-shaped parts were used for chamber division. Poured asphalt was used as an acid-resistant top coating in the beet chambers.
The maize and grass silage feed system consists of a compact solids container. The sugar beets are put in into an acid-resistant stainless steel hopper screw.
The gas is processed into organic natural gas by organic-physical purification and fed into the regional natural gas network of HanseWerk AG, formerly e.on Hanse.
Durability, high degree of automation, low maintenance and operating costs, coupled with a high profitability of the plant, were the inspiration for the entire general planning. Accordingly, a plant layout has been developed which optimally takes into account the procedural requirements of process biology and the underlying conditions in terms of licensing aspects.