Biogas facility in Hohenheim

Biogas facility in Hohenheim to become the core of the Baden-Württemberg bioenergy research platform

As of autumn 2006, the facility in Hohenheim is to convert to the large-scale transformation of biomass into electrical energy, gas, heat and fuel. Research will focus on which renewable materials work most efficiently with which technology.

The foundation stone was ‘laid’ in the grounds of the experimental station of the University of Hohenheim. However, this time it was not a stone but a lime tree. By planting this symbol of sustainability, Minister Peter Hauk and Professor Dr. Hans-Peter Liebig, Vice Chancellor of the University of Hohenheim, marked the start of construction of the most modern biogas facility in Germany and the kicking-off of the Baden-Württemberg bioenergy research platform. The Baden-Württemberg government is contributing a total of 2.4 million euros to the establishment of the bioenergy platform.

Planting a lime tree: Klaus Saiger, Managing Director of FairEnergie, Agricultural Minister Peter Hauk (2nd from the left), District Administrator Thomas Reumann, Mayor Margarete Krug and Vice Chancellor of the University of Hohenheim Prof. Dr. Liebig. The tree is referred to as “cooperation lime tree” or tongue in cheek as “tilia conspirata”

The “Unterer Lindenhof” experimental station is part of the University of Hohenheim and an ideal place for establishing the new biogas facility. Extensive stabling, field and grassland areas, laboratories and plant areas form a suitable environment for the recycling of biomass and are practically able to produce all the raw materials to be tested on site. The biogas facility can be used by all partners for research and development work, including the institutes of the University of Hohenheim and all other interested scientific and industrial institutions that are part of the interdisciplinary research platform.

In Sweden, biogas is mainly produced from residual biogenic wastes. The raw gas is washed to attain the quality of natural gas and, following compression, used as fuel in buses and cars.

Dr. Hans Oechsner, Head of the State Institute for Farm Machinery and Farm Structures at the University of Hohenheim, explains the concept: “We intend to carry out cooperative projects that also have a demonstrative character. Many institutions were involved in the planning phase and they came up with numerous complex approaches. We will focus on biogas production as well as biogas purification and utilisation.” The long-term intention is to replace natural gas with green gas produced from biomass, which will be used in petrol engines in cars. In order to achieve this, researchers will open completely new paths of inquiry such as testing the use of Stirling engines. “Stirling engines do not need much maintenance, which is a particular benefit in our work,” said Oechsner.

Oechsner is already working on procedural aspects that he hopes to integrate in the new pilot plant. One of his objectives is the fermentation of biomass without using liquid manure as substrate, i.e. solid waste fermentation. Other Hohenheim projects deal with the cultivation of plants that lead to particularly high biogas yields such as what is known as “energy maize”. The researchers are cooperating with commercial plant growers as well as with other research partners such as the State Institute for Agriculture in Weihenstephan.

Enormous know-how and experience are required

The outstanding research know-how in terms of bioenergy that the Hohenheim researchers have gained over the last few years is particularly advantageous for the projects. At the end of 2004, an ultramodern biogas laboratory was put into operation, enabling comparative examinations under controlled conditions. To date, the University of Hohenheim operates 384 small and 28 medium-sized fermenters in order to examine and optimise biogas production.

Feeding of a solid waste dosage system (volume: 45 m³) with renewable materials

“The biogas laboratory was practically the starting point of the whole. Now, we are working on the “upscaling” of the system. The new pilot plant is equipped with two large-scale fermenters, thereby expanding our opportunities. For example, we need these fermenters for investigating gas purification processes. Problems related to process control and process stability can only be examined effectively using large-scale fermenters,” said Oechsner. The purification of gas is extremely important because biogas consists not only of methane but also contains undesired trace gases that might damage combustion engines.

As part of the new bioenergy research platform, the researchers also intend to investigate the direct combustion of biomass for use in the production of heat. This might require the drying of biomass, which can be achieved with the powered combustion of the biogas in an energy efficient way. Another alternative for converting biomass into gas is seen in thermochemical gasification. Like anaerobic fermentation, this process also leads to gases – though through physical and chemical means. The bioenergy platform of the “Unterer Lindenhof” experimental station is also open to researchers, who wish to carry out further investigations associated with this technology.


leh - 19.05.2006
© BIOPRO Baden-Württemberg GmbH

For further information, contact:
University of Hohenheim
State Institute of Farm Machinery and Farm Stuctures
Dr. Hans Oechsner
Garbenstrasse 9
70599 Stuttgart
Phone: [phone] - 2683
Fax: [phone] - 2111
E-mail: [e-mail]