Biogas plants have become well-known sights throughout Germany and are usually built according to standardised concepts. The biogas plant that is currently being constructed in the village of Zermatt below the Matterhorn presented the GICON Großmann Ingenieur Consult GmbH planners with a particular challenge. The geographical and climatic conditions of the area and seasonal waste variations due to seasonally fluctuating tourist numbers required them to come up with an individualised solution.
GICON GmbH is a consulting and engineering company that provides engineering services in all phases of the implementation of bioenergy projects. The independent company has already constructed a broad range of very different biogas plant types in Europe as well as in Asia and North America. In addition to Germany, the company is active in other European markets such as France, Switzerland and Poland. GICON’s branch in Konstanz specialises in the planning of bioenergy projects and has extensive knowledge of the utilisation of different substances, ranging from energy crops to agricultural residues and food waste.
The GICON engineers are able to put their vast experience to good use for the development of innovative concepts for the construction of biogas plants that are optimally suited to clients’ individual requirements. The new biogas plant that is currently being constructed at the foot of the Matterhorn is a good example of this. “The mountainside location imposed very particular planning and construction demands. We had to come up with innovative solutions that took into account the specific requirements of the area and the quantities of waste produced,” says Heribert Krämer, head of GICON’s Konstanz branch and of its Wet Fermentation Department.
Biogas plants are designed to produce energy-rich methane through anaerobic digestion of biomass such as kitchen waste or livestock manure. The resulting gas can be used for producing energy in combined heat and power stations and the fermentation residues can be used as fertilisers in agriculture. “The biogas plant at the foot of the Matterhorn will use the kitchen waste produced by the village of Zermatt, as well as liquid and solid sheep manure,” says Krämer explaining the basic principle employed by the Zermatt biogas plant.
The implementation of such a system requires a large enough site for the extensive construction work, and for the accommodation of the biomass storage tanks and the complicated technology. It goes almost without saying that this was one of the major challenges of the Matterhorn project, as the mountainous terrain restricted the space available to the engineers. “The construction area was very limited, which required us to shift massive quantities of earth in a rather confined space,” says Krämer.
This lack of space had a major influence on overall project design. Instead of constructing the facility above ground as is usually the case, the planners took into account the hillside location and decided to build most of the facility underground. This enabled the operator of the plant, farmer and hotelier Paul Julen, to build a new sheep and cattle barn on the roof of the biogas plant, thus making optimal use of the space. This was another challenge for the engineers. They had to find a solution that enabled Julen to keep the animals in the immediate vicinity of the biogas plants and ahere to strict hygienic and sanitary measurres to prevent the sheep from contracting infections from the stored organic material.
In addition, the operators had to ensure that they are able to correctly dispose of the village’s kitchen waste year round. The construction site was therefore chosen in an area that enabled waste to be transported to the biogas plant in difficult weather conditions including when there is a risk of avalanche in the winter period. “The project was rather complex and many different requirements had to be taken into account. Basically everything had to be specifically planned to meet the needs of this special location, starting from the selection of the construction site to the actual construction of the plant,” says Krämer. The operators and planners also had to take into account the fact that the biogas plant is located in a very attractive tourist area. “We had to ensure that holidaymakers would not be affected by unpleasant odours and that the system does not compromise the beautiful landscape,” says Krämer.
One of the biggest challenges was the extreme seasonal variation of the biomass used for the production of biogas. “During the summer months, and to an even greater extent during the ski season, Zermatt is a very popular tourist resort with a very large number of tourists, which of course leads to a significant increase in the organic waste that needs to be recycled,” says Krämer.
Since a biogas plant can only effectively handle excessive biomass quantities for a limited period of time, the Zermatt biogas plant had to be designed to be able to handle such large - and seasonally varying - biomass quantities. In addition to the large number of tourists visiting the area during the winter season, animal farming also adds to the unbalanced seasonal distribution of organic biomass. “During the winter months, sheep and cows are kept in barns where they produce manure. And this coincides with the ski season in Zermatt and the greatest influx of tourists,” says the project leader, referring to the special conditions that affected the project. GICON therefore had to develop a concept that ensured smooth operation during peak periods and the utilisation of the plant’s capacity during the off-season. The GICON engineers took these biomass fluctuations into account by setting up large tanks for storing manure that can then be used at times when less biomass is available.
Another important aspect that had to be taken into account was the isolated location of the biogas plant construction site. “If something goes wrong, that’s it. We do not have a plan B,” says Krämer. The engineers therefore put design emphasis on a plant that is easy to maintain and where the technical processes are kept as simple as possible.
The planning and design of the Zermatt biogas plant was an extraordinary feat. The remote location of the biogas plant would normally have required biomass to be transported there at relatively high cost. The objective was therefore to find a solution that would not be dependent on the transport of biomass. “The remote location makes the transport of the biomass rather costly, and also affects the transport costs of excessive waste that needs to be disposed of and of the external substrates that are required,” explains Krämer. After a lengthy planning period, the village of Zermatt now has an almost self-sufficient biogas plant where it can dispose of its organic waste and produce energy. It is expected that the biogas plant will become operational in late 2014 and produce between 500,000 to 700,000 kWh of electricity per year. This is enough to supply 200 homes with energy for a year.
For GICON, the biogas plant in Zermatt will be a model on which to base the design of future plants that need to take seasonal tourist variations into account. Krämer does not see much potential for similar projects in Baden-Württemberg. “Here we have a different infra- and waste disposal structure, which does not require the construction of biogas plants of the Zermatt type,” he concludes.
Further information:GICON Großmann Ingenieur Consult GmbHKonstanz BranchHeribert KrämerHead of Bioenergy/Wet FermentationTel.: +49 (0)7531-819950E-mail: h.kraemer(at)gicon.de