The biogas experiment has been a success - this summarises the experiences of Stadtwerke Gießen after the first year of operation of the biogas plant in Großen-Buseck. "We compared the values of our plant with those of 61 other biogas plants in Germany," says project engineer Stefan Seibel from SWG. The analysis shows above-average values for all important parameters. For example, the SWG plant has been producing climate-neutral biogas from liquid manure and plant biomass by fermentation for a year, which is then used to generate electricity for 400 households and heat for 130 households. The biogas plant also supplies a school and a swimming pool with energy. The electrical utilisation rate, which is so important for energy-efficient operation, was 92 per cent over the past twelve months, well above the national average of 85 per cent. In terms of thermal utilisation, which refers to the use of the heat generated, the SWG plant even achieved the highest value in Germany at 83 percent. "Of the 61 biogas plants included in a study by the Agency for Renewable Resources, the best has so far only achieved 67 per cent. Our plant in Großen-Buseck is therefore a record-breaker," says Stefan Seibel happily. In total, the municipal utility's plant ran for considerably more than 8,000 hours over the past twelve months; the reference value here is still below 7,500 hours on average.
"With our first biogas plant, we have placed ourselves right at the forefront of the field in terms of technology and, above all, have made a big difference in terms of climate protection," explains Matthias Funk, head of the SWG heating department. "In the first year alone, we replaced the equivalent of 800,000 litres of heating oil or 78,000,000 cubic metres of natural gas by using biogas in Großen-Buseck." In relation to fossil heating oil, the use of climate-neutral biogas has thus resulted in the avoidance of a total of around 2000 tonnes of the greenhouse gas CO2. SWG had already voluntarily committed to a considerable reduction in climate-damaging greenhouse gases in 2010 as part of the "Charter for Climate Protection" of the state of Hesse.
The sustainable design of the plant, which was originally initiated by engineer Besim Krasnici as a relatively small biogas plant on the farm of farmer Dietmar Klos, also contributed to this success. Because the plant's output was deliberately limited, it does not require more biomass than the surrounding area can supply. This avoids unnecessarily long delivery journeys and thus noise and CO2 emissions due to fuel consumption and other negative effects such as sprawling monocultures of maize or similar energy crops in the wider area around the plant. The Technische Hochschule Mittelhessen and Justus Liebig University Giessen have also contributed to the optimisation of the fermentation processes and thus the energy yield as scientific research partners.
The energy transition is possible - with expertise
"The energy transition is possible - if you know how," says Reinhard Paul, SWG's Chief Technology Officer. The idea of decentralised energy generation coupled with a local heating network for the effective use of the heat generated during electricity production, which SWG has been promoting for years, has once again proven to be the right approach. Reinhard Paul warned that legislators must now fully recognise the role of combined heat and power generation (CHP). CHP is technically mature. In addition, the necessary network infrastructure is already in place in many places - unlike many of the alternatives being discussed. Heating grids and combined heat and power generation therefore have the potential to be a key player in the energy transition and should no longer be neglected. "With the positive experience we have gained in Großen-Buseck in the area of climate-neutral energy generation based on biogas, we will hopefully be able to initiate a few more projects in the coming years," said Reinhard Paul, outlining the energy strategy of Stadtwerke Gießen for the coming years. The mayor of Buseck, Erhard Reinl, and the head of the local authority's building department, Eckhard Körber, were also impressed by the successful contribution to the energy turnaround.
20.06.2012