The Koehler Group is extensively investing in the expansion and conversion of its combined heat and power plant in Oberkirch in order to use environmentally friendly biomass as fuel in the future. The large-scale project hit a milestone in June of this year when the last piece of coal was fired. The boiler was then fired with biomass for the first time ever on August 20th, after which a test run with extensive fine-tuning kicked off. As a result of the switch to biomass, more than 150,000 metric tons of direct fossil CO₂ emissions will be cut per year at the Oberkirch site.
Complex fine-tuning as part of test run
Once initial firing adjustments were made and the boiler system’s steam output was gradually increased, the steam turbine and its generator went online on August 30th as scheduled. This first synchronization run was the first time ever that power was fed into the public electricity grid in what is referred to as “gridconnected mode.” The power generation system had been running in island mode previously, meaning that the corresponding electricity was only used to power Koehler’s own electrical systems.
Since then, the power delivered by the converted power plant has been ratcheted up as part of the test run. All three incoming fuel areas, together with the corresponding fuel treatment and conveyance systems and four fuel silos, are now operating normally, and the converted power plant is generating around 12 MW of green power.
Measures for reducing noise emissions taken in close consultation with residents
The size of the investment, coming in at over 70 million euros, is representative of just how large and complex the process of converting the former coal-fired power plant has been. Part of that is the fact that the process requires an extensive test run in order to be able to get the optimum settings for operation.
One of the focal points of the aforementioned test run is reducing noise emissions. To this effect, an extremely broad variety of measures revolving around the biomass power plant have already been taken in consultation with the area’s residents. For example, an access hatch in the boiler house’s envelope has been closed, and a large number of operating parameters have been fine-tuned. In addition, planned noise barriers have now been installed. Hartmut Felsch, the mill director at the Koehler Paper plant in Oberkirch, had the following to say: “We’ve arranged for third-party noise control experts to work with us throughout the entire commissioning and optimization process, which is really important as far as we’re concerned. These experts are helping us identify objectionable sources of noise and take measures to fix them as appropriate.”
In addition, the company is constantly discussing things with residents during the test run so as to be able to quickly respond to changes in how they perceive any noise. At the same time, other remaining work is also in the home stretch. “Above all, we’ll be fixing up the grounds and restoring the public swimming pool parking lot in the coming weeks,” Felsch adds. Final acceptance testing for the new biomass power plant by TÜV is expected to take place at the beginning of the second quarter of 2025.
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