German Flex operation adapts biogas plant to the needs of farmers.

In Verblek in Lower Saxony (Germany), ETW Energietechnik increased the capacity of its agricultural biogas plant by installing a storage power plant in 2019. The CHP experts were supported by the planning company Energethik from Osnabrück. In addition to the new Flex CHP plant with a TCG 2020 V20 biogas engine from MWM with a capacity of 2 megawatts electric and 2.3 megawatts thermal, ETW installed an 8490 combined gas storage tank and a 1000 cubic meters heat storage tank. The total investment is 1.6 million euros.

In addition to increasing production volumes, the plant now operates flexibly. In return, Rolfs will receive an additional flexibility bonus of 40 euros per kilowatt over the next five years. After that, the farmer can optionally apply for a further ten-year EEG payment through a tender. Its main advantage: thanks to the Flex CHP plant, its installation now works in such a way that electricity and heat can always be supplied at the most productive time of the day. For this purpose, the biogas plant is managed directly by the marketer in such a way that the storage tanks are always optimally filled when prices are at their highest and that the maximum possible amounts of electricity and heat are available for this purpose. The plant runs on desulfurized biogas. For this purpose, the sulfur content is reduced from about 5000 parts per million (ppm) to about 2 parts per million. A safety alarm with integrated shutdown of the storage gas supply protects the CHP plant at sulfur levels above 2 ppm. This is especially necessary because the sulfur content can rise faster with flexible operation. After a preventive shutdown, the operation of the engine is maintained by gas from the storage tank.