Case Story Germany

BIOLOGICAL METHANATION DEMONSTRATION PLANT IN ALLENDORF, GERMANY

An upgrading facility for biogas

October 2018

MISSION AND VISION

The power-to-gas concept is an energy storage solution suitable for long-term and large-scale storage of intermittent renewable electricity. Initially renewable electricity is used to produce hydrogen via electrolysis. Further conversion to renewable methane is conducted by reacting hydrogen with a carbon source (4H2 + CO2 = CH4 +2H2O). The plant concept is based on a biological methanation process using the carbon dioxide in raw biogas as the carbon source. Thus, the technology doubles as a biogas upgrading process ideally suited for small biogas plants and as an energy storage for otherwise curtailed renewable electricity. The generated methane gas serves as an advanced gaseous transport fuel or may be used for renewable heat (Figure 1).

PLANT DESCRIPTION

The first demonstration plant worldwide using the power to gas combination of electrolysis and biological methanation was established in Germany at the Schwandorf wastewater treatment plant. This was a collaboration project between MicrobEnergy GmbH, Schmack Carbotech GmbH (Essen, Germany), Viessmann Werke GmbH & Co. KG and Schmack Biogas GmbH (Schwandorf, Germany). The facility moved to Allendorf (Eder, Germany) in late 2014 (Figure 2). The plant consists of a PEM-electrolyzer (Carbotech) and a methanation unit (BiON technology, MicrobEnergy GmbH). The methanation unit forms the core of the plant and converts either carbon dioxide from the gas processing plant or directly from the raw biogas (Figure 3).