Germany’s Erdinger Weißbräu brewery is now served by a new cogeneration fuel cell system, fuelled by biogas also produced on-site, from the Tognum MTU Onsite Energy. The HotModule HM300 distributed energy system generates 240 kW of electrical power and more than 200 kW of thermal energy. The brewery uses the thermal energy to heat the brewery buildings and to heat water for the brewing process.

Apart from its high degree of efficiency, the fuel cell’s additional strength is its extremely low emission levels. Nitrous and sulphur oxides are nearly non-detectable, says Tognum, and carbon monoxide emissions are almost ten times lower than in engine-powered cogeneration systems. For this reason, the term ‘exhaust gas’ does not apply for the fuel cell: Tognum refers to exhaust air.

Erdinger uses vast quantities of water at various temperatures for the brewing process and to clean the brewing equipment. Before being flushed into the public sewage system, the waste water is pre-conditioned via an in-house anaerobic pre-sewage treatment system. A by-product of this process is biogas with an 85% methane content, making it an excellent energy source for the fuel cell. A gas cleansing system also developed by Tognum removes possible sulphur residues from the biogas which would otherwise be detrimental to the fuel cell stack. At a temperature of approximately 650°C, the biogas is then converted into hydrogen which reacts electrochemically with the airborne oxygen. Almost 50% of the biogas energy content is converted into electrical power, while more than 40% translates into waste heat, which has a temperature of roughly 400°C. Taken together, the result is an exceptionally streamlined overall efficiency of more than 90%.

‘The brewing industry is an intensively energy-consuming business. For this reason, we are continuously looking for possibilities to use energy more efficiently and to become less dependent on fossil fuels’, said Peter Liebert, Managing Director of the Engineering segment of the private brewery.