Convion demonstrates SOFC in waste water application

Convion has started operating a biogas fuelled C50 SOFC system in Italy. The start-up marks an important milestone along the path to commercialisation of the system, says Convion. After a successful trial operation of the module in Finland and completion of site installation at the Collegno waste water treatment plant of SMAT, the unit started producing power and heat for the plant’s own consumption. The installation is the largest solid oxide fuel cell plant in the world directly fuelled by biogas.

The installation is part of the EU sponsored DEMOSOFC programme (see previous item) and is designed to demonstrate implementation of SOFC fuel cells in a replicable application such as waste water treatment. Cleaning of waste water is energy intensive and therefore capturing the energy value of the waste can be very beneficial.

The Collegno waste water treatment plant serves a population of about 180 000. As part of the waste water treatment process, organic matter is digested by an anaerobic, microbial process producing biogas with approximately 60-65% methane content. Converting the gas to power and heat directly in a fuel cell minimises losses due to transportation and eliminates the need to upgrade the biogas to biomethane compatible with pipeline transmission.

Use of the biogas in the SOFC based CHP unit reduces the waste water treatment plant’s need to purchase power from the grid by about 30%, while recovered waste heat from the SOFC’s exhaust is sufficient to provide all the heating necessary for the waste water treatment process.