Operation of the Wärtsilä FC20 fuel cell power unit at the Wärtsilä New Energy validation site in Vaasa, Finland has been very successful. The WFC20 unit is the first of its kind, and runs on methane-rich gas originating from a nearby landfill site. The WFC20 is based on planar solid oxide fuel cell (SOFC) technology supplied by Topsoe Fuel Cell in Denmark.

The fuel cell unit produces an electric output of approximately 20 kW, which is enough to power approximately 10 households in the area. The thermal output of the unit ranges from 14 to 17 kW.

The varying composition of the methane-rich gas from the landfill has been one of the main engineering challenges for the test site. This has led to the development of an efficient control system, the functionality of which has been fully validated.

Landfill gas contains also a number of impurities, such as sulfur compounds, which need to be removed from the fuel before being fed to the fuel cell system. This has also been successfully achieved.

The exhaust gas emissions from the WFC20 fuel cell are extremely low. The fuel cell unit does not produce any measurable levels of harmful particles, sulfur oxide (SOx), or nitrogen oxide (NOx) emissions, even under part-load conditions. When using biogas as fuel, the CO₂ emissions are very close to carbon neutral.