The Power-to-Gas plant in Dietikon has made a pioneering contribution to efforts to remodel the Swiss energy system by efficiently combining existing waste treatment and upgrading processes to create a new carrier of energy: synthetic methane produced using the electricity generated in the municipal waste incineration plant (MWIP) and carbon dioxide (CO2) contained in the digester gas from the wastewater treatment plant (WWTP).
In an electrolysis unit, town water from the water treatment plant is split into oxygen and hydrogen using the electricity from the MWIP. In the biological methanation unit, with the addition of sewage gas from the wastewater treatment plant containing CO2, the hydrogen is metabolised by microorganisms into synthetic methane. The methane is brought to the requisite quality for feeding into the gas grid in a multi-stage gas treatment process. This produces up to 18,000 MWh of natural gas substitute a year.