Case Story Switzerland

Biological Power-2-Gas – LIMECO

December 2024

Summary

Limeco (Dietikon/Switzerland) is an inter-municipal institution that has a 65-year record of provision of waste management services. It specialises in wastewater treatment, waste incineration, and district heating, for its eight member municipalities and various contracting municipalities (Table 1). In the past, up until 2015, the biogas from sewage sludge was utilized via combined heat and power (CHP) units.

Swisspower, is a strategic alliance of 21 Swiss municipal utilities, who have an ambition to provide a fully renewable, CO2-free energy system by 2050. In 2016, Swisspower partnered with Limeco and Kanadevia Inova Schmack GmbH to build a biological Power-2-Gas (P2G) plant. The motivation behind this project was to harness synergies from existing facilities—including electricity generation, biogas, and sewage sludge treatment—to contribute flexible energy to a future-oriented CO2-neutral energy system. This distinctive approach fosters innovative integration, whilst unlocking potential for a more cohesive and adaptable energy production model.

The Limeco site was ideal, as the wastewater treatment plant supplies sewage sludge and biogas, while electricity from the waste incineration plant is available at market prices for electrolysis, without grid fee. During the planning phase, additional co-operation partners were sought to support Limeco in the project. The developed business model envisions that the eight member municipalities will purchase biomethane at cost price for a period of 15 years. Following a planning and construction phase, the P2G plant became operational in March 2022. The total costs for planning, construction, and process engineering reached CHF 14 million, equivalent to about US$16 million.

Limeco’s biological P2G plant is Switzerland’s first industrial, full-scale P2G facility, representing a significant milestone in the energy transition. It can produce up to 18 GWh of energy annually (2MW renewable methane capacity) and reduces CO₂ emissions by up to 5,000 tonnes per year (or 277 kg CO2/MWh renewable methane or 2.77 kg CO2/m3 renewable methane, or 277 g CO2/kWh).