Project meeting of STEP at the site of the company ATS - Agro Trading & Solutions in Hardegsen (Photo: DBFZ)

sector coupling | CHP Power Biogas Biomass technologies Validation market potential Biomethane strategy System integration Biofuels

Project ID 03EI5421

Kläffizient - Flexible and demand-oriented conversion of sewage gas for energy storage and increased plant efficiency

Project 03EI5421 Kläffizient: Sewage treatment plant with precleaning high-load activation stage and digestion tanks (Source: Susanne Vogel, City of Nürnberg)


  • 01.10.2020-30.09.2023


Friedrich Alexander-University Erlangen-Nürnberg (FAU)
Chair of Energy Process Engineering
Fürther Straße 244f
90429 Nürnberg

Prof. Dr. Jürgen Karl – project leader
Telephone: +49 (0) 911 5302 9021

Jonas Miederer – direct contact person / project coordinator
Telephone: +49-(0) 911 5302 9402


03EI5421B - Stadtentwässerung und Umweltanalytik Nürnberg
03EI5421C - eta Energieberatung GmbH

Associated partners

Cooperation partners



Planned results:

  • Plant level: procedure, demo plant, plant modules/system components, retrofitting exisiting plants
  • Concept level: plant concept
  • Market level: market forecast, patent, marketable technologies, business model, transfer pilot-/demo plant into commercial use
  • Data level: model/modeling, scenerios, methods (analytical/process descriptive etc.)
  • Publications: scientific paper (ISI, peer-reviewed)
  • Others: strategy


The main topic of the project is the use of sewage gas in the context of the overall energy system in order to optimise the energy management of sewage treatment plants and to contribute to the achievement of climate protection goals through the production of a renewable natural gas substitute. This is carried out within the framework of an energy system analysis with a so-called digital twin. Kläffizient (“Sewage Efficient”) is further developing the upgrading of sewage gas for a more flexible sewage treatment plant operation using sector coupling technologies. This dynamic direct methanation of sewage gas with a heat-pipe-cooled reactor is demonstrated at the site of the Nuremberg wastewater treatment plant.


The aim of the main project is, on the one hand, to optimise the energy management of the sewage treatment plant with regard to the overall energy system and, on the other hand, to make a contribution to achieving the German climate protection targets. To this end, the upgrading of sewage gas to biomethane is to be further developed. Finally, the valuable material "sewage gas" is to be made usable for a coupling of the energy sectors electricity, gas and heat.



  • Implementation of a digital twin of a wastewater treatment plant of the city of Nuremberg
  • Incorporation of a methanation concept
  • Testing of sewage gas methanation in the laboratory and at the sewage treatment plant site

Stadtentwässerung und Umweltanalytik der Stadt Nürnberg

  • Provision of load data and technical know-how for plant operation
  • Provision of the plant site and operation of a methanation reactor

eta Energieberatung GmbH

  • Profitability analysis
  • Development of marketing strategies



  • Optimised sewage gas treatment through methanation and development of an energy system model

Stadtentwässerung und Umweltanalytik der Stadt Nürnberg

  • Plausibilisation of energy system model and demonstration of direct methanation of sewage gas at the waste water treatment plant site

eta Energieberatung GmbH

  • Commercialisation and economic feasibility


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