Climate-friendly living in Augsburg –

Commercial power-to-gas system with methanation for the partially self-sufficient
and emission-reduced energy supply of 70 flats in existing residential buildings

For the first time in the world, a decentralised power-to-gas system was installed in an old residential complex. The innovative energy supply through green electricity and heat was supplied and installed by EXYTRON. The project was commissioned and initiated by Augsburg’s public utility company “Stadtwerke”, in a residential complex (existing housing) of the Augsburg housing group that has been in existence since 1974.

A photovoltaic system was installed on the roof of a residential block with almost 5,400 square metres of living space that was initially refurbished (in accordance with the development bank energy efficiency rating “KfW 100”). The electricity is preferably consumed directly by the tenants. Excess electricity is used to produce hydrogen in an electrolyser. This is immediately converted with carbon dioxide to synthetic, regenerative natural gas and can be easily stored in tanks. If required, heat and electricity for the tenants will be generated from the natural gas obtained in this way using a commercially available combined heat and power unit and condensing boilers.

A closed circuit
The CO2 released during the combustion of natural gas is recycled and constantly reused as a valuable material for the production of regenerative natural gas. The innovative SmartEnergyTechnology reduces the emission of carbon dioxide, nitrogen oxide and particulate matter by up to 100 per cent. This means that the system can be operated CO2-free. This means that no CO2 tax is levied on the emission-free energy generated by the EXYTRON system. In addition, the feed-in tariff (EEG) levy will cease to apply in the near future. The plant is, therefore, now becoming a highly viable and economical option. (Please also read an Interview with Alfred Müllner, Stadtwerke Augsburg (energate messenger, 25.02.2019))

Utilisation rate of around 90 per cent
The preferential direct use of electricity from the PV system and an intelligent, forward-looking energy management system to control the production, storage and consumption of electricity and heat in the buildings results in an unprecedented degree of utilisation of around 90 per cent of the self-generated energy.

This highly efficient cycle, patented by EXYTRON, can significantly reduce the CO2 footprint of the old, renovated building block to the comparable level of a Passive House Plus standard, which has not yet been achieved in the field of existing buildings.

This means that the climate protection standard of the Federal Government, which is not envisaged until 2050, can already be implemented economically for older existing buildings.

Energy costs remain stable for tenants
The system can be installed in existing buildings without great effort. If the self-supply cycle is interrupted, electricity and gas connections ensure that energy and heat are still available. Despite the environmentally friendly supply, the energy costs for the tenants in the 70 apartments remain stable, thus ensuring that the refurbishment of the apartments is socially acceptable.

This particular social compatibility of the conversion was the reason for the Federal Environment Agency selecting the project and accompanying it with the TRAFIS research programme.

Inserting the storage tanks next to the residential complex in Augsburg.

from left: Alfred Müllner, Managing Director of Stadtwerke Augsburg, Dr. Mark Dominik Hoppe, Managing Director of Wohnbaugruppe Augsburg, Dr. Kurt Gribl, Lord Mayor of the City of Augsburg (2008 – 2020), Dr. Albrecht Meier, Manager at EXYTRON.