Project "Virtual Biogas"

Biogas – an energy carrier with magnificent future
Biogas is a sustainable, biogenous and renewable energy carrier that is normally used today for the production of electric power. Contrary to other biogenous energy carriers, biogas has the potential to substitute up to 25% of the natural gas demand in Austria. The portion of biogas in Austria’s primary energy could be drastically increased, if biogas could successfully be upgraded and injected into the natural gas grid. Upgraded biogas could consequently be transported to the customers without losses who could efficiently use the primary energy content of the gas.

The project consortium
A consortium consisting of Biogas Bruck an der Leitha, Energiepark Bruck an der Leitha, Axiom Angewandte Prozesstechnik GmbH, EVN Wärme GmbH, OMV Gas & Power GmbH, OMV Future Energy Fund GmbH, Wien Energie Gasnetz GmbH, AVL List GmbH, LUPower Energie-Projekte GmbH & Co.KG and Grazer Energieagentur GmbH together with the academic research partners University of Natural Resources and Applied Life Sciences, Vienna University of Technology and University of Vienna want to upgrade biogas at a scale of 180 m³/h, inject this upgraded gas to the natural gas grid and use it in a vehicle fleet. In order to enhance the acceptance of gas as a vehicle fuel, the gas pressure on the fuel dispenser will be increased resulting in an increased range of coverage for the vehicles.

New upgrading process
For the development of the technology on pilot plant scale and for the realisation of the profitability for a commercial implementation, a novel membrane separation technique is applied for the first time to upgrade the biogas of the biogas plant Bruck an der Leitha to natural gas quality and to inject this biomethane to the natural gas grid. Subsequently, this gas is dispensed “virtually” (means calculatory) to consumers which are distant from the point of grid injection. The fastest way to reach the profitability of the overall process is to use this virtual biogas as a vehicle fuel for methane-propelled cars.

The work packages
The project consortium has defined ten work packages covering the whole value-added chain from the plant to the engine. The results will contribute to the efforts of enhancing the prospects of an eco-efficient utilisation of biogas as an all-purpose energy carrier.

Figure: Work packages in the project “Virtual Biogas”

The technical solution – Biogas upgrading using membranes
In this upgrading plant approximately 180m³/h of raw biogas are upgraded to the required natural gas quality according to the quality standards ÖVGW G31/G33 applying a two-stage membrane separation process (Gaspermeation). Subsequently, this gas is injected to the natural gas grid owned by EVN Netz GmbH at elevated pressure. For this purpose, the external biological desulphurisation had to be readjusted to a dosing of pure oxygen. The thereby preliminary conditioned biogas subsequently is finally cleaned from hydrogen sulphide, compressed, cleaned from ammonia and a part of the moisture and finally cleaned from carbon dioxide and moisture in the membrane separation step. The thereby upgraded biomethane is odorised – that means the “typical smell of natural gas” is added – and injected into the local natural gas grid. During the summer operation, a part of the produced biomethane is high-pressure compressed and fed to a higher-ranking regional gas grid. Key technology in this process steps is the so called Gaspermeation, a membrane technology using semi-permeable membranes selectively permeable for carbon dioxide and water, but impermeable for methane. As an essential advantage of this process, the product biomethane remains under high pressure and can be injected into the gas grid without further compression. Additionally, the necessity of a downstream gas drying step is dispensed due to the very good drying characteristics of the membranes.

This project is funded by the “Klima- und Energiefonds” and is conducted within the research programme “ENERGIE DER ZUKUNFT“.