In order to mitigate anthropogenic climate change, it is essential to reduce the use of fossil fuels such as natural gas in the future. However, certain industrial high-temperature applications such as cement or steel production will remain dependent on fuels. 

Biomethane represents an alternative to natural gas. To date, Austrian biogas is mainly converted into electricity and heat directly at the production site in combined heat and power plants. By feeding it into the existing gas grid, the energy could be stored for longer periods and also be used in industrial plants where there is a lack of alternatives to using fuels for process-related reasons.

Biogas is produced decentrally in many small plants in Austria. Before it can be fed into the gas grid as biomethane, processing steps are required. In addition, a corresponding pipeline connection to a feed-in point is necessary. This results in considerable investment costs for both the plant operators and the grid operators. 

To keep biomethane production costs as low as possible, an optimization problem is formulated. The aim is to minimize the total cost of treatment plants and pipelines to the feed-in points as well as necessary compressor systems. The following figure shows an exemplary result to the optimization problem, indicating the cost-optimal clustering of existing biogas plants to connect them to defined feed-in points. The placement of the necessary biogas treatment plants is also modelled, considering scenarios with decentralized treatment at the biogas production plants and centralized treatment just before the feed-in point, as well as different treatment technologies. 

Connection lines between several biogas plants and various feed-in points into the gas grid are visualized in a schematic diagram. All theoretically possible connections are shown in light color. Those connections that lead to cost-optimal clustering of the biogas plants are highlighted.

Schematic figure representing optimization results

  1. D. Huber, F. Birkelbach, R. Hofmann (2024) Network Optimization for Sustainable Integration of Decentralized Biogas Production. In Proceedings of the ASME 2024 18th International Conference on Energy Sustainability (ES2024), Anaheim, California, USA.