Development of a GIS-based register of biogas plant sites in Lower Saxony, Germany: a foundation for identifying P2G potential

Background

Although Germany’s biogas capacity accounts for almost 7% of its installed worldwide capacity, the expansion of biogas plants has stagnated owing to the expiry of Germany’s Renewable Energy Sources Act Erneuerbare–Energien–Gesetz (EEG) subsidies for existing biogas plants. Indeed, without alternative concepts such as power-to-gas (P2G) ensuring their continuing operation, many existing biogas plants must close down to ensure their continuous operation. A detailed spatial register of biogas plant sites must be developed to evaluate the potential for further operation (and thereby promote Germany’s sustainable energy transition). In particular, Lower Saxony, a German federal state, was hit hardest by the expiry of subsidies, as there is a lack of spatially high-resolution information to identify which biogas plants have P2G potential as an end-of-subsidy strategy. This study discusses the development of a geographic information system-based register for these plants.

Methods

A register was developed using geographic information system (GIS). Spatial data on existing biogas plants in Lower Saxony were selected from the Digital Landscape Model (DLM) data, with additional information coming inter alia from the Marktstammdatenregister, the Germany-wide core energy market data register. The data were merged into a single register for Lower Saxony, and aerial photographs were used to validate the biogas plant site.

Results

A total of 1704 biogas plant sites were identified throughout Lower Saxony. Spatially resolved plant information on production capacity suggests that three quarters are suitable for inclusion in a methanization concept. Because plants at 85% of the sites will no longer be subsidised by 2035, end-of-subsidy strategies will soon become relevant.

Conclusions

The GIS-based analysis is a reliable and low-error method for identifying biogas plant sites in Lower Saxony. Almost all plants were included in the registry. The greatest advantages over existing registers and at the same time the unique characteristics of our register were the exact spatial localisation of the plants and the highly up-to-date nature of the data. The register enables the initial (spatial) identification, characterisation, and analysis of potential sites for P2G end-of-subsidy strategies. Overall, the register has significant potential as an advisory basis.