A Review of Geospatial Prediction and Modelling Approaches in Biogas Plant Suitability Assessment

The European Union and Croatia's energy policy aims to ensure accessible, safe, affordable, and competitive energy through significant technical, technological, and social changes in all sectors of the economy. New production capacities, such as biogas plants, can alleviate capacity shortages, increase system flexibility, and significantly improve the security of supply. Therefore, this paper provides an overview of the factors that affect the selection of a location for biogas plants. Geospatial biogas potential assessment is the first step in determining the feasibility of biogas plants. Several factors can contribute to the economic viability and sustainable production of biogas plants, while sufficient availability of feedstock, as well as cost-effective logistics related to transportation and fulfilment of institutional requirements, are essential. There are two geospatial state-of-the-art methods for land suitability determination: Geographic Information System (GIS)-based multicriteria analysis and machine learning regression. These studies were dominantly based on the GIS-based multicriteria analysis using the analytic hierarchy process (AHP), using distance rasters to supply sources, roads, and settlements as primary criteria. They also strongly considered land use, slope, and elevation for the determination of biogas plant suitability. However, three key gaps were noted in the current state-of-the-art approach: 1) crude geospatial modelling of biomass supply, which is required for biogas production using co-digestion, except for single crop; 2) the lack of geospatial modeling of soil contamination as criteria; and 3) the lack of independent validation of predicted biogas plant suitability.