Distribution Mapping and Accessibility Analysis of Biogas Digester in Sambak Village, Indonesia using Nearest Neighbor Analysis Method

Biogas has gained attention as a potential renewable energy solution due to its dual role in waste management and clean energy production. This study investigates the spatial distribution and accessibility of biogas digester units in Sambak Village, Central Java, Indonesia, using Geographic Information System (GIS)-based spatial analysis. Biogas in the village is primarily produced from tofu wastewater, with six digesters installed in selected hamlets. Spatial methods employed include Nearest Neighbor Analysis (NNA) and Multiple Ring Buffer analysis using ArcGIS Pro. Results from NNA reveal a significantly dispersed distribution pattern, supported by a nearest neighbor ratio of 1.718, a z -score of 3.367, and a p -value of 0.000760, indicating non-random dispersion with statistical confidence at the 99% level. The proximity analysis further shows that while 63.67% of residential areas fall within 250 m of the digesters, only 25.14% of the total administrative area is served, suggesting inequitable access to infrastructure. This spatial disparity highlights the need for optimized placement of future digesters to ensure equitable access to biogas services. The study contributes practical insights for biogas infrastructure planning in rural Indonesia and reinforces the importance of spatial tools in renewable energy development.