P-graph approach for the optimisation of biomass supply network for biogas production in urban areas

The utilization of anaerobic systems for biogas production integrates various aspects such as renewable energy generation, waste management, waste treatment, and biofertilizer production. This study introduces a model that focuses on the economic optimization of a biomass supply network for biogas production in urban areas. The selected feedstocks considered in the model are biowaste and residues sourced from restaurants, shops, and the food and beverage industry. This study introduces two significant advancements. Firstly, it employs an enhanced GIS-based approach that integrates greenhouse gas (GHG) requirements by incorporating a maximal allowed transport distance. This integration aims to achieve minimal GHG savings from biogas usage. These GHG-based requirements align with the specifications outlined in Directive 2018/2001, which promotes the use of renewable energy sources and stipulates a minimum 80% reduction in greenhouse gas emissions from biogas plants operating from 2026, in addition to meeting environmental sustainability criteria. Secondly, the study introduces a novel approach that combines GIS mapping of biomass potential with a P-graph framework for optimizing the biomass supply network. This integration facilitates comprehensive and efficient optimization of the network for biogas production. The model is developed and solved using P-Graph Studio, while feedstock availability and transportation distances are determined using the QGIS tool. The approach is tested under two scenarios: one with an annual production of 36,000 GJ and another with an annual production of 72,000 GJ. The p-graph approach enables the identification of the optimal economic solution for both scenarios. As the most of the biogas potential is concentrated in a single brewery, the specific cost of the biomass supply network, including feedstock and transport, remains comparable for both scenarios, with values of 12.44 EUR/GJ and 12.61 EUR/GJ for the second case.