Utilisation of farm manure for biogas production Environmental and economic analysis of local and central biogas plants, including pipeline transport of biogas
DisBiogass is a collaborative project between Telemark University College (HiT), Tel-Tek and Ostfold Research focusing on climatic and economic impacts through the value chain of biogas production from manure. The project was funded by the Norwegian Research Council through Oslofjordfondet and was carried out from 2011 to 2013.
The analysis comprises five scenarios modelled to explore the importance of localisation and size of biogas plants, and transportation modes used to transport manure, digestate and biogas when utilising manure from farms for biogas.
• Scenario 0: Direct use of manure (replaces mineral fertilizers).
• Scenario 1: Central biogas plant with central upgrading of the biogas to fuel quality (the farmers deliver manure and get back digestate).
• Scenario 2: Local biogas plant, local utilization of biogas (replaces heat).
• Scenario 3: Local biogas plant, central upgrade plant. Compression and transportation of biogas to upgrading plant.
• Scenario 4: Local biogas plant, central upgrade plant. Transportation of produced biogas through pipeline network to upgrading plant.
The Ostfold Research Biogas Model (Møller et al. 2013), developed in 2011 (with further development in 2012) is used as basis for the analysis. The model is based on LCA methodology (ISO 14040-44), and is developed as a net emissions model. The model includes ten phases of which eight contribute to emissions and two contribute to avoided emissions. Avoided emissions arise because produced biogas replaces products and energy that does not have to be produced when the biogas and digestate are produced. The Biogas Model also includes an economic value chain model which was developed to enable comprehensive decision making processes including both environmental and economic factors, and to easily facilitate the decision processes of investors, governments and farmers when considering establishment of central and local (farm) biogas plants. The economic model is developed as a tool in Microsoft Excel.
Both the climatic and economic results from the scenario analysis show that all scenarios where manure is utilised for biogas production (Scenarios 1-4) represent a considerable advantage compared to the scenario where manure is used directly by the farm as fertiliser (Scenario 0). Scenario 4, which is the scenario where raw biogas is transported in a pipe line from the farm to the centralised upgrading plant, comes out as the best scenario. However, the difference between transporting compressed biogas to a centralised upgrading plant and transporting raw biogas through a pipe line (scenario 4 and 3), is almost negligible.