Machan, N. (2008). Production of biomass based methane in Styria : perspective for short term applications [Diploma Thesis, Technische Universität Wien]. reposiTUm. https://resolver.obvsg.at/urn:nbn:at:at-ubtuw:1-35638
This work discusses two principal ways to produce biomass based methane for natural gas grid applications based on the available biomass feedstock and local conditions in Styria. The result of this work provides the basis for the pre-selection of the most promising biomass conversion concept and a mid term scheduled project with the aim to develop a detailed technical realization concept for biomass based methane production in Styria. The two conversion paths investigated were the biological conversion of organic feedstock like organic fertilizer, renewable energy crops and residues from communities and agro industries and the thermochemical conversion of woody biomass. Therefore feedstock availability, state of technology and cost affects was investigated. Methane production based on agricultural feedstock achieves the largest theoretical potential for the biological conversion path of approximately 2,600,000 MWh in total. The most interesting feedstock in this field is liquid manure with a biomass based methane potential of approx. 800,000 MWh/a. Compared to the potential of agricultural feedstock non agricultural feedstock have a rather low biomass based methane potential with nearly 70,000 MWh/a from agro industry, 77,000 MWh/a from organic residues from households and communities and approx. 56,000 MWh/a for sewage sludge. For thermochemical produced biomass based methane a secured and adequate supply of woody biomass in Styria could not be predicted seriously due the existing challenge in lot of other energy areas in particular to provide the recourses for the existing and planed power plants based on biomass. Under consideration of the mobilisation of 10% of available not utilized forest increase in Styria (100,000 solid cubic metres) a theoretical biomass based methane potential of approximately 245,000GMWh/a. could be achieved. From the technical point of view the production of biomass based methane along the biological chain is state of the art technology. Biomass based methane production based on thermo chemical conversion respectively SNG (Synthetic Natural Gas) production seems to be not available under commercial conditions at the market within the next 10 to 15 years. From the economical point of view most effecting parameter for production costs of biomass based methane along the biological conversion path are the feedstock costs and costs for feedstock upgrading demands. Therefore the utilization of liquid manure and bio waste seems to be auspicious Thermochemical produced biomass based methane needs high capacities (>6,250 m³/h) to achieve production costs in the same range as stated at the biological conversion path. The most cost affecting parameter are investment and operating costs for gas upgrading devices. Compared to an average energy price for natural gas of 2.1 - 2.6 EUR-Cent/kWh it can be pointed out, that in the case of feeding the biomass based methane into the natural gas grid both conversion paths needs different amounts of subsidies to be competitive to the current energy market at the moment in Austria! Based on the results mentioned before and under consideration of short term realization the process based on the biological conversion was selected to be investigated more detailed to be able to develop a concept for realisation.