Techno economic assessment of CCUS for a biogas facility in Sweden : Evaluating the economic feasibility for three CCUS concepts

Sammanfattning: Many countries strengthen their commitments to reduce greenhouse gas emissions to limit climate change and meet the Paris Agreement (Masson-Delmotte et al., 2019). Commitments include achieving net-zero emissions or in some cases even negative emissions (Government offices of Sweden, 2020a; United Nations, 2021a). To achieve these goals, carbon dioxide capture, utilization, and storage (CCUS) is considered as an essential strategy. Carbon capture storage and utilization are recognized methods of reducing or avoiding greenhouse gas emissions (IEA, 2019a, 2020). However, the uncertainty regarding costs, financial incentives, and pricing is impeding adoption. Further information is needed for CCUS concepts both in respect to cost estimates and required market prices for CCUS, this to provide guidance for decision makers and market actors. In this report a study has investigated the economic feasibility of three CCUS concepts for a biogas facility. One CCS concept where CO2 was captured and liquefied on-site to be transported to a terminal for shipping and end storage injection. The CCS concept annual capacity was ~16 500 ton net stored CO2. Two CCU concepts were considered, where synthetic natural gas (SNG) was produced via biologic methanation with on-site produced hydrogen, both with annual production of ~88 GWh SNG. A techno-economic assessment (TEA) was carried out where the key cost-drivers were identified, and the economic feasibility assessed. With performance and cost estimates for each process step in the different considered concepts a model was built where a cash flow was created and a net present value (NPV) could be calculated. The study found transportation to be the most prominent cost driver for CCS where shipping and storage represented 57 % of the total cost of CO2 removal. The cost driver for CCU concepts was found to be hydrogen production, where the electricity for the electrolyser constituted 65 % of the total cost of produced SNG. None of the concepts were found economic feasible when the Swedish market was considered. The break-even price for CO2 removal in the CCS concept was found to be 151 €/ton, just above the assumed base value used in this study. As the voluntary market is still undeveloped it is difficult to know what price that could be expected, however, in discussion with market experts a range between 150-200 €/ton would not be unthinkable for the concept studied. For the CCU concepts to be economically feasible, the estimated minimum price levels for SNG were 184 and 193 €/MWh respectively. Comparing to the benchmark price of diesel of 125 €/MWh, both CCU concepts were concluded to be unfeasible. The sensitivity analysis showed that the CCU concepts were very sensitive to variations in electricity price. When the German fuel market was considered, all studied concepts yielded a positive business case. CCS was the only concept showing economic feasibility, while the CCU concepts remained unfeasible. In the German market a GHG reduction quota credit was accounted for which was valued higher than the carbon removal credits in the voluntary market.