Navigating Deep Uncertainty in Carbon Capture Technologies - An Investigation of CCS and CCU Investments at a Swedish Waste-to-Energy Plant using Robust Decision Making

Sammanfattning

With Sweden and the EU aiming to reach net-zero carbon dioxide emissions by 2045 and 2050, the interest in carbon capture technology such as Carbon Capture and Storage (CCS) and Carbon Capture and Utilisation (CCU) is on the rise, not least in hard-to-abate sectors such as waste incineration. Several Swedish waste management actors are now considering CCS or CCU, among them Tekniska Verken i Linköping AB (TvAB), who are the owners of the waste-to-energy plant Gärstadverken. However, there are many financial uncertainties related to CCS and CCU investments, such as uncertainty in transport and storage costs, potential revenue from CCU products and CCS carbon credits, electricity price development, and more. As a result, evaluating the profitability of CCS and CCU projects is challenging. To provide TvAB with additional decision support, this study adopts Robust Decision Making (RDM) to examine what conditions could favour or disfavour a carbon capture investment at Gärstadverken. The alternatives examined are CCS and CCU with the production of electronic Sustainable Aviation Fuel (eSAF). Through discussions with TvAB representatives and literature research, a model of the investment decisions was created using the open-source Python library Rhodium. This model was evaluated in 120 000 futures, and the results were analysed using Sobol sensitivity analysis, Classification and Regression Trees (CART) and the Patient Rule Induction Method (PRIM). The simulation results show that for CCS, the most important factor is the price TvAB can receive for their carbon credits, even when emission allowances are expensive and a large fraction of the emitted CO2 is biogenic. Transport and storage costs and carbon capture investment costs are also shown to be important factors. For CCU, the most crucial factor is the price that TvAB charges for their eSAF. However, CCU could be favourable at lower eSAF prices if the electrolyser costs are reduced and/or if electricity and emission allowance prices are low. However, it should be noted that the limited study scope resulted in many simplifications – notably when modelling the development of eSAF and carbon credit prices. As such, more efforts should be put into investigating the development of the eSAF and carbon credit markets.