CO2 transportation infrastructure and biomass supply systems for carbon capture and storage - A modeling study of Swedish industry

Licentiate thesis, 2022

Rapid decarbonization of the industrial sector is crucial if the world is to manage to meet the target set in the Paris Agreement of limiting global warming to “well below 2°C”. The main technological pathways for achieving a low-carbon industry are the substitution of fossil feedstocks and energy supply with bio-based alternatives, electrification, and implementing carbon capture and storage (CCS). This thesis investigates the deployment of CCS and bioenergy CCS (BECCS) in industry, using Sweden as a case study. CCS involves the capture of CO2 at the emissions source, transportation of CO2 to a storage location, and storage in a deep geologic formation. This work considers CO2 capture and transportation infrastructure and the potentials and costs for supplying regional logging residues – branches and tops left in the forest after logging operations – to act as an enabler of BECCS in the pulp and paper industry by supplying the additional heat demand imposed by CO2 capture, assuming maintained production levels.

To evaluate the potential for logging residues to supply heat for the capture process, heat balance calculations on the site level were combined with an assessment of regional availability and existing use of logging residues. This work shows that the potential for regional logging residues to act as an enabler of BECCS is dependent upon regional conditions, primarily the existing biomass use in the district heating sector. The cost of transporting logging residues is highly distance-dependent, therefore, the ability to mobilize large volumes of these residues as close as possible to the plant applying capture is important. The costs for supplying logging residues to the plants investigated are in the range of 21–28 €/tCO2 captured. These costs increase rapidly per tCO2 captured and end up with higher costs in southern Sweden than in the north of the country.

The development of a large-scale CCS system that includes the capture, liquefaction, truck transport on-shore and ship transport off-shore was investigated by developing and using a cost-minimizing optimization model. To incentivize capture, CO2 pricing, emission budgets and targets for capture were implemented. The use of an integrated CO2 transportation infrastructure that connects several CCS plants with a CO2 storage site is shown to be cost-efficient at emissions price levels of around 80 €/tCO2 (excluding the cost for final storage). As the cost structure of CCS systems, including the capture, liquefaction, and transportation infrastructure, is primarily composed of the cost for capture and liquefaction, the system build-up over time and the total cost are most sensitive to cost uncertainties in relation to the on-site installations.  Ships for offshore transportation also make up a significant part of the cost, so smaller sites located close to the final storage location can be favored over larger sites, despite having a higher cost for capture. The incentive structures chosen for motivating capture influence which sites are economically optimal to implement CO2 capture at, and at which point in time. Waste-fired heat and power plants are economically feasible when capture targets are set for biogenic CO2 in combination with a cost for fossil CO2 emissions. Including BECCS in emission budgets reduces the system cost but tends to delay investments in mitigation and compensate at a later stage with BECCS. To facilitate technology development and near-term implementation of CCS and BECCS, it is important to consider that including carbon dioxide removal into the same policy regime that controls fossil CO2 emissions, may result in the cost optimal strategy entailing a delay in fossil fuel mitigation.