Post-combustion capture of CO2 at an integrated steel mill – Part II: Economic feasibility

In this paper the economics of the technical possibilities presented in Part I (Arasto et al., 2013) for applying post-combustion CO2 capture at an integrated steel mill were studied. Implications of different CO2 amounts captured, solvents and process integration levels to the greenhouse gas balances and economics of operation are compared to the reference case without CCS trough several case studies using variable market prices of electricity and CO2 emission allowances.The break-even price (BEP) of CO2 emissions (e.g. CO2 emission allowances), where CCS becomes more profitable than the reference case, is about 72 €/t CO2 with an electricity price of 100 €/MWh in the most favourable studied case using a MEA solvent. For the more advanced solvents considered, the BEP level is about 64 €/t CO2. With higher prices of electricity, the costs for CCS increase rapidly. The costs for globally avoided emissions, based on a streamlined life-cycle analysis, are generally higher than the BEP's, depending on the fuels that are assumed to eventually compensate the decreased electricity production in the energy system. The amounts of captured CO2 corresponding to the above presented prices in the most favourable cases are typically in the range of 2–3 Mt CO2/a, which accounts for 50–75% of the site emissions.

► Greenhouse gas balances with and without CCS mapped for the studied steel mill.
► Operation economics with CCS compared to the base case steel production.
► Feasibility of CCS with varying prices of CO2 emission allowances and electricity.
► The lowest break-even price for CCS is over 60 €/t CO2 with electricity price of 100 €/MWh.