Tackling the technological, environmental, legal, and economic challenges of ocean alkalinity enhancement: A case study from the Baltic sea.

Ocean alkalinity enhancement (OAE) is a possible climate mitigation technology that can remove CO2 from the atmosphere. Here, we studied the feasibility of OAE in a case study using serpentinite gangue and examined the carbon dioxide removal (CDR) potential, the legal requirements, and the economic viability. The carbon emission factor was estimated to stay below 70 kg CO2e t-1 CO2 removed. Permitting would require the risks for marine ecosystems at the site to be carefully considered. Under the assumptions of this case study, OAE would require CDR credit prices higher than 100 € t-1 CO2 removed to be economically viable. Commitments of public and private actors to buy OAE credits would reduce market uncertainty and could be a way to promote OAE if the environmental impacts are acceptable.