Work

Spain's realistic potential for ocean alkalinity enhancement: Carbon dioxide removal through industrial integration

Year: 2026

Type: article

Abstract: A common challenge for carbon dioxide removal (CDR) approaches, including those falling under ocean alkalinity enhancement (OAE), is the need to develop new global industries and supply chains to underpin their sustainable scale-up. To facilitate roll-out, OAE approaches could be incorporated into existing industries, notably by: i) partially substituting silica sand in existing beach nourishment projects with (ultra)mafic (e.g., olivine-rich) sand for carbon dioxide drawdown through coastal enhanced weathering; ii) using the spare capacity of the cement industry to produce slaked lime for ocean liming; and iii) producing sodium hydroxide from waste desalination brines through electrochemical brine splitting. Here, the gross CDR capacities of these OAE approaches were examined for Spain by considering spare capacities, technical constraints, and engineering restrictions and challenges. Prospective life cycle assessment (pLCA) revealed their net-negativity and their sensitivity to future climate scenarios and particularly technology maturity. Spain's gross/net CDR capacity via OAE amounted to 13.52/8.27, 38.35/26.50, and 40.54/38.13 Mt CO 2 yr −1 in 2030, 2040, and 2050, respectively. Future decarbonisation and improved technology readiness levels and spare capacities drive this increase. Therefore, technological maturity and decarbonised economies, particularly decarbonised energy, are needed for CDR technologies to achieve their full potential. Finally, we considered how complex social, regulatory, and governance factors may impinge on the feasibility of these three OAE approaches. Regulatory clarity and innovation, governance frameworks, and social acceptance are needed, which also requires robust efforts to consult and engage communities. Overall, OAE could underpin national long-term strategies and form an essential part of climate-neutrality strategies.

Source: Journal of Cleaner Production

DOI: 10.1016/j.jclepro.2026.149298