Economic Assessment of Ocean Alkalinity Enhancement Through Electrodialysis: The Role of Carbon Credits in Comparing Solar Energy and Thermal Waste Technologies

This study evaluates the economic feasibility of an Ocean Alkalinity Enhancement (OAE) plant for CO2 removal by comparing Solar Energy (SE) and Thermal Energy Waste (TEW) configurations under varying carbon credit price and inflation scenarios in order to assess investment attractiveness. The methodology is based on a discounted cash flow model, using Net Present Value (NPV) as the primary indicator, applied to a plant with an annual CO2 removal capacity of 878 tonnes, located in the United States and assessed over a 20-year time horizon. Results show that project profitability is highly sensitive to carbon credit prices. Under high-price scenarios, positive NPVs can be achieved, whereas medium and low-price scenarios consistently result in negative outcomes. Break-even thresholds are estimated at approximately 1177–1472$/tCO2 for the TEW configuration and 1300–1602$/tCO2 for the SE configuration, depending on inflation assumptions and the opportunity cost of capital. The TEW configuration appears more economically robust, exhibiting a higher likelihood of financial viability under favorable market conditions. These findings underline the crucial role of stable carbon markets and supportive policy frameworks in improving the economic sustainability of OAE technologies and fostering circular economy-based business models aligned with marine ecosystem protection, supporting SDG 14.