Background Combined cycle power plants located on the coast generally use seawater for their cooling processes. This can lead to biofouling – growth of flora and fauna on surfaces – which can be micro or macrofouling, depending on the size of the organisms. Macrofouling is a problem for industrial facilities. In order to eliminate the organic matter, chlorinated compounds are generally used. Despite preventive measures to avoid the discharge of these compounds into water, they cause significant problems in the environment due to their persistence, slow degradation and great potential for accumulation. For example, the consumption of sodium hypochlorite in a plant varies from 700 to 1500 tonnes/year. Objectives The CO2FORMARE project will demonstrate that it is possible to use carbon dioxide from the flue gas of industrial facilities located close to the sea as a replacement for the chlorinated products used in these facilities against biofouling. Dangerous substances will be reduced or even completely removed, and the atmospheric emissions of these gases will be reduced because the CO2 will be captured and reused. The project will be carried out in the Iberdrola Combined Cycle Gas Turbine (CCGT) plant in Castellón, where the CO2 will act as an inhibitor of macrofouling. The results will be fully replicable in similar industrial sectors. More specifically, the project aims to: Assess the concentration of organisms in seawater used for cooling; Inhibit the settlement and development of the organisms, through a moderate pH decrease in the seawater used as a coolant, using a CO2 dosage in the water; and Produce water streams with different saturation values of CO2 for the CCGT plant cooling unit. Expected results: A system that allows CO2 to be captured and used in seawater at different concentration values; Reduction in the use of chlorinated compounds by 4500 tonnes during a three-year period; and The capturing and reuse of 150 000 tonnes of CO2 during a three-year period. Initial estimates indicate that 50 000 tonnes CO2/year (with an approximate consumption of 3-8 tonnes/hour) could be used from the power station.