Hitachi, Ltd. and others will begin a demonstration project at Hitachinaka Port in Ibaraki Prefecture to create seaweed beds using breakwaters and permanently fix CO2 through seaweed sunk into the beds. The project is also described as distinctive for using discharged treated wastewater at the port.
Against the backdrop of the slow expansion of blue carbon initiatives in Japan, Hitachi, Ltd. and others are proceeding with a plan to install wire mesh and other materials on the inner walls of breakwaters to create seaweed beds, then sink the cultivated seaweed to the seafloor at depths of more than 200 to 1,000 m. The initiative aims to create a large-scale seaweed bed using port infrastructure on a world-first scale.
The plan is expected to deliver secondary benefits in addition to reducing wave impacts and absorbing CO2 through seaweed growth, including measures against rocky-shore denudation and the restoration of marine ecosystems. The Hitachinaka Port District Blue Carbon Field Demonstration Test Council, in which Hitachi, Ltd. and others participate, is advancing the demonstration project.
The backdrop is the difficulty of achieving Japan's target for annual CO2 absorption through blue carbon. Port breakwaters can readily provide an environment where seaweed can attach and grow, and Japan has approximately 1,200 km of port breakwaters in total. The effects of nutrients in discharged treated wastewater have also been confirmed through field surveys.