Abstract: A breakwater apparatus for generating electrical power by extracting energy from sea waves. A novel array of subsurface fixed-position flexible-walled pneumatic bags or cells, in a closed cycle system, react to surface-wave-correlated static pressure variations by expiring compressed gas into a supply header to a generator-driving pneumatic motor while simultaneously inspiring return gas in a return header from such motor. Alternate inspirational-expirational operation of individual cells involves use of a supply check valve at each cell, discharging into the supply header, and a return check valve at each cell, receiving from the return header.