Abstract
Floating platforms housing hydrogen plants operated with 100 MW of OTEC-generated electricity have been conceptualized. These plantships, deployed throughout the tropical oceans, could provide a significant source of energy in the form of liquid hydrogen. Large suspended pipes would transport cold seawater from depths of 1000 m to the heat exchangers onboard.
A 285 000-tonne ship-shaped vessel is first proposed. It provides deck space for the OTEC plant, hydrogen plant, storage, and crew quarters. A length of 250 m and a beam of 60 m are sufficient to accommodate five seawater sumps. The operational draught is 20 m. Four 3000 hp thrusters permit grazing at one-half knot and some maneuvering capability.
A more compact plantship jet-propelled by the momentum flux of the OTEC discharge is also presented. The length is reduced to 200 m, for a displacement of 225 000 tonnes. Only one sump is required, and warm seawater is fed through lateral openings.