Abstract: The invention relates to a platform for utilization of the thermal energy of the sea, comprising a floating structure carrying a downwardly extending tube (2) for taking up cold water and supporting at least two power modules (3) each comprising an evaporator (15) and a condensor (12) and pumps for circulation of hot and cold water, each power module being connected to a turbine-driven generator set (19,19').According to the invention, the support structure has open cells receiving the power modules and each module has its component parts arranged in a vertical array so as to constitute a cylindrical assembly extending through the support structure.Preferred applications: offshore manufacture of aluminium, ammonia and hydrogen.