Ocean Thermal Energy Conversion OTEC is a technically feasible clean energy production method. It is basicly a Rankine cycle of Ammonia. The difference between deep ocean cold water temperature and hot sea surface water temperature must be at least 20 degrees Celsius to be able to make the plant work. There are some working plants of companies and electric production history in the world. The main challenges are capital costs, the deficiency of piping to meet the required high volume water flow to build continuously growing with higher capacity new projects. I can solve this challenge. Building costs obviously can be lower for land-based projects if project site is selected for example on Micronesian atolls due to existing steep depths for shorter piping. Temperature difference between deep water and surface water is also maximum in Micronesia. If we can install evaporator and condenser below sea level in the plant we can decrease pumping requirements thanks to natural water flow. If we manufacture flexible Titanium metal pipes which will be built with rolled concave rings, flat rings and rolled convex rings and strengthen the flexible pipe with Titanium elastic chains then we can have OTEC power plants of economical scale.