In total, it is estimated that about 10 TW (10 trillion W or 10 billion kW) of power, approximately equal to the current global energy demand [13], could be provided by OTEC without affecting the thermal structure of the ocean [10]. However, with the current cost of electricity generation from OTEC varying between 8 and 24 cents/kW h [1], significantly higher than fossil fuel costs, it is unlikely that this resource will be fully developed unless it is subsidized. The greatest potential for OTEC is probably for use on small island developing states (SIDS), which need both domestic power and fresh water. Full use of ancillary benefits (fresh water, aquaculture, air conditioning, etc.) is most likely necessary for economic feasibility. OTEC may not make a great contribution to worldwide power needs