I have written a bit about ocean thermal energy conversion on this site. This technology use the temperature difference between the ocean surface and deep seawater. The larger this difference, the greater the energy that can be harvested.
The picture above shows that the best spots for OTEC are away from the coast and hence if we want to really take advantage of this energy source, we need to transport it somehow. I believe that off shore synfuel production would be the best method to do this.
Synfuel is made from hydrogen and carbon dioxide. Fortunately scientists from Stanford University have found a way to produce hydrogen directly from seawater. Once off shore hydrogen has been produced it can either be shipped to customers or be used to make synfuels such as menthol.
Once we have another look at the map, we will see the geopolitical implication of OTEC based synfuels. If this scenario would become reality, it will shift power away from the Middle-East towards South-East Asia. In particular the Philippines, Indonesia and Papua New Guinea will benefit due to their location.
Also offshore synfuel could provide a economic rationale for seasteading, though I still doubt whether this will ever fulfill the Libertarian aspirations of most of the seasteading movement.