The world needs renewable energy badly this century because the oil and gas economy is doomed due to both high extraction costs and environmental concerns. Forms of renewable energy are hydroelectricity, solar, wind, biomass, ocean waves and tides, river flows, geothermal, and nuclear fusion.
Ocean Thermal Energy Conversion (OTEC) System
The OTEC system, which stands for "Ocean Thermal Energy Conversion", taps into the stored solar energy in the ocean through the difference between the sea-surface temperatures and under 300m depth, which can be harnessed for extracting work through a Rankine cycle. The ocean is indeed a huge solar capacitor, its temperature at about 1,000 m depth is steadily around 4ºC, and at the tropics the sea-surface temperatures range from 15ºC to 30ºC on a 24/7 basis, which turns out to be a base load energy source, and a reliable and clean energy solution.
Organizations working on OTEC R&D are: