The natural energy of Earth is thermodynamic. When hot masses of ocean surface water meet cold masses of air or cold polar water, natural processes dissipate the heat, producing energy in the form of rain, wind, waves, atmospheric fronts, hurricanes, tornadoes, and other climatic phenomena. The dissipation of heat is inexorable, and the generation of ordered energy is fixed, as described by the Carnot equation. A good way of understanding this is to consider temperature as a measure of chaos. So if we cool hot chaos with cold chaos, the only chaos that can be converted to orderly energy is the energy that is transferred from the hot source to the environment as it becomes the cold source. If we could somehow transform this ordered energy into energy beneficial to humans, we would meet the goal of environmentally sustainable development.

It was with this motivation that the State of Hawaii established the Natural Energy Laboratory of Hawaii (NELH) in 1971. Initially it was believed that economically viable electrical energy could be obtained from the temperature difference between warm, tropical surface water and cold water from the deep ocean in the energy-generating process dubbed OTEC (ocean thermal energy conversion). The oceanic regions of the world in which OTEC-suitable temperature differences between surface and deep waters prevail are significant.

We now recognize that the generation of electrical energy may be one of the lesser uses that can result from Earth’s natural energy machine. Indeed, we now realize that the primary energy resource is deep ocean water itself, which, lying below the photic zone, is not only cold, but pathogen-free and rich in nutrients. Many beneficial products can be derived from utilizing this "elan vital" of the ocean. Developments at NELH have demonstrated that the technology is in place for the design, construction, and deployment of prototypes for self-sufficient, deep-ocean water systems. These systems include closed-cycle electricity generation, air-conditioning and industrial cooling, fresh water generation, cold-water agriculture of more than 100 terrestrial crops, and aquaculture of a complete spectrum of marine plants and animals.