Ocean thermal energy conversion (OTEC) uses the temperature difference between cooler deep and warmer shallow or surface seawaters to run a heat engine and produce useful work, usually in the form of electricity.
Abiotic examples include things that are not alive but you will find in an ecosystem such as air, gases, water, sand, stones and rocks.
Abiotic factors are essentially non-living components that effect the living organisms of the freshwater community. When an ecosystem is barren and unoccupied, new organisms colonising the environment rely on favourable environmental conditions in the area to allow them to successfully live and reproduce.