Some 60-70% of energy used in industrial processes is wasted as heat that pollutes the environment. Capturing and converting this waste heat into electricity via thermoelectric energy conversion would make a tremendous impact on our overall energy use as well as on the environment. This purely solid state means of energy conversion uses charge carriers as a working fluid and requires no moving parts, which makes the process exceptionally reliable. Thermoelectricity has enabled deep space explorations as a sole source of on board electrical energy and is currently intensely explored for a variety of terrestrial power generation applications. To make it broadly applicable, the efficiency of thermoelectric materials must be improved. Some of the most prospective families of thermoelectric materials will be discussed and a wide range of possible applications illustrated.