In Engineering fields related to power generation, ''free energy'' means an energy source available directly from the greater environment and which cannot be expected to be depletable by humans. ''Free energy'' in this sense may be categorised as '' Renewable Energy '', although most ''renewable energy'' sources would not normally be called ''free energy'' sources.
--- ''Free energy'' is energy which may be directly utilized (and returned) by a device from the surroundings ('' Electromagnetic free energy'' is sometimes referred to as '' Radiant Energy '').
--- ''Free energy'' can also mean a primary energy source that is ''free'' (i.e. does not cost anything) for consumption. Examples include Wind Power , Earth Batteries , Water Power , and Solar Power . Remaining so-far-unexploited forces of nature which are well documented in scientific literature include Atmospheric Electricity , and Atmospheric Pressure change.
''Free energy'' can mean more fantastical forces attributed by fewer qualified scientists and engineers, and are generally considered Perpetual Motion . These devices utilize '' Telluric Currents '', QuantumVacuum perturbation (which cannot really be considered to be a force as much as it is a bending of time-space), Quantum Vacuum Energy , rotating Magnets (employed in ways hitherto unpracticed), as well as some purported methods to ''crack Hydrogen ''.
--- '' Free Energy Suppression '' is the notion that corporate energy interests deliberately suppress technologies that may provide energy at very little cost. Widespread existence of such technologies would diminish use of some corresponding sector of the energy industry, and the existing energy infrastructure has momentum defined in ''trillions-of-dollars''. From these one fact and a supposition is derived the possibility that genuine (virtually-) free-energy-powered technologies exist, but have been well suppressed. Following the same logic, a third possibility is that false claims would arise to exploit the doubt of the situation. A fourth extension of this logic is that great argument would arise about the realities of various claims. And for this fourth point, there is evidence...
---Some labelled as '' Conspiracy Theories '' range at least from, allegations that light-bulb companies secretly own the patents to manufacture light bulbs that never burn out, to the idea that fuel companies are sitting on designs for highly efficient vehicles, to the belief that perpetual motion is a practiced but suppressed technology.
For ''free energy'' pertaining to DNA studies, see '' Free Energy (DNA) ''
