Free energy may refer to:
Science Free energy perturbation, a method based on statistical mechanics used in computational chemistry Free energy principle, a variational formulation of self-organisation in biological systems, applied in particular to neuroscience Free-energy relationship, a relationship in physical organic chemistry Principle of minimum energy, a thermodynamic formulation based on the second law Thermodynamic free energy, the energy in a physical system that can be converted to do work, including: Gibbs free energy Landau free energy (also known as grand potential) Helmholtz free energy Variational free energy, a construct from information theory that is used in variational Bayesian methods
Pseudoscience Free energy device, a hypothetical perpetual motion device that is supposedly capable of drawing energy from a hidden free energy field, which is unknown in science Free energy suppression conspiracy theory, in which advanced energy technologies are suppressed by governments or special interest groups History of perpetual motion machines, history of devices supposedly capable of drawing unlimited energy
Other uses In economics, energy from sources that do not require an input, for example, fuel, which has to be paid for. Usually a sub-set of renewable energy. Common examples include hydroelectric dams, solar panels, wind turbines, and geothermal power, as well as sources where the fuel is essentially free, such as waste-to-energy power stations. Free Energy (band), a 5-piece rock band on DFA Records