1. Any of various machines having a rotor, usually with vanes or blades, driven by the pressure, momentum, or reactive thrust of a moving fluid: A turbine can be operated by steam, water, hot gases, or air, either occurring in the form of free jets or as a fluid passing through and entirely filling a housing around the rotor.
2. A general term for any machine capable of generating rotary mechanical power by converting the kinetic energy of a stream of fluid, such as water steam or hot gas: Turbines operate through the principle of impulse or reaction, or a combination of the two.

Turbines have been around for hundreds of years

• Primitive hydraulic turbines made of wooden discs carrying straight blades were believed to exist in Egypt and Mesopotamia in the 5th century B.C.
• Turbines were also in existence in ancient India and China in about the same time period.
• These early machines were used for milling corn and other cereals.
• Until the end of the Middle Ages, hydraulic and wind turbines were the only non-animal source of mechanical power.
• The modern development of the hydraulic turbine began towards the end of the 18th century where it powered sawmills, textile, and manufacturing industries.
• The first steam turbines in commercial service were installed in the norther United States by W. Avery, in 1831, to power some sawmills.
• Modern development of steam turbines began in the 1920s when large industrial groups like General Electric, Allis-Chalmers, Westinghouse, and Brown-Boveri applied these machines to generate electricity.
• The significant advances for the gas turbine came from its aeronautic applications.
• The majority of fossil fuel thermo-electrical conversion locations use steam turbines, and gas turbines as mechanical converters.

A common type of turbine with axial flow through the runner blades axially to the turbine shaft: An axial-flow turbine normally has 1-3 rotating stages and the flow of gas is essentially axial.

1. A turbine that generates power from the combustion of a fuel.
2. A heat engine that converts the energy of fuel into work by using compressed, hot gas as the working medium and which usually delivers its mechanical output power either as torque through a rotating shaft (industrial gas turbines) or as jet power in the form of velocity through an exhaust nozzle (aircraft jet engines).
3. An internal combustion engine in which liquid or gaseous fuel is used to generate mechanical energy through a rotating shaft, which then drives an electric generator or another piece of equipment.
4. One of a class of heat engines that use fuel energy to produce mechanical output power, either as torque through a rotating shaft (industrial gas turbines) or as jet power in the form of velocity through an exhaust nozzle (aircraft jet engines).

The fuel energy is added to the working substance, that is gaseous in form and most often air, either by direct internal combustion or indirectly through a heat exchanger.

A steam turbine in which the exhaust steam is condensed and the water formed from this process is then used to supply the feedwater for the generator: Condensing turbines were built in the USSR at the Leningrad Metal Works in 1924.

A steam turbine in which a portion of the working fluid is tapped between stages of an expansion process and used for purposes other than generating mechanical power: The extraction turbine has provided many rooms with heating because of the devices that allow the hot vapor to be utilized.

A pistonless rotary engine having a four faces articulated rotor with a free and accessible center, rotating without vibration or dead time, and producing a strong torque at low RPM under a variety of modes and fuels; Qurbine: The Quasiturbine can be used as an air motor, steam engine, Stirling engine, compressor and pump. The Quasiturbine is also an optimization theory for extremely compact and efficient engine concepts.

The Quasiturbine is at the crossroad of three modern engines. Inspired by the turbine, it perfects the piston, and improves upon the Wankel.

The Quasiturbine is universal in relation to energy sources: Liquid and gaseous fuel, hydrogen, steam, pneumatic, and hydraulic. The Quasiturbine engine was invented by the Saint-Hilaire family and first patented in 1996. The engine makes use of a complex computer calculated oval shape stator housing, creating regions of increasing and decreasing volumes as the rotor turns. It is capable of burning fuel using detonation, the optimal combustion mode of the future which the piston cannot stand.

Ocean-power technology splits into two broad categories, tidal and wave power.

1. Wave power involves the use of the up and down motions of the waves to produce electricity.
2. Tidal power consists of harnessing the action of the tides with underwater turbines, which twirl like wind machines.
3. A third type of power generation, called ocean thermal, has the objective of exploiting temperature differences between the surface and the deep ocean, and is primarily applicable to tropical areas.
4. Some experts claim that ocean electrical power has more advantages than wind power because water is about 850 times denser than air, and so it consists of far more energy.
5. The ocean's waves, tides, and currents are also considered to be more predictable than the wind.
6. The negative aspect is that seawater can batter and corrode machinery, and costly undersea cables may be needed to bring the electrical power to shore and the machines are considerably more expensive to build.
7. General Electric, which builds wind turbines, solar panels, and other equipment for virtually every other type of energy, has so far stayed clear of ocean energy because of the much greater costs.