A steam turbine is a machine that converts the kinetic energy of steam (formed by heating water) into the kinetic energy of turbine rotation. Compared to the single-stage reciprocating steam engine originally invented by James Watt, the turbo steam engine greatly improves the thermal efficiency, is closer to the ideal reversible process in thermodynamics, and provides more power. It has almost replaced the reciprocating steam engine. Power plants that use turbine steam engines are called thermal power plants, which are particularly suitable for thermal and nuclear power generation. About 80% of the world's electricity is generated by turbine steam engines. Many of the old ships also use turbo steam engines, but most of them have been replaced by gas turbine engines or diesel engines in modern ships. Only a few special machines such as modern machines still use steam turbines.