Work out steam turbine power instantly with clear inputs, formula shown and shareable results.
Turbine shaft power is steam mass flow in kilograms per second times enthalpy drop in kilojoules per kilogram, giving kilowatts. Mechanical losses in bearings and gearing and generator losses then reduce it to electrical output, typically taking 3-4% in total on a large machine.
Turbine power
Shaft power (MW) = mass flow (kg/s) x enthalpy drop (kJ/kg) / 1000
Electrical output
Electrical = shaft power x mechanical efficiency x generator efficiency
From steam tables or a Mollier chart: the enthalpy at inlet pressure and temperature, less enthalpy at exhaust conditions along the actual expansion line.
Steam bled for feedwater heating or process use does not expand to the exhaust, so power must be computed stage by stage with the flow remaining after each extraction.