Steam Turbine Power Calculator

Work out steam turbine power instantly with clear inputs, formula shown and shareable results.

About Steam Turbine Power Calculator

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.

Formulas

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

Worked example

With the default values below, Steam Turbine Power Calculator returns Electrical Output of 70.386. Change any input above and every figure here is recalculated in your browser.

Inputs used

Steam Flowminimum 0 t/hour: 250 t/hour
Enthalpy Drop Across Turbineminimum 0 kJ/kg: 1,050 kJ/kg
Mechanical Efficiencyaccepts 1–100 %: 98 %
Generator Efficiencyaccepts 1–100 %: 98.5 %

Results

Electrical Output: 70.386
Shaft Power: 72.917
Steam Mass Flow: 69.4444
Mechanical And Generator Loss: 2.5302

Step by step

1Values used
2Turbine power
3Electrical output
4Electrical Output= 70.386
5Shaft Power= 72.917
6Steam Mass Flow= 69.4444
7Mechanical And Generator Loss= 2.5302

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 4 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Where does the enthalpy drop come from?

From steam tables or a Mollier chart: the enthalpy at inlet pressure and temperature, less enthalpy at exhaust conditions along the actual expansion line.

Why does an extraction turbine complicate this?

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.