Work out hydro power output instantly with clear inputs, formula shown and shareable results.
Hydro power is P = rho g Q H, or 9.81 x flow in cubic metres per second x net head in metres, giving kilowatts. Net head is gross head less friction losses in the penstock. Turbine efficiency reaches 90-94% for a well-matched Francis or Kaplan machine, and generator efficiency 95-98%.
Hydro power
P (kW) = 9.81 x Q (m3/s) x H (m) x turbine efficiency x generator efficiency
Hydropower development requires water abstraction rights, environmental flow requirements and dam safety approvals. Confirm regulatory requirements before design.
Pelton for high head above 100 m with low flow, Francis for 20-300 m medium head, Kaplan and propeller for low head under 30 m with high flow. Cross-flow turbines suit small low-head sites.
Friction in the intake, penstock and draft tube consumes head that never reaches the runner. On long penstocks losses of 5-10% of gross head are common and must be designed against.