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Hydro Power

Karl / Sanyal · 3 concepts · 4 questions

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Hydro Power Formulas

Main power equation:

P_turbine = η_s · ṁ_water · g · h_useful

= η_s · q̇_water · ρ_water · g · h_useful


  • η_s = hydraulic efficiency (85–92%)
  • q̇_water = volumetric flow rate [m³/s]
  • ρ_water = 1000 kg/m³
  • g = 9.81 m/s²

Flow rate: q̇ = v · A

Mass flow: ṁ = ρ · q̇


Useful head:

h_useful = (h_u − h_l) + (p_u − p_l)/(ρ·g) + (v_u² − v_l²)/(2·g)


Example: q̇ = 100 m³/s, h = 50 m, η = 0.88:

P = 0.88 · 100 · 1000 · 9.81 · 50 = 43.2 MW