Free Online Micro-Hydro Power Calculator

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Run-of-River Micro-Hydro Power Output Calculator

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Inputs

Flow rate, Q		X
Gross head (elevation drop), H_gross		X
Penstock head losses, h_L (See notes)		X
Plant efficiency, η (0–1) (See notes)		X

Results

Net head, H_net	Net head, H_net	X
Power output, P	Power output, P	X
Annual energy at 100% capacity (See notes)	Annual energy at 100% capacity (See notes)	X

Power Equation: P = η × ρ × g × Q × H_net, where ρ = 1000 kg/m³ (fresh water) and g = 9.806 m/s².
Net Head: Net head = gross head − penstock head losses. A common first estimate is h_L ≈ 5% of H_gross. Use the Darcy-Weisbach calculator for more accurate penstock loss estimates.
Efficiency: Typical plant efficiency η ranges from 0.70 to 0.85 for Pelton and cross-flow turbines common in micro-hydro. Use 0.75 as a conservative first estimate.
Annual Energy: Annual energy assumes continuous full-flow operation (8760 hours/year). Actual production will be lower due to seasonal flow variation, maintenance downtime, and load factor.