Hydroelectric Power Calculator

The core calculation for potential energy conversion relies on fluid dynamics and gravity. The primary equation for gravitational potential hydro power is expressed as:

Power = η × ρ × g × h × Q

Where η represents the turbine efficiency (as a decimal), ρ is the water density (approximately 1000 kg/m³), g is the acceleration due to gravity (9.81 m/s²), h is the hydraulic head height in meters, and Q is the volumetric discharge rate in cubic meters per second. When assessing kinetic energy from open streams without significant drop height, the calculator uses velocity head: Power = 0.5 × η × ρ × Q × v², where v is water velocity. Financial revenue is subsequently derived by multiplying the continuous power output by the operational duration and regional electricity tariff.

Consider a small river site selected for a micro-hydro installation with the following measured specifications:

• Hydraulic Head (h): 15 meters
• Discharge Rate (Q): 2.5 cubic meters per second
• System Efficiency (η): 85% (0.85)
• Water Density (ρ): 1000 kg/m³
• Gravity (g): 9.81 m/s²
• Electricity Tariff: $0.10 per kilowatt-hour (kWh)
• Operating Period: 365 days (continuous operation)

Step 1: Compute Power Output
Power = 0.85 × 1000 × 9.81 × 15 × 2.5
Power = 313,946 Watts, or approximately 313.95 kW.

Step 2: Calculate Annual Revenue
Total Hours in a Year = 365 days × 24 hours = 8,760 hours.
Total Energy = 313.95 kW × 8,760 hours = 2,750,202 kWh.
Revenue = 2,750,202 kWh × $0.10 = $275,020.20 per year.

Accurate site assessment is critical for realistic energy projections. Always measure water discharge across multiple seasons, as dry summer months or frozen winter periods can drastically reduce volumetric flow and actual energy yield. Furthermore, account for frictional head losses within penstocks and piping systems; neglecting minor losses can cause your estimated power output to exceed real-world generation by 10% to 15%.