Water stored behind the dam falls through the penstock, spinning turbines connected to generators. The available power depends on how much water flows and how far it falls (the head).
Q = flowMax * (gate / 100) * turbines [m³/s]
P = η · ρ · g · Q · H [W]
ρ = 1000 kg/m³, g = 9.8 m/s²
η = efficiency, peaks near matched turbine load
- Reservoir head — the vertical drop from the water surface to the turbine; higher head means more potential energy per litre.
- Dam gate opening — throttles how much water is allowed to flow into the penstock.
- Turbine load match — how well the electrical load matches the turbine's optimal operating point; mismatched load wastes energy as heat and vibration.
- Turbine count — number of parallel turbine units sharing the flow.
- Reset gate — restores the default operating point.
Real-world relevance: this is the same principle behind facilities from small run-of-river micro-hydro plants to the Hoover Dam — roughly 15% of the world's electricity comes from falling water.