Original: Power The power available in a stream of water is; where:      power (J/s or watts)   turbine efficiency   density of water (kg/m³)      acceleration of gravity (9.81 m/s²)      head (m).
Simplified: Power The power available in a stream of water is; where:      power (J/s or watts)   turbine efficiency   density of water (kg/m3)      acceleration of gravity (9.81 m/s2)      head (m).