**Hydro power is very efficient its over all efficiency ranges from 75%-90% , the losses in hydro-power are due to :**

**drag friction and turbulent water flow .****frictional and magnetic losses in the turbine and the generator.**

**the efficiency of the hydro-power planet = the total electrical energy delivered from the generator/potential energy of the head of the water.**

**the output power of the power planet(Kw)=g*η*Q*h.**

**where g=the gravitational acceleration (9.81 m/s^2).**

**η= the efficiency of the turbine-generator 0<η<1.**

**Q: the volumetric flow rate of the water(m^3/s).**

**h:effective head(m).**

**example: assume we have a stream with effective head about 100m and flow rate of 10 m^3/s , assume the planet efficiency about 80% , how much is the output power ?**

**using the equation of power above the output-power =g*η*Q*h.**

** = 9.81x.83x10x100**

** = 8142.3 kw = 8.1423 Mw**