Question

write the energy conversion that takes place in a hydro power plant.

Answer 1

"...What energy transformations take place in a hydroelectric power plant?..." 
Gravitational energy is converted into electricity. Gravity moves water and the moving water spins electric generators. 

Answer 2

According to the universal energy equilibrium theory,we cannot destroy all create energy, we can just change the form of the energy.

Similarly,in the hydroelectricity manufacturing plants energy conversation happens.

Here the kinetic energy in the speedy water flow converts into the electricity energy with the help of the rotating turbine.