Compare and contrast bio-mass and hydro-electricity as sources of energy.

Explanation

(i) Bio-mass is a renewable source of energy only if we plant trees in a planned manner which is not the case with hydroelectricity.
(ii) The energy from bio-mass can be obtained by using a chullah or a gobar gas plant whereas hydroelectricity requires construction of dams on rivers.
(iii) Bio-mass provides pollution-free enegry only when converted into biogas whereas hyroelectricity is totally pollution-free.