If you could use any source of energy for heating your food, which one would you use and why ?

Explanation

Fuel to be used should be easily accessible, should be easy to store and transport and should be economical.
If we are in city area, L.P.G. should be used since it does not produce pollution, is easily available and is economical.
In rural area, Gobar gas or biogas should be used. It is almost free has high calorific value and is pollution free. it is also renewable source of energy.