Why is biogas regarded as a better fuel than cowdung cakes?
Answers
Burning of animal dung cause lot of pollution whereas biogas is a smokeless fuel
Animal dung cakes leaves residue after burning whereas biogas leaves no residue
Answer
Because it doesn't leave any residue. It's a clean fuel like natural gas because it releases also water with carbon dioxide. This is better than many other fuels like petroleum or coal as it releases water instead of carbon mono oxide or any other harmful gas with carbon dioxide. Being it's a gas, it won't leave any residue. It's even better than natural gas as it can be prepared easily with bio-degradable wastes and can be used at many places where natural gas is used.
Bonus
Hydrogen is considered the cleanest fuel as it only releases water when burnt. Burning hydrogen releases more than 3 times the energy of burning petroleum products or any other fuel. But this much energy is unstable and is very hard to control. That's why it's used as rocket fuel.