Any source of heat energy is termed as fuel. The term fuel includes all combustible substances obtainable in bulk.

Fuel is a substance which produces a large amount of heat when burnt with oxygen of atmospheric air.

Fuels are primarily used for heating purposes.

Fuels are-


A. Solid Fuels:

Coal, peat, lignite, wood, coke, Anthracite, Bituminous.

B. Liquid Fuels:

Petrol, Diesel, Kerosene, Coal tar, Molasses, Spirit, Shale Oil.


C. Gaseous Fuels:

Methane, Coal gas, Producer gas, compressed Blast furnace gas, town gas, Cock oven gas, water gas, compressed butane

D. Electricity:

Other classification of fuels


(I) Naturally Occurring/Primary fuels- Wood, Peat, lignite, Anthracite, Oils, Shale, petroleum.

(II) Prepared/Secondary, derived from (I) Fuels.

Charcoal, semi coke, coke, Coal tar, Spirit, Kerosene, diesel, gasoline, Producer gas, water gas, compressed butane.

Good/Ideal Fuel- Which


(a) Has low ignition point

(b) Has high calorific value

(c) Produces minimum quantity of smoke

(d) Should be easy to store & convenient for transportation & is economic.


(e) Has moderate rate of combustion

(f) Has low content of non Volatile material

(g) Produces no poisonous products on combustion

(h) Is readily & plentiful available