Major energy resources include Coal, Natural Gas, Oil, Wood, Nuclear, Solar, Hydrogen, wind and Tidal power etc. Since the beginning of industrialization in the 17th century, the use of these energy resources has been increasing year by year. Coal which is the traditional resource of energy has slowly given way to the latest resources such as, oil, gas and nuclear fuel. in 2000, percentage share of coal was 21 % but oil led with a percentage of 39. Similarly, natural gas has a share of 15 percent. Out of these resources, coal, petroleum and natural gas are non-renewable. According to recent surveys,petroleum and gas reserves will last for 100 years and coal for 300 to 400 years.

Nuclear energy is another modern source of energy which is gaining currency in many countries rapidly. but poor nations cannot afford it because cost of establishing nuclear plants is very high. Moreover, permanent risk of atomic radiation is involved.