The invention of steam engines replaced the burning of wood by coal and coal was later replaced to a great extent by oil. This ultimately led to exploration and use of several alternate sources of energy.
Growing Energy Needs:
Development in different sectors relies largely upon energy. Agriculture, industry, mining, transportation, lighting, cooling and heating in buildings, all needs energy. With the demands of growing population the world is facing further energy deficit.
The fossil fuels like coal, oil and natural gas which is at present are supplying 95% of the commercial energy of the world resources and are not going to last for many more years. Our life style is changing very fast and from a simple way of life we are shifting to a luxurious life style. If we just look at the number of electric gadgets, private cars and scooters in our locality we will realize that they have multiplied many folds and all of them consume energy.
Energy consumption is an index of advancement of a country. During the hunter gatherer stage of civilization, energy requirement per capita was only 2000-4000 kcal/ day, which was obtained from food chain.
Soon after 19th century, industrialization increased rapidly which took the per capita energy utilization to about 70,000 kcal, about 30% of the world’s population, living in industrialized countries, consumes about 80% of global energy. In India, the per capita energy consumption is only 221 kg of oil equivalent/year, a very low rate compared with other developed countries.
CountriesGross National Product (GNP)kg
Renewable energy sources can be generated continuously in nature and are in-exhaustive. They are also known as non-conventional sources of energy and can be used again and again in an endless manner.