ENERGY SOURCES
Humans have always been using some source of energy for a variety of purposes – cooking, warming, ploughing, transportation, lighting etc. To start they used fire wood and later kerosene or coal or rather lately the electricity. He used animal power (horse, bullock, camel, yak etc.) for transportation and for running minor mechanical devices like the Persian wheel for irrigation or for running “kolhu” for extracting oil from oil seeds. During the last century or so, electricity has been produced from thermal plants (using coal) or from hydroelectric plants (using water current).
We can broadly categorise the source of energy according to periods of usage as follows-
- Conventional source of energy, which are easily available and have been in usage for long time.
- Non-conventional source of energy, that are other than the usual or that are different from those in common practice.
Sources of Energy
- Most of the renewable resources of energy are directly or indirectly related to sun or solar energy. Renewable sources of energy or non-conventional energy sources include sunlight, wind, water and biomass (firewood, animal dung, crop residue, agricultural wastes, biodegradable waste from cities and towns). Energy received from sun is known as solar energy, energy generated by water is hydel energy and energy obtained from underground hot dry rocks, magma, hot water springs or natural geysers etc is called geothermal energy. Tidal energy is derived from waves and tidal waves of oceans and seas.
Renewable or Non-Conventional Sources of Energy
The rapid depletion of fossil fuel sources and the escalating demand for energy have made it essential to explore alternative energy sources. These alternatives are known as renewable or inexhaustible sources of energy.
Definition of Non-conventional energy
| Inexhaustible energy resources can be defined as: “Those resources which can be harnessed without depletion.” |
- Free from pollution
- Usable in many places
- Sustainable over time
- Solar energy — directly from the sun.
- Flowing water (hydropower) — indirectly from the sun driving the water cycle.
- Wind energy — indirectly from solar heating causing air movements.
- Hydrogen energy — produced from water or other materials.
- Geothermal energy — heat from inside the Earth.