Energy may be defined as, “any property, which can be converted into work.” (or) Energy is defined as, “the capacity to do work.”
Forms of energy, some of immediately used to do work; others require some process of transformation Life is unthinkable without energy.
All the developmental activities in the world are directly or indirectly dependent upon energy.
Energy production and energy utilization are the indicators of a country’s progress.
2 Development of energy
The first form of energy is the fire.
The early man discovered fire and used it for cooking and heating purposes Wood is the main source of energy, which is later replaced by coal.
Coal is now being replaced by the oil and gas.
Now due to insufficient availability and price hike, people started of thinking and using several alternative sources of energy.
Wood - - > coal - - > oil - - > alternate energy (solar, wind, tidal energy)
3 Growing energy Needs
Energy is essential to all human societies.
All industrial process like, mining, transport, living, heating and cooling in buildings, all require energy.
With the demands of growing population, the world is facing further energy deficit,
Our life style is also changing from al simple way of life to luxurious life style. At present 95% of the commercial energy is available only from the fossil fuels like coal, oil and natural gas, and are not going to last for many years. It would be really ironic if fuel becomes more expensive than food.
4 Energy Distribution –World Scenario
U.S.A and Canada 5% of the world’s population- consume 25% of the available world’s energy resources.
It has been observed, that in U.S.A and Canada an average person consumes 300 GJ (Giga Joules; equal to 60 barrels of oil) per year.
But in poor countries like Bhutan, Nepal and Ethiopia, an average person consumes less than 1 GJ per year.
So a person in a developed country consumes almost as much energy in a single day as one person consumes in a whole year in a poor country.
From the above scenario it is clear that our life style and standard of living are closely related to energy needs.
1. Renewable energy resources (or) non-conventional energy resources
Natural resources can be regenerated continuously and are inexhaustible. They can be used again and again in an endless manner.
Example: Wood, solar energy, wind energy, hydropower energy, etc.,
Merits of renewable energy resources
3. Unlimited supply.
2. Provides energy security.
3. Fits into sustainable development concept.
4. Reliable and the devices are modular in size.
5. Decentralized energy production.
2. Non- Renewable energy resources (or) Conventional energy resources
Natural resources which cannot be regenerated once they are exhausted. They cannot be used again. Example: Coal, petroleum, natural gas, and nuclear fuels.
Even our renewable resources can become non-renewable if we exploit them to such extent their rate of consumption exceeds their rate of regeneration.
Wood is renewable resources but not coal-why?
Wood is renewable resources because we can get new wood by growing sapling into a tree within 15-20 years.
But the formation of coal from trees has taken million of years and cannot be regenerated in our life time.