The capacity to do work is called energy. Anything from which energy can be obtained is called a source of energy. Firewood, gobar gas, coal, LP gas, petroleum products and the Sun are all sources of energy.
Think for a moment about which kinds of energy you need in order to get through an ordinary day. Light from the Sun or from some other source is what lets us see the things around us. Along with light, the heat that comes from the Sun keeps the temperature of the Earth comfortable enough for living things to survive. Sound energy is what lets us talk to one another, and sound energy is produced when we watch television, listen to a song or play an instrument we enjoy. Electricity is an important source of energy in our lives, needed for lighting a lamp, watching television and running a computer, and its use is growing day by day.
Where the energy in your body comes from
We need energy in order to do work. The energy we need for the various jobs we do each day comes from food. The energy a person needs is obtained in the form of food from plants and animals. The energy needed to run vehicles, aeroplanes and the machines in factories comes from diesel, petrol, kerosene, coal or electricity.
Here is a chain worth following to the end, because it is the single best idea in this topic and the book only hints at it. The energy in your legs came from your dinner. Your dinner was rice, which is a plant, and the plant built itself using sunlight. If you ate meat, the animal ate plants, and those plants used sunlight. Now try firewood: a tree, built from sunlight. Coal: a buried forest, built from sunlight millions of years ago. Petrol: buried sea creatures, which lived on tiny plants, which used sunlight. Hydroelectricity: falling water, which was lifted into the sky as vapour by the Sun's heat. Wind: air moving because the Sun heats some places more than others. Almost every source in this chapter is stored sunlight wearing a different disguise, and the two real exceptions are nuclear energy and geothermal heat.
Renewable and non-renewable sources
What is used in your house for cooking? How are firewood, gobar gas, LP gas and electricity obtained or produced? Somebody may use firewood, gobar gas, LP gas, or an electric heater or induction stove. Firewood is obtained from the forest. Hydroelectricity is made by using the energy in flowing water, and LP gas is taken out by refining mineral oil. Energy is also needed to run vehicles, to warm the body in cold weather, to dry grain, and to run the various tools used in construction work.
| Kind | Definition | Examples |
|---|---|---|
| Renewable energy | A source of energy which, once used, is produced again in nature within a short time | Electricity, wind energy, solar energy, firewood, biogas and gobar gas. Because they are produced again in a short time, their use should be given emphasis. |
| Non-renewable energy | A source of energy which, once used, cannot be produced again in nature within a short time | Diesel, petrol, kerosene, LP gas, coal and nuclear energy. Using them continuously makes them decrease and finally run out. |
Fossil fuel
These days most means of transport run on diesel and petrol. Trains can be run and machines in factories operated using the heat energy that comes out of burning coal. Have you ever thought about how petrol, diesel, kerosene and coal are made?
When large changes took place in the surface form of the Earth, forests and sea creatures were buried and turned into fossils. Because of very great pressure and heat, over an interval of hundreds of thousands of years, those fossils went on to become mineral coal and oil. That is why mineral oil, which includes petrol, diesel and kerosene, and coal are called fossil fuels.
| Advantages of fossil energy | Disadvantages of fossil energy |
|---|---|
| It is the most easily available of all the kinds of fuel. | Continuous heavy use of fossil fuel brings the danger that its store will run empty. |
| Mineral oil can be transported easily from one place to another. | Burning fossil fuel causes environmental pollution. |
| It is a fuel with many uses, so it is used to run different vehicles and factories. | The carbon dioxide released adds to air pollution and to the warming of the Earth. |
| A great deal of heat energy is obtained from fossil energy, so it is used heavily in industries and factories. | It took hundreds of thousands of years to form, so nothing we do can replace what is used. |
Alternative energy
A source of energy used in order to reduce the consumption of non-renewable energy is called alternative energy. Hydroelectricity, solar power, gobar gas and biogas are some of the alternative energies already in use in Nepal.
Because Nepal is an agricultural country, farming is done in village households, and cattle are kept both for that farming and for milk and curd. The gobar gas that comes out of using the dung and urine of those cattle can be used for cooking. In places where electricity has not reached and which are geographically remote, solar power can also be a suitable substitute for non-renewable energy. So, looking at the geography and the circumstances of Nepal, solar power and gobar gas are in use as suitable sources of alternative energy. To increase the use of alternative energy, the Government of Nepal also provides financial grants or other concessions.
Notice the logic of the sentence about gobar gas, because it explains something more general. The gas is not made from a resource that had to be bought, mined or imported. It is made from dung that a farming household already has, in a country where cattle are already kept for ploughing and for milk. The fuel is a by-product of something that was happening anyway, and what comes out of the plant at the end is still good manure for the field. That is what makes an alternative energy suitable rather than merely possible. The right question is never simply whether a technology works, but whether it fits what a place already has.
Ways of saving energy
At present the demand for fossil energy and its consumption are extremely high all over the world. The severe condition of energy shortage that can arrive in the near future because of the excessive use of non-renewable energy is called an energy crisis. To stop an energy crisis from arriving, energy must be saved. Using energy economically and in the right way is itself the saving of energy, and the habit of using energy economically helps to reduce the problem of an energy crisis.
In the context of our country, the following measures can be adopted to reduce the problem of an energy crisis.
| No. | Measure |
|---|---|
| 1 | Not using energy unnecessarily. |
| 2 | Since Nepal is an agricultural country, giving emphasis to the use of gobar gas in rural areas. |
| 3 | Increasing the production of hydroelectricity and using it heavily for many useful purposes, such as cooking and running electric vehicles. |
| 4 | Using solar panels and putting the electricity produced to various uses. |
| 5 | Using renewable sources of energy as far as possible in place of mineral oil, coal or natural gas. |
| 6 | Spreading public awareness to teach people about the ways of saving energy. |
What the world needs today is to make human life easier by using energy properly and well. If we take to using energy for useful work rather than for destructive work, life for people can be made easier and simpler still.
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