Non-conventional sources of energy
Firewood Firewood or fuel wood is an energy source for a number of people in our country. Fuel wood is mostly obtained from twigs and branches of trees that have dried and fallen down. However, many people often cuts trees and then the wood obtained is called firewood or fuel wood. Firewood is more common in the rural areas where people do not access to any other source of energy.
Advantages of firewood
Disadvantages of firewood
Coal is a non-renewable source of energy. Coal is a readily combustible black or brownish black rock. Coal was the first fossil fuel to be seriously used. It triggered the entire industrial revolution in Europe. It is the largest source for generation of electricity world wide, as well as largest source of carbon dioxide emissions, which contribute to climatic change and global warming. Our country has rich supplies of coal but not of petroleum.
Process of formation of coal Coal is called a fossil fuels as it was formed from the remains of vegetations that grew as long a 400 million years ago. It is often referred to as " buried sunshine" as the plants which formed coal captured energy from the sun through photosynthesis to create the compounds that make up the plant tissue. The most important element in the plant material which gives a lot of energy is carbon. Most of our coal was formed around 300 million years ago, when much of the earth was covered by swampy areas. As plants and tress died, their remains sank to the bottom of the swampy areas, accumulating layer upon layer and eventually forming a soggy, dense material called peat. Over the long periods of time, the makeup of the earth's surface changed, and seas and great rivers caused deposits of clay, sand and other material to accumulate, burying the peat. The pressure caused by the weight squeezed water from the peat. In the presence of heat and pressure, coal was formed. The whole process is called carbonization.
Types of coal There are five different categories of coal based on the period and area of formation. The quality of coal and its capacity to yield energy is judged form the percentage of carbon in the coal. More the carbon, better the coal is. There are five different types of coal:
Disadvantages of coal There are various demerits of coal. Some of them are:
Petroleum Petroleum is derived from two words- petra meaning " rock" and oleum meaning " oil". It consists of hydrocarbons mixed with oxygen, sulfur, nitrogen and other elements in varying proportion. From crude petroleum, various products are made by fractional distillation and other processes. For example, fuel oil, petrol, kerosene, diesel and lubricating oil. Petroleum products and chemicals are used in large quantities in the manufacture of detergents, artificial fibers, plastics, insecticides, fertilizers, pharmaceuticals, toiletries and synthetic rubber.
Process of formation of petroleum
Petroleum was formed from the remains of marine plant and animal life that existed millions of years ago. Some of these remains remained deposited under the sea where they were decomposed anaerobically by bacteria. The bacteria changed the fats into the sediments of the body into fatty acids which were then changed into an asphaltic material called kerogen. This was then converted over millions of years ago into petroleum by the combined action of heat and pressure. Petroleum generally occurs trapped between two impermeable layers of rock. Impermeable layers are non-porous.
Natural gas Natural gas is a gaseous fossil fuel. It consists primarily of methane. Other gases included are ethane, propane, butane and pentane. Methane is a molecule that is made up of one carbon atom anf four hydrogen atoms. Natural gas is a fossil fuel like oil and coal.
It remained associated with coal and petroleum deposits. Natural gas has many applications. Compressed natural gas(CNG) is a cleaner alternative to other automobile such as petrol and diesel. Natural gas is a vital component of the world's energy supply. It is one of the cleanest, safest and most useful of all energy sources.
Similarly, Liquified natural gas(LNG) is natural gas that has been liquified under pressure and then stored in containers. It is mostly used in cylinders for cooking purposes. As it is odorless, a foul smelling gas called "methyl mercaptane" is added to detect its leakage.
Advantages of CNG Following are the merits of CNG gas: