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बेसिक इंग्लिश का दूसरा सत्र (कक्षा प्रारंभ : 22 अक्तूबर, शाम 3:30 से 5:30)
Non-renewable Energy Sources
Feb 12, 2015

Non-renewable resources are resources for which are of in limited supply. The supply comes from the Earth itself and, as it typically takes millions of years to develop, is finite. There are many countries, which have recorded significant reduction of these sources and are currently suffering from the side effects of drilling these energy reserves from deep underground. Examples of these countries include China and India. The environmental impact is so great that just by travelling to these two countries, you can get a firsthand experience on the case studies that are there to be seen by the naked eyes. There are three major forms of fossil fuels: coal, oil and natural gas and on worldwide basis they provide approximately 90% of energy consumed.

Fossil fuels :

Fossil fuels (coal, oil and natural gas) were formed from animals and plants that lived hundreds of millions of years ago (before the time of the dinosaurs). They were formed during the Carboniferous period. The plants that lived millions of years ago converted the Sun's light energy into chemical energy through the process of photosynthesis. This 'solar' energy was (and still is) transferred down the food chain in animals, and when living organisms die, the chemical energy within them was trapped.

a) Coal: It is the most abundant form of fossil fuel available on earth. They were formed by the decay of old plants and animals several centuries ago. coal is mostly found below the earth and is major source of fuel for electricity generation as of today. Most power stations on earth require huge reserves of coal to produce electricity continuously without break. When coal is burnt, it produces heat that is used to convert the water into stream.

Coal an be classed into three types: lignite, bituminous and anthracite. Lignite coal is found close to the Earth surface, making it easy to mine, but it has high sulphur content. Bituminous coal is the most common coal we burn, and it is less polluting than lignite. Anthracite is the highest quality of coal – it is dark and shiny and found deeper in the Earth. In addition to pollutants from burning coal, coal mining creates problems for the environment, as the coal must be dug from the ground. Large volumes of unwanted dirt and rock are removed, which can lead to water pollution, unstable ground and, in many cases, it is not appealing to look at.

Coal Mining: It is mined from both 

(i) Surface mining: This disrupts and drastically changes the natural landscape and destroys the natural vegetation and the habitat of many species, some of which  ay already be endangered. Mining operations, involving digging, blasting, removal of rocks and soil lying over the coal seam, cause serious problems of air and noise pollution. Surface mining may also cause soil erosion and silt loading.

(ii) Underground mining: Most coal seams are too deep underground for opencast mining and require underground mining, a method that currently accounts for about 60 percent of world coal production. Underground mining may cause collapse or land subsidence in the mining areas during or after mining operations are over. Coal fires in underground mines may happen which naturally caused give out much smoke and hazardous fumes caused several respiratory disease to people living nearby.

b) Petroleum: Oil was formed from the remains of animals and plants (diatoms) that lived millions of years ago in a marine (water) environment before the dinosaurs. Over millions of years, the remains of these animals and plants were covered by layers of sand and silt. Heat and pressure from these layers helped the remains turn into what we today call crude oil.  These are primarily found along geologically young tectonic belt at plate boundaries, where large depositional basins are more likely to occur and these are found in syncline folded strata. 

Source: British Geological Survey

c) Natural Gas: Natural gas is a mixture of several gases including methane, ethane, propane and butane. It burns completely and leaves no ashes. It causes almost no pollution and is one the cleanest form of fossil fuel. Of these gases, methane is highly inflammable. It has no colour, taste or odour. This is the reason that some chemicals are added to it before it can be supplied to individual homes so that a leakage can easily be detected. Middle Eastern countries particularly Iran and Iraq hold high reserves of natural gas.  Although this is cleaner fuel but extracting it can cause environmental problems. Fracturing rocks can cause mini-earthquakes. The high-pressure water and chemicals that are forced underground can also leak to other sources of water. The water sources, used for drinking or bathing, can become contaminated and unsafe.

Technique of Hydraulic fracturing,” or fracking. (Hydraulic means they use water and fracturing means to “split apart) is used to extract Natural gas. The process uses high-pressure water to split apart the rocks underground. This releases the natural gas that is trapped in rock formations. If the rock is too hard, they can send acid down the well to dissolve the rock. They can also use tiny grains of glass or sand to prop open the rock and let the gas escape.

Other Sources of Energy:

A) Nuclear fuels: It is usually considered another non-renewable energy source. Although nuclear energy itself is a renewable energy source, the material used in nuclear power plants is not. Radioactive minerals are used to generate nuclear energy through high technological methods.Nuclear energy can be used to make electricity, but it must first be released. Nuclear energy can be released from atoms through nuclear fusion and nuclear fission.

In nuclear fission, atoms are split apart to form smaller atoms, releasing energy. Nuclear power plants use this energy to produce electricity. In nuclear fusion, energy is released when atoms are combined or fused together to form a larger atom. This is how the sun produces energy. Nuclear fusion is the subject of ongoing research, but it is not yet clear whether or not it will be a commercially viable technology for electricity generation. In this process, small nucleus like those of isotopes of hydrogen, namely deuterium and tritium etc. fuse or join together to form heavier nuclei, releasing vast amounts of energy. 

The material most often used in nuclear power plants is the element uranium. Although uranium is found in rocks all over the world, nuclear power plants usually use a very rare type of uranium, U-235. Uranium is a non-renewable resource.

Nuclear power plants do not pollute the air or emit greenhouse gases. They can be built in rural or urban areas, and do not destroy the environment around them.

However, nuclear energy is difficult to harvest. Nuclear power plants are very complicated to build and run. Many communities do not have the scientists and engineers to develop a safe and reliable nuclear energy program.

Nuclear energy also produces radioactive material. Radioactive waste can be extremely toxic, causing burns and increasing the risk for cancers, blood diseases, and bone decay among people who are exposed to it. 

Raw material related to Nuclear energy in India, monazite that is the main source of thorium, is found in commercial quantities on the Travancore coast between Kanya Kumari and Quilon, while uranite or pitchblende mineral of uranium is found in Gaya (Bihar), Ajmer (Rajasthan) and Nellore (Andhra Pradesh). 

Non-renewable energy sources have fuelled the world’s industrial complex for far too long. It has reached a point where the word is facing rapid starvation in this sector. With increased exploitation of these fossil fuels, there are many associated environmental effects like land pollution and air pollution which in turn affect both animal and plant life. The far-reaching consequences of non-renewable sources are inexplicable and the trend has to be reversed soon before it is too late to do anything. Carbon is a major source of fuel in non-renewable energy sources. When combustion takes place, carbon is mixed with oxygen and form carbon dioxide. It pollutes the environment and is responsible for global warming.  The need of the hour is to look for some alternative sources of energy and protect our environment from such harmful gases. 

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