|
|
| |
|
|
|
|
| |
Non Renewable Energy
: |
|
 |
| |
|
|
| |
Non
Renewable Energy
Fossil
fuels
The Industrial Revolution in Europe in the 19th century
fired man’s search for alternative sources of fuel to
meet energy needs of the mushrooming industries. With the realization
that fossil fuels could meet this requirement, the energy needs
of the world were fulfilled for the time being.
Fossil fuels are called so because they have been derived from
fossils, which were formed millions of years ago during the
time of the dinosaurs. They are fossilized organic remains that
over millions of years have been converted to oil, gas, and
coal. Because their formation takes so long, these sources are
also called non-renewable.
These fuels are made up of decomposed plant and animal matter.
When plants, dinosaurs, and other ancient creatures died, they
decomposed and were buried, layer upon layer under the ground.
Their decomposed remains gradually changed over the years. It
took millions of years to form these layers into a hard, black
rock-like substance called coal, a thick liquid called oil or
petroleum, and natural gas—the three major forms of fossil
fuels.
Fossil fuels are usually found below ground. Coal is either
mined or dug out while oil and natural gas are pumped out. Coal
is widely distributed and is easier to locate than oil and gas.
Fossil fuels take millions of years to make, but burn and disappear
in seconds. Once they are used, they cannot be reused. People
have irretrievably damaged the planet by extracting and burning
these fuels. It is best not to waste fossil fuels as they are
not renewable. We have to learn to conserve these sources of
energy.
Every year, millions of tonnes of coal is consumed as energy.
This has led to global warming (greenhouse effect) and the depletion
of resources.
At present, the worldwide burning of coal, oil, and natural
gas releases billions of tonnes of carbon dioxide (measured
as carbon) into the atmosphere every year. Burning any fossil
fuel means pollution of some sort. Even if the fuel is low in
sulphur, the atmosphere contains nitrogen, which combines with
oxygen at the high burning temperatures found in boilers, jet,
or car engines. This yields nitrogen oxides, which like sulphur
dioxide, dissolves in rain to form nitric acid. Both gases are
poisonous to humans.
Mining and exploration for fossil fuels can cause disturbance
to the surrounding ecosystem. The burning of fossil fuels emits
oxides of sulphur and nitrogen into the atmosphere.
Coal
Coal is by far the most abundant fossil fuel on earth. It is
essentially carbon and is mainly used as a combustion fuel.
The large-scale use of coal began with the Industrial Revolution
in the 19th century. As the number of industries increased,
demand for more sources of energy grew.
Coal is the product of plants, mainly trees, that died tens
or hundreds of millions of years ago. Due to water logging in
low-lying swampy areas or in slowly sinking lagoons, dead trees
and plants did not decompose as they normally would. The dead
plant matter was covered with water and protected from the oxidizing
effect of air. The action of certain bacteria released the oxygen
and hydrogen, making the residue richer and richer in carbon.
Thick layers of this carbon-rich substance, called peat, built
up over thousands of years. As more material accumulated above
the peat, the water was squeezed out leaving just carbon-rich
plant remains. Pressure and temperature further compressed the
material. This aided the process of producing coal as more gases
were forced out and the proportion of carbon continued to increase.
The carbon slowly metamorphosed into coal over millions of years.
There are three main types of coal: lignite, bituminous, and
anthracite. Lignite and bituminous have a lesser percentage
of carbon in them and therefore burn faster. They release a
great deal of pollutants into the atmosphere. Anthracite has
about 98% carbon and therefore burns slowly and releases much
less smoke. Coal of all types contains sulphur to some degree.
Sulphur is the worst of the pollutants and causes damage to
human health and to vegetation. Though petroleum gained importance
over the 20th century and continues to do so, coal remains essential
for the industrial sector. It is the principal heat source for
electricity generation in most countries and is used directly
in such heavy industries as iron and steel making.
Until recently, most coal came from underground mines. But now
there are a large number of opencast mines. Underground coal
mines are notorious killers due to roof falls and explosions.
Accidents have resulted in the deaths of hundreds of miners.
Almost 80% of today's coal comes from surface strip mines (opencast
mines), which is much safer. Huge earth-moving equipment strips
off the soils and rocks covering the buried coal seams. The
land is backfilled and returned to normal after the coal has
been removed, thereby repairing the landscape. But most companies
do not refill the excavated area and leave it damaged. Most
countries have now enforced backfilling by law.
Coal mining in India
India has about seven per cent of the world's proven coal reserves.
Coal supplies more than 50% of the country's total energy requirements.
By current estimates, the reserves are enough to meet India's
needs for at least another 100 years.
Coal mining in India dates back to the 18th century. The regulation
of its use in the industrial sector was conceived in 1923. In
1972-73, the Indian government nationalized the coal industry,
primarily to develop the sector, since it was considered to
be of strategic importance for rapid industrial development.
India's coal demand is expected to increase several fold within
the next 5–10 years due to the completion of ongoing coal-based
power projects, and demand from metallurgical and other industries.
Coal is the dominant source of fuel in the industrial sector,
with a share of nearly 72.5% in the total energy consumption.
The industrial sector is the largest consumer of electricity,
with a share of 41% of the total consumption. The transport
sector is the largest consumer of petroleum products, and accounts
for nearly 50% of the total consumption.
The small amount of coal presently consumed adds atmospheric
pollutants, some of which precipitate into the ground and water.
This assault on the environment has been the cause of heavy
pollution in many areas of the world.
Oil
and Gas
Almost all oil and natural gas are found deep underground in
tiny holes in rocks. Millions of years ago a sea covered much
of what is now dry land. In prehistoric times, tiny plants and
animals lived in the sea. When these creatures died, they sank
to the bottom of the sea, and got buried in layers of mud and
sand. As the ages passed, this organic material sank deeper
and deeper. The earth's crust changed its shape, and put intense
pressure and heat on what was once only plants and tiny animals.
Heat from the earth's interior and the weight of the overlying
rocks gradually changed the energy-containing substances in
the accumulated plants into hydrocarbon liquids and gases. As
millions of years passed, these deposits turned into chemicals
that are now called ‘hydrocarbons’.
Hydrocarbons are simple molecules made up of carbon and hydrogen
atoms joined together in chains or in rings. These molecules,
being light and mobile, migrated upwards through the rocks but
eventually became trapped beneath impermeable rock structures
in the earth's crust. That is where oil and natural gas come
from. Some were created millions of years ago, some were created
thousands of years ago, and some are being created right now!
Much of the oil and gas production now comes from underneath
the sea-bed. As the technology for extraction continues to advance,
production becomes possible from deeper and deeper waters. But
the supplies are limited. Every drop of oil burnt adds to the
monumental environment problems already created by pumping gases
like carbon dioxide into the atmosphere. Many scientists worry
that this continual release of carbon dioxide is an important
cause of global warming.
Natural gas is usually found underground near an oil source.
It is a mixture of light hydrocarbons including methane, ethane,
propane, butane, and pentane. Other compounds found in natural
gas include carbon dioxide, helium, hydrogen sulphide, and nitrogen.
It is found around the world, but the largest reserves are in
the former Soviet Union and the Middle East. This gas is lighter
than air and is highly flammable, made up mainly of a gas called
methane. Methane is a simple chemical compound that is made
up of carbon and hydrogen atoms. Natural gas usually has no
odour and cannot be seen. Before it is sent to the pipelines
and storage tanks, it is mixed with a chemical that gives it
a strong odour, almost like rotten eggs. The odour makes it
easy to detect a leak.
Natural gas is the cleanest burning fossil fuel. When it is
burned, it gives off less carbon dioxide than oil or coal, virtually
no sulphur dioxide, and only small amounts of nitrous oxides.
Natural gas is mostly composed of methane and other light hydrocarbons.
Both the carbon and the hydrogen in methane combine with oxygen
when natural gas is burned, giving off heat. Coal and oil contain
proportionally more carbon than natural gas, therefore giving
off more carbon dioxide per unit of energy produced. Natural
gas gives off 50% of the carbon dioxide released by coal and
25% less carbon dioxide than oil, for the same amount of energy
produced. Carbon dioxide is the most important greenhouse gas
contributing to global warming.
To find oil and natural gas, companies drill through the earth
to the deposits deep below the surface. The oil and natural
gas are then pumped from below the ground by oil rigs. They
then usually travel through pipelines.
At oil refineries, crude oil is split into various types of
products by heating the thick black oil. The products include
gasoline, diesel fuel, aviation fuel, home heating oil, oil
for ships, and oil to burn in power plants to make electricity.
Oil is used for transportation cars, airplanes, trucks, buses,
and motorcycles.
Oil is stored in large tanks until it is sent to various places
to be used. Oil is also made into many different products fertilizers
for farms, clothes, toothbrush, plastic bottle, and plastic
pen. There are thousands of other products that come from oil.
Almost all plastic comes originally from oil. Oil is transported
in huge pipelines and tanker ships to places where it is made
into other products.
The origin of the oil industry in India can be traced back to
the last part of the 19th century when petroleum was discovered
in Digboi in north-east India. Thereafter large numbers of oil
fields have been discovered both inland and off-shore. This
has led to the setting up of refineries to process the oil and
gas for use in various sectors. |
|
| |
|
|
|
|
 |
Adds |
|
