TYPES OF RESOURCES

1. 2. NATURAL RESOURCES
A resource is anything we get from the environment (Earth's life-support systems) to meet our needs
and desires, which has dependability through time. All forms of life need resources such as food, water
and shelter for survival and good health.
Definition:-
“Any portion of nature which improves the well being of humans” is known as natural resources
Classification:-
Natural resources can be classified into 2 broad categories. They are
A) Living and Non- living resources
 Living resources are biological resources that are used by human beings
e.g. forests, croplands and animal resources.
 Non- living resources are not derived from biological materials
e.g. soil, land and water
B) Renewable resources & Non-renewable resources.
 Renewable resources are also known as inexhaustible resources. These have ability to
reappear or replenish themselves by recycling, reproduction or replacement.
E.g. forests, wildlife, wind, biomass, water
 Non-renewable resources are also known as exhaustible resources. These involve earth’s
geologic endowments and cannot be generated in a time span
e.g. Minerals, fossil fuels, non mineral resources.
C) Conventional and Non- Conventional energy
 Conventional sources of energy are non- renewable sources of energy (coal, petroleum &
natural gas). They have been in use since a long time and most of these energy sources
cause pollution when used.
 Non- Conventional Energy sources are renewable sources of energy. These sources are
recently developed and are still developing; they do not cause any pollution (Solar energy,
wind energy etc.)
2.2 Environmental Components:
There are four Environmental Components in the environment:
1. Atmosphere, 2.Hydrosphere, 3. Lithosphere, 4. Biosphere.
1) Atmosphere
• Oxygen for human respiration (metabolic requirements)
• Oxygen for wild fauna in natural ecosystems and domestic animals used by man as food Oxygen
as a part of carbon dioxide, used for the growth of plants (in turn are used by man)
• There 4 segments present in our natural environment.
They are
i. Troposphere, ii. Stratosphere, iii. Mesosphere, iv. Ionosphere.

2. i) Troposphere:
• It is just adjacent to earth crust.
• It contains more than 80% of volume in total.
• It extended up to 7 & 15 Km at polar & equator regions respectively. All living beings present
here only. Clouds, rainfall occurs here only. It contains more than 78% of Nitrogen & 21% of
Oxygen. The temperature decreases with increased height.
ii) Stratosphere:
• It is 2nd
layer of Atmosphere. ,It extended up to 50 Km.
• Temperature increases with increased height. Ozone layer is in this layer which absorbs UV
radiation. and sulphate layer which form the precipitation
iii) Mesosphere:
• It is 3rd
layer of Atmosphere. It extended up to 100 Km.
• Temperature decreases with increased height.
iv) Ionosphere:
• It is 4th
layer of Atmosphere. It extended up to 500 Km.
• Temperature increases with increased height. Different ions present here, so called the name.
2) Hydrosphere
The hydrosphere covers three-quarters of the Earth's surface. A major part of the hydrosphere is the
marine ecosystem in the ocean, while only a small part is fresh water, the freshwater in rivers, lakes and
glaciers is perpetually being renewed by a process of evaporation and rainfall; some of this freshwater is
stored in underground aquifers.
3) Lithosphere
The lithosphere began as a hot ball of matter which formed the Earth about 4.6 billion years ago.
About 3.2 billion years ago, the Earth cooled down considerably and a very special event took place-
life begun our planet. The crust of the Earth is 6-7 km thick and lies under the continents. Of the 92
element in the lithosphere, only eight are common constituents of crustal rocks. Of these constituents,
47% oxygen, 28% is silicon, 8% is aluminum, and 5% is iron, while sodium, magnesium, potassium
and calcium constitute 4% each. Together, these elements form about 200 common mineral
compounds. Rocks, where broken down, form soil on which man is dependent for agriculture. Their
minerals are also the raw material used in various industries.
4) Biosphere
This is the relatively thin layer on the Earth in which life can exist. Within it the air, water,rocks a
soil and the living creatures form structural and functional ecological units, which together can
considered as one giant global living system, that of our Earth itself.
All living organisms which exist on earth live only in the relatively thin layer of the lithosphere and
hydrosphere that is present on the surface of land and in the water. The biosphere which they form has
countless associations with different parts of the three other 'spheres'.

3. FOREST RESOURCES
Introduction:
Forests are important renewable resources. The word forest is came from Latin FORIS means
boundary, outside of villages
A forest is a biotic community, predominantly of trees, shrubs, or any other woody vegetation usually
closed with canopy. Forests contribute substantiality to economic development of country
World forests:
According to United Nations Food and Agriculture Organization (FAO) world’s forest cover is 29%.
(1994). Africa consist of 33%, Latin America consist of 25%, Former USSR 14%, Asia 14% and Europe
consist of 3% forest cover. There are different types of forests present around the globe depends upon
the climate, rainfall and altitudes. There are Tropical rain forests, temperate forests, boreal forests,
Woodlands, etc. Tropical rain forests are thickest forests of world. These present around the both sides of
Equator.
Indian forests:
As per State of Forest Report, the total forest cover of India is 19.39% of total geographical area of the
country. Out of this more than 11.5% is dense forest, 7.76% is open forest and 0.15% is mangrove
forest.
There are 6 types of forests n India. They are moist tropical, dry tropical, mountain sub-tropical,
mountain temperate, sub-alpine and alpine forests.
USES OF FORESTS
 The chief economic product of forest is timber, which is primarily used as building materials such
as lumber, plywood, hardboard, etc.
 Provides raw materials for a variety of industries for example provides pulp for paper industry,
provides ingredients for pharmaceutical industries, etc.
 Provides fuel wood: Fuel woods are the major source of household energy in the developing world.
Worldwide about half the timber cut each year is used as fuel for heating and cooking, especially in
less developed countries.
 Provides employment: millions of people; the worldwide trade in forest produce is estimated to be
100 billion U.S dollars annually.
 Serves as habitat for a variety of species, which live on the edge of the forests and in the adjoining
ecosystems. Deep, continuous forests are important to other species, which require large habitats
without human interference.
 Serves as an important biodiversity reserve and as a gene reserve of a variety of wild species. This
biodiversity is a very vital source for evolving new economic varieties in agriculture, horticulture,
veterinary and medical fields.
 Moderates Greenhouse effect: By absorbing atmospheric CO., they act as big sinks for CO, and
moderate the greenhouse effect.
 Regulates stream flow: Vast expansion of forests and other vegetation slows the runoff of water
and allows water to percolate into the soil thus helping and regulating the stream flow. Further the
leaf and plant debris on the forest floor slow water as it runs along the ground. This reduces erosion

4. by allowing water to soak into the soil, rather then runoff.
 Regulates earth's temperature regimes and increases rainfall occurrences, Balances/Regulates
CO2, O3, nutrient and wafer cycles
 Increases the water holding capacity of the soil: Because of the thick layer, loose soil, and soil-
retaining powers of the tree's long roots, forests are vitally important for preserving adequate water
supplies. Tree roots penetrate compacted soils and increase soil porosity. This allows water to
percolate into the soil and increasing the water holding capacity of the soil.
 Checks soil erosion/ silting/ landslides/floods. Also has aesthetic and touristic
DEFORESTATION:-
Deforestation refers to the removal of trees in the forest or falling/cutting down the trees from a
forest area is called deforestation.
It is of two types Peripheral and fragmentation deforestation.
 Peripheral deforestation involves cut down of trees around the forest area.
 Fragmentation deforestation involves cut down of trees in a series deep into the forest. Finally it
makes forest into fragments.
Causes for deforestation
o Shifting cultivation,
o Over grazing,
o Rising demand for Agriculture
(Commercial Agriculture),
o Industrialization & Urbanization,
o Timber extraction (Fuel wood),
o Mining & petroleum
explorations,
o Infrastructure development etc.
Effects of Deforestation
Deforestation adversely affects and damages the environment
 Economic Loss & Ecological imbalance
 Loss of biodiversity --- loss of habitat
 Soil erosion, Floods may be intensified.
 Expansion of deserts, Decreased rain fall,
 Climatic changes, such as lower precipitation.
 Exploitation of tribal people by contractors.
 Lowering of water tables,
 Indigenous people may be forced to new way of
life.
 Induces and accelerates mass movement /
landslides.
 Breaks the water cycle and nutrient cycle.
 Increase the rate of global warming
 Soil erosion, especially on slope.
 Sedimentation of irrigation system.
 Timber extraction and its effects on forests
Timber is essential to meet the ever increasing demands of the growing population; the unscientific
destruction of forests for timber may cause destruction of habitat and extermination of a number of
valuable plants and animal species. It may also cause change in the composition of the natural forests
and increase the risk of a subsequent transition in favor of other land uses. It exposes the soil to the
tropical sun and torrential rains. This can affect the soil by increasing its compaction, reducing its
organic material, leaching out its few nutrients available.

5. The intrusion of men and logging machinery with the resulting changes in the forest ecosystem,
displaces many of life forms especially birds and higher animals
 Mining and its effects on forests and tribal people
In order to mine the underlying minerals the overlying forests are ruthlessly destroyed. Its effect may
range from total destruction of a variety of floral and faunal species to destruction of habitat of wild
species.
The overburden i.e; the material that lies above the mineral deposit is removed and dumped nearby and
such areas are susceptible to soil erosion eventually entering into nearby water streams and sit in their
bed. This reduces their channels to become shallow (decrease in the depth) which in turn may increase
flash floods causing destruction of community ecosystems.
 Dams and their effects on forests and tribal people
Hydroelectric development is another important factor, which may cause forest destruction.
Submergence of large tracts of forestlands especially in case of large dams is inevitable. This would
cause reduction in forest cover, destruction of habitats and extermination of valuable wild species.
Forest submergence would greatly affect the tribal people by the way of submerging their dwellings
and agricultural lands. The lifestyle of the tribal is intricately webbed / connected with the forests. But
when the forests are destroyed their livelihood is greatly affected.
It would induce micro-climatic changes in the area in and around the reservoir which may affect the
composition of the forests in the area.
It would include changes in the water flow characteristics which may affect the forests and the tribals
especially in the downstream areas.
WATER RESOURCES
Water is an indispensable natural resource on this earth on which all life depends. About 97% of the
earth's surface covered by water is too salty (Oceans) and cannot used for drinking, irrigation or
construction. Remaining 3% is fresh water. About 2.997% is locked up in ice caps or glaciers or buried
so deep that it costs too much to extract. Only about 0.003% of earth’s total volume of water is easily
available to us in moisture, exploitable ground water, water vapour, lakes and streams.
Water is characterized by certain unique features which make it a marvelous resource:
i. It exists as a liquid over a wide range of temperature i.e. from o° C
to 100°C
.
ii. It has the highest specific heat, due to which it warms up and cools down very slowly without
causing shocks of temperature jerks to the aquatic life.
iii. It has a high latent heat of vaporization. Hence; it takes a huge amount of energy for getting
vaporized. That's why it produces a cooling effect as it evaporates.
iv. It is an excellent solvent for several nutrients. Thus, it can serve as a very good carrier of nutrients,
including oxygen, which is essential for life. But, it can also easily dissolve various pollutants and
become a carrier of pathogenic microorganisms.
v. It has anomalous expansion behaviour i.e. as it freezes; it expands instead of contracting and thus
becomes lighter. It is because of this property that even in extreme cold, the streams freeze only on

6. the surface. Being lighter the ice keeps floating, whereas the bottom waters remain at a higher
temperature and therefore, can sustain aquatic organisms even in extreme cold.
Hydrological Cycle
The water we use circulates endlessly within the nature through Hydrological cycle,
There are five stages in water cycle
 Evaporation: water from water bodies enter into atmosphere as water vapour by absorption of solar
radiation, or conversion of liquid state of water into gaseous state is called evaporation
 Transpiration: water release from the plant leaves into the atmosphere through their stomata,
 Condensation: the liquid and gaseous state of water cools and convert back liquid (Formation of
cloud) known as condensation
 Precipitation: Condensed cloud moves in direction of wind lose its weight due to gravity and
disperse as water drops called precipitation / Rainfall.
 Infiltration: The rainwater that reaches the ground being and absorbed by the soil seen to percolate
down forming ground water aquifers.
 Groundwater
A layer of sedimentary rock that is highly permeable and contains water is called an aquifer. Layers
of sand and gravel are good aquifers while clay and crystalline rocks (like granite) are not since they
have low permeability. Aquifers may be of two types:
• Unconfined aquifers which are overlaid by permeable earth materials and they are recharged by
water seeping down from above in the form of rainfall and snow melt.
• Confined aquifers which are sand witched between two impermeable layers of rock or sediments
and are recharged only in those areas where the aquifer intersects the land surface. Sometimes the
recharged area is hundreds of kilometers away from the location of the well. Fig 3.2 shows the
groundwater system. Groundwater is not static, it moves, though at a very slow rate of about a meter
or so in a year.
Fig. the groundwater system.
An unconfined aquifer (water table) is formed when water collects over a rock or compact clay.
A confined aquifer is formed sand witched between two layers having very low permeability.
• Effects of Groundwater Usage

7. (i) Subsidence: When groundwater withdrawal is more than its recharge rate, the sediments in the
aquifer get compacted, a phenomenon known as ground subsidence. Huge economic losses may
occur due to this phenomenon because it results in the sinking of overlying land surface. The
common problems associated with it include structural damage in buildings, fracture in pipes,
reversing the flow of sewers and canals and tidal flooding.
(ii) Lowering of water table: Mining of groundwater is done extensively in arid and semi-arid regions
for irrigating crop fields. However, it is not advisable to do excessive mining as it would cause a
sharp decline in future agricultural production, due to lowering of water table.
(iii) Water logging: When excessive irrigation is done with brackish water it raises the water table
gradually leading to water-logging and salinity problems.
 Surface Water
The water coming through precipitation (rainfall, snow) when does not percolate down into the ground
or does not return to the atmosphere as evaporation or transpiration loss, assumes the form of streams,
lakes, ponds, wetlands or artificial reservoirs known as surface water. The surface water is largely
used for irrigation, industrial use, public water supply, navigation etc. A country's economy is largely
dependent upon its rivers.
Uses of Surface water:
 Agricultural activities
 Industrial activities
 Domestic purposes
 Recreational activities
 Environmental Concerns
Effects due to Surface water
 Floods
Floods occur most commonly when water from heavy rainfall, melting ice or snow or a
combination of these, exceeds the carrying capacity of the receiving river system.
In some countries like India and Bangladesh rainfall does not occur throughout the year, rather,
90% of it is concentrated into a few months (June-September). Heavy rainfall often causes floods in
the low-lying coastal areas. Prolonged downpour can also cause the over-flowing of lakes and rivers
resulting into floods.
Deforestation, overgrazing, mining, rapid industrialization, global warming etc. have also
contributed largely to a sharp rise in the incidence of floods, which otherwise is a natural disaster.
Floods have been regular features of some parts of India and Bangladesh causing huge
economic loss as well as loss of life.
 Droughts
Drought is a devastating phenomenon. It defined as an extended period –a season, a year,
several years-of deficient rain fall relative to the statistical multiyear average for the region. Lake of
rain fall leads to inadequate water required by plant, animals and human beings. A drought leads to
other disasters, namely food in security, famine, malnutrition, epidemics and displacement of
populations from one year to another year.
When annual rainfall is belownormal and less than evaporation, drought conditions are created.
Ironically, these drought- hit areas are often having a high population growth which leads to poor

8. land use and makes the situation worse.
• Anthropogenic causes: Drought is a meteorological phenomenon, but due to several anthropogenic
causes like overgrazing, deforestation, mining etc. there is spreading of the deserts tending to
convert more areas to drought affected areas
• In Maharashtra there has been no recovery from drought for the last 30 years due to over-
exploitation of water by sugarcane crop which has high water demands.
Desertification
The processes by which an area becomes even more barren, less capable of retaining vegetation, and
progresses towards becoming a desert.
This may result either due to a natural phenomenon linked to climatic change or due to abusive land use.
In fact even for climatic change, these are the improper land use practices which are largely responsible.
Removal of vegetal cover brings about marked changes in the local climate of the area. Thus,
deforestation, overgrazing etc. bring about changes in rainfall, temperature, wind velocity etc. and also
lead to soil erosion. Such changes then lead to desertification of the area.
Famine: It is a catastrophic food shortage affecting large numbers of people due to climatic,
environmental and socio economic reasons. The cause of the famine may produce great migration to
less affected areas
Big dams- benefits and problems
 Benefits
 River valley projects with big dams have usually been considered to play a key role in the
development process due to their multiple uses.
 These dams are often regarded as a symbol of national development.
 The tribals living in the area pin big hopes on these projects as they aim at providing employment and
raising the standard and quality of life.
 The dams have tremendous potential for economic upliftment and growth.
 They can help in checking floods and famines, generate electricity and reduce water and power
shortage, provide irrigation water to lower areas, provide drinking water in remote areas and
promote navigation, fishery etc.
Environmental Problems
The environmental impacts of big-dams are also too many due to which very often the big dams
become a subject of controversy. The impacts can be at the upstream as well as downstream levels.
The upstream problems include the following:
a. Displacement of tribal people
b. Loss of forests, flora and fauna
c. Changes in fisheries and the spawning grounds
d. Siltation and sedimentation of reservoirs
e. Loss of non-forest land
f. Stagnation and water logging near reservoir
g. Breeding of vectors and spread of vector-borne
diseases
h. Reservoir induced seismicity (RIS) causing
earthquakes
i. Growth of aquatic weeds.
j. Microclimatic changes.
The downstream impacts include the following:

9. i) Water logging and salinity due to over irrigation,
(ii) Micro-climatic changes
(iii). Reduced water flow and silt deposition in river, Flash floods,
(iv) Salt water intrusion at river mouth
(v). Loss of land fertility along the river, as the sediments carrying nutrients get deposited in the
reservoir
MINERAL RESOURCES
A mineral is a naturally-occurring substance of definite chemical composition and identifiable physical
properties. An ore is a mineral or combination of minerals from which a useful substance, such metal, can be
extracted and used to manufacture useful products.
Minerals are formed over a period of millions of years in the Earth's crust.
Mineral Extraction Method
Minerals and their ores need to be extracted from the Earth's interior. The process of removal of minerals from
the deep layers of the earth is known as mining. Mining operations generally progress through four stages:
(1) Prospecting: Searching for minerals.
(2) Exploration: Assessing the size, shape, location, and economic value of the deposit.
(3) Development: The work of preparing access to the deposit so that the minerals can be removed from it.
(4) Exploitation: Extracting the minerals from the mines.
In the past, mineral deposits were discovered by prospectors in areas where mineral deposits form of
veins were exposed on the surface. Today modern prospecting methods include the use of sophisticated
instruments, like (survey and study the geology of the area and discover placers.
The method of mining has to be determined depending on whether the ore or mineral deposit is nearer the
surface or deep within the Earth. The topography of the region and the physical nature the ore deposit are
also studied.
Types of Mining
Mining is done by two ways -
 Surface mining (open-cast or strip mines)
 Sub – surface mining (Deep mines).
The sub surface is more destructive, dangerous and expensive including risks of occupational hazards and
accidents.
Surface mining can make use of any of the following three types:
 (a) Open-pit mining in which machines dig holes and remove the ores (e.g. copper, iron, gravel, limestone,
sandstone, marble, granite).
 (b) Dredging in which chained buckets and draglines are used which scrap up the minerals from under-
water mineral deposits.
 (c) Strip mining/ shallow mining in which the ore is stripped off by using bulldozers, power shovels and
stripping wheels (e.g. phosphate rocks).
Uses and exploitation
Minerals find use in a large number of ways in everyday use in domestic, agricultural, industrial and commercial

10. sectors and thus form a very important part of any nation's economy.
The main uses of minerals are as follows:
(i) Development of industrial plants and machinery.
(ii) Generation of energy e.g. coal, lignite, uranium.
(iii) Construction, housing, settlements.
(iv) Defence equipments-weapons, armaments.
(v) Transportation means.
(vi) Communication- telephone wires, cables, electronic devices.
(vii) Medicinal system- particularly in Ayurvedic System.
(viii) Formation of alloys for various purposes (e.g. phosphorite).
(ix) Agriculture-as fertilizers, seed dressings and fungicides (e.g. zineb containing zinc, Maneb-containing
manganese etc.).
(x) Jewellery- e.g. Gold, silver, platinum, diamond.
Type of Minerals:
I. Based on their properties, minerals are basically of two types:
 Non metallic minerals ------- e.g. graphite, diamond, quartz, feldspar.
 Metallic minerals -------- e.g. Bauxite, quartz, haematite etc.
II. Based on the use minerals are sometimes classified as Critical and Strategic.
 Critical minerals are essential for the economy of a nation
e.g. iron, aluminum, copper, gold etc.
 Strategic minerals are those required for the defense of a country
E.g. Manganese, cobalt, platinum, chromium etc.
III. Based on energy generation minerals are classified as two types
 Energy generating minerals- used generating thermal and nuclear energies
E.g. Coal and Lignite, Uranium
 Commercially used minerals- E.g Aluminium, iron, copper etc
Impacts of mining
The environmental damage caused by mining activities is as follows:
(i) Devegetation and defacing of landscape: The topsoil as well as the vegetation is removed
from the mining area to get access to the deposit. While large scale deforestation or
Devegetation leads to several ecological losses as already discussed in the previous section, the
landscape also gets badly affected. The huge quantities of debris and tailings along with big
scars and disruptions spoil the aesthetic value of the region and make it prone to soil erosion.
(ii) Subsidence of land: This is mainly associated with underground mining. Subsidence of mining
areas often results in tilting of buildings, cracks in houses, buckling of roads, bending of rail
tracks and leaking of gas from cracked pipelines leading to serious disasters.

11. (iii) Groundwater contamination: Mining disturbs the natural hydrological processes and also
pollutes the groundwater. Sulphur, usually present as an impurity in many ores is known to get
converted into sulphuric acid through microbial action, thereby making the water acidic. Some
heavy metals also get leached into the groundwater and contaminate it posing health hazards.
(iv) Surface water pollution: The acid mine drainage often contaminates the nearby streams and
lakes. The acidic water is detrimental to many forms of aquatic life. Sometimes radioactive
substances like uranium also contaminate the water bodies through mine wastes and kill aquatic
animals. Heavy metal pollution of water bodies near the mining areas is a common feature
creating health hazards.
(v) Air pollution: In order to separate and purify the metal from other impurities in the ore,
smelting is done which emits enormous quantities of air pollutants damaging the vegetation
nearby and has serious environmental health impacts. The suspended particulate matter (SPM),
SOx, soot, arsenic particles, cadmium, lead etc. shoot up in the atmosphere near the smelters
and the public suffers from several health problems.
(vi) Occupational Health Hazards: Most of the miners suffer from various respiratory and skin
diseases due to constant exposure to the suspended particulate matter and toxic substances.
Miners working in different types of mines suffer from asbestosis, silicosis, black lung disease
etc
Energy resources
The sun is the primary energy source in our lives. Energy is defined by physicists as the capacity to
do work. Energy is found on our plant in a variety of form
Energy resources
The sun is the primary energy source in our lives. Energy is defined by physicists as the capacity to do
work. Energy is found on our plant in a variety of forms, some of which are immediately use full, while
others require a process of transformation
 Types of Energy resource
Available conventional energy source can be divided into two categories
1) Renewable Energy Sources
2) Non Renewable Energy Sources
Solar, wind, tidal, hydroelectric power are the examples of renewable sources and coal, oil, natural
gas, nuclear fuels are the examples of non-renewable sources of energy.
(1) Renewable Energy Resources
Renewable energy are such sources as the sun, wind, water, agricultural residue, firewood, and
animal dung which do not exhaust.
(2) Nonrenewable energy resources
These are energy raw materials, which are available in limited quantity and are of greatest practical
significance. These are fossil fuels such as coal, oil, natural gas, all of which are mixtures of compounds
containing carbon and hydrogen.
Renewable Energy Resources
Solar Energy

12. The sun is often mentioned as the ultimate answer to the world’s energy problem. It provides a
continuous supply of energy that far exceeds the world's demands. In fact, the amount of energy received
from the sun each day is six hundred times greater than the amount of energy produced each day by all
other energy sources combined. The major problem with solar energy is its
intermittent nature.
 P.V. Cell
Through Solar Photovoltaic (SPV) cells, solar radiation gets converted into DC electricity directly.
This electricity can either be used as it is or can be stored in the battery. This stored electrical energy
then can be used at night. SPV can be used for a number of applications such as :
(a) domestic lighting
(b) street lighting
(c) village electrification
(d) water pumping
(e) desalination of salty water
(f) powering of remote telecommunication repeater stations and
(g) railway signals.
The solar photovoltaic cells are still two to five times as costly as power from the grid. Yet, the sale of
solar photovoltaic cells expanded 42 percent.
The photovoltaic (PV) technology uses solar cells to generate electrical energy directly from sunlight.
Photovoltaic provide power in desired quanta for a large number of different applications like lights,
fan, water pumps, solar cookers etc. In many sizes across a broad range of environments to locations
where it was not feasible
. Wind Energy
Wind energy is the kinetic energy associated with the movement of atmospheric air. It has been
used for hundreds of years for sailing, grinding grain, and for irrigation. Wind energy systems convert
this kinetic energy to more useful forms of power. Wind energy systems for irrigation and milling have
been in use since ancient times and since the beginning of the 20th
century it is being used to generate
electric power. Windmills for water pumping have been installed in many countries particularly in the
rural areas.
Wind turbines transform the energy in the wind into mechanical power, which can then be used
directly for grinding etc. or further converting to electric power to generate electricity. Wind turbines
can be used singly or in clusters called 'wind farms'. Small wind turbines called aero-generators can be
used to charge large batteries.
Fig: wind mills

13. Geothermal Energy
The core of the earth is very hot and it is possible to make use of this geothermal energy (in Greek it
means heat from the earth). The earth's core, with temperatures as high as 60000°C, is a molten mass
of material processing vast amounts of energy. In some regions, this material sometimes breaks
through the earth and produces volcanoes. In other regions, the hot material is close enough to the
surface to heat underground water and form steam.
Geysers and hot springs are natural areas where this steam and hot water come to the
surface. In areas where the steam is trapped underground, geothermal energy is tapped by drilling
wells to obtain the steam. The steam is then used to power electrical generators. Present geothermal
energy is practical only in areas where this hot mass is near the surface
The main source of this energy is the decay of radioactive uranium, thorium, and
radioactive isotope of potassium.
Fig: geothermal energy generations
The geological structures of a potential power source region/area are generally associated with the
following characteristics:
1. A source of heat (a magma body, a cooling intensive body; presence of thin crust etc.). However,
heat stored in rocks underground in any type of area is extractable, through deep circulations of,
ground water or by injecting water through naturally occurring channels or induced fractures.
2. An aquifer i.e., presence of permeable zone having fractured or porous rocks through which water
can flow.
3. Presence of subsurface layer of bed rock.
4. A source of water to replenish the aquifer.
5. A cap rock to prevent the escape of heat through steam and/or hot water to the atmosphere
. 1. Hot Water System: These represent geothermal sources containing hot water with temperature
between 50° C and 80° C.
2. Hot Rock System: These represent rock systems with high temperature gradient but containing no
water or water vapour. Heat can be extracted directly from these systems by boring a hole and letting
the water flow through the hot region and extracting the heat.

14. 3. Wet Steam System: In areas where the ground water contacts the hot rock, it becomes superheated
to temperatures ranging from 180°C to 350°C. This steam or superheated water is extracted by means
of wells that are drilled through the cap rock.
4. Dry Steam System: In this system, dry super heated steam can either be extracted from a
geothermal reservoir or comes out directly with temperature up to 350° C and pressure of 30 to 35
bars. It can be used directly to run a turbine to produce electricity.
Biomass Energy
Biomass is organic material which has stored sunlight in the form of chemical energy. Biomass
fuels include wood, wood waste, straw, manure, sugar cane, and many other byproducts from a
variety of agricultural processes.
By photosynthesis, solar energy can be converted into biomass which in turn can be stored and
used as fuel in various forms. So far the only use of plant material as fuel is in the form of burning
firewood. Currently, a number of thermal conversion systems are in various stages of development.
These include pyrolysis, gasification and hydrogenation. All these processes require feedstock of
relatively low water content and operate at a higher temperature. Biological conversion processes,
however can handle feedstock of high water content and operate at a temperature range 25-65°C.
Sources of Biomass for Fuel Conversion
1. Land crops containing lignocelluloses material like trees of eucalyptus, starch crops like maize and
cassava and sugar crops like cane and beet.
2. Aquatic plants will include unicellular algae, multicellular algae and water weeds.
3. Wastes like manures, domestic rubbish, crop residues like straw, husks, citrus,
peel, begasse, molasses etc.
Numerous biomass electric power plants, as well as steam producing plants for industrial purposes
(especially in the wood and paper products industry) are located throughout the country.
Biogas plants have been set up in many areas and are becoming very popular. Using local resources,
namely cattle waste and other organic wastes, energy and manure are derived. A mini-biogas digester
has recently been designed and developed, and is being in-field tested for domestic lighting.
A typical biogas sample has 68% methane, 31 % CO2, 1 % N2 and gives calorific value of 5871
Kcal/M3
. Calorific value of biogas is 80% of that of natural gas and depends on its CO2 content. Heat
value of biogas can be improved by about 30% by reducing its CO2 content.
Fig.: Biogas plant
Biogas forms a combustible mixture in the range of 6% to 15% concentration in air. It takes nearly 350
Kg/Cm2
pressure to liquefy it for easy storage (propane liquefies at 10.5 Kg/Cm2
).

15. Methanobacterium and methanococcus spp use CO2 as an electron acceptor and methane is produced.
Non-renewable energy sources
Coal: It is the non-renewable, commercial or conventional source of energy.
Coal is the first fossil fuel to be exploited on a large scale; so industrial revolution enabled coal to be
mined at even greater depths.
About 6 lakhs billion tonnes of coal lies under the earth and now over to 200 billion tones have been
used.
If coal is used at this rate it may last one or two decades.
 Types of coal
1) Peat 2) Lignite
3) Bituminous 4) Anthracite
Peat contains 5% of carbon, 5% of volatile matter and 90% moisture. It is having low calorific value.
It is generally in dry condition.
Lignite is the lowest form of coal. It is brown in colour. Hence it is called as a coal. Pure lignite has
38% of carbon, 19%ofvd matter and 43% of moisture.
Bituminous coal is also called soft coal. It contains 3% of water. It is hi flammable. It has 65% of
carbon, and 32% of volatile matter.
Anthracite is a hard and dense coal. It is relatively free from ion compound moisture. This type of coal
contains 96% of carbon, 1% of volatile matter and 3% of moisture. It also called as hard (or)
metamorphic coal. It has the highest energy co of all coals and is used for space heating and
generating electricity.
 Oil (or) Petroleum
Oil provides 45% of world energy consumption. Petroleum is an inflammable liquid composed of
hydrocarbons, which constitute the majority and the remain organic compounds like O2, N2 , S and
traces of organic-metallic compounds.
It is pumped to the surface as crude oil and refined to get the desired products
Fig: Petroleum fractionation process
 Petroleum gas
It is the mixture of three hydrocarbons such as butane, propane and ethane. The main constituent of
petroleum gas is butane. The above gases are in gaseous state in ordinary pressure but they can be
liquefied under high pressure. So it is called as LPG. (Liquefied Petroleum Gas).
A domestic cylinder contains 14 kg of LPG. A strong smelling substance called Ethyl mercapten is
added to LPG gas cylinder to help in the detection of gas leakage.

16.  Natural gas
It consists of methane with small quantities of ethane and propane. It is available in deep under crust of
the earth, either alone or along with oil above the petroleum deposits. Natural gas is a by-product to
petroleum mining.
It meets about 24% of the world's energy requirement. In our country few natural gas fields have been
discovered recently in Tripura, shore area of Bombay and in the Krishna, Godavari delta.
Natural gas is formed under the earth by decomposition of materials by anaerobic organisms in the
absence of oxygen.