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LECTURE II
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ENERGY NEEDS
1. The world population rose from 2000 million to 4000 million since theturn of the century and will increase to 6000 million by the year 2000.
2. World energy demand is increasing rapidly due to which Gas and Oildeposits will be running low by the next century. This puts extrapressure on coal.
Also the unequal distribution of fuel e.g. USA being 1/6 of the worldpopulation but it consumes 1/3 of the worlds fuel.
The unequal distribution of physical resources.
Environmental constraints on the exploration of non-renewable energyresources E.g. green house effects, high temperatures, which meltsice on the poles, Resulting in floods.
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RENEWABLE ENERGY
Energy Resource Origin Solar Energy: Mother of all energy resources
Wind Energy: Due to Difference in
temperature
Biomass: Organic substance
Geothermal Energy: Heat Energy under earth
Wave Energy: Wind Energy
Tidal Energy: Gravitational force between
earth and moon
Fuel Cell: man Made process
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RESOURCES FORM OF
DELIVERED
ENERGY CURRENT
DISTRIBUTE
ON REMARKS/ COMMENTS
1. SOLAR Total solar radiation absorbed by
the earth and its
atmosphere is
3.8x 1024 J/Y
Low Temp heat(space heating)
Low temp heat
(water heating)
Electricity
LARGESMALL
NEGLIGIBLE
The Sun maintains ambienttemperature of the planet at 200-
300 Celsius degrees above absolute
zero in addition passive solar gains
through windows and .walls meet a
large fraction of world space
heating demand. In UK 15-20 % of
domestic heating is obtained fromsolar energy 10-15 MW of solar
cells are installed. 1-2 MW of
Power towers are in operation.
2. WIND
The kinetic energy
available in the
atmosphere circulation
is
7.5 x1022 j
ELECTRICITY NEGLIGIBLE Several Multi MW wind turbines
are in operation, e.g. 4 MW
machines for wind farm iii Hawaii.
There are about one million wind
pumps in use. The total capacity is
1 GegaWatt. Sailing ships have
traditionally been used for in shore
and off shore shipping.
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3. BIOMASS
The total solar radiation
absorbed by the
planet is 1.3x lO21J/Yr
The worlds standing
biomass has an energy
constant of about 1.5xlO22J
High Temp
Heating
Biogas
Alcohol
SIGNIFICANT
SMALL
NEGLIGIBLE
Biomass principally wood. It accounts
for about 15% of the world’s fuel
consumption. It provides 80% of
the energy need of many
developing countries.
4. GEOTHERMAL
The heat Flux from the
earth's interior
through the surface is
9.5x1020 j/yr
Low Temp Heat
(Bathing)
Low Temp Heating
(space & water
heating)
Electricity
SMALL
SMALL
Negligible
Geothermal energy supplies 5350 MW
of heat for use in bathing,
principally in Japan but in 1
Hungary and Iceland about 100000
houses are supplied with heat from
geothermal wells. The installedelectricity capacity is 2500 MW
and is expected to increase more
than 7 folds by the year 2000.
5. HYDRO: Hydro by
annual precipitation
over
Land amounts to 1.1x107 Kg of water. Taking the
average elevation of
the land area as 840
M the annually
accumulated potential
energy would be 9x
1020 J.
Electricity SIGNIFICANT. Large Hydro schemes provide about 1/4
of the world’s total electricity and
more than 40% of the electricity
used in developing countries. Theinstalled capacity is 363 Gega
Watts.
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6. TIDAL: Energy
dissipation in
connection with
slowing down the earth
ns a result of tidal
action is around lO20
J/Yr.
Electricity NEGLIGIBLE Only one large tidal barrage is in
operation in France. There are also
small schemes in Russia and
China. Total installed capacity is
240 MW.
7. WAVES: The amount
of energy stored as
kinetic and potential
energy in waves may
be of the order of lO9 J.
Electricity NEGLIGIBLE The Japanese wave energy
research vessel has an installed
capacity of 1 MW. There are in
addition several hundred wave
powered navigational setups.
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SOLAR PROSPECTS
1.The Sun is the potential source of energythat can replace oil, gas and coal. It isbasically a fusion reactor.
2.Incoming energy absorbed by earth and
its atmosphere in one year is 3.8X10^24 J,which is 15 to 20 times the amount of energy stored in all of the worlds resourcesof renewable hydrocarbons.
3.Unlike capital energy resources,renewable can not be exhausted onlylimitation is, the rate at which they areused.
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4. Renewable already supply major parts of the worlds energy needs.
BIOMASS accounts for l/7th of all the fuel
consumed and supplies 90% of energy needsof the third world countries.
Hydro generates l/4th of the world electricityand 2/3rd of that is used in 35 Countries.
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Sun contributes directly to space heating in virtually all the buildings, throughwalls and windows.
Renewable energy technology is in manyways more attractive than theconventional energy technology.
They can be matched in scale to theneed and can be built close to the site
where it is required thus minimizing thecost. They can be produced in large number
and introduced quickly. Rapid planning and construction lowers unit cost.
Diversity of systems available alsoincreases flexibility and security of supply.
Comparing to other non renewableresources they are less hazardous.
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SUN
Solar energy is a source of life. It maintains a temperature of 150°C onthe earth surface; also Oxygen in the atmosphere (upper) reacts withsun rays to form ozone which protects from ultraviolet radiations. Sunalso causes circulation of the air, differential heating of earth's surfacewhich generates high and low pressure regions thus causing movementof air which blows forming waves of the oceans. Sun is also responsible
for evaporating surface waters which leads to rain and feed themountain streams. Plants can not grow without sun light. Plants andother organic matter collectively are known as 'BIOMASS'. Water, Windand Waves are all form of solar energy. They are by definition renewablebecause they are continuously being regenerated by the Sun.