3. ENERGY RESOURSES
Energy consumption of a nation is usually considered as an
index of its development. This is because almost all the
developmental activities dependent upon energy.
The first form of energy technology probably was the fire,
which produced heat and the early man used it for cooking
and heating purposes. Wind and hydropower have also
been in use for the last 10,000 years. The invention of
steam engines replaced the burning of wood by coal and
coal was later replaced to a great extent by oil.
9. SOLAR ENERGY
Sun is the ultimate source of energy, directly
or indirectly for all other forms of energy. The
nuclear fusion reactionsoccurring inside the
sun release enormous quantities of energy in
the form of heat and light. The solar energy
received by the near earth space is
approximately 1.4 kilojoules/second/m2
known
as solar constant.
10.
11. SOLAR ENERGY
Solar heat collectors:
● These can be passive or active in nature.
● Passive solar heat collectors are natural materials like
stones, bricksetc. or material like glass which absorb
heat during the day time andrelease it slowly at night.
● Active solar collectors pump a heat absorbingmedium
(air or water) through a small collector which is normally
placed on the top of the building.
13. SOLAR ENERGY
Solar cells:
● They are also known as photovoltaic cells or PV cells. Solar cells are
made of thin wafers of semi conductor materials like silicon and
gallium.
● When solar radiations fall on them, a potential difference is produced
which causes flow of electrons and produces electricity.
● Silicon can be obtained from silica or sand, which is abundantly
available and inexpensive. By using gallium arsenide,cadmium
sulphide or boron, efficiency of the PV cells can be improved.
● The potential difference produced by a single PV cell of 4 cm2
size is about 0.4-0.5 volts and produces a current of 60 milli amperes.
15. SOLAR ENERGY
Solar cooker:
● Solar cookers make use of solar heat by reflecting the solar
radiations using a mirror directly on to a glass sheetwhich
covers the black insulated box within which the raw food is kept.
● A new design of solar cooker is now available which involves a
spherical reflector (concave or parabolic reflector)instead of
plane mirror that has more heating effect and hence greater
efficiency.
● The food cooked in solar cookers is more nutritious due to slow
heating. However it has the limitation that it cannot be used at
night or on cloudy days. Moreover, the direction of the cooker
has to be adjusted according to the direction of the sun rays.
16.
17. SOLAR ENERGY
Solar water heater:
● It consists of an insulated box painted black from
inside and having a glass lid to receive and store
solar heat.
● Inside the box it has black painted copper coil
through which cold water is made to flow in, which
gets heated and flows out into a storage tank.
● The hot water from the storage tank fitted on roof
top is then supplied through pipes into buildings like
hotels and hospitals.
18.
19. SOLAR ENERGY
Solar furnace: Here thousands of small plane
mirrors are arranged in concave reflectors, all of
which collect the solar heat and produce as high a
temperature as 3000°C.
Solar power plant: Solar energy is harnessed on a
large scale by using concave reflectors which
cause boiling of water to produce steam. The
steam turbine drives a generator to produce
electricity. A solar power plant (50 K Watt capacity)
has been installed at Gurgaon,Haryana.
20. Tidal Power
●
Located at some coastal sites - usually estuaries and bays with
large tidal range.
●
Shape of coastal site above and below sea level determines
range.
●
At high tide reservoir of water is created which is allowed through
turbines located in dam.
●
These turbains rotate and generate electricity
●
There are only a few sites in the world where tidal energy can be
suitably harnessed.
●
The bay of Fundy Canada having 17-18 m high tides has a
potential of 5,000 MW of power generation.
●
The tidal mill at La Rance, France is one of the first modern tidal
power mill.
●
In India Gulf of Cambay, Gulf of Kutch and the Sunder bans deltas
are the tidal power sites.
21.
22. Biomass Energy
●
What is it?
– Biomass energy is the use of living and recently dead biological
material as an energy source
– Ultimately dependent on the capture of solar energy and
conversion to a chemical (carbohydrate) fuel
– Theoretically it is a carbon neutral and renewable source of
energy
●
How it works?
– Traditional: forest management, using wood as fuel
– Use of biodegradable waste
●
Examples: manure, crop residue, sewage, municipal solid
waste
– Recent interest in agricultural production of energy crops
●
Should be high yield and low maintenance
●
Examples: corn, sugarcane, switchgrass, hemp, willow, palm
oil, rapeseed, and many others
●
Does not have to be a food crop
●
Recent interest in bioengineered (GM) plants as fuel sources
23. Biomass Energy
●
cycle of sunlight - photosynthesis - plant growth - absorption of
CO2 - emission of O2.
●
combustion of wood - heat
●
some plants - alcohol
●
decomposition - methane/landfill gas/fuel for heating.
25. Biomass Energy
●
Advantages
– Versatile
– Renewable
– No net CO2 emissions (ideally)
– Emits less SO2 and NOx than fossil fuels
– Energy plantations
– Agricultural and urban waste biomass
– Petro-crops
26. The Hydrogen as Fuel
●
Definition
– The Hydrogen Economy is a hypothetical large-scale
system in which elemental hydrogen (H2) is the primary
form of energy storage
●
Fuel cells would be the primary method of conversion of
hydrogen to electrical energy.
– Efficient and clean; scalable
●
In particular, hydrogen (usually) plays a central role in
transportation.
●
Potential Advantages
– Clean, renewable
– Potentially more reliable (using distributed generation)
27. Hydrogen Production
●
Fossil Fuels
– Steam Reforming of Natural Gas
●
Combination of methane and steam produces hydrogen gas
– Carbon monoxide is also produced
– The “water gas shift” reaction can produce further hydrogen
from the carbon monoxide. Carbon dioxide is produced too.
●
Most economical; main current method
– Carbon sequestration one method to reduce CO2 emission
– Partial Oxidation (POX) of Hydrocarbons
●
HC partially oxidized to produce hydrogen and carbon monoxide
– Coal Gasification
●
Gasified at high temps, then processed
●
Can also be used to get hydrogen from biomass
28. Hydrogen Production
●
Electrolysis
– Efficiencies 70-85%
– Produces highest purity of hydrogen
– Currently, the electricity consumed is usually worth
more than the hydrogen produced
●
Experimental methods
– Biological hydrogen production
– Direct photolysis
– Thermolysis
31. Biogas
• Biogas is defined as a mixture of different gases produced by
the breakdown of once living organisms in the absence of
oxygen. Biogas can be produced from raw materials such as
agricultural waste, manure, municipal waste, plant
material,sewage, green waste, or food waste.
Advantages of Biogas
• Provides non-polluting and renewable source
• efficient way of energy conversion( saves fuelwood)
• saves women and children from carrying firewood and exposure to kitchen smoke
