The document provides an extensive overview of renewable energy systems, covering various sources such as wind, solar, biomass, geothermal, and hydro energy, along with their environmental impacts and advantages. It discusses the limitations of conventional energy resources and the need for sustainable alternatives due to their depletion and pollution effects. Additionally, it examines the principles, technology, and site suitability for wind energy generation, emphasizing the importance of choosing optimal locations for efficient energy production.

1. EE8703-RENEWABLE ENERGY SYSTEMS
PART – I
Prepared by
Dr.N.Lakshmipriya M.E., Ph.D
Associate Professor,
Department of Electrical and Electronics Engineering

2. UNIT I RENEWABLE ENERGY (RE) SOURCES
Environmental consequences of fossil fuel use, Importance of
renewable sources of energy, Sustainable Design and
development, Types of RE sources, Limitations of RE sources,
Present Indian and international energy scenario of
conventional and RE sources.
UNIT II WIND ENERGY
Power in the Wind – Types of Wind Power Plants(WPPs)–
Components of WPPs-Working of WPPs- Siting of WPPs-Grid
integration issues of WPPs.

3. UNIT III SOLAR PV AND THERMAL SYSTEMS
Solar Radiation, Radiation Measurement, Solar Thermal
Power Plant, Central Receiver Power Plants, Solar
Ponds.- Thermal Energy storage system with PCM-
Solar Photovoltaic systems : Basic Principle of SPV
conversion – Types of PV Systems- Types of Solar
Cells, Photovoltaic cell concepts: Cell, module, array
,PV Module I-V Characteristics, Efficiency & Quality
of the Cell, series and parallel connections, maximum
power point tracking, Applications.

4. UNIT IV BIOMASS ENERGY
Introduction-Bio mass resources –Energy from Bio mass:
conversion processes-Biomass Cogeneration-Environmental
Benefits. Geothermal Energy: Basics, Direct Use, Geothermal
Electricity. Mini/micro hydro power: Classification of hydropower
schemes, Classification of water turbine, Turbine theory, Essential
components of hydroelectric system.
UNIT V OTHER ENERGY SOURCES
Tidal Energy: Energy from the tides, Barrage and Non Barrage Tidal
power systems. Wave Energy: Energy from waves, wave power
devices. Ocean Thermal Energy Conversion (OTEC)- Hydrogen
Production and Storage- Fuel cell : Principle of working- various
types - construction and applications. Energy Storage System-
Hybrid Energy Systems.

5. UNIT –I
RENEWABLE ENERGY (RE) SOURCES

6. Based on the usability of energy
Primary
Secondary
Based on Traditional Use
Conventional
Non - Conventional

7. Based on Long Term Availability
Renewable
Non – Renewable
Based on Commercial Application
Commercial Energy Resources
Non Commercial Energy Resources

8. Based on the origin
 Fossil Fuels
 Nuclear
 Hydro
 Solar
 Wind
 Biomass
 Geothermal
 Tidal
 Ocean energy

9. Resources available in the nature that are available in raw
form are called primary resources.
Ex: Fossil fuels (coal, oil and gas), uranium and
hydropower.

10. Secondary energy resources are obtained from primary
energy resources by processing. Processing helps in
transformation of primary resources into the secondary or
usable energy form so that it can be utilized by
consumers.
Ex: Electricity, steam, hot water, petrol, diesel, LNG and
CNG

11. Resources that have been used traditionally for many
years are called as Conventional energy resources. These
resources are also widely used at present and likely to be
depleted.
Ex: Coal, Petrol, Diesel, Nuclear, CNG and LPG

12. These are alternate energy resources to the
conventional energy resources which are being
considered to be used on large scale. The conventional
energy resource are likely to be depleted in about 50–60
years were as non- conventional resources will not
deplete.
Ex: Solar, Wind, Tidal, Geothermal and biogas

13. Renewable energy is energy obtained from sources that
are essentially inexhaustible Or Resources which can be
renewed by nature again and again. The most important
feature of renewable energy is that it can be harnessed
without the release of harmful pollutants
Ex: wind power, solar power, geothermal energy, tidal
power and hydroelectric power.

14. Resources which are available in certain finite quantity
and cannot be replenished are called non-renewable.
Ex: Fossil fuel

15. The secondary usable energy resources such as electricity,
CNG, LPG, petrol and diesel are essential for commercial
activities. The economy of a nation highly depends on its
ability to process and transform the natural raw energy
sources into usable commercial energy sources.

16. The energy which can be derived directly from nature so
as to be used without passing through any commercial
outlet is known as the non- commercial energy.

17.  The environmental pollution has reached such a high level
that it becomes a serious threat for vegetables growth, wild
life and human health.
 Air pollution can cause health problems and it can also
damage the environment and property. It has caused
thinning of the protective ozone layer, which is leading to
climate change.
 Hundreds of elements and compounds such as
benzene and formaldehyde are known to be emitted during
the combustion of coal, oil, natural gas, engine of vehicles,
furnaces and even fireplaces.
 Dust storms in desert areas and smoke from forest fires and
grass fires contribute to chemical and particulate pollution
of the air.

18. Air Pollutant Sources Effects
Carbon monoxide
(CO)
Colorless, odorless gas.
Incomplete burning of
carbon-based fuels
including petrol, diesel
and wood.
Produced from the
combustion of natural
and synthetic products
such as cigarettes.
It lowers the amount of
oxygen that enters our
blood. It can slow our
reflexes and make us
confused and sleepy.
Carbon dioxide (CO2) greenhouse gas emitted
as a result of human
activities such as the
burning of coal, oil, and
natural gases
It leads to breathing
problem

19. Air Pollutant Sources Effects
Chlorofluorocarbons
(CFC)
These are gases that are
released mainly from air
conditioning systems
and refrigeration.
It lead to a reduction of
the ozone layer that
protects the Earth from
the harmful ultraviolet
rays of the Sun.
It leads to skin problem.
Lead This is present in petrol,
diesel, lead batteries,
paints, hair dye products,
etc.
Lead affects children in
particular. It can cause
nervous system damage
and digestive problems
and, in some cases,
cause cancer.

20. Air Pollutant Sources Effects
Ozone (O3) This occurs naturally
in the upper layers of
the atmosphere.
It shields the Earth from
the harmful ultraviolet
rays of the Sun.
Ozone makes our eyes
itch, burn, and water. It
lowers our resistance to
colds and pneumonia.
Nitrogen oxide (NOx) It is produced from
burning fuels including
petrol, diesel, and coal.
This causes smog and
acid rain.
Nitrogen oxides can
make children
susceptible to respiratory
diseases in winters.

21. Air Pollutant Sources Effects
Sulphur dioxide (SO2) This is a gas produced
from burning coal,
mainly in thermal power
plants. Some industrial
processes, such as
production of paper and
smelting of metals,
produce sulfur dioxide.
It cause smog and acid
rain.
Sulfur dioxide can lead
to lung diseases.

24. Types of
Renewable
Energy
Systems
Solar
Wind
Biomass
Geothermal
Ocean
Tidal
Ocean
Wave
Ocean
Thermal
Energy
Conversion

25.  Conventional energy resources are insufficient to meet
growing demand.
 Conventional energy resources are depleting fast.
 It causes pollution which degrades environment.
 Need to conserve fossil fuels for future generation

26.  It is cheaper than Renewable Energy Systems
 It is easy to store
 It is more compatible and affordable
 It can be efficiently converted to the type of energy
required.
 It is easy to transport

27.  It produces greenhouse gases
 Its byproducts cause damage to the environment.
 Its residual products are non-biogradable.
 Responsible for acid rain

28.  Green house gas emissions
 Air pollution
 Acid Rain
 Water Pollution
 Soil Pollution
 Non – Biodegradable waste generation
 Oil Spills
 Depletion of Ozone layer

29.  No threat of depletion
 No running cost
 More site specific which makes no need of
transmission and distribution of power.
 No pollution
 Create local employment

30.  High Capital Cost
 Electricity Generation can be unreliable
 Energy Storage is a challenge
 It is impacted by environmental conditions
 It uses larger land masses

32.  Solar power is generated directly from sunlight (photons).
Solar thermal panels are filled with water which heats up
in the sunlight.
 The heated water is then pumped through a tank heating
the water that is connected to the taps in the house.
 Solar photovoltaic (PV) cells use the suns energy to
convert are made from two layers of silicon crystal. When
photons hit the top layer of silicon they ‘excite’ the
negatively charged electrons in the silicon atoms giving
them enough energy to move towards the positively
charged lower layer, inducing an electrical current.

33. Advantages
 Almost limitless source of energy
 Solar energy is available freely in nature
 Does not produce air pollution
Disadvantages
 It is available only during daytimes and clear days
 Solar energy obtainable also depends on seasonal
variations
 It requires a large area to entrap appreciable solar
energy for the generation of an economical amount of
electricity.

35.  Wind turbines are built to harness wind energy (kinetic
energy). When the wind blows the blades move and
spin a turbine connected to a generator which produces
electricity.

36. Advantages
 Renewable
 It is freely and abundantly available in nature
 Relatively inexpensive to generate
 Does not produce air pollution
 Windmills require minimal maintenance and operating cost
Disadvantages
 Only suitable in windy areas
 Produces less energy
 Wind mill is big, bulky and inconvenient to use as
compared to other forms of energy

37.  Biomass energy includes energy from all plant
matter (tree, shrub, and crop) and animal
dung.
 Biomass, unlike other renewables, is a
versatile source of energy.
 It can be converted to modern forms such as
liquid andgaseous fuels, electricity, and
process heat.

38. Advantages
 Suitable in most locations.
 Varying capacity can be installed; any
capacity can be operated, even at lower loads;
no seasonality.
 Need for storage of energy is not required.
Disadvantages
 It is dispersed and land intensive source
 Produces smoke
 It has low energy density

40. • Geothermal energy = heat energy from the Earth
• Decay of radioactive elements and residual heat
from planetary formation 4.5 billion years ago
• Water is pumped down into hot rock where it is
heated.
• Steam can then be used to heat buildings directly or to
generate electricity by spinning a turbine.

41. Advantages
 Significant cost saving
 Environmentally friendly
 No Pollution
 It has a good potential to meet the power
requirement
Disadvantages
 Not widespread source of energy
 Emission of greenhouse gases during extraction of
heat from ground.
 Groundwater is likely to be polluted from gaseous
effluents
 Suited to Particular region

43. Unit II
Wind Energy

44. The amount of power, and therefore electricity, a wind
turbine can produce is largely based on wind velocity
using this equation:
Power = ½ ρAV3
ρ = air density; ~1 kg m3
A = swept area (π r2 )
V = velocity (m s-1)

45.  Chord - Width of the blade or distance from one edge (fore) of the blade to the
other
 Wind Velocity, uo - Velocity of free air in the neighbourhood of wind turbine (at a
distance where the disturbances due to rotation of turbine does not reach)
 Incident Wind Velocity, u1 - Velocity of air passing through the rotor, i.e. the
velocity at which the wind strikes the blade, which is slightly less than uo
 Blade Element Linear Velocity, v - Linear circumferential velocity of the blade
element due to rotation of blade
 Relative Wind Velocity, vr - Velocity of air relative to the blade element as both
the air and blade elements move
 Angular Speed, ω Angular speed of rotor in rad/s

46.  Angle of Attack (or Angle of Incidence), α - Angle between central line of the blade element and relative
wind velocity vr
 Blade Setting Angle (or Pitch Angle), γ - Angle between central line of the blade element and direction of
linear motion of the blade element or angle between relative wind velocity vr and normal to the plane of
blade
 Drag Force, ΔFD Incremental force acting on the blade element in the direction of relative velocity of
wind
 Lift Force, ΔFL Incremental force acting on the blade element in a direction perpendicular to the relative
velocity of wind
 Axial Force, ΔFA - Incremental force acting on the blade element along the axis of rotation of blade
 Tangential Force, ΔFT - Incremental force acting on the blade element tangential to circular path of
rotation

47. • “rotary engine in which the kinetic energy of a
moving fluid is converted into mechanical energy by
causing a bladed rotor to rotate”
• opposite of a fan
– turbine blades spin from the wind and make
energy, instead of using energy to make wind
– Wind rotates the turbine blades
• spins a shaft connected to a generator
• The spinning of the shaft in the generator makes
electricity

48.  A wind turbine extracts energy
from moving air by slowing the
wind down, and transferring
this energy into a spinning
shaft, which usually turns a
generator to produce electricity.
 The power in the wind that’s
available for harvest depends
on both the wind speed and
the area that’s swept by the
turbine blades.

49. • Horizontal Axis Wind
Turbines
• Vertical Axis Wind
Turbines

51.  The power available in the wind increases rapidly with
the speed, hence wind energy conversion machines
should be located preferable in areas where the winds
are strong and persistent.
 Although daily winds at a given site may be highly
variable, the monthly and especially annual average are
remarkably constant from year to year.
 The most suitable sites for wind turbines would be
found in areas where the annual average wind speeds
are known to be moderately high or high.

52.  If the wind energy power plant sites are wrongly or
poorly chosen the net wind electrics generated energy
per year may be sub optimal with resulting high capital
cost for the WECS apparatus, high costs for wind
generated electric energy, and low Returns on
Investment.
 Technical, Economic, Evironmental, Social and Other
actors are examined before a decision is made to erect a
generating plant on a specific site.

53. 1. High annual average wind speed
2. Availability of anemometry data
3. Wind structure at the proposed site
4. Altitude of the proposed site
5. Terrain and its aerodynamic
6. Local Ecology
7. Distance to road or railways
8. Nearness of site to local centre/users
9. Nature of ground
10. Favourable land cost

54.  The speed generated by the wind mill depends on cubic
values of velocity of wind, the small increases in
velocity markedly affect the power in the wind.
 It is obviously desirable to select a site for wind energy
power plant with high wind velocity. Thus a high
average wind velocity is the principle fundamental
parameter of concern in initially appraising wind
energy power plant site.

55.  The aenometry data should be available over
some time period at the precise spot where
any proposed wind energy power plant is to
be built and that this should be accomplished
before a sitting decision is made.

56.  The ideal case for the wind power plant sites that the a
smooth steady wind that blows all the time; but a
typical site is always less than ideal.
 Wind specially near the ground is turbulent and gusty,
and changes rapidly in direction and in velocity.
 This depature from homogeneous flow is collectively
referred to as “the structure of the wind”.

57.  It affects the air density and thus the power in the wind
and hence the useful WECS electric power output.
 the wind tend to have higher velocities at higher
altitudes.
 One must be carefully to distinguish altitude from
height above ground. They are not the same except for
a sea level wind power plant site.

58.  If the wind power plant is to be placed near the top but not
on the top of a not too blunt hill facing the prevailing wind,
then it may be possible to obtain a ‘speed-up’ of the wind
velocity over what it would otherwise be.
 the wind here may not flow horizontal making it necessary
to tip the axis of the rotor so that the aeroturbine is always
perpendicular to the actual wind flow.
 It may be possible to make use of hills or mountains which
channel the prevailing wind into a pass region, thereby
obtaining higher wind power.

59.  If the surface is base rock it may mean lower hub
height hence lower structure cost.
 If trees or grass or vegetation are present, all of which
tend to destructure the wind, the higher hub heights will
be needed resulting in larges system costs that the bare
ground case.

60.  This is another factor the system engineer must
consider for heavy machinery, structure, materials,
blades and other apparatus will have to be moved into
any choosen wind power plants site.

61.  This obvious criterion minimizes transmission line
length and hence losses and cost.
 After applying all the previous string criteria, hopefully
as one narrows the proposed wind energy power plants
sites to one or two they would be relatively near to the
user of the generated electric energy.

62.  Ground condition should be such that the foundation
for a wind energy power plants are secured.
 Ground surface should be stable.
 Erosion problem should not be there, as it could
possibly later wash out the foundation of a wind energy
power plants, destroying the whole system.

63.  Land cost should be favourable as this along
with other siting costs, enters into the total
wind energy power plants system cost.