This document summarizes different renewable energy sources including hydroelectric, wind, tidal, solar photovoltaic, solar thermal, geothermal, and biogas power systems. For hydroelectric power, it describes the basic components and layout of hydroelectric dams as well as how water is used to spin turbines and generate electricity. For wind power, it discusses how wind turbines convert kinetic energy from the wind into electrical energy. It also summarizes the basic components and functioning of tidal, solar photovoltaic, solar thermal, geothermal, and biogas power generation systems.

1. UNIT IV
POWER FROM RENEWABLE ENERGY
Hydro Electric Power Plants – Classification, Typical
Layout and associated components including
Turbines. Principle, Construction and working of
Wind, Tidal, Solar Photo Voltaic (SPV), Solar Thermal,
Geo Thermal, Biogas and Fuel Cell power systems.

2. Hydro Electric Power Plants

3. Hydro Electric
Converts Hydraulic Energy to Electrical Energy
• The water falls through a certain height, its
potential energy is converted into kinetic energy
and this kinetic energy is converted to the
mechanical energy by allowing the water to flow
through the hydraulic turbine runner. This
mechanical energy is utilized to run an electric
generator which is coupled to the turbine shaft.

4. Power Calculation

5. Site Selection
• Water Available
• Water-Storage
• Head of Water
• Distance from Load Center
• Access to Site

6. Classification
The hydro-power plants can be classified as below:
1. Storage plant
(a) High head plants
(b) Low head plants
(c) Medium head plants.
2. Run-of-river power plants
(a) With pondage
(b) Without pondage.
3. Pumped storage power Plants.

7. Layout of Hydro Electric Power Plant

8. Components of Hydro Electric Power
Plant

9. 1) Dam The dam is the most
important component of
hydroelectric power plant.
The dam is built on a large
river that has abundant
quantity of water throughout
the year. It should be built at
a location where the height of
the river is sufficient to get
the maximum possible
potential energy from water.

10. 2) The Penstock The penstock is
the long pipe or the shaft that
carries the water flowing from
the reservoir towards the power
generation unit, comprised of the
turbines and generator. The water
in the penstock possesses kinetic
energy due to its motion and
potential energy due to its height.
The total amount of power
generated in the hydroelectric
power plant depends on the
height of the water reservoir and
the amount of water flowing
through the penstock. The
amount of water flowing through
the penstock is controlled by the
control gates.

11. 3) Water Turbines Water flowing from the
penstock is allowed to enter the power
generation unit, which houses the turbine
and the generator. When water falls on
the blades of the turbine the kinetic and
potential energy of water is converted
into the rotational motion of the blades
of the turbine.

12. Wind Energy

13. Wind Turbine Operates

14. Theoretical Power Generated by Wind Turbine
Power = ½ (ρ)(A)(V)3
A = swept area = (radius)2
, m2
V = Wind Velocity, m/sec.
ρ = Density of air

15. Components of Wind Turbine

16. • Components:
• Rotor- The hub and the blades together are referred to as
the rotor. Wind turns the blades which turn the drive shaft.
• Shaft- Two different shafts turn the generator. One is used
for low speeds while another is used in high speeds.
• Gear Box- Gears connect the high and low speed shafts and
increase the rotational speeds from about 10-60 rotations
per minute to about 1200-1800 rpm, the rotational speed
required by most generators to produce power.
• Generator- The generator is what converts the turning
motion of a wind turbine's blades into electricity.
• Tower- Tall tubular metal shaft. The taller the tower, the
more power produced.

17. components
• Storage :
storage systems are used to store energy
when there is excess power developed and to
discharge it when there is a lack in power.
• Energy convertors
Usually, the electricity produced from wind energy is
direct current. Using alternator convert it to AC
before supply to power grid

18. Characteristics of wind turbine
• Wind power system do not pollute
environment
• Fuel provision and transport do not required
• Its renewable source of energy
• It can produce on small scale is cheap but it is
competitive with conventional power
generation system

19. Advantages
• Clean
• Free
• Place ability
• Decentralised
• Domestic
• Remote areas supply

20. Advantages and Disadvantages
• Vertical Axis Advantages
– Can place generator on
ground
– You don’t need a yaw
mechanism for wind
angle
• Disadvantages
– Lower wind speeds at
ground level
– Less efficiency
• Horizontal Advantages
– Higher wind speeds
– Great efficiency
• Disadvantages
– Angle of blade is
relevant
– Difficult access to
generator for repairs

21. Types of wind mills
• Lift type wind turbine
– High speed turbines based on lift force
• Drag type wind turbine
– Low speed turbines are slower than wind, mainly driven by
drag force
• Based on the axis of rotation
– Horizontal axis
– Vertical axis

22. Turbines: Two Types
• Horizontal Axis Wind Turbines
• Vertical Axis Wind Turbines

23. Types of wind mills

24. TIDAL ENERGY

25. How tides form?
• Mainly tides are produced by gravitational
attraction of the moon and sun on the water
of earth.
• 70% of the tide produces force due to moon
• 30%of the tide produces force due to sun

26. Tidal Energy
• It is a form of hydro power that converts the
energy of tides into useful form of power ,
mainly electricity. It is only form of energy
whose source is moon

27. Energy generated from tides
E= 5.04 h2 kJ
Where h = tide amplitude

28. Components of Tidal Barrage power
plants

29. Ebb generation

30. Flood generation

31. Two way generation

32. TIDAL POWER PLANT
1. Single Basin Arrangement
•Low Tide
•High Tide
2. Double Basin Arrangement

33. Single basin Arrangement

34. Double basin Arrangement

35. Site selection
• It should be nearer to the ocean
• It should be protected from the high ways
• It should not hamper shipping traffic

36. Solar Photovoltaic (PV)
A photovoltaic system, also solar PV power system, or PV
system, is a power system designed to supply usable solar
power by means of photovoltaic. It consists of an
arrangement of several components, including solar
panels to absorb and convert sunlight into electricity

37. PV SYSTEM
• Energy conversion devices which are used to
convert sunlight into electricity by the use of
the photovoltaic effect are called solar cells
• A single converter cell is called a solar cell,
more generally a photovoltaic cell and
combination of such cells are designed to
increase the electric power output called solar
module or solar array.

38. Basics of Semi conductor
• A semi conductor is an element with electrical
properties between those of a conductor and
insulator
• A best semiconductor has 4 valance electrons
• Example: Silicon
• If an electron attracted by the nucleus, extra
energy is needed to lift electrons to the higher
energy level are light , heat and voltage

39. Photo voltaic effect
• Whenever a heat and light energy fall on the
photovoltaic cell it induce movement of the
electrons and holes. This will generate the
potential difference. This effect is called photo
voltaic effect.
• Current depends upon the light intensity
because absorption of more light results in
additional electron flow.

40. Photo voltaic Materials
• Single crystalline Si cells
• Poly crystalline Si cells
• Amorphous Si cells
• Cadmium telluride
• Copper – Indium Selenide
• Nano crystalline solar cell

41. Solar Photovoltaic (PV)

42. Solar PV power generation systems
• Solar array
• Blocking Diode
Without a blocking diode, the battery would discharge back through the solar
array at the time of no isolation.
• Battery storage
• Inverter/Converter
• Switches and circuit breakers

43. Types of solar PV power generation
system
• Standalone power system
• Grid connected system
• Hybrid system

44. Standalone power system

45. Central system or grid connected
system

46. Hybrid system

47. Solar thermal power systems
• A solar collector is a device used for collecting
the solar radiation and it transfer the energy
to fluid passing in contact with it.
• Flat type solar collector
• Focusing type solar collector

48. Factors affecting the Solar system
efficiency
• Shadow effect
• Cosine loss factor
• Reflective loss factor

49. Solar Thermal Vs Solar PV

50. Flat plate collectors
• They are generally in rectangular type panels
about 1.7 to 2.9 m2
• They are relatively simple to construct and
erect.
1.Liquid heating collectors
2.Air heating collectors
3.Evacuated tubular collector

51. Liquid heating collectors

52. Modified flat plate collector

53. Solar air heaters
• Applications of solar water heater
Heating green house buildings
Drying agricultural products
Air-conditioning buildings
Heat source for heat engine

54. Evacuated tubular collector

55. Solar focusing collector or
Concentrating collector
• Main difference between flat type and
concentrating collector is that flat plate
collector only concentrates only direct
radiation but concentrating collector collect all
the incident radiation

56. Parabolic collector

57. Mirror strip reflector

58. Fresnel lens collector

59. Compound parabolic concentrator

60. Power generation using flat plate
collector

61. Power generation using solar
distributed collector

62. Power generation using central
receiver system

63. Geothermal Energy

64. Working of Geothermal Power Plant

65. Geothermal Energy
Geothermal power is an alternative source of energy that
harnesses the Earth’s heat in order to generate electricity. In
locations with shallow ground water at high temperatures,
wells are drilled in order to extract the steam or hot water.
There are three types of geothermal energy generation plants
•Dry Steam Power Plant
•Flash Power Plant
•Binary Power Plant

66. Dry Steam Power Plant

67. Flash Steam Power Plant
The heated water is sprayed into a tank held at much lower pressure than the
fluid. This causes the fluid to vaporize rapidly, or “flash.” The vapor then drives a
turbine to run the generator.

68. Binary Power Plant

69. Application of Geothermal Energy
Space Heating Air Conditioning Drying
Hot Water
Greenhouses
Aquaculture

70. ADVANTAGES
Environment friendly.
Renewable energy source.
High potential.
Low operational cost.
More reliable than other alternatives.

71. DIS ADVANTAGES
High installation cost .
May release harmful gases
.
Earthquakes .
Transportation .

72. BIO GAS

73. What is biogas?
• A mixture of methane and
carbon dioxide
CH4
CO2 • Methane or ‘swamp gas’,
produced naturally in
swampy ponds

77. Aerobic and Anaerobic Digestion

79. Biogas
plants
Dome
d
shape
Continuo
us or
Floating
type 79

80. • A fixed-dome plant comprises of a closed,
dome-shaped digester with an
immovable, rigid gas-holder and a
displacement pit, also named
'compensation tank'.
• When gas production starts, the slurry is
displaced into the compensation tank.
• Gas pressure increases with the volume
of gas stored. 80

81. 81

82. • Relatively low construction costs.
• The absence of moving parts and rusting
steel parts.
• If well constructed, fixed dome plants have
a long life span.
• The underground construction saves
space and protects the digester from
temperature changes.
82

83. • Fluctuating gas pressure complicates gas
utilization.
• Amount of gas produced is not
immediately visible.
• Fixed dome plants need exact planning of
levels.
83

84. • A floating-drum plant consists of a
cylindrical or dome-shaped digester and a
moving, floating gas-holder, or drum.
• The gas-holder floats either directly in the
fermenting slurry or in a separate water
jacket.
• The drum in which the biogas collects has
an internal and/or external guide frame that
provides stability and keeps the drum
upright. 84

85. 85

86. • Floating-drum plants are easy to
understand and operate.
• They provide gas at a constant pressure.
• The stored gas-volume is immediately
recognizable by the position of the drum.
86

87. • The steel drum is relatively expensive and
maintenance-intensive.
• Removing rust and painting has to be
carried out regularly.
• The life-time of the drum is short
87

88. • Updraft Gasifier

89. • Downdraft Gasifier

91. Parts of a Fuel Cell
• Anode
– Negative post of the fuel cell.
– Conducts the electrons that are freed from the hydrogen molecules so that they
can be used in an external circuit.
– Etched channels disperse hydrogen gas over the surface of catalyst.
• Cathode
– Positive post of the fuel cell
– Conducts electrons back from the external circuit to the catalyst
– Recombine with the hydrogen ions and oxygen to form water.
• Electrolyte
– Proton exchange membrane.
– Specially treated material, only conducts positively charged ions.
– Membrane blocks electrons.
• Catalyst
– Special material that facilitates reaction of oxygen and hydrogen
– Usually platinum powder very thinly coated onto carbon paper or cloth.

92. Fuel Cell Operation
• Pressurized hydrogen gas (H2) enters cell on anode side.
• Gas is forced through catalyst by pressure.
– When H2 molecule comes contacts platinum catalyst, it splits into two
H+ ions and two electrons (e-).
• Electrons are conducted through the anode
– Make their way through the external circuit (doing useful work such as
turning a motor) and return to the cathode side of the fuel cell.
• On the cathode side, oxygen gas (O2) is forced through the
catalyst
– Forms two oxygen atoms, each with a strong negative charge.
– Negative charge attracts the two H+ ions through the membrane,
– Combine with an oxygen atom and two electrons from the external
circuit to form a water molecule (H2O).

93. Hydrogen Oxygen Fuel cell
http://www.news.cornell.edu/releases/Nov03/Fuelcell.institute.deb.html

94. Fuel Cells: Types
– Electrolyte Types
• Alkaline
• Polymer Electrolyte Membrane (Proton Exchange
Membrane)
• Direct Methanol
• Phosphoric Acid
• Molten Carbonate
• Solid Oxide

95. Alkaline Fuel Cell
• First AFC developed by Francis Bacon (1930s)
• In the Apollo missions
– 85% KOH
– 200-230oC
– Ni anode and NiO cathode
– Acidic fuel cells had been used, but alkaline had faster oxygen
reduction kinetics
– Fuel cells were used to provide electricity, cool the ship, and
provide potable water

96. 35%
KOH
O2
H2
H2O
OH-
Alkaline Fuel Cell
Anode: C/Pt or
C/Raney Ni/Pt
Cathode: C/Pt
H2 + 2OH-  H2O + 2e-
O2 + H2O + 2e-  HO2
- + OH-
HO2
- + H2O + 2e- 3OH-
1 A/cm2 at 0.7 V
r.t.-80oC

97. Alkaline Fuel Cell
 Advantages:
Low cost electrolyte solution (KOH 30-35%)
Non-noble catalyst withstand basic conditions
O2 kinetics faster in alkaline solution

98. Polymer Electrolyte Membrane Fuel Cell
• Used by NASA in Gemini mission
– employed polystyrene sulfonate (PSS) polymer (unstable) as electrolyte.
• Shorter side chain and only one ether oxygen
• No longer available

99. Polymer Electrolyte Membrane Fuel Cell
H2  2H+ + 2e- O2 + 2H+ + 2e-  H2O2
H2O2 + 2H+ + 2e-  H2O
Anode: C/Pt Cathode: C/Pt
Solid
polymer
85-105oC
H2 O2
H+
H2O

100. Polymer Electrolyte Membrane Fuel Cell
• Advantages:
– Nonvolatile membrane
– CO2 rejecting electrolyte

101. Direct Methanol Fuel Cell
Anode: Pt/Ru/C Cathode: Pt/C
CH3OH + H2O CO2 + 6H+ + 6e-
O2 + 2H+ + 2e-  H2O2
H2O2 + 2H+ + 2e-  H2O
85-105oC
400 mA/cm2 at 0.5V
at 60oC

102. Direct Methanol Membrane Fuel Cell
• Advantages:
– CH3OH – natural gas or biomass
– Existing infastructure for transporting petrol can be converted to MeOH
• Problems:
– High catalyst loading (1-3mg/cm2 v. 0.1-0.3 mg/cm2)
– CH3OH hazardous
– Low efficiency

103. Phosphoric Acid Fuel Cell
• Most commercially developed fuel cell
– Mainly used in stationary power plants
– More than 500 PAFC have been installed and tested around the
world
– Most influential developers of PAFC
• UTC Fuel Cells, Toshiba, and Fuji Electric

104. Phosphoric Acid Fuel Cell
Anode: Pt/C Cathode: Pt/C
H2 – 2e- = 2H+ O2 + 4H+ + 4e-  2H2O
200oC
100%
H2PO4
Si matrix
separator
PTFE binding
CH4 or H2 O2
H+
H2O

105. Phosphoric Acid Fuel Cell
• Advantages:
– H2O rejecting electrolyte
– high temps favor H2O2 decomposition
• O2 + H2O +2e-  H2O2
• Stable H2O2 lowers cell voltage and corrodes electrode
• Problems:
– O2 kinetic hindered
– CO catalyst poison at anode
– H2 only suitable fuel
– low conducting electrolyte

106. Molten Carbonate Fuel Carbonate
• Developed in the mid-20th century
• Developed because all carbonaceous fuel produce
CO2
• Using CO3
2- electrolyte eliminates need to regulate
CO3
2- build up

107. Molten Carbonate Fuel Carbonate
Anode: Ni/Al or Ni/Cr Cathode: NiO
CH4 + 2H2O  4H2 + CO2 + 4e-
H2 +CO3
2-  H2O + CO2 + 2e-
O2 + 2CO2 + 4e-  2CO3
2-
Li2CO3
and
Na2CO3
LiAlO3 used to
support
electrolyte
580-700oC
150 mA/cm2 at
0.8 V at 600oC
H2, CxH2x+2 O2, CO2
CO3
2-

108. Molten Carbonate Fuel Cell
• Advantages:
– Higher efficiency
– No noble metal catalyst (High T increases O2 kinetics)
– No negative effects from CO or CO2
• Problems:
– Materials resistant to degradation at high T
• Ni, Fe, Co steel alloys better than SS

109. Solid Oxide Fuel Cell
Cathode = La1-xSrxMnO3
ZrO2
Anode = NiO-YSZ cermet 800-1000oC
H2 + O2-  H2O + 2e- OR
CH4 + 4O2-  2H2O + CO2 + 8e-
O2 + 2e-  2O2-
Interconnector
material = Mg
or Sr doped
lanthanum
chromate
1mA at 0.7V
H2, CxH2x+2 O2
O2-

110. Solid Oxide Fuel Cell
• Advantages:
– Solid electrolyte eliminates leaks
– H2O management, catalyst flooding, slow O2 kinetic are not
problematic
• Problems:
– Severe material constraints due to high T
• Stainless steal at lower temperatures

111. Applications
Fuel cells are being developed for application
in:
Stationary power plants
Automobiles
Portable electronics
To enable mobile power source, fuel must also
be portable