This document provides an overview of renewable energy sources for an undergraduate course. It discusses the global and national energy scenario, the need for renewable energy sources, and the development and types of renewable energy sources. It also covers renewable electricity generation, climate change, the carbon reduction potential of renewable energy, and the concept of hybrid energy systems. Specific renewable sources discussed include solar, wind, hydro, geothermal, and biofuels. Limitations and advantages of different renewable technologies are also summarized.

1. Renewable Energy Sources For ECE
B.Tech. IV Year II Sem. L/T/P/C
Course Code:
Name of The Faculty:
Dr. P. Badari Narayana
M.Tech (Energy Systems), P.hD.,
Associate Professor,
Dept. of Mechanical Engg.
Renewable Energy Sources Unit I * Part I
Topic:
Introduction to Renewable Sources
of Energy

2. Syllabus * Unit I
• Global and National Energy Scenario
• Overview of Conventional and RES
• Need for RES
• Devpt & Types RES
• Future of Energy Use
• Energy For Sustainable Devpt
• Potential of RES
• RE Electricity and Key Elements
• Global Climate Change
• CO2 Reduction Potential of Renewable Energy
• Concept of Hybrid Systems

7. Niti Ayog - Figures

8. • CO2 is at 407ppm (Oct
2018) increased by 90ppm
in the last 70 years
• Global warming ~1.1°C in
the past 200 years
• Ocean acidification
• Rising sea level ~3.2mm
each year
• Decreasing ice sheet mass
• Retreating glaciers
• Decreasing Arctic ice at a
rate of 13% each decade
Renewable energy is crucial for mitigating climate change

11. Renewables share of power generation
Renewable energy
0%
5%
10%
15%
20%
25%
30%
1995 2010 2025 2040
Geothermal
and biomass
Solar
Wind
Fuel shares in power
0%
10%
20%
30%
40%
50%
2000 2010 2020 2030 2040
Gas
Coal
Renewables
Hydro & Nuclear
2019 BP Energy
Outlook
© BP p.l.c. 2019

14. • R is the total yearly energy requirement for a population of N
people.
E is the per capita energy-use averaged over one year, related
closely to provision of food and manufactured goods.
•
On a world scale, the dominant supply of energy is
from commercial sources, especially fossil fuels;
• significant use of non-commercial energy may occur (e.g. fuel
wood, passive solar heating),
• total commercial energy use, the average per capita value of E
worldwide is about 2 kW; however, regional average values range
widely, with North America 9 kW, Europe as a whole 4 kW, and
several regions of Central Africa as small as 0.1 kW , 1 kW in India

15. Renewable energy. ‘Energy obtained from natural and persistent
flows of energy occurring in the immediate environment’.
An obvious example is solar (sunshine) energy, where ‘repetitive’
refers to the 24-hour major period. Note that the energy is already
passing through the environment as a current or flow, irrespective
of there being a device to intercept and harness this power. Such
energy may also be called Green Energy or Sustainable Energy.
Non-renewable energy. ‘Energy obtained from static stores of
energy that remain underground unless released by human
interaction’.
Examples are nuclear fuels and fossil fuels of coal, oil and natural
gas. Note that the energy is initially an isolated energy potential,
and external action is required to initiate the supply of energy for
practical purposes. To avoid using the ungainly word ‘non-
renewable’, such energy supplies are called finite supplies or Brown
Energy.

19. Energy flow diagrams for Austria in 2000
Primary supply to end-use

21. India

23. LAWS OF CONSERVATION
LAWS OF THERMODYNAMICS

24.  The internal energy of an isolated system is constant.
 A closed system may exchange energy as heat or work. Let us consider a close system at
rest without external fields.
 There exists a state function U such that for any process in a closed system:
dq = U + dw [1]
 q → heat flow in to the system
 w → work done on the system (work done by the system is negative of above- this is just ‘one’ sign convention)
q & w are not state functions → i.e. they depend on the path of a process.
 U is the internal energy. Being a state function for a process U depends only of the final
and initial state of the system. U = Ufinal – Uinitial. In contrast to U, q & w are NOT state
functions (i.e. depend on the path followed).
The Laws of Thermodynamics The First Law

25.  It is impossible to build a cyclic machine* that converts heat into work with 100%
efficiency  Kelvin’s statement of the second law.
 Another way of viewing the same:
it is impossible to construct a cyclic machine** that completely (with 100% efficiency)
converts heat, which is energy of random molecular motion, to mechanical work, which is
ordered motion.
 The unavailable work is due to the role of Entropy in the process.
The Second Law
Heat reservoir Cyclic engine
Heat q
Work (w)100%
Not possible
Heat reservoir Cyclic engine
Heat q
Work (w)
Cold Reservoir
Heat q’


Kelvin’s
statement of the
second law
The second law comes in many equivalent forms
* For now we are ‘building’‘conceptual machines’!
** These ‘engines’ which use heat and try to produce work are called heat engines.
Called the sink
Possible
Called the source G
T SH

28. RE Electricity and
Key Elements

29. Electricity

31. Source Installed Capacity (MW) Share
Coal 194,489.50 54.17%
Large hydro 45,399.22 12.64%
Other renewables 80,467.22 22.41%
Gas 24,937.22 6.90%
Diesel 637.63 0.24%
Nuclear 6,780.00 1.97%
Total 358970.78 100.00%
Grid connected installed capacity from all sources as of 30 June 2019[17]

45. CO2 reduction Potential of
Renewable Energy

46. RE Sources of Energy
• Solar Energy
• Wind Energy
• Nuclear Energy
• Hydro Electric Power
• Geothermal Energy
• Biofuel and biomass energy sources

47. Solar Energy

48. MAJOR SYSTEM COMPONENTS
• SOLAR PV PANEL - IT CONVERTS LIGHT ENERGY TO ELECTRICAL ENERGY
• INVERTER – IT CONVERTS DC POWER TO AC POWER
• BATTERY – IT STORES THE ELECTRICAL ENERGY
• DISTRIBUTION BOXES – IT DISTRIBUTES THE ENERGY TO LOAD
• GRID SUPPLY – TO FEED EXTRA POWER CONVERTED

49. Solar PV Module
• The output from a solar module depends upon some conditions
such as ambient temperature and intensity of incidence light.
Hence the rating of a solar module must be specified under such
conditions. It is standardized practice to express rating of PV or
solar module at 25oC temperature and 1000 w/m2 light radiation.
The solar modules are rated with their output open circuit voltage
(Voc), short circuit current (Isc) and peak power (Wp).
• That means these three parameters (Voc, Isc and Wp) can be
delivered by a solar module safely at 25oC and 1000 w/m2 solar
radiations.
These conditions i.e. 25oC temperature and 1000 w/m2 solar
radiations are collectively called Standard Test Conditions.
The Standard Test Conditions may not be available at site where the
solar modules to be installed. This is because the solar radiations
and temperature vary with location and time.

50. V-I Characteristic of Solar Module
If we draw a graph by taking X-axis as
voltage axis and Y-axis as currents of a solar
module, then the graph will represent V-I
characteristic of a solar module.

52. Layers in SPV Module

53. WHAT IS BATTERY ANY WHY IT IS REQUIRED?
• Batteries:
– It is an electrical energy storage device.
– It is a electrochemical device.
– It stores electrical energy in the form of chemicals.
• Required to:
— store charge for long time
— accept charging at any time
— discharge at any time
— Ready to use
— Eco-Friendly & User friendly
— Cheaper

54. Schematic

55. Merits & Demerits of Solar Power Plants
• Merits – Clean Energy, Pollution is Zero, Cheap Power to buy,
Easy to Install & Maintain
• Demerits – Commercial scale – subsidies required to reduce
Paybacks, Industrial Scale – Require 5 Acre/ MW, Limited by
the Solar Resource, Current produced will reduce during
Cloudy scenario, Cleaning Problem, Offgrid Battery systems
are very costly.

56. Wind Energy Conversion Systems
Principal components of most wind energy conversion systems.
Source: Masters, Gilbert M. Renewable and Efficient Electric Power Systems, 2nd Edition. Wiley-Blackwell,
21/06/2013.

60. • Environmental benefits
• No emissions
• No fuel needed
• Distributed power
• Remote locations

61. Limitations of Wind Power
 Power density is very low.
 Needs a very large number of wind mills to produce
modest amounts of power.
 Cost.
 Environmental costs.
 material and maintenance costs.
 Noise, birds and appearance.
 Cannot meet large scale and transportation
energy needs.

62. Nuclear Power
This prime mover uses the heat energy of atoms by fission or fusion process to
develop the
mechanical power. Uranium is another non-renewable source, but it is not a
fossil fuel. Uranium is converted to a fuel and used in nuclear power plants
➔ The energy can be released through either of the two processes: Nuclear
Fission or Nuclear Fusion.
➔ Nuclear fission: It is the most common technique to harness nuclear energy.
During nuclear fission, a neutron collides with a uranium atom and splits it,
releasing a large amount of energy in the form of heat and radiation. More
neutrons are also released when a uranium atom split. These neutrons continue
to collide other uranium atoms, and the process repeats itself over and over
again. This process is called a nuclear chain reaction. This reaction is controlled
in nuclear power plant reactors to produce a desired amount of heat
➔ Like fossil fuels, nuclear does not produces any greenhouse emissions.
Nuclear power plants produce some sort of nuclear waste called radioactive
elements.

63. ➔ Nuclear fusion: In fusion process, where atoms are combined or
fused together to form
a larger atom. During the process, an extremely small fraction of mass is
converted into energy, which is in the form of heat at high temperature.
➔ Nuclear fusion reactions are also called thermonuclear reactions

64. The main components of this station are nuclear reactor, control rods,
steam generators, steam turbine, coolant pump, feed pump, condenser,
cooling tower.
Nuclear Reactor: - A nuclear reactor is a device in which nuclear chain
reactions are initiated, controlled, and sustained at a steady rate, as
opposed to a nuclear bomb, in which the chain reaction occurs in a
fraction of a second and is uncontrolled causing an explosion.
Control Rods: - Control rods made of a material that absorbs neutrons
are inserted into the bundle using a mechanism that can rise or lower
the control rods. The control rods essentially contain neutron
absorbers like, boron, cadmium or indium.
Steam Generators: - Steam generators are heat exchangers used to
convert water into steam from heat produced in a nuclear reactor core.
Either ordinary water or heavy water is used as the coolant.

65. Steam Turbine: - A steam turbine is a mechanical device that extracts
thermal energy from pressurized steam, and converts it into useful
mechanical. Various high-performance alloys and super alloys have been
used for steam generator tubing.
Coolant Pump: - The coolant pump pressurizes the coolant to pressures
of the order of 155bar. The pressure of the coolant loop is maintained
almost constant with the help of the pump and a pressurizer unit.
Feed Pump: - Steam coming out of the turbine, flows through the
condenser for condensation and recirculated for the next cycle of
operation. The feed pump circulates the condensed water in the working
fluid loop.
Condenser: - Condenser is a device or unit which is used to condense
vapor into liquid. The objective of the condenser is to reduce the turbine
exhaust pressure to increase the efficiency and to recover high quality
feed water in the form of condensate & feedback it to the steam
generator without any further treatment.
Cooling Tower: - Cooling towers are heat removal devices used to
transfer process waste heat to the atmosphere. Water circulating
through the condenser is taken to the cooling tower for cooling and
reuse.

66. ➔ Advantages:
i. Nuclear power generation does emit relatively low amounts of carbon
dioxide (CO2).
ii. The emissions of greenhouse gases and therefore the contribution of
nuclear power plants to
global warming is therefore relatively little.
iii. This technology is readily available, it does not have to be developed
first.
iv. It is possible to generate a high amount of electrical energy in one
single plant.
➔ Disadvantages:
i. The problem of radioactive waste is still an unsolved one.
ii. High risks: It is technically impossible to build a plant with 100%
security.
iii. The energy source for nuclear energy is Uranium. Uranium is a scarce
resource; its supply is
estimated to last only for the next 30 to 60 years depending on the actual
demand.

67. Renewable Energy (non-conventional) Energy Sources: Renewable sources
of energy can be used over and over again. Renewable resources include solar
energy, wind, geothermal energy, biofuel and hydropower. They generate much
less pollution, both in gathering and production, than non-renewable sources.
➔ Advantages:
i. Non-exhaustible.
ii. Can be matched in scale to the need and can deliver quality energy.
iii. Can be built near the load point.
iv. Flexibility in the design of conversion systems.
v. Local self-sufficiency by harnessing locally available renewable energy.
vi. Except biomass, all other sources are pollution free.
Disadvantages:
i. Intermittent nature of availability of energy such as solar, wind, tidal etc. is a
major setback in the continuous supply of energy Solar energy received at the
earth is dependent on local atmosphere conditions, time of the day, part of the
year etc.
iii. Sources such as wind, tidal etc. are concentrated only in certain regions.
iv. Technology is not fully developed to meet the present energy requirements.
v. Systems such as solar cells require advanced technologies and hence costlier.
vi. Application to transport sector has been found to be not viable as on today

68. 1) Hydel: Water is one of the oldest sources of energy for producing
mechanical and electrical
energy. Dams and rivers generate electricity.
➔ The total power generation capacity of the hydroelectric power
plants depends on the head
of water and volume of water flowing towards the water turbine
HYDRO ELECTRIC POWER PLANTS

69. ➔ Water is stored at high elevation contains potential energy.
➔ To generate electricity, water must be in motion.
➔ When water starts flowing, potential energy gets converted to
kinetic (moving) energy.
➔ When flowing water turns blades in a turbine, the form is
changed to mechanical (machine) energy.
➔ The turbine turns the generator rotor which then converts
this mechanical energy into another energy form - electricity.
➔ After doing useful work water is discharged from the turbine
to the river through a water to the tail race through a draft tube.
➔ Since water is the initial source of energy, we call this
hydroelectric power or hydropower.
Merits: - Environmental friendly source, large scale power
generation, energy at free of cost.
➔ Demerits: - expensive to build the dam, summer water may
not sufficient to produce
electricity.

70. 4) Geothermal: The term geothermal energy refers to the harnessing of heat
from underground sources ranging from the volcanoes, hot springs, and geysers
beneath the Earth. Applications can be broadly divided into three categories:
power generation, direct heating, and ground source heating and cooling.
➔ The geothermal gradient, which is the difference in temperature between the
core of the planet and its surface, drives a continuous conduction of thermal
energy in the form of heat from the core to the surface.
➔ Geothermal power is cost effective, reliable, sustainable, and environmentally
friendly, but has historically been limited to areas near tectonic plate
boundaries.
Geothermal Energy

71. Geothermal Energy
From the surface down through the crust, the normal temperature gradient - the
increase of temperature with the increase of depth - in the Earth's crust is 17 °C -- 30
°C per kilometer of depth

73. 5) Bio-fuel: Biofuels are energy sources that are produced from biomass - the
living matter of plants or organic waste. As an energy source, biomass can
either be used directly via combustion to produce heat, or Indirectly after
converting it to various forms of biofuel.
➔ This biomass may be transformed by physical, chemical and biological
processes to biofuels.
➔ In chemical forms biomass is stored solar energy and can be converted into
solid, liquid and gaseous energy.
➔ A variety of fuels can be produced from biomass resources including liquid
fuels, such as ethanol, methanol, biodiesel and gaseous fuels, such as hydrogen
and methane. The biomass resource base for biofuel production is composed
of a wide variety of forestry and agricultural resources, industrial processing
residues, and municipal solid and urban wood residues.
BIOMASS ENERGY

75. • Advantages
– Versatile
– Renewable
– No net CO2 emissions (ideally)
– Emits less SO2 and NOx than fossil fuels
• Disadvantages
– Low energy density/yield
• In some cases (eg, corn-derived bioethanol) may yield no net energy
– Land conversion
• Biodiversity loss
• Possible decrease in agricultural food productivity
– Usual problems associated with intensive agriculture
• Nutrient pollution
• Soil depletion
• Soil erosion
• Other water pollution problems

76. There are many different types of biofuels and the majority used around the
world today can be classified as first-generation biofuels.
➔ First-generation biofuels are made from sugar, starch, vegetable oil, or
animal fats using conventional technology. The basic feedstock for the
production of first-generation biofuels come from agriculture and food
processing.
• Bioethanol: Plant sugars or starches of biofuel crops, such as sugar cane and
maize, are fermented to produce ethanol. Ethanol can be blended with
gasoline fuel in quantities of 5-10% for use in normal cars – higher
percentages of ethanol need specially adapted cars.
• Biodiesel (or bio-esters): They are produced by a chemical reaction
between vegetable oil and alcohol, using the oily seeds of rapeseed or
soybean. Biodiesel shares similar properties to diesel and so can be easily
mixed. Vegetable oils may be burned directly in modified diesel engines
Bio-oil: Thermo-chemical conversion of biomass. A process still in the
development phase.
• Biogas: Anaerobic fermentation or organic waste, animal manures, crop
residues an energy crops applied as fuel in engines suitable for compressed
natural gas