RES UNIT-1 PPT-suresh.pdf

M.SURESH M.Tech(NITW).,(Ph.D)
Associate Professor
EEE Department
RISE KRISHNA SAI PRAKASAM GROUP OF INSTITUTIONS
Vallur, Ongole, Prakasam (Dt), AP
UNIT– I
Fundamentals of Energy Systems
&
Solar energy

RES- Course Outcomes
After the completion of the course the student should be able to:
M.SURESH, EEE Dept
CO No. Outcome BT Level
C413.1
Analyze solar radiation data, extraterrestrial
radiation, and radiation on earth’s surface.
Analyzing
C413.2 Design solar photo voltaic systems. Analyzing
C413.3
Develop maximum power point techniques in
solar PV and wind energy systems.
Analyzing
C413.4
Explain wind energy conversion systems, wind
generators, power generation.
Understanding
C413.5
Explain basic principle and working of hydro, tidal,
biomass, fuel cell and geothermal systems
Understanding
3

UNIT–I: Fundamentals of Energy Systems
and Solar energy
• Energy conservation principle
• Energy scenario (world and India)
• various forms of renewable energy
• Solar radiation: Outside earth’s atmosphere
• Earth surface
• Analysis of solar radiation data
• Geometry-Radiation on tilted surfaces
• Numerical problems.
M.SURESH, EEE Dept 4

Introduction to Energy
• Any physical activity in this world whether by human beings or by nature,
is caused due to flow of energy in one form or the other.
• Energy is required to do any kind of work.
• The word ‘energy’ itself is derived from Greek word ‘en-ergon’, which
means ‘in-work’ or ‘work content’.
• The work output depends on the energy input and the capability to do
work depends on the amount of energy one can control and utilize.
• Energy can be neither be created nor be destroyed but it can transfer from
one form to the another form.
• Energy is required for economic growth & development of a country.
• Before the industrial revolution which began around 200 years ago people
depends on manual & animal labour.
• Life was simple and with limited demands, and the environment was
relatively clean.
• Later on, he started using animal power to supplement manual energy to
enhance his work output.
• Gradually, he learnt harnessing energy from wind and falling water to
further enhance the work output.

• In 1785, the invention of steam engine by James Watt of Scotland brought
industrial revolution.
• It was the beginning of mechanical age or age of machines.
• Though increase in energy consumption had been gradual throughout the
history, however, post industrialization the rate of consumption showed
dramatic increase over a period of just a few generations.
• Internal combustion engine in the late nineteenth century gave further
momentum to the trend.
• Gradually, industrial revolution spread to the whole world.
• In 1888, Nickola Tesla invented commercial induction motor.
• The introduction of electrical machines along with commercial availability of
electrical power started the new electrical age.
• All this led to increase of energy requirement by leaps and bounds.
• Energy has been the life-blood for continual progress of human civilization.
• Thus, with progress of human civilization the energy consumption also
accelerated.

Fig(1): Energy use with progress of human civilization

• Energy is most important input for economic growth and human
development and to fulfilling basic social needs.
• This is because energy services have an effect on productivity, health,
education, safe and potable water and communication services.
• Modern services such as electricity, natural gas, modern cooking fuel and
mechanical power are necessary for improved health and education,
better access to information and industrial as well as agricultural
productivity.
• Thus, secure, reliable, affordable, clean and equitable energy supply is
fundamental to global economic growth and human development.
• In world, at present is that approximately 1.2 billion people live without
any access to modern energy services.
• Access to energy is a fundamental pre-requisite for modern life and a key
tool in eradicating extreme poverty across the globe.
Energy, Economy and Social Development

• Broadly, there are four major energy end use sectors:
 Commercial
 Industrial
 Residential
 Transportation
• As energy is main driving force in all the sectors, consumption of large
amount of energy in a country indicates more activities in these sectors.
• That implies better comfort at home due to use of various appliances of
comfort, better transport facilities and more agricultural and industrial
production.
• All this amounts to better quality of life.
• Therefore, the per capita energy consumption of a country is an index of
standard of living or prosperity of the people of the country.
• In Table 1.1, the comparative data of annual primary energy consumption
and GDP(Gross domestic product) of some countries are given to
emphasize this point.

• Sector wise Energy Consumption Pattern
Sectors International Level International Level State Level
Industry 51.7% 29% 25%
Transport 26.6% 30% 0.6%
Domestic 13.95 27% 49%
Commercial 7.8% 9% 17%
Others 0 5% 8.4%

Country
Per Capita Primary Energy Consumption
in KGOE (kg of oil equivalent) (year 2013)
Per Capita GDP in USD
(year 2014)
USA 6,909 54,629
Germany 3,874 47,624
UK 2,967 45,603
Japan 3,560 36,194
China 2,143 7,593
India 637 1630
Global
Average
1,919 (year 2012) 13,100 (year 2013)
Table 1: Annual Primary Energy Consumption and GDP of selected countries
• In Table-1, the comparative data of annual primary energy consumption
and GDP(Gross domestic product) of some countries are given to
emphasize this point.

Classification of Energy Sources
 Based on Usability of Energy
 Primary resources
 Secondary Resources
 Based on Traditional Use
 Conventional Energy resources
 Non-conventional Energy resources
 Based on Long-Term Availability
 Non-renewable Resources,
 Renewable energy
 Based on Commercial Application
 Commercial Energy Resource
 Non-commercial Energy
 Based on origin
 Fossil fuels energy
 Nuclear energy
 Hydro energy
 Solar energy
 Wind energy
 Biomass energy
 Geothermal energy
 Tidal energy
 Ocean thermal energy
 Ocean wave energy
• Energy resources can be classified on the basis of following criteria:

• Primary resources: These include resources embodied in nature prior to
undergoing any human-made conversions or transformations.
• This only involves extraction or capture.
• Examples: coal, crude oil, sunlight, wind, running rivers, vegetation and
radioactive material like uranium etc.
• These are available in raw forms and are, known as raw energy resources.
• Generally, this form of energy cannot be used as such.
• These are located, explored, extracted, processed and are converted to a form
as required by the consumer.
• Thus some energy is spent in making the resource available to the user in a
usable form.
• The energy yield ratio of an energy extraction process is defined as follows:
• Secondary Resources: The energy resources supplied directly to consumer for
utilization after one or more steps of transformation are known as secondary
or usable energy,
• Examples: electrical energy, thermal energy (in the form of steam or hot
water), refined fuels or synthetic fuels such as hydrogen fuels, etc.
Classification of Energy Sources: Based on Usability of Energy

Classification of Energy Sources: Based on Usability of Energy

• The global average consumption trend of various primary energy
resources of the world is indicated in Fig.(2), though the trend differs from
one country to another.
• Looking at this figure, the heavy dependence on fossil fuels stands out
clearly.
• About 82 per cent of the world’s energy supply comes mainly from fossil
fuels.
Consumption Trend of Primary Energy Resources
Fig(2): Percentage consumption of various
primary energy resources

• Based on Traditional Use:
• Conventional Energy resources, which are being traditionally used, for
many decades and were in common use around oil crisis of 1973, are called
conventional energy resources,
• Examples: fossil fuels, nuclear and hydro resources.
• Non-conventional Energy resources, which are considered for large-scale
use after the oil crisis of 1973, are called non-conventional energy sources.
• Examples: solar, wind, biomass, etc.

• Based on Long-Term Availability
• Non-renewable Resources, which are finite and do not get replenished
after their consumption, are called non-renewable
• Examples: fossil fuels, uranium, etc.
• They are likely to deplete with time.
• Renewable energy is energy obtained from sources that are essentially
inexhaustible.
• Examples: wind power, solar power, geothermal energy, tidal power and
hydroelectric power.
• The most important feature of renewable energy is that it can be harnessed
without the release of harmful pollutants.

• Based on Commercial Application:
• Commercial Energy Resource The energy sources that are available in the
market for a definite price are known as commercial energy.
• By far the most important forms of commercial energy are electricity, coal
and refined petroleum products.
• Commercial energy forms the basis of industrial, agricultural, transport
and commercial development in the modern world.
• In the industrialized countries, commercialized fuels are predominant
sources not only for economic production, but also for many household
tasks of general population.
• Examples: Electricity, lignite, coal, oil, natural gas etc
• Non-commercial Energy The energy sources that are not available in the
commercial market for a price are classified as non-commercial energy.
• Non-commercial energy sources include fuels such as firewood, cattle
dung and agricultural wastes, which are traditionally gathered, and not
bought at a price, used especially in rural households.
• Non-commercial energy is often ignored in energy accounting.
• Examples: firewood, agro waste in rural areas, solar energy for water
heating, animal power for transport, irrigation and crushing of sugarcane,
etc.

• Based on origin:
• Fossil fuels energy
• Nuclear energy
• Hydro energy
• Solar energy
• Wind energy
• Biomass energy
• Geothermal energy
• Tidal energy
• Ocean thermal energy
• Ocean wave energy

Importance of Non-Conventional Energy Sources
• The concern for environment due to ever-increasing use of fossil fuels and rapid
depletion of these resources has led to development of alternative sources of
energy, which are renewable and environment friendly.
• Following points may be mentioned in this connection:
 Conventional sources (except hydro) are non-renewable and finite assets. With
present rate of consumption their availability is rapidly declining.
 The demand of energy is increasing exponentially due to rapid industrialization
and population growth, the conventional sources of energy alone will not be
sufficient in the long run, to meet the growing demand.
 Conventional sources (fossil fuels, nuclear) also cause pollution leading to
degradation of the environment. Ultimately, their use has to be restricted within
acceptable limits.
 Large hydro resources affect wild life, cause deforestation and pose various social
problems.
 In addition to supplying energy, fossil fuels are also used extensively as feedstock
for the manufacture of organic chemicals. As reserves deplete, the need for
using fossil fuels exclusively for such purposes may become greater.
• Due to these reasons it has become important to explore and develop
nonconventional energy resources to reduce too much dependence on
conventional resources.

Energy Chain
• Generally, we cannot use the energy available from primary energy
sources directly.
• For example we cannot drive an electric motor from uranium or coal.
• The energy available from primary energy source is known as raw energy.
• This energy undergoes one or more transformation stages before
supplying to consumer.
• The sequence of energy transformations between primary and secondary
energy (usable energy) is known as energy chain or energy route.

Common Forms of Energy
Electrical Energy:
• Electrical energy is considered to be the top grade energy.
• It is used universally as vehicle of energy.
• About 30–40% energy distribution in the world is met through electrical supply system at present.
• It can be very conveniently and efficiently converted to other forms of energy.
Mechanical Energy:
• Mechanical energy is required for movement of objects, changing the shape of the
• objects, etc.
• It is used in transportation, agriculture, handling, processing, and other industrial processes.
Thermal Energy:
• Thermal energy is considered to be of lower grade as compared to electrical and mechanical energy.
• It is used to raise the temperature of an object during industrial processes.
• It can also be converted to mechanical energy with the help of heat engines.
• There are three grades of thermal energy depending on the temperature at which it available:
 High grade (500–1000 °C and higher): It can be converted efficiently into mechanical energy.
 Medium grade (150–500 °C): It can be converted into mechanical energy with difficulty and with lower
efficiency.
 Low grade (80-50 °C): It cannot be ordinarily converted into mechanical energy and used mostly for the
purpose of heating only.
Chemical Energy:
• Fuels and organic matter contain chemical energy. Exothermic chemical reactions release heat energy.
• Also chemical energy is directly converted into electrical energy in fuel cells, storage batteries, etc. and
into thermal energy by combustion.

Advantages & Disadvantages of Conventional
Energy Sources
• Fossil fuels, nuclear and hydro resources are considered as conventional
sources.
• There use has following advantages and disadvantages.
Advantages
• Cost : At present these are cheaper than non-conventional sources.
• Security : As storage is easy and convenient, by storing certain quantity,
the energy availability can be ensured for certain period.
• Convenience: These sources are very convenient to use as technology for
their conversion and use is universally available.

Disadvantages
• Fossil fuels generate pollutants. These pollutants degrade the environment, pose
health hazards and cause various other problems and for global warming also.
• Coal is also a valuable petro-chemical and is used as raw material for various
chemical, pharmaceuticals and paints, etc. industries.
• There are safety and technical issues with nuclear energy. Major problems
associated with nuclear energy are as follows:
 The waste material generated in nuclear plants has radioactivity of dangerous level;
it remains above safe limit for a long period of time and thus is a health hazard.
 Possibility of accidental leakage of radioactive material from reactor.
 Uranium resource, for which the technology presently exists, has limited
availability.
 Sophisticated technology is required for using nuclear resources. Only few countries
possess the required expertise to use nuclear energy.
• Hydroelectric plants are cleanest but large hydro-reservoirs cause following
problems:
 As large land area submerges into water, it leads to deforestation
 Causes ecological disturbances such as earthquakes
 Affects wild life
 Causes dislocation of large population and their rehabilitation problems
Advantages & Disadvantages of Conventional
Energy Sources

Salient Features of Non-conventional Energy Sources
Merits
• Non-conventional sources are available in nature free of cost.
• They produce no or very little pollution. Thus by and large they are
environment friendly.
• They are inexhaustible.
• They have low gestation period.
Demerits
• In general the energy is available in dilute form from these sources.
• Though available freely in nature the cost of harnessing energy from
nonconventional sources is generally high.
• Uncertainty of availability: the energy flow depends on various natural
phenomena beyond human control.
• Difficulty in transporting this form of energy.
• Difficulty in storage.

World Energy Status
• Present Situation
• The world annual primary energy supply and consumption along with
electricity generation are given in Table(3).
• The primary energy supply differs from the final energy consumption
because much of the energy that is acquired by humans is lost as other
forms of energy during the process of its refinement into usable forms of
energy and its transport from its initial place of supply to consumers.
• In 2012, the world annual primary energy consumption was 8,979 MTOE.
• Fossil fuels roughly provide about 82% of this energy and will continue to
provide more than 80 per cent of the total energy demand well into the
future. Approximately 28% of this energy is consumed in transportation
sector and remaining 72% by industries, domestic, agriculture and social
consumers.

Energy demand-2021-WORLD
Energy demand
(quadrillion BTUs, unless otherwise noted)
Average annual
change
% change
Share of total
2019 2019
Energy by Region 2000 2010 2019 2020 2025 2030 2040 2050 2050 2050 2019 2050
World 405 512 576 541 601 626 651 659 0% 14% 100% 100%
OECD 220 224 221 202 218 217 206 194 0% -12% 38% 29%
Non OECD 185 288 355 339 383 409 445 464 1% 31% 62% 71%
Africa 22 29 36 34 39 44 53 62 2% 74% 6% 9%
Asia Pacific 122 199 248 237 266 283 300 306 1% 23% 43% 46%
China 46 100 131 128 142 146 148 143 0% 9% 23% 22%
India 18 27 37 34 42 48 58 65 2% 78% 6% 10%
Europe 77 80 76 70 75 72 67 61 -1% -19% 13% 9%
European Union 61 64 59 54 57 55 50 45 -1% -24% 10% 7%
Latin America 19 25 27 24 28 31 34 36 1% 36% 5% 6%
Middle East 17 28 35 34 38 41 46 49 1% 38% 6% 7%
North America 111 109 111 101 111 112 109 105 0% -6% 19% 16%
United States 94 91 91 83 91 91 87 82 0% -10% 16% 13%
Russia/Caspian 37 42 42 41 43 43 42 40 0% -6% 7% 6%
OECD - Organization for Economic Co-operation and Development
Non-OECD - Not a member of the Organization for Economic Co- operation and Development.
BTUs- British thermal unit

Energy demand-2021-WORD
ENERGY BY TYPE– World
Average annual
change
% change
Share of total
2019 2019
Energy by type 2000 2010 2019 2020 2025 2030 2040 2050 2050 2050 2019 2050
Primary 405 512 576 541 601 626 651 659 0% 14% 100% 100%
Liquids 147 166 185 166 193 199 205 208 0% 12% 32% 32%
Oil 147 164 181 163 188 193 197 199 0% 10% 31% 30%
Natural gas 89 115 139 136 155 164 176 185 1% 33% 24% 28%
Coal 91 140 146 135 136 133 116 92 -1% -37% 25% 14%
Nuclear 27 29 29 28 31 35 40 40 1% 38% 5% 6%
Biomass/Waste 40 45 50 48 51 52 52 52 0% 5% 9% 8%
Hydro 9 12 15 14 15 16 18 20 1% 36% 3% 3%
Other
Renewables
3 7 16 17 25 33 52 72 5% 343% 3% 11%
Geothermal 2 2 4 4 5 5 6 7 2% 82% 1% 1%
Wind 0 1 5 5 9 12 21 30 6% 516% 1% 5%
Solar 0 1 4 4 7 10 17 26 6% 577% 1% 4%
Biofuels 0 2 4 4 5 6 8 9 3% 148% 1% 1%

SECTOR WISE DEMAND -WORLD
Average annual
change
% change
Share of total
2019 2019
Sectors 2000 2010 2019 2020 2025 2030 2040 2050 2050 2050 2019 2050
Residential and commercial
Total 95 109 118 116 124 128 135 139 1% 17% 100% 100%
Oil 13 12 12 11 11 10 10 9 -1% -22% 10% 7%
Natural gas 21 24 28 27 29 29 29 28 0% 0% 23% 20%
Biomass/Waste 29 30 28 27 28 27 26 24 0% -13% 24% 18%
Electricity 23 32 39 38 45 51 60 67 2% 74% 33% 49%
Other 10 11 12 12 12 11 11 10 -1% -17% 10% 7%
Transportation
Total 77 95 115 99 124 130 136 142 1% 24% 100% 100%
Oil 76 91 108 92 114 117 116 112 0% 4% 94% 79%
Biofuels 0 2 4 4 5 6 8 9 3% 148% 3% 7%
Natural gas 0 1 2 2 3 4 5 7 4% 242% 2% 5%
Electricity 1 1 1 1 2 3 7 12 7% 795% 1% 8%
Other 1 1 1 1 2 4 8 14 8% 943% 1% 10%
Industrial
Total 144 194 218 208 224 234 246 247 0% 14% 100% 100%
Oil 45 50 54 52 57 60 68 74 1% 38% 25% 30%
Natural gas 37 44 54 52 58 61 65 66 1% 22% 25% 27%
Coal 26 52 49 45 44 44 41 32 -1% -36% 23% 13%
Electricity 22 31 40 39 44 47 53 59 1% 48% 18% 24%
Other 14 17 20 19 20 21 19 17 -1% -18% 9% 7%

Power generation -WORLD
Average annual
change
% change
Share of total
2019 2019
Primary 145 190 219 209 233 248 265 279 1% 28% 100% 100%
Oil 14 11 8 7 6 5 4 4 -3% -55% 4% 1%
Natural gas 31 46 55 54 65 70 77 85 1% 53% 25% 30%
Coal 61 84 93 86 88 86 73 59 -1% -36% 42% 21%
Nuclear 27 29 29 28 31 35 40 40 1% 38% 13% 14%
Hydro 9 12 15 14 15 16 18 20 1% 36% 7% 7%
Wind 0 1 5 5 9 12 21 30 6% 516% 2% 11%
Solar 0 0 2 3 5 8 15 22 7% 823% 1% 8%
Other
Renewables
4 7 12 12 14 15 17 20 2% 62% 6% 7%
Electricity demand (terawatt hours)
World 13224 18595 23476 23015 26714 29753 35132 40586 2% 73% 100% 100%

Energy demand-2021-WORD
GDP by region (2015$, trillions)
Average annual
change
% change
Share of total
2019 2019
GDP 2000 2010 2019 2020 2025 2030 2040 2050 2050 2050 2019 2050
World 48 65 84 81 100 115 149 189 3% 124% 100% 100%
OECD 36 43 51 48 57 63 74 87 2% 71% 60% 46%
Non OECD 12 22 33 33 42 52 75 102 4% 205% 40% 54%
Africa 1 2 3 3 3 4 5 7 3% 185% 3% 4%
Asia Pacific 11 19 30 29 38 46 65 87 4% 194% 35% 46%
China 3 8 15 15 20 25 37 50 4% 241% 17% 26%
India 1 2 3 2 4 5 8 13 5% 370% 3% 7%
Europe 15 17 20 19 22 24 28 32 1% 57% 24% 17%
European
Union
11 13 15 14 16 17 20 22 1% 50% 17% 12%
Latin America 3 4 4 4 5 5 7 9 2% 111% 5% 5%
Middle East 1 2 3 2 3 3 5 6 3% 135% 3% 3%
North America 16 19 23 22 26 29 36 43 2% 89% 27% 23%
United States 14 16 20 19 23 26 31 38 2% 89% 24% 20%
Russia/Caspian 1 2 2 2 2 3 3 4 2% 86% 2% 2%

Global Energy Demand By Sector -Primary energy –
quadrillion BTUs

Energy demand led by non-OECD-
Primary energy – quadrillion BTUs

Global energy mix shifts to lower-carbon fuels

• Oil continues to play a leading role in the world’s energy mix, with growing
demand driven by commercial transportation and feed stocks for the
chemicals industry.
• Natural gas grows the most of any energy type, reaching almost 30% of all
demand.
• Renewable and nuclear see strong growth, contributing around 55% of
incremental energy supplies to meet demand growth.
• Coal use remains significant in parts of the developing world, but drops
below15% global share as China and OECD nations transition toward
lower-emission sources like renewables, nuclear and natural gas.
• Electricity, an energy carrier and not an energy source, grows
approximately four times faster than overall energy demand.
Global energy mix shifts to lower-carbon fuels

Future energy mix has a large range of potential
outcomes- Share(%) by fuel type within primary
energy mix in 2050

• It is important to understand how the Outlook is developed, how Scenarios are developed, and how
Outlook and Scenarios are used. Learn more about how we develop the Outlook and how we use
scenarios.
• The IEA’s Stated Policies Scenario reflects current policy settings based on a sector-by-sector
assessment of the specific policies that are in place, as well as those that have been announced by
governments around the world.
• It offers arelevant scenario to compare and contrast with ExxonMobil’s Outlook.
• The IPCC Lower 2°C and the IEA Net Zero by 2050 scenario, are scenarios that are targeting more
stringent climate goals, aligned with the Paris Agreement.
• There is a wide range of potential outcomes under the IPCC’s Lower 2°C scenarios, as many of the
required technologies will require innovation and policy support to accelerate deployment.
• By 2050, the current sources all still play a role in the global energy mix:
• Oil and gas remain important contributors to the energy system.
• In most of the scenarios, coal use declines more than the Outlook projects.
• While nuclear has the ability to provide energy at scale and with low emissions today, few scenarios
project high growth.
• Biomass can play an important role providing bio fuels for transportation, and even providing
negative emissions if CO₂ from the flue gases of power plants can be captured and stored.
• Solar and wind would have to accelerate their build out rates to be in line with the scenarios.
• The IEA NZE by 2050 is an even more stringent pathway to reduce emissions than the average of the
IPCC Lower 2°C scenarios. It accelerates growth of lower-carbon solutions while also further
reducing fossil sources.
Future energy mix has a large range of potential
outcomes- Share(%) by fuel type within primary
energy mix in 2050

Transportation
• Commerce and trade drive transportation energy consumption up almost 25% by
2050.
• Over the past few decades the movement of people and goods has grown
dramatically, driven by vast growth in the purchasing power of individuals.
• Likewise, technology advancements have provided new and more efficient
mobility options.
• Global transportation demand is driven by differing trends for commercial
transportation and light-duty passenger vehicles.
• As economic activity expands, especially in developing regions, commercial
transportation is expected to grow.
• The majority of the growth comes from heavy-duty trucking as a result of goods
movement, but increased aviation travel also plays a role as individual purchasing
power expands.
• Passenger vehicle ownership and travel is expected to increase as a result of the
dramatic growth in the middle class and expanded urbanization.
• The fuel mix continues to evolve with more alternatives, like electric vehicles (BEV
and PHEV).
• In this Outlook, hypothetical sensitivities for light-duty demand showed that if by
2035 100% of all new car sales were Electric Vehicles instead of 20%, liquids
demand could fall to 2010 levels by 2050.
• Alternatively, a slowdown in fuel efficiency improvement of internal combustion
engines, could increase fuel demand by almost 3 million barrels per day by 2050.

Transportation energy demand growth driven by commerce-
Global sector demand – million oil-equivalent barrels per day
(MBDOE)

• Global transportation-related energy demand is expected to grow by
almost 25%from 2019 to 2050.
• Personal vehicle ownership continues to grow as purchasing power rises;
higher efficiency and more electric vehicles lead to a peak and decline in
light-duty vehicle energy demand in the mid-2020s.
• Commercial transportation (heavy-duty trucking, aviation, marine and rail)
energy demand is led by growth in economic activity and personal buying
power, which drives increasing trade of goods and services.
• Aviation demand sees the highest annual growth rate at 1.8% from 2019
to 2050 due to rising economic activity as well as rapid growth of the
middle class, specifically in emerging economies.
Transportation energy demand growth driven by commerce-
Global sector demand – million oil-equivalent barrels per day
(MBDOE)

Access to personal mobility increases

Light-duty fleet by type- Million vehicles

Light-duty demand by fuel- MBDOE

• Personal mobility rises with incomes, resulting in a growing demand for
cars and motorcycles.
• Motorcycles offer a lower-cost entry point to personal mobility, with
ownership particularly high in Asia Pacific.
• China and India lead the growth of car ownership, with larger growth in
non-OECD countries.
• In the OECD, while the number of cars per 1,000 people increases, the
associated vehicle fuel demand declines by almost 45% by 2050.
• In 2019, the global fleet was about 1.2 billion vehicles, with ~7 million
(0.6%) of the fleet being plug-in hybrids, battery electric, or fuel cell.
• By 2050, these advanced vehicles grow to ~40% of the fleet (~835 million)
and more than 50% of new car sales, driven by decreasing battery costs,
policies for tailpipe emissions, efficiency and reduced dependence for
countries that must import oil.
• Light-duty vehicle demand for internal combustion engine (ICE) fuels is
projected to peak around 2025 and then decline to levels seen in the
early-2000s by 2050.
• The reduction in fuel demand, while driven in part by electrification, is
mostly connected with efficiency gains across all vehicle types.
Light-duty demand by fuel- MBDOE

Light-duty fuels demand sensitivities

• When calculating the reduction of CO emissions achieved by using electric
vehicles rather than those with internal combustion engines, it is
important to recognize the emissions associated with the incremental
electricity required to power the EV.
• This light-duty vehicle sensitivity analysis helps assess the potential impact
to light-duty liquids demand using alternate assumptions around electric
vehicles penetration, changes in fuel efficiency or broader mobility trends.
• In the Outlook, we project battery-electric vehicles to be 20% of all new
car sales by 2035 and 35% by 2050.
• This sensitivity assumes 100% electric vehicle sales from 2035 onward,
resulting in a fully electrified global car fleet by 2050.
• This 100% electric fleet would reduce global demand for oil (excluding bio
fuels) to the levels of the early 2010s.
• CO emissions decrease 4% versus the Outlook, with the decline in light-
duty CO emissions partially offset by emissions from increased power
generation.
• In the Outlook projection towards 2050, the average annual fuel efficiency
improvement is on average about double the rate of improvement as
observed over the period 2000-2019.
• If the improvement rate slows down and is similar to historical levels, it
could increase fuel demand by almost 3 million barrels per day by 2050.
Light-duty fuels demand sensitivities

Commercial transportation grows in all aspects
Commercial transportation energy demand –
MBDOE

• Commercial transportation rises in all regions, with more than 80% of the growth
in the non-OECD countries, driven by increases in population and GDP.
• While all regions see some increased demand, Asia Pacific leads the growth,
accounting for more than 40% of commercial transportation energy demand
by2050.
• Continued improvements in efficiency will moderate the sector’s energy demand,
which is historically associated with expanding economic activity.
• All modes of commercial transportation grow from 2019 to 2050, with heavy-duty
transportation growing the most and air transportation growing the fastest.
• Electrification plays a role in certain applications (for example, short-haul trucks
and buses), but is less suitable in heavy long-haul, and is unlikely to play a
substantial role in international marine, and aviation that require higher energy
storage to meet range requirements.
• Hydrogen is expected to make inroads into commercial transportation as
technology improves to lower its cost and policy develops to support the needed
infrastructure development.
• Natural gas (LNG on ships) and bio fuels (sustainable aviation fuels) are expected
to take a larger share than electricity.
Commercial transportation grows in all aspects
Commercial transportation energy demand –
MBDOE

Heavy-duty landscape
• Heavy-duty transportation demand is driven by economic activity, which
leads to increased commerce and movement of goods across oceans,
nations, and cities.
• Fuel demand in this sector is influenced by the type of truck and its use, so
understanding fleet dynamics and fuel usage is important for projecting
future demand.
• For example, alight commercial vehicle (LCV) for intra-city deliveries has
different energy needs versus a heavy commercial vehicle (HCV) for cross-
country shipments of goods.
• Additionally truck fleets can be quite different from region to region based
on the distribution of various sector and economic needs, such as heavy
industry, manufacturing or resource extraction.

2015 Heavy-duty fleet/fuel usage mix

• Fleet breakdown and truck usage play a critical role in understanding the
types of alternate fuels available for substitution in trucking.
• In 2015, HCV long-haul trucks made up ~15% of the fleet, but used ~55%
of the fuel for trucking driven by the heavy loads carried over long
distances.
2015 Heavy-duty fleet/fuel usage mix

Heavy-duty sensitivity
• We use sensitivity analyses to provide greater perspective on how changes
to our base Outlook assumptions could affect the energy landscape.
• Our hypothetical sensitivities explore different fuel efficiency trends in a
higher demand case as well as deep penetration of alternatives, such as
electricity, bio fuels, gas and hydrogen in a lower demand case.

Heavy-duty fuels demand sensitivities World – MBDOE

Liquids demand sensitivities by sector World – MBDOE

• The 2019 Outlook assumes that future efficiency improves on average at double the historical
rate from 2000 - 2016, and that alternative fuels grow to ~13% of demand
• In comparison, the high demand sensitivity above assumes future efficiency improves only at
the historical rate, which could increase demand ~30% versus
• the 2019 Outlook, and highlights the need for continued technology investments in efficiency
improvements.
• The low demand sensitivity assumes a deeper penetration of alternative fuels with
accompanying efficiency gains. The penetration assumptions vary by truck type and usages.
• LCVs see nearly 100% penetration of Electric Vehicles due to shorter, start/stop routes, MCVs
see 70% alternative fuels, and HCVs see ~20%alternatives, mostly bio fuels due to the need for
high energy density fuels in long-haul trucks.
• This sensitivity would require a rapid acceleration in the early 2020s of both alternate fuels into
the heavy-duty fleet as well as infrastructure build-out to support the alternatives. The
resulting fuel penetration is approximately three times the 2019 Outlook in 2040, with
traditional fuel demand peaking prior to2025 before declining to mid-2000s levels.
• The impact on total liquids demand from the high sensitivity shows liquids demand could be
~7% above the 2019 Outlook, while in the low demands ensitivity total liquids demand could
peak in the mid-2030s as growth in chemicals, aviation and marine are offset by the heavy-duty
decline.
• These hypothetical sensitivities highlight the difficulty of decarbonizing heavy-duty
transportation and the need for further technology development one conomic, lower-emission
solutions.
Liquids demand sensitivities by sector World – MBDOE

Transportation energy demand: Bridge to lower
2°C -World - quadrillion BTUs

• The Outlook projects that by 2050, plug-in hybrids, battery electric and fuel cells will
grow to ~40% of the fleet (~835 million) and more than 50% of new car sales, driven by
decreasing battery costs, policies to reduce tailpipe emissions, efficiency improvements,
and reduced energy dependence for oil importing countries.
• The need for energy-dense fuels makes commercial transportation harder to electrify.
• The annual growth rate from 2019 to 2050 of electricity across transportation in the
Outlook is comparable to the annual growth within the IPCC Lower 2°C scenarios over a
similar interval.
• Oil demand is lower in the IPCC scenarios reflecting assumptions for fuels witching and
increased vehicle efficiency. Assuming the underlying transportation activity is similar to
the Outlook, the fuel efficiency in the average of the IPCC Lower 2°C scenarios would be
~20% higher in 2050.
• Bio fuels can play a key role, which would require substantial scale-up of biomass
feedstock production and conversion of refineries to bio-refineries. To bridge from the
Outlook to a biomass demand in line with the average of the Lower 2°Cscenarios by
2050, the annual growth rate would need to be more than double. By 2050, this would
mean that bio fuels are 4.5 times today’s demand, compared to the Outlook’s projection
of 2.5 times.
• Hydrogen, or hydrogen-based fuels such as ammonia, could also become part of the
solution set for transportation with substantial scale-up of hydrogen.
Transportation energy demand: Bridge to lower
2°C -World - quadrillion BTUs

Residential and commercial
• As populations grow and prosperity rises, more energy will be needed to
power homes, offices, schools, shopping centers and hospitals.
• Combined residential and commercial energy demand is projected to rise
by around15% through 2050.
• Led by the growing economies of non-OECD nations, average worldwide
household electricity use will rise about 30% between 2019 and 2050.
• Energy efficiency plays a big role in constraining energy demand growth
within the residential and commercial sectors as modern appliances,
advanced materials and policies shape the future.

Demand shifts to non-OECD with growth primarily
supplied by electricity

• In addition to the energy people need to heat or cool their homes
and keep appliances running, this sector also includes the energy
required in hospitals, schools, grocery stores, retail shops, offices,
sports facilities and cultural centers.
• With rising prosperity and expanding commercial activity comes an
increased demand for lighting, heating, cooling and power in homes
and offices of more than 15% by 2050.
• Strong middle-class growth in non-OECD nations increases energy
demand by almost 40%.
• Improving building efficiencies reduce energy demand in OECD
countries by almost 15% by 2050.
• Globally, electricity demand rises by 1.8% per year, growing to
almost 50% of this sector by 2050, as traditional biomass, coal and
oil demand decline.
Demand shifts to non-OECD with growth primarily
supplied by electricity

Industrial- Almost half of the world’s energy use is
dedicated to industrial activity
• As the global middle class continues to grow, demand for durable
products, appliances and consumable goods will increase. Without
exception, industrial activities are required to manufacture these products
and their components.
• Industrial activities, such as textile manufacture, car assembly or creation
of construction materials, take place in almost all regions, and for all this
activity energy is required.
• Industry grows in emerging markets, like India, Southeast Asia, the Middle
East and Africa.
• Industry also evolves in OECD nations as businesses and consumers strive
to reduce their environmental impact by using energy more efficiently.
• Industrial growth takes energy. It also takes innovation.
• This Outlook anticipates technology advances, as well as the increasing
shift toward cleaner sources of energy such as electricity and natural gas.
• The industry of the future will be more energy efficient and less carbon
intensive than it is today.

Historical perspective on industrial product demand
Industrial product demand - growth indexed to 1990

• Demand for industrial products has seen enormous growth in the past
decades.
• Efficiency gains have kept energy demand from rising as fast as production,
and the resulting emissions per unit of primary energy used (excluding
emissions associated with the electricity used) by the industry have stayed
fairly flat.
• This growing product demand trend is expected to continue as more of the
world’s people advance to the middle class and gain access to products
essential for modern living.
• Addressing CO emissions coming from the energy use in industry will be key.
• Switching to lower-carbon fuels, such as natural gas and hydrogen,
electrification and CCS will be crucial.
• PLASTICS are used in medical supplies, cleaning products, electric vehicles,
and many household goods.
• CEMENT is needed for construction of dams (hydropower), construction of
energy-efficient buildings, etc.
• ALUMINUM is used in power grids and construction as well as in the making
of vehicles.
• STEEL is used for large-scale construction, shipping containers, trains and
ships.
Historical perspective on industrial product demand
Industrial product demand - growth indexed to 1990

Industrial sector energy supports economic
progress -World – quadrillion BTUs

Heavy industry transitions toward cleaner fuels
2019-2050 change in quadrillion BTUs

• The industrial sector provides more than a billion jobs for people who
work to feed, clothe, shelter and improve the lives of people around the
world.
• Rising population and prosperity trigger demand for modern cities,
medical equipment, mobility and home appliances that underpin the need
for steel, cement and chemicals.
• In 2019, the industrial sector used about half the world’s electricity and
nearly as much primary energy as the transportation and
residential/commercial sectors combined.
• Increased options for consumers to ‘reduce, reuse, recycle’ and
manufacturers’ efforts to improve industrial processes and efficiency can
conserve fuel and mitigate emissions.
• Heavy industry (steel, cement, metals and manufacturing) and chemicals
(plastics, fertilizer and other chemical products) are expected to account
for nearly all of the growth to 2050.
Heavy industry transitions toward cleaner fuels
2019-2050 change in quadrillion BTUs

Oil, gas and electricity fuel industrial growth
World – quadrillion BTUs

• Industry uses energy products both as a fuel and as a feedstock for
chemicals, asphalt lubricants, waxes and other specialty products.
• Oil, natural gas and electricity contribute almost all the energy needed to
replace coal and meet the industrial energy growth to 2050.
• Oil grows because it is particularly well suited as a feedstock; companies
choose natural gas and electricity for their versatility, convenience and
lower direct emissions.
• Coal use declines as nations and businesses strive to reduce their
environmental impact; it is expected to keep playing a role in steel and
cement manufacturing.
• Shifting to lower-carbon fuels reduces the industrial sector’s 2050 direct
emissions by 15% versus 2019 even as primary energy demand increases
by 10%.
Oil, gas and electricity fuel industrial growth

Heavy industry energy intensity improves
Thousand BTUs per dollar of GDP

• Heavy industry energy intensity measures the amount of energy used in
heavy industry and manufacturing per dollar of overall economic activity
(GDP).
• Producing more value with less energy has a positive impact –
economically and environmentally – for manufacturing companies and
countries.
• OECD nations have lower energy intensity thanks to their service-based
economies and predominance of higher-value, energy-efficient industries.
• China's intensity, which spiked as it invested in infrastructure and heavy
industry, has been improving rapidly as its economy matures and
efficiency increases.
• Optimizing energy use via advances in technology, processes and logistics
can help companies remain competitive and contribute to gains in global
energy intensity.
Heavy industry energy intensity improves
Thousand BTUs per dollar of GDP

Consumer demand boosts chemicals energy growth
Quadrillion BTUs

• Chemicals are the building blocks for thousands of products that people
rely one very day.
• Demand for fertilizer, cosmetics, textiles and plastics grows through2050
as people’s rising living standards enable them to buy more medical
devices, food, cars, computers and home goods.
• Asia Pacific’s chemicals production grows to meet the needs of its rising
middleclass.
• Producers in the U.S. and Middle East chemicals production tap abundant,
affordable energy supplies (used as feedstock and fuel) to gain
competitive advantage.
• Europe, Russia, South Korea and Japan remain important contributors to
global chemicals production.
Consumer demand boosts chemicals energy growth
Quadrillion BTUs

Chemicals production relies on oil and natural gas

• The chemical industry uses hydrocarbon products as both a feedstock and
a fuel.
• Naphtha and natural gas liquids are primarily used as feedstock; natural
gas is used as both a feedstock (notably for fertilizer) and a fuel.
• Natural gas liquids use grows by more than 80% from 2019 to 2050, as
unconventional oil and natural gas production in the U.S. expands supply.
• Naphtha is expected to remain the dominant feedstock in Asia; the Middle
East is expected to rely on natural gas liquids and natural gas.
• Advances in plastic materials and chemical processes can save energy as
the industry continues to meet rising consumer demand for high-
performing products.
Chemicals production relies on oil and natural gas

Industrial energy demand: Bridge to lower 2°C
World - quadrillion BTUs

• Transforming and decarbonizing the manufacturing industry will be
challenging, due to the complexity and scale of the industry, as well as the
need for large amounts of heat to make basic materials such as cement
and steel.
• Our projections indicate more efforts will be required to further
decarbonize thei ndustry to reduce emissions to the level of the IPCC
Lower 2°C scenarios.
• Switching from coal to lower-carbon fuels is a theme in both the Outlook
and the IPCC Lower 2°C scenarios. Natural gas and hydrogen are well-
placed to reduce the emissions from coal use.
• Electrification will need to be made available for even higher-temperature
industrial processes, requiring further research into the materials used for
equipment that can accommodate these new production techniques.
• Carbon capture and storage can provide a scalable solution to capture
thee missions of both energy use and processing, for example from
cement production. Large industrial clusters could benefit from combining
captured CO streams to increase the efficiency of the storage.
Industrial energy demand: Bridge to lower 2°C

Electricity and power generation
Global electricity demand rises more than 70%
• Electricity demand is expected to grow around the globe, supplied
primarily by growth in wind, solar, natural gas-fired generation, and
nuclear.
• Besides meeting residential, commercial, and industrial demand, the
increase in electricity demand is also fueled by the growth of electric
vehicles in light-duty transportation.
• Cost reductions in transportation batteries are being leveraged for other
applications including larger-scale electricity storage.
• Today, batteries represent a small share of installed capacity on the grid,
and are used for short-duration storage.
• The increased variable production from weather-dependent wind and
solar triggers additional transmission build-out, storage and flexible gas
peaking generation but results in reduced asset efficiency.
• Further breakthroughs that provide new solutions deployable at
commercial scale to maintain reliable and affordable electricity for
consumers are needed.

Electricity generation highlights regional diversity
Net delivered electricity – thousand TWh

• The mix of electricity generation varies geographically based on factors
including technology costs, domestic resource availability and policy
targets (for example, renewable portfolio standards for local generation).
• Much of the world continues to shift further to lower-emission sources for
electricity generation, led by wind and solar, natural gas and nuclear,
based on local opportunities and policies.
• In 2019, coal-fired generation was the leading source of electricity
(accounting for more than 45% in developing countries).
• China’s coal-fired electricity is fore cast to fall by almost half through 2050,
replaced primarily by a combination of wind, nuclear, natural gas, and
solar.
• The share of electricity use in transportation is expected to grow from
today’s low levels with increasing penetration of electric vehicles as a
result of emissions/fuel economy targets and cheaper batteries.
Electricity generation highlights regional diversity
Net delivered electricity – thousand TWh

Renewables and natural gas dominate growth
Global growth 2019-2050 – thousand TWh (net delivered)

Renewables penetration increases across all regions
Wind/Solar share of delivered electricity – % share of TWh

• Wind and solar generation grow the most to 2050, supported by technology cost
reductions (particularly for solar) and policies targeting lower CO 2emissions.
• Natural gas grows both in and out of the OECD countries. OECD growth comes
from coal-to-gas switching, and half of the non-OECD growth is in gas-producing
Middle East and Africa.
• A majority of new nuclear generation is built in China. OECD demand is projected
to decline as some countries phase out nuclear generation.
• Coal-fired generation drops from 45% to 20% share by 2050 in the non-OECD
countries, and from 20% to 2% in the OECD as the world aims to reduce its
emissions.
• Wind and solar grow across the globe, but penetration in 2050 varies based on
natural resource quality and levels of policy support. Globally, wind and solar’s
share of delivered electricity grows, from 6% in 2019 to almost 35% in 2050.
• In 2050, wind and solar are expected to deliver around 40% or more of electricity
in Europe and North America, contributing to renewables policy goals.
• Renewables growth in Asia Pacific contributes to local air quality improvements
and energy security goals.
• Up to 20-30% wind and solar penetration can be achieved without significant
additional costs to the power grid. Higher penetration levels incur additional costs
to manage intermittency through flexible backup generation, transmission build
out and storage to ensure reliable electricity delivery.
Renewables penetration increases across all regions
Wind/Solar share of delivered electricity – % share of TWh

Different policy or technology choices can impact gas demand
Global natural gas demand sensitivity – BCFD

• Lower-cost wind and solar with efficient storage could increase
penetration to50% of supply.
• Ratable reductions in both coal and natural gas by region would reduce
global natural gas demand by about 100 billion cubic feet per day.
• Decline in coal-fired generation occurs predominantly in developed
countries out to 2050. Switching 50% of the remaining coal to natural gas
would increase natural gas demand by about 15%.
Different policy or technology choices can impact gas demand
Global natural gas demand sensitivity – BCFD

Power Generation: Bridge to Lower 2°C

• Given the high degree of electrification of end-use across the IPCC Lower 2°Cscenarios by 2050, these
scenarios on average require about twice the energyinput to produce the required electricity versus
today.
• To attain the level of renewables envisioned in the scenarios, much faster deployment of solar and
wind versus recent years would be required .
• Solar would be required to deploy at 7.5 times the recent historic rate over the next three decades,
and wind at about 3.5 times the recent rate.
• The Outlook assumes solar and wind will be deployed at about twice the historic rate, considering
available policy support and reduced effectiveness areas with lower resource quality.
• Bio energy would grow 5 times today’s energy demand under the IPCC Lower 2°Cscenarios, although it
would still be a minor contributor.
• The increased biomass production would require a step-up in agriculture activity and corresponding
logistics.
• When combined with carbon capture and storage, biomass provides a route to negative CO emissions.
• Nuclear significantly increases its contribution to power generation in the IPCC scenarios, to a level
almost double what the Outlook assumes by 2050.
• The Outlook forecasts a 30% decline in electricity supplied by coal from 2019levels; the IPCC scenarios
call for a reduction of 70%.
• The role of natural gas would expand by almost 75% in the Outlook projection. In the IPCC scenarios, it
falls by 10%.
Power Generation: Bridge to Lower 2°C

Energy Conservation
• Energy conservation is the act of saving energy by reducing a service.
• In other words, to conserve energy, you need to cut back on your usage.
• Examples include driving your car fewer kilometers per week, turning your
air conditioner thermostat up a degree or two during summer and
unplugging your computer or home appliances when they are not in use.
• In all of these examples, you are reducing the amount of energy you use
by doing without or making due with less fuel or electricity.

Important Aspects Of Energy Conservation
• Conserving usable energy, which is otherwise wasted, has a direct impact on economy,
environment and long-term availability of non-renewable energy sources.
• Energy conservation implies reduction in energy consumption by reducing losses and
wastage by employing energy efficient means of generation and utilization of energy.
• There are three important aspects of energy conservation:
1. Economic Aspect
(a) Reduction in Cost of Product Energy conservation ultimately leads to economic benefits
as the cost of production is reduced.
• In some energy intensive industries like steel, aluminum, cement, fertilizer, pulp and
paper etc., cost of energy forms a significant part of the total cost of the product.
• Energy cost (expressed as per cent of total cost of the product) in the entire industrial
sector in India varies from as low as 0.36 per cent to as high as 65 per cent.
• We must strive for good energy economy using energy efficient technologies.
• This will reduce the manufacturing cost and lead to production of cheaper and better
quality products. This is essential to stay competent with our commercial rivals.
(b) New Job Opportunities Energy conservation usually requires new investments in more
efficient equipment to replace old inefficient ones, monitoring of energy consumption,
training of manpower, etc. Thus, energy conservation can result in new job
opportunities.

2. Environmental Aspect
• Every type of energy generation / utilization process affects the environment to
some extent either directly or indirectly.
• The extent of degradation of environment depends mainly on the type of primary
energy source.
• Also during any energy conversion stage a part of energy escapes to surroundings
and appears in the form of heat.
• Thus energy is generated and utilized at the expense of adverse environmental
impacts.
• Adoption of energy conservation means can minimize this damage.
3. Conservation of Non-Renewable Energy Assets
• The vast bulk of energy used in the world today comes from fossil fuels, which are
non-renewable.
• These resources were laid down many millions of years ago and are not being
made any longer.
• This finite, non-renewable asset is being used up very fast.
• The quantity of fossil fuels the world community uses up in one minute what it
took the earth a millennium to create.
• Therefore, its prices are bound to go up relative to everything else.
• We must abandon wasteful practices in energy utilization and conserve this
resource by all means for future generations.
Important Aspects Of Energy Conservation

Salient Features of “Energy Conservation Act, 2001”
• The Act provides a long-range consequence, which is appended below:
• The establishment of Bureau of Energy Efficiency (BEE) in place of existing
Energy Management Centre (EMC) to implement the provisions of the act
• Declaration of a user or class of users of energy as a designated consumer
• To lay down minimum energy consumption standards and labeling for
identified appliances/equipment and norms for industrial processes for
energy intensive industries
• Formation of energy consumption codes
• Dissemination of information and best practices
• Establishment of Energy Conservation Fund both at the central and state
levels
• Provision of penalties and adjudication
• The BEE would act as a facilitator for the evolution of a self-regulatory
system and organizations would regulate on their own with a view to save
energy and thereby bring the commercial concept in the organization
• The Central Government has established the BEE with effect from March
1, 2002.

Energy Conservation Opportunities
classification of energy conservation opportunities
• Based on energy audit and analyses of the plant, a number of potential energy
saving projects may be identified. These may be classified into three
categories:
1. Category A: Minor ECOs
• Minor ECOs are simple, easy to implement, requiring less investment and
implementation time. These are related with stopping of leakage points,
avoiding careless waste, housekeeping, lapses and carelessness of O & M
personnel.
2. Category B: Medium ECOs
• Medium ECOs or intermediate ECOs are slightly complex, requiring additional
• investment and moderate implementation time.
3. Category C: Major ECOs
• Major ECOs provide significant energy conservation opportunity. These are
high tech., complex and require heavy investment and long implementation
period.

General Electrical ECOs
1. Class A: Simple Electrical ECOs
(a) Switching off the loads (i.e. lights, heaters, ACs, TVs, etc.) when not in use
(b) Changing from electrical heating to solar heating or gas burner heating
wherever possible
(c) Proper housekeeping
(d) Reducing peak demand by staggering the use of large loads
(e) Providing automatic thermostatic (or any other) control to water heaters,
refrigerators, air-conditioners, etc.
(f) Using recently developed ‘tiny switches’ which switch off the electronic
apparatus during their sleeping mode
(g) Changing operating cycle of electrical equipment to conserve energy. For
example, electrical furnaces may be used continuously in three shifts
(instead of two shifts) for better economy.
(h) Replacing inefficient lamps by energy efficient lamps

2. Class B: Intermediate Electrical ECOs
(a) Installation of static VAR sources at substations
(b) Employing automatic controlled load switches
(c) Heat recovery from cooling oil associated with transformer
(d) Automatic voltage control of power consuming devices by means of ON
load tap changer
(e) Installation of shunt capacitors near inductive load for power factor
improvement and reducing kVA demand
(f) Improvement in Operation and Maintenance, reducing down time
3. Class C: Comprehensive Electrical ECOs
(a) Modern more efficient and easy to maintain plant equipment may replace
old less efficient ones
(b)The simple manual / semi manual controlled equipment in an electrical
plant are retrofitted with energy efficient computer controlled equipment.
The energy input is matched with optimum energy requirement.
General Electrical ECOs

Some Important Areas of Energy Saving in Industry
1. Conservation of Electricity
(a) Electric Motors One of the key areas for electricity conservation is to improve the
efficiency of electric motors. Electric motors, on an average, consume over 60% of
the total electric energy consumed in the industrial sector. Selection of motors of
right rating and optimum efficiency would help improve power factor. Capacitors
can be used to bring the power factor near to unity.
(b) Electrolysis and Electrical Heat This is another important area which accounts for,
on an average 20% of the power consumption. Auto trace selflimiting electric heat
technology may be adopted to enable the heater to vary its output power.
(c) Illumination This is another area of large-scale power consumption in the industrial
units. To the extent possible, industrial architecture should build in active and
passive system of solar energy utilization to minimize artificial lighting as also air
conditioning. Illumination load could be brought down by good housekeeping
practices, having the right height for electrical fixtures, choosing the right type of
light, etc. Solid-state time switches or photo controls can be used to monitor and
maintain lighting loads.
(d) Refrigeration and Air-conditioning This is an area where 15–20% of energy saving
is easily possible through simple measures such as having proper insulation, low
roof and roof cooling. Use of soft water as make-up water and frequent cleaning of
cooling tower with chlorine to retard algae formation are some of the other
measures which can bring about energy savings.

2. Conservation of Furnace Oil
(a) Storage and Handling Better storage and handling practices such as preventing
leakages and spillages along with periodical cleaning of storage tanks will save
furnace oil.
• Elevation of service tanks to facilitate gravity flow, installation of coarse filter
before the pumps and using gear pumps for pumping are other measures that will
save furnace oil at this stage.
(b) Preheating To enhance the efficiency at the burning stage, preheating of furnace
oil, removing suspended impurities and properly adjusting and maintaining the
preheaters and thermostat will help minimize furnace oil use.
(c) Burners Antiquated burners should be replaced by standard and quality ones.
• Separate controls for atomizing air and primary air blowing to cope with varying
load conditions would also add to energy saving.
(d) Industrial Furnaces In the industrial furnaces, apart from adequate refractory
insulation and effective sealing of the furnace for flame and combustion leaks,
installation of chimneys of the right height and size and monitoring of flue gas
would help maximize energy savings.
(e) Boiler House Instrumentation Use of control instruments in the boiler house
would help ensure combustion efficiency and keep a close watch over the
operational parameters.

3. Conservation of Coal
(a) Better Storage 5–10% coal savings are possible through reduction of
carpet losses while storing, prevention of spontaneous combustion,
correct sizing procedure and minimization of segregation of coal.
(b) Correct Sizing Inconsistent sizing of coal feeds and the use of coal of
varying sizes in combustion equipment causes significant coal wastage.
(c) Selection of Boilers Conventional boilers are not suitable for solid fuel
firing system needed for burning coal of varying quality. Selection of
boilers should therefore, be done carefully. Antiquated boilers waste as
much as 30% of coal.
(d) Steam Management Efficient steam management is another important
area for conservation of coal and furnace oil. Boiler houses should be
provided with the requisite control instruments. The steam distribution
network should be carefully designed to avoid wastes. Equally important
would be to have proper insulation and to install correct steam traps.
Proper monitoring and management of steam pressure would also be
necessary. Excessive blow-downs as also steam leaks should also be
avoided.

4. Cogeneration
• Cogeneration (generation of electricity and useful heat in a single installation) should be used
wherever feasible and economically viable, instead of separate generation of electricity and heat.
• While thermal power station has a thermal efficiency of 28–32%, cogeneration installations achieve
thermal efficiency up to 75%.
• In some industries cogeneration may result in 30 per cent lower fuel consumption as compared to
that where electricity and heat are generated separately.
5. Recycling and Reusing
• Recycling and reusing of materials offers substantial energy savings.
• Every finished product has an intrinsic value depending upon original energy input during its
production process.
• For example, newspaper material has more gained energy than the energy in raw material that goes
in making the paper.
• Reclaiming the useful scrap material by its recycling can save that invisible energy which was used in
producing and processing the original raw material. Recycling has three benefits:
• (a) saving of energy*;
• (b) same amount of new (virgin) material is also displaced; and
• (c) solves the problem of waste disposal to a great extent.
• Recycled aluminum cans require only 6% of the energy needed to make the can in the first place.
• Recycling of an Aluminium can would save enough energy to run a TV for 3 hours.
• Japan serves as an example of a premiere recycling country.
• Half of its waste material is recycled. This includes 95 per cent of all newspapers and 50% of all other
papers.

6. Modernization of Technology
• In most cases, considerable energy savings could be affected by replacing
old inefficient machinery or simply retrofitting the existing plant.
• Developed countries have been able to reduce the energy consumption
significantly compared to developing countries by adopting energy
efficient modern technology.
• For instance, energy used by Indian steel industry is 9.50 million kcal per
ton, which is more than double the amount used by Italy or Japan, which
is around 4 million kcal per ton.
• Similarly, in case of cement industry, energy requirement works out to be
around 2 million kcal per ton as against 0.95 million kcal per ton in USA
and 0.89 million kcal per ton in Italy.
• Therefore, modern energy efficient technology should be adopted by
replacing / retrofitting the existing old inefficient equipment.

7. Waste Heat Recovery
• Various industrial processes require heat of different grades. Waste heat
from one process that uses intense heat can serve the need of other,
which requires heat at lower grade. Let us consider an example of glass
industry:
(a) Glass industry requires heat to melt glass at about 1500 °C. It produces
waste heat at about 400–500 °C in the form of flue gases from the
furnace.
(b) Flue gases may be used to raise medium pressure steam and fed to
backpressure turbine to generate electric power. (In backpressure turbine,
the exhaust steam is not condensed but is withdrawn at desired pressure
for process use as against condensing turbine where the steam leaves the
turbine at a very low pressure.)
(c) The exhaust from backpressure turbine, which is at about 120 °C, may
further be used for crop drying or for paper drying. (In paper industry 1.5
tons of water have to be evaporated for each ton of paper produced.
Approximately 30 per cent of the total energy required for paper
production is utilized for drying purpose.)
(d) The condensed water vapour, which is at about 60 °C, may be used for
heating of space, fish farm or greenhouse.

8. Proper Housekeeping
• The elements of effective housekeeping programme are as follows:
(a) Dust and Dirt Removal Vacuum cleaners are suitable for removing light
dust and dirt. Industrial models have special fittings for cleaning walls,
ceilings, ledges, machinery, and other hard-to-reach places where dust
and dirt may accumulate.
(b) Employee Facilities Employee facilities need to be adequate, clean and
well maintained. Lockers are necessary for storing employees’ personal
belongings. Washroom facilities require cleaning once or more each shift.
They also need to have a good supply of soap, towels plus disinfectants, if
needed. The eating area should be separate from the work area and
should be cleaned properly each shift.

(c) Surfaces
(i) Floors: Poor floor conditions are a leading cause of accidents so cleaning
up spilled oil and other liquids at once is important.
• Allowing chips, shavings and dust to accumulate can also cause accidents.
• Trapping chips, shavings and dust before they reach the floor or cleaning
them up regularly can prevent their accumulation.
• Areas that cannot be cleaned continuously, such as entrance ways, should
have anti-slip flooring.
• Keeping floors in good order also means replacing any worn, ripped, or
damaged flooring that poses a tripping hazard.
(ii) Walls: Light-coloured walls reflect light while dirty or dark-coloured walls
absorb light.
• Contrasting colours, warn of physical hazards and mark obstructions such
as pillars.
• Paint can highlight railings, guards and other safety equipment, but should
never be used as a substitute for guarding.
• The programme should outline the regulations and standards for colours.

(d) Maintain Light Fixtures Dirty light fixtures reduce essential light levels.
Clean light fixtures can improve lighting efficiency significantly.
(e) Aisles and Stairways Aisles should be wide enough to accommodate
people and vehicles comfortably and safely. Aisle space allows for the
movement of people, products and materials. Warning signs and mirrors
can improve sight-lines in blind corners. Arranging aisles properly
encourages people to use them so that they do not take shortcuts through
hazardous areas. Keeping aisles and stairways clear is important. They
should not be used for temporary “overflow” or “bottleneck” storage.
Stairways and aisles also require adequate lighting.
(f) Spill Control The best way to control spills is to stop them before they
happen. Regularly cleaning and maintaining machines and equipment is
one way. Another way is to use drip pans and guards where possible spills
might occur. When spills do occur, it is important to clean them up
immediately. Absorbent materials are useful for wiping up greasy, oily or
other liquid spills. Used absorbents must be disposed of properly and
safely.

(g) Tools and Equipment Tool housekeeping is very important, whether in the
tool room, on the rack, in the yard, or on the bench. Tools require suitable
fixtures with marked locations to provide orderly arrangement, both in the
tool room and near the workbench. Returning them promptly after use
reduces the chance of being misplaced or lost. Workers should regularly
inspect, clean and repair all tools and take any damaged or worn tools out
of service.
(h) Maintenance The maintenance of buildings and equipment may be the
most important element of good housekeeping. Maintenance involves
keeping buildings, equipment and machinery in safe, efficient working
order and in good repair. This includes maintaining sanitary facilities and
regularly painting and cleaning walls. Broken windows, damaged doors,
defective plumbing and broken floor surfaces can make a workplace look
neglected; these conditions can cause accidents and affect work practices.
So it is important to replace or fix broken or damaged items as quickly as
possible.

(i) Waste Disposal The regular collection, grading and sorting of scrap
contribute to good housekeeping practices. It also makes it possible to
separate materials that can be recycled from those going to waste disposal
facilities.
(j) Storage Good organization of stored materials is essential for overcoming
material storage problems whether on a temporary or permanent basis.
There will also be fewer strain injuries if the amount of handling is
reduced, especially if less manual materials handling is required.
• (i) Stored materials should not obstruct aisles, stairs, exits, fire equipment,
emergency eyewash fountains, emergency showers, or first aid stations.
All storage areas should be clearly marked.
• (ii) Flammable, combustible, toxic and other hazardous materials should
be stored in approved containers in designated areas that are appropriate
for the different hazards that they pose. Storage of materials should meet
all requirements specified in the fire codes and the regulations of
environmental and occupational health and safety agencies in your
jurisdiction.

9. Judicial use of Proper Type of Energy
• Although all forms of energy are expressed in same unit (Joules), the
financial value of energy varies enormously with its grading. Some of the
energy forms are mentioned here in decreasing order of grading:
(a) Electrical energy (top grade energy)
(b) Mechanical energy
(c) Thermal energy
• (i) High-grade thermal energy (500 °C and above)
• (ii) Medium-grade thermal energy (150–500 °C)
• (iii) Low-grade thermal energy (80–150 °C)
• For economic reasons, one should never use a higher-grade energy then
required. For example, electrical energy should preferably not be used for
heating purpose; instead, thermal energy, which may be obtained directly
by burning of fuel or solar thermal system, may be used.

10. Judicial use of Proper Type of Fuel
• A cheaper primary source should be preferred wherever possible in place of a
costly one. For example, coal (gasified, pulverized or other forms) and bio-fuel, etc.
which are relatively abundant or renewable, may be considered in place of oil or
gas, which are costlier and nonrenewable.
11. Training of Manpower
• Manpower should be trained to adopt habits in efficient use of energy.
12. Adopting Daylight Saving Time
• Daylight Saving Time may be adopted to save a significant amount of energy
during certain season in a year. In summer, when the sun rises early the clock may
be set one hour ahead of the local standard time. This increases the number of
useful hours of the daylight and provides extra sunlight in the evenings. Due to
this, daily activities of many people finish earlier and the bedtime come soon after
it is dark. As a result, they do not have to use artificial light and could save fuel and
electricity. The idea of daylight saving was introduced by Benjamin Franklin in 18th
century to the people of Paris but it was not adopted then. Later during World War
I, daylight saving laws were passed. Germany was the first country to adopt
daylight saving time in 1915, followed by England (1916) and the US (1918).
13. Proper Operation and Maintenance
• The system should be monitored to operate on optimum working conditions.
Leakages must be carefully plugged. Proper lubrication should be maintained in
moving parts. Proper thermal insulation should be utilized in thermal systems.

Availability of Resources and Future Trend
1. Conventional Sources
• (a) Fossil Fuels: Fossil fuels include coal, oil and gas.
• These fuels are major source of energy since about 1850, the start of industrial era.
• Fossil fuels are so called because these are in fact the fossils of old biological life that once
existed on the surface of earth.
• It is formed in several parts of earth at varying depths, during several million years by slow
decomposition and chemical actions of buried organic matter under favourable pressure, heat
and bacterial marine environment.
• coal Despite its poor environmental credentials, coal remains a crucial contributor to energy
supply in many countries.
• Coal’s dominant position in the global energy mix is largely due to the fact that it is abundant,
widely distributed across the globe and affordable.
• Coal is the most widespread fossil fuel around the world, found in about 75 countries and
actively mined in 50 countries.
• The future of coal depends primarily on the advance of clean coal technologies to mitigate
environmental risk factors, CO2 emissions, in particular.
• It is the world’s largest source of electricity, accounting for around 40 per cent of global
electricity production.
• World present (year 2013) proved reserves of coal is estimated as 8, 91,530 MT, which based
on current production rates should last for around 115 years.
• The annual production and proved reserves of few top coal producing countries is given in
Table 1.6.

• Oil: Oil is a premier energy source with a wide range of possible applications.
• Its main use however, will be shifting towards transport and the petrochemical sector.
• The annual production and proven reserves of few top oil producing countries are given
in Table 1.7.
• Apart from the above-mentioned conventional oil resource other possible future
unconventional oil resources are “Oil shale” and “Tar sands”.
• These are cross-linked chain of hydrocarbons. (A cross-link is a bond that links one
polymer chain to another. They can be covalent bonds or ionic bonds).
• Oil shale refers to “Kerogen” a solid form of petroleum.
• When oil shale is heated, the kerogen decomposes and gives crude oil.
• The distillation of crude oil from oil shale is not economical so far.
• The world’s estimate of crude oil from oil shale is about (2800 to 3300) × 109 barrels with
largest reserves in USA.
• Tar sands (oil sands or bituminous sands) are loose sand or partially consolidated
sandstone containing naturally occurring mixtures of sand, clay, and water, saturated with
a dense and extremely viscous form of petroleum referred to as bitumen or tar due to its
similar appearance, odour and colour.
• Synthetic crude oil can be obtained from tar sand.
• The world’s total estimated reserve of crude oil from tar sand is about 249.67 × 109
barrels, out of which 70.0% are located in Canada.
• Recently, new technology has enabled profitable extraction of petroleum from tar sands.
• If the unconventional oil resources, including oil shale and oil sands, etc. are taken into
account, the global oil reserves will be four times larger than the current conventional
reserves

• Gas The cleanest of all fossil-based fuels, natural gas is plentiful and
flexible.
• It is increasingly used in the most efficient power generation technologies,
such as, Combined Cycle Gas Turbine (CCGT) with conversion efficiencies
of about 60%.
• The reserves of conventional natural gas have grown by 36% over the past
two decades and its production by 61%.
• The exploration, development and transport of gas usually require
significant upfront investment.
• Close coordination between investment in the gas and power
infrastructure is necessary.
• The annual production and proved reserves of few top gas producing
countries is given in Table 1.8.
• There are four main categories of unconventional natural gas: shale gas,
coalbed methane, gas from tight sandstones (‘tight gas’) and the least
well-known methane
• hydrates.

• Shale gas refers to natural gas that is trapped within shale formations.
• Shales are fine-grained sedimentary rocks that can be rich resources of
petroleum and natural gas.
• Shale gas is not a “new” energy resource.
• The first commercial gas well in the USA, drilled in New York State in 1821
was in fact a shale gas well.
• Over the years, limited amounts of gas were produced from shale
formations, until the recent “Shale Gas Revolution” changed the natural
gas scene, first in the United States and subsequently in other countries
around the globe.
• It is believed that the total shale gas resource base is both large and wide-
spread around the world.
• However, this potential resource has not yet been quantified on a national
level in the majority of countries.
• The most credible studies put the global shale gas resource endowment at
about 16,110 tcf (456 tcm).
• It is assumed that nearly 40% of this endowment would be eventually
recoverable.
• The United States and the CIS (Commonwealth of Independent States)
countries together account for over 60 per cent of the total estimate.

• Coalbed methane (also known as colliery gas or coal seam gas) is present in some
coal seams.
• It can be found in absorbed form within the coal matrix or unabsorbed in gaseous
pockets.
• The gas generally lacks hydrogen sulphide but has a potentially higher level of
carbon dioxide than natural gas.
• This resource is usually found at depths of 300–2000 metres below ground.
• Tight gas refers to natural gas deposits which are particularly difficult to access from
a geological viewpoint.
• Contained in rocks with very low permeability in deep formation, and is typically
deeper than 4500m.
• Extraction of this gas would require a combination of extraction processes such as
the hydraulic fracturing and horizontal drilling.
• Methane Hydrate is a solid clathrate compound in which a large amount of
methane is trapped within a crystal structure of water, forming a solid similar to ice.
• Methane hydrate is found in extensive seams under deep water in various parts of
the world.
• A recent academic assessment of gas hydrates calculates the amount of gas hydrates
in resource-grade deposits to be at least one third more than 2010 estimates of
global natural gas reserves.

• (b) Hydro Resources Among all renewables, hydropower is the most advanced and
flexible source of power.
• It is a well-developed and established source of electric power.
• The early generation of electricity from about 1880 often derived from hydro
turbines.
• A number of large and medium sized hydro schemes have been developed.
• Due to requirement of huge capital investment and strong environmental concerns
about large plants, only about one third of the realistic potential has been taped
so far.
• Hydro installations and plants are long lasting (turbine life is about 50 years).
• This is due to continuous steady operation without high temperature or other
stresses.
• Therefore, it often produces electricity at low cost with consequent economic
benefits.
• The global installed (2012 data) generating capacity of hydro power is about 1,025
GW, which produces about 16.5% of the world’s total electrical energy.
• Eight countries make up more than two third of the world’s hydropower
production.
• These are listed in Table 1.9 along with their installed capacities.
• Biggest Hydro plant is located at “Three Gorges” in China with capacity of 22.5 GW.
• Norway derives 96.7% of its required electric power from hydro resources.

(c) Nuclear Resources U235, U233 (isotopes of uranium) and Pu239 (plutonium) are used as nuclear fuels in
nuclear reactors (thermal reactors) and are known as fissile (or fissionable) materials.
• Out of these, only U235 occurs in nature. U233 and Pu239 are produced from Th232 (thorium) and U238
respectively in fast breeder reactors (FBRs).
• Th232 and U238 are known as fertile materials. Natural Uranium contains 0.71 per cent of U235 and 99.29%
of U238.
• Uranium reserves in the world are small and its recovery is expensive.
• Concentrated deposits of Uranium are not available.
• The content of natural Uranium in Uranium ore is about 0.1–0.5 %.
• Major available sources of Uranium are in Australia, Canada, and Kazakhstan and to a lesser extent the
USA.
• There are also a large number of smaller low grade sites.
• Thorium reserves are expected to be more than those of uranium.
• Nuclear power is the least-cost, low-emission technology that can provide base load power.
• The nuclear industry has a relatively short history.
• The first nuclear reactor in the world was commissioned in the Former Soviet Union’s Obninsk in 1954.
• As in year 2012 there are around 427 nuclear power plants in the world, operating in 31 countries
producing 10.9% world’s electricity.
• France produces 76.1% of its total electrical power by nuclear means.
• Nuclear energy policy differs between European Union and some other countries, such as Austria and
Ireland, which have no active nuclear power stations.
• The annual production and installed generating capacity of few top nuclear power producing countries is
given in Table 1.10.

• Presently, most commercial reactors are thermal reactors.
• Fast Breeder Reactors (FBRs) utilize fast neutrons and generate more
fissile material than they consume.
• They generate energy as well as convert fertile material (U238, Th232) into
fissile material (Pu239 and U233 respectively).
• The breeder technology is not yet commercially developed.
• Main problem being their slow breeding rate and therefore long doubling
time (the time required by an FBR to produce sufficient fissile material, to
fuel a second, identical reactor) of around 25 years.
• With continuing R & D efforts in this direction, it is hoped that by 2050,
FBRs will be the main source of power after overcoming the present
difficulties.
• Nuclear fusion reaction has a lot more potential and vast resources are
available.
• However, controlled fusion reaction has not been achieved yet.
• It is predicted that by year 2500 some breakthrough will take place in
fusion technology and once this happens, nuclear fusion reaction will be
the main source of energy on earth.

2. Non-conventional Sources
• Non-conventional technologies are presently under development stage.
• At present its share is very small.
(a) Solar Energy Solar energy can be major source of power and can be
harnessed by using thermal and photovoltaic conversion systems.
• Maximum solar radiation received on the surface of earth, normal to it, on
bright sunny day, at noon is approximately 1 kW/m2, at sea level.
• The earth continuously intercepts solar power of 178 billion MW, which is
about 10,000 times the world’s demand.
• But so far it could not be developed on a large scale.
• According to one estimate, if all the buildings of the world are covered
with solar PV panel, it can fulfill electrical power requirements of the
world.
• Solar PV power is considered as an expensive source of power.
• However, the prices are decreasing steadily.
• The price of SPV system has dropped from USD 10 per W in year 2000 to
USD 3 per W in year 2013.
• The use of solar energy is growing strongly around the world, in part due
to the rapidly declining solar panel manufacturing costs.
• The Installed SPV generating capacity of top few countries is given in Table
1.11.

• (b) Wind Energy The power available in the winds over the earth surface is
• estimated to be 1.6 × 107 MW, which is more than the present energy
requirement of the world.
• Wind power has emerged as the most economical of all renewable energy
sources.
• The installation cost of wind power is 4 crore / MW (which is comparable
to that of conventional thermal plants).
• There has been remarkable growth of wind power installation in the
world.
• Wind power generation is the fastest growing energy source.
• The installed wind power and annual electricity generation of top few
countries is given in Table 1.12.
• China, with about 114.6 GW, has the highest installed capacity while
Denmark, with over 4.8 GW, has the highest level per capita.
• Wind accounts for about 39% of Denmark’s electricity production.

(c) Biomass Energy Energy resources available from animal and vegetation
are called biomass energy resources.
• Historically, humans have harnessed biomass derived energy since the
time when people began burning wood to make fire.
• Even today, biomass is the only source of fuel for domestic use in many
developing countries.
• This is an important resource for developing countries, especially in rural
areas.
• The principal biomass resources are:
• Trees (wood, leaves and forest industry waste)
• Cultivated plants grown for energy
• Algae and other vegetation from ocean and lake
• Urban waste (municipal and industrial waste)
• Rural waste (agricultural and animal waste, crop residue, etc.)
• Solar energy absorbed by plants (through photosynthesis process) is
estimated to be 2 × 1021 J / Year.
• Biomass material may be transformed by chemical or biological processes
to other usable intermediate bio-fuels such as biogas (methane), producer
gas, ethanol, biodiesel and charcoal etc.
• At present there are millions of biogas plants, in the world, most of them
are located in China

(d) Geothermal Energy Geothermal energy comes from the natural heat of the Earth primarily due
to the decay of the naturally radioactive isotopes of uranium, thorium and potassium.
• Geothermal energy is derived from huge amount of stored thermal energy in the interior of
earth.
• However, its economic recovery on the surface of the earth is not feasible everywhere. Its
overall contribution in total energy requirement is negligible.
• However, it is a very important resource locally.
• Of the countries utilising their geothermal resource, almost all use it directly but only 24 use it
for electricity generation.
• At end-2012, approximately 1,1490 MWe of geothermal electricity generating capacity was
installed, producing over 68,630 GWh/yr.
• Installed capacity for direct heat utilisation amounted to about 50,000 MWt, with an annual
output of around 4,30,000 TJ (equivalent to about 1,20,000 GWh).
• The annual growth in energy output over the past five years has been 3.8% for electricity
production and around 10% for direct use (including geothermal heat pumps).
• The countries with the largest installed capacity were the USA, China, Sweden and Germany,
accounting for about 63% of the installed capacity and the five countries with the largest annual
energy use were: China, USA, Sweden, Turkey and Japan, accounting for 55% of the world use.
• The oldest geothermal power generator is located at Lordarello in Italy, commissioned in 1904.
• The installed capacity and annual outputs in respect of electricity generation and direct use,
respectively for top few countries is given in Table 1.13.

(e) Ocean Tidal Energy Tidal energy is a form of hydropower that converts energy of tides
into electricity or other useful forms of power.
• Although not yet widely used, tidal power has potential for future electricity
generation.
• Tides are more predictable than wind energy and solar power. It is in developing stage.
• There are at present only few operational tidal power plants.
• The first and the biggest 240 MW tidal plant was built in 1966 in France at the mouth
of La Rance river, near St. Malo on the Brittany coast.
• A 20 MW tidal plant is located at Nova Scotia, Canada and a 400 kW
• capacity plant is located at Kislaya Guba, near Murmansk, Russia on the Barents Sea.
• Many sites have been identified in USA, Argentina, Europe, India and China for
development of tidal power.
(f) Ocean Wave Energy Wave power refers to the energy of ocean surface waves and the
capture of that energy to do useful work.
• Good wave power locations have a flux of about 50 kilowatts per meter of shoreline.
As per an estimate, the potential for shoreline-based wave power is about 50,000 MW.
• Deep-water wave power resources are truly enormous, but perhaps impractical to
capture.
• The worldwide resource of wave energy has been estimated to be greater than 2 TW.

(g) Ocean Thermal Energy Conversion OTEC technology is in infant stage.
• Conceptual designs of small OTEC plants have been finalized. Their
commercial prospects are quite uncertain.
• The potential is likely to be more than that of tidal or wave energy.
• The resource potential for OTEC is considered to be much larger than for
other ocean energy forms. Up to 88,000 TWh/yr of power could be
generated from OTEC without affecting the ocean’s thermal structure.
• While OTEC technology has been demonstrated in the ocean for many
years, the engineering and commercial challenges have constrained the
development of the technology.

Energy Scenario In India
1. Overall Production and Consumption (2012–13 Data) [2,15]
• India is both a major energy producer and consumer. India currently ranks
as the world’s 5th largest energy producer after China, USA, Russian
Federation and Saudi Arabia, accounting for about 4% of the world’s total
annual energy production.
• Also it is the world’s 4th largest energy consumer trailing China, USA and
Russian Federation and accounting for 5.9% of the world’s total annual
energy
• consumption. Thus India is a net energy importer, mostly due to large
imbalance between oil production and consumption.
• The production and consumption of primary energy for top few countries
are listed in Table 1.14.
• The per capita primary energy consumption is 637 KGOE for India,
whereas the world average per capita primary energy consumption is
1,919 KGOE (2012 end data).

2. Electrical Power Generation
• The present total installed electricity generating capacity in India is 2,
75,911 MW (as on July 31, 2015), from various resources as given in Table
1.15.
• During calendar year 2014, power sector has registered an annual growth
rate of 10%.
• The distribution of this total installed capacity in various sectors is given in
Table 1.16.

Availability of Primary Energy resources
• 1. Conventional
• (a) Fossil Fuel India has vast reserves of coal, 5th largest in the world after the USA, Russia, China
and Australia.
• According to a rough estimate, total recoverable coal in India is 60,600 million tons, about 6.8% of
world’s total.
• Our coal production is not enough to meet the growing consumption. Net coal import dependency
has risen from a negligible percentage in 1990 to nearly 23% in 2014.
• Indian coal has high ash content (25–50%), low heat value (3000–4000 kcal/kg) and low sulfur
content (1%).
• We have very little oil and gas reserves.
• The estimated reserve of crude oil is 762 MT, which is 0.34% of global oil reserves.
• Likewise the estimated reserve of Natural gas is 1427 bcm, which is 0.68% of global gas reserves.
• Oil and gas reserves are insufficient even for transportation sector. India at present imports 75% of
oil and 25% of its natural gas needs.
• The domestic production is decreasing slowly. Largest consumer of natural gas is fertilizer industry
followed by power industry.
• (b) Hydro Resources India stands 7th in the list of nations with hydro resources.
• Total potential is 100,000 MW. Approximately 41,997 MW has been developed (as on July 31,
2015).
• Huge installation cost, environmental and social problems are major difficulties in its development.
• Also, 56 sites for pumped storage schemes with an aggregate installed capacity of 94,000 MW have
been identified.

• (c) Nuclear Resources India has modest (1 to 2% of global) reserves of Uranium,
mostly located at Jadugoda, Jharkhand.
• There are 21 nuclear reactors at 7 plants located at Narora, Rawatbhatta, Kakrapar,
Kaiga, Kalpakkam, Kudanulam and Trombay (18 PHWR, 2BWR and 1 VVER).
Present, nuclear power installed capacity is 5,780 MW, which is 2.1% of total
installed electricity generating capacity. (as on July 31, 2015)[13].
• There are six reactors totaling 4,300 MW under construction in Tamil Nadu,
Gujarat and Rajasthan. India now envisages to increase the contribution of nuclear
power to overall electricity generation capacity from 2.1% to 9% within 25 years.
• By 2020, India’s installed nuclear power generation capacity is expected to
increase to 20 GW.
• Thorium is available in abundance in India in the form of Monazite (ore) in sand
beaches of Kerala. The reserve of thorium in India is estimated at 3,00,000 tonnes,
which is 25% of world’s thorium reserves (as per IAEA, International Atomic Energy
Agency estimate).
• Some other estimates claim much higher than this amount.
• Thorium is a fertile material, which is converted into a fissionable material U233 in a
Fast Breeder Reactor (FBR).
• The U233 so obtained may be used in a normal thermal reactor such as PHWR.
• The Government has established a research facility IGCAR (Indira Gandhi Center
for Atomic Research) way back in 1971 at Kalpakkam, Tamil Nadu for development
of the nuclear energy technology.

2. Non-conventional
• Located in the tropical region, India is endowed with abundant renewable
energy, i.e., solar, wind and biomass including agricultural residue which
are perennial in nature.
• Harnessing these resources is best suited to meet the energy requirement
in rural
• areas in a decentralized manner. India has potential of generating more
than 900 GW (assuming 3% wasteland is made available) from
commercially exploitable renewable energy resources.
• Up to July 31, 2015, the electrical power generation by non-conventional
resource has reached 36,642.7 MW, which is about 13.2% of total installed
electrical power generation capacity.
• India aims to install 60 GW of wind power capacity and 100 GW of solar
power capacity by 2022.
• The current status (as on 31.07. 2015) of various resources are given in
Table 1.17:

(a) Wind Energy The wind power program in India was initiated in 1983–84.
• The highly successful India’s wind power programme is entirely market
driven.
• This sector has been growing very fast for the last few years. India currently
(year 2015) stands 5th in the world among countries having large installed
capacity wind generators, after China, USA, Germany and Spain.
• Current (July 31, 2015) installed capacity for wind power stands at 23,864.9
MW, mostly located in Tamil Nadu, Gujrat, Maharashtra and Rajasthan.

(b) Solar Energy India, receives solar energy equivalent to more than 5,000 trillion kWh per year, which
is far more than its total annual consumption.
• The average daily global radiation is around 5 kWh per sq. m per day with the sunshine ranging
between 2300 and 3200 hours per year in most parts of India.
• Though the energy density is low and the availability is not continuous, it has now become possible
to harness this abundantly available energy very reliably for many purposes by converting it to
usable heat or through direct generation of electricity.
• The conversion systems are modular in nature and can be appropriately used for decentralized
applications.
• Ministry of New and Renewable Energy (MNRE) had launched a program on “Development of Solar
Cities” in February 2008.
• The programme has been modified / revised on January 2014 for implementation during the 12th
Five Year Plan.
• The Solar City aims at minimum 10 per cent reduction in projected demand of conventional energy
at the end of five years, which can be achieved through a combination of energy efficiency
measures and enhancing supply from renewable energy sources in the City.
• The “Development of Solar Cities” programme is designed to support/encourage Urban Local
Bodies to prepare a Road Map to guide their cities in becoming ‘renewable energy cities’ or ‘solar
cities’.
• A total of 60 cities / towns are proposed to be supported for development as “Solar / Green Cities”.
At least one city in each State to a maximum of seven cities in a State may be supported by the
Ministry.
• The Ministry has already initiated various programmes in the Urban Sector for promoting solar
water heating systems in homes, hotels, hostels, hospitals and industry; deployment of SPV
systems/devices in urban areas for demonstration and awareness creation; establishment of
‘Akshya Urja Shops’; design of Solar Buildings and promoting urban and industrial waste/ biomass
to energy projects.
• The solar city programme aims to consolidate all the efforts of the Ministry in the Urban Sector and
address the energy problem of the urban areas in a holistic manner.

(c) Biomass Energy A large quantity of biomass is available in our country in
the form of dry waste like agro residues, fuel wood, twigs etc. and wet
wastes like cattle dung, organic effluents, sugarcane bagasse, banana stem
etc.
• Potential for generation of electric power/cogeneration is 25 GW from
agro residue and bagasse. The potential from urban waste is 1,700 MW.
• Also there is vast scope for production of bio diesel.
• The biodiesel producing plants require little care, can be grown on fallow
land and can survive in harsh climatic conditions.
• Energy farming may be adopted in marginal and infertile land of the
country.
(d) Small Hydro Resources Hydro resources of capacity less than 25 MW are
called small, less than 1 MW are called mini and less than 100 kW are
called micro hydro resources.
• Total potential is 20 GW out of which 4,130 MW has been realized.

(e) Geothermal Energy Potential in geothermal resource in the country is 10,600 MW of
electric power generation.
• As a result of various resource assessment studies/surveys, nearly 350 potential hot
springs have been identified throughout the country.
• Most of them are low temperature hot water resources and can best be utilized for direct
thermal applications.
• The surface temperature of the hot springs ranges from 35 °C to as much as 98 °C. (the
reservoir temperature is higher than surface temperature). Only some of them can be
considered suitable for electrical power generation.
• These springs are grouped into seven geothermal provinces, i.e., Himalayan (Puga,
Chhumathang), Sahara Valley, Cambay Basin, Son-Narmada-Tapi (SONATA) lineament belt,
West Coast, Godavari basin and Mahanadi basin.
• Some of the prominent geothermal resources include Puga Valley and Chhumathang in
Jammu and Kashmir, Manikaran in Himachal Pradesh, Jalgaon in Maharashtra and Tapovan
in Uttarakhand. A new location of geothermal power energy has also been found in
Tattapani in Chhattisgarh.
• In addition, Gujarat is set to tap geothermal electricity through resources which are
available in Cambay between Narmada and Tapi river.
• A 300 kW demonstration electric power production plant is being installed at Tattapani.
Geothermal resource is being used mostly for heating purpose and very little has been
developed. Total thermal installed capacity is 203 MW and direct thermal use is 446
GWh/year.

(f) Ocean Energy Oceans cover 70% of the earth’s surface and represent an
enormous amount of energy in the form of wave, tidal, marine current
and thermal gradient.
• The energy potential of our seas and oceans well exceeds our present
energy needs.
• India has a long coastline with the estuaries and gulfs where tides are
strong enough to move turbines for electrical power generation.
• A variety of different technologies are currently under development
throughout the world to harness this energy in all its forms including
waves (40,000 MW), tides (9000 MW) and thermal gradients (180,000
MW).
• Deployment is currently limited but the sector has the potential to grow,
fueling economic growth, reduction of carbon footprint.

• ocean tidal Energy There is no functional tidal plant at present.
• The identified economic tidal power potential has been estimated as
8,000–9,000 MW.
• Three sites have been identified for development of tidal energy.
• (a) Gulf of Kutch: potential = 1200 MW
• (b) Gulf of Cambay (Khambat): Potential = 7,000 MW
• (c) Sundarbans: potential = 100 MW
• The ministry of non-conventional energy sources has sponsored the
preparation of a feasibility report by the West Bengal Renewable Energy
Development Agency (WBREDA) to set up a 3.75 MW capacity
demonstration tidal power plant at Durgaduani Creek in the Sunderbans
area of West Bengal.
• ocean Wave and OTEC resources Primary estimates indicate that the
annual wave energy potential along the Indian coast is between 5 MW to
15 MW per meter, thus a theoretical potential for a coast line of nearly
6,000 Km works out to 40,000–60,000 MW approximately.
• A 150 kW demonstration plant has been installed and operating at
Vizhinjum harbor near Thiruvananthapuram, Kerala since 1991.
• There is a proposal for an OTEC plant at Minicoy Island of Lakhshdweep.

(g) Emerging Technologies Emerging technologies like ‘fuel cell’ and
‘hydrogen energy’ are suited for stationary and portable power
generation, which suits for transportation purposes.
• In view of the growing importance of Fuel cells and Hydrogen, a National
Hydrogen Energy Board has been created.
• The Board will
• provide guidance for the preparation and implementation of the National
Hydrogen Energy Road Map, covering all aspects of hydrogen energy
starting from production, storage, delivery, applications, safety issues,
codes & standards, public awareness and
• capacity-building.
• Eco-friendly electric vehicles for transportation are being field tested for
improving their performance.

Solar Energy—Basic Concepts
• The sun radiates energy uniformly in all directions in the form of
electromagnetic waves.
• When absorbed by a body, it increases its temperature.
• It provides the energy needed to sustain life in our solar system.
• It is a clean, inexhaustible, abundantly and universally available renewable
energy source. Major drawbacks of solar energy are: it is a dilute form of
energy, which is available intermittently, uncertainly and not steadily and
continuously.
• However, it is more predictable than wind energy.
• Also peak solar insolation (incident solar radiation) often coincides with peak
daytime demand; it can be well matched to commercial power needs.
• The output of sun is 2.8 × 1023kW.
• The energy reaching the earth is 1.5 × 1018kWh/year.
• Solar energy can be utilized directly in two ways:
• (i) by collecting the radiant heat and using it in a thermal system or
• (ii) by collecting and converting it directly to electrical energy using
Photovoltaic system.
• The former is referred to as ‘Solar Thermal’ and the later as ‘Solar
Photovoltaic’ (SPV) system.

• Solar energy is also used by various well-known natural effects and
appears in nature in some other forms of energy. These are indirect forms
of solar energy.
• Thus solar energy is the mother of all forms of energy: conventional or
non-conventional, renewable or non-renewable, the only exception being
nuclear energy.
• Various sources of energy find their origin in sun, as mentioned below:
 Wind energy
 Biomass energy
 Tidal energy
 Ocean wave energy
 Ocean thermal energy
 Fossil fuels and other organic chemicals
 Hydro energy
• Warming the body during winters is perhaps the earliest uses of direct
solar heat man has made.
• Indeed drying of clothes, timber, fodder, salt water (to get salt) and
agriculture produce remained the most extensive use of direct solar
energy in the history of mankind.
• All other devices for harnessing direct solar energy have fairly recent
origin.
Solar Energy—Basic Concepts

The SUN as Source of Energy
• The sun, which is the largest member of the solar system, is a sphere of intensely
hot gaseous matter with a diameter of 1.39 × 109 m and, at an average distance of
• 1.495 × 1011 m from the earth.
• As observed from the earth the sun rotates on its axis about once in every four
weeks, though it does not rotate as a solid body.
• The equator takes about 27 days and the polar region takes about 30 days for each
rotation.
• At the innermost region, the core, the temperature is estimated between 8×106 to
40 × 106 K.
• The core has density of about 100 times that of water and pressure of 109 atm.
• Such a high inner temperature is maintained by enormous energy released due to
continuous fusion reaction.
• Thus, the sun is a big natural fusion reactor with its constituent gases as the
“containing vessel” retained by gravitational forces.
• Several fusion reactions have been suggested to be the source of the energy
radiated by the sun.
• Most important of them is a reaction in which four hydrogen atoms (protons)
combine to form one helium atom.
• The mass of the helium nucleus is less than that of four protons, the difference of
mass having been converted to energy in fusion reaction as follows:
• The surface of the sun is maintained at a temperature of approximately 5800 K.

THE EARTH
• The earth is shaped as an oblate spheroid – a sphere flattened at the poles
and bulged in the plane normal to the poles.
• However, for most practical purposes, the earth may be considered as a
sphere with a diameter of about 1.275 × 107 m. The earth makes
• one rotation about its axis every 24 hours and completes a revolution
about the sun in a period of approximately 365.25 days.
• Its axis is inclined at an angle of 23.5°.
• As a result the length of days and nights keep changing.
• The earth reflects about 30 per cent of the sunlight that fall on it.
• This is known as earth’s albedo.
• The geometry of earth–sun relationship is shown in Fig.(a).
• The eccentricity of earth’s orbit is such that the distance between the sun
and the earth varies by ±1.7% .
• The sun subtends an angle of 320 on earth at an average sun–earth
distance of 1.495 × 1011 m, a distance of one astronomical unit.

Fig(a): Sun–earth relationship
THE EARTH

SUN, EARTH Radiation Spectrum
• The wavelength distribution of radiation emitted by a black body is given by Planck’s law:
• where, C1 and C2 are often called Planck’s first and second radiation constants
respectively.
• Their suggested values are C1 = 3.74 × 10–16 Wm2, and C2 = 0.01439 mK.
• ‘ λ ’ is the wavelength in m and T is temperature in Kelvin.
• Total energy emitted by the black body at temperature T is obtained by integrating Wλ
over the wavelengths.
• Using this formula the power density distribution of solar radiation at the surface of the
sun considering the surface temperature to be 5760 K can be calculated.
• Also the same for the earth surface can be found out assuming the average earth
temperature to be 288 K (15 °C).
• The comparison of these radiations from the sun and the earth is shown in Fig. (b).
• It is clear from Fig.(b) (i) and (ii) that the radiation emitted from the sun at about 5760K
lies in the range of short wavelengths, peaking around 0.48 μm and that from earth at
288 K (15 °C) lies in the range of long wavelengths, peaking around 10 μm.

Fig Radiant powers per unit wavelength at the surface of sun and earth

• A useful term, Solar Constant, Isc is defined as the energy received from
the sun per unit time, on a unit area of surface perpendicular to the
direction of propagation of the radiation, at the earth’s mean distance
from the sun.
• The World Radiation Center (WRC) has adopted a value of solar constant
as 1367 W/m2.
• This has been accepted universally as a standard value of solar constant.
SUN, EARTH Radiation Spectrum

Extraterrestrial & Terrestrial Radiations
• The intensity of solar radiation keeps on attenuating as it propagates away
from the surface of the sun, though the wavelengths remain unchanged.
• Solar radiation incident on the outer atmosphere of the earth is known as
Extraterrestrial Radiation, Iext.
• The extraterrestrial radiation deviates from solar constant value due to
two reasons.
• The first is the variation in the radiation emitted by the sun itself.
• The variation due to this reason is less than ±1.5% with different
periodicities.
• The second is the variation of earth–sun distance arising from earth’s
slightly elliptic path.
• The variation due to this reason is ±3% and is given by:
• where, n is the day of the year starting from January 1.

• The extraterrestrial radiation, being outside the atmosphere, is not
affected by changes in atmospheric conditions.
• While passing through the atmosphere it is subjected to
mechanisms of atmospheric absorption and scattering depending
on atmospheric conditions, depleting its intensity.
• A fraction of scattered radiation is reflected back to space while
remaining is directed downwards.
• Solar radiation that reaches earth surface after passing through the
earth’s atmosphere is known as Terrestrial Radiation.
• The terrestrial radiation expressed as energy per unit time per unit
area (i.e. W/m2) is known as Solar Irradiation.
• The term Solar Insolation (incident solar radiation) is defined as
solar radiation energy received on a given surface area in a given
time (in J/m2 or kWh/m2).
• The positions of extraterrestrial and terrestrial regions are indicated
in Fig.
Extraterrestrial & Terrestrial Radiations

Fig: Propagation of solar radiation through atmosphere

Spectral Power Distribution of Solar Radiation
• Solar radiation covers a continuous spectrum of electromagnetic radiation in a
wide frequency range.
• About 99% of the extraterrestrial radiation has wavelengths in the range from
0.2 to 4 μm with maximum spectral intensity at 0.48 μm (green portion of
visible range).
• About 6.4% of extraterrestrial radiation energy is contained in ultraviolet region
(λ<0.38 μm); another 48% is contained in the visible region (0.38 μm < λ < 0.78
μm) and the remaining 45.6% is contained in the infrared region (λ>0.78 μm).
• There is almost complete absorption of short wave
• radiation in range (λ<0.29 μm) and infrared radiation in range (λ>2.3 μm) in the
atmosphere.
• Thus, from the point of view of terrestrial applications of solar energy, the
radiation only in the range of wavelengths between 0.29 and 2.3μm is
significant.
• The spectral solar irradiation distribution both for extraterrestrial and terrestrial
radiation is shown in Fig.
• The areas under these curves indicate the total radiation intensities in W/m2
respectively for extraterrestrial and terrestrial regions.

Fig: Special solar irradiation, extraterrestrial and terrestrials

Depletion of Solar Radiation
• The earth’s atmosphere contains various gaseous constituents, suspended
dust and other minute solid and liquid particulate matter.
• These are air molecules, ozone, oxygen, nitrogen, carbon dioxide, carbon
monoxide, water vapour, dust, and water droplets.
• Therefore, solar radiation is depleted during its passage through the
atmosphere.
• Different molecules do different things as explained below:
1. Absorption
• Selective absorption of various wavelengths occurs by different molecules.
• The absorbed radiation increases the energy of the absorbing molecules, thus
raising their temperatures:
 Nitrogen, molecular oxygen and other atmospheric gases absorb the X-rays
and extreme ultraviolet radiations.
 Ozone absorbs a significant amount of ultraviolet radiation in the range (λ <
0.38 μm).
 Water vapour (H2O) and carbon dioxide absorb almost completely the infrared
radiation in the range (λ > 2.3 μm) and deplete to some extent the near
infrared radiation below this range.
 Dust particles and air molecules also absorb a part of solar radiant energy
irrespective of wavelength.

2. Scattering
• Scattering by dust particles, and air molecules (or gaseous particles of
different sizes) involves redistribution of incident energy.
• A part of scattered radiation is lost (reflected back) to space while
remaining is directed downwards to the earth’s surface from different
directions as diffuse radiation.
• It is the scattered sunlight that makes the sky blue.
• Without atmosphere and its ability to scatter sunlight, the sky would
appear black, as it does on the moon.
• In cloudy atmosphere,
 a major part of the incoming solar radiation is reflected back into the
atmosphere by the clouds,
 another part is absorbed by the clouds
 the rest is transmitted downwards to the earth surface as diffuse
radiation.

• The energy is reflected back to the space by (i) reflection from clouds, plus (ii)
scattering by the atmospheric gases and dust particles, plus (iii) the reflection from
the earth’s surface is called the albedo of earth-atmosphere system and has a
value of about 30 per cent of the incoming solar radiation for the earth as a whole.
• Thus on the surface of earth we have two components of solar radiation: (i) direct
or beam radiation, unchanged in direction and (ii) diffuse radiation, the direction
of which is changed by scattering and reflection.
• Total radiation at any location on the surface of earth is the sum of beam radiation
and diffuse radiation, what is known as global radiation.
• These terms may be properly defined as follows:
• Beam radiation: Solar radiation propagating in a straight line and received at the
earth surface without change of direction, i.e., in line with sun is called beam or
direct radiation.
• Diffuse radiation: Solar radiation scattered by aerosols, dust and molecules is
known as diffuse radiation. It does not have a unique direction.
• Global radiation: The sum of beam and diffuse radiation is referred to as total or
global radiation.
• Even on clear days, there will be some diffuse radiation depending upon the
amount of dust particles, ozone and water vapour present in the atmosphere.
• On overcast days when the sun is not visible, all the radiation reaching the ground
will be diffuse radiation.

• In general, the intensity of diffuse radiation coming from various directions in the
sky is not uniform.
• The diffuse radiation is therefore said to be anisotropic in nature.
• However, in many situations (like heavy cloud cover), the intensity from all
directions tends to be reasonably uniform and it thus becomes isotropic in nature.
• The radiation thus available on earth’s surface is less than that is received outside
the earth’s atmosphere and this reduction in intensity depends on the
atmospheric conditions (amount of dust particles, water vapour, ozone content,
cloudiness, etc.) and the distance traveled by beam radiation through atmosphere
before it reaches a location on earth’s surface.
• The later factor in turn depends on solar altitude.
• The path length of solar beam through the atmosphere is accounted for in the
term ‘Air Mass’, which is defined as the ratio of the path length through the
atmosphere, which the solar beam actually traverses up to the ground to the
vertical path length (which is minimum) through the atmosphere.
• Thus at sea level the air mass is unity when the sun is at the ‘zenith’ (highest
position), i.e., when inclination angle a is 90°.
• Mathematically:

Fig: Direction of sun’s ray with respect to atmosphere

Measurement of Solar Radiation
• Solar radiation data are measured mainly by following instruments:
(i) Pyranometer: A pyranometer is designed to measure global radiation,
usually on a horizontal surface but can also be used on an inclined surface.
• When shaded from beam radiation by using a shading ring, it measures
diffuse radiation only.
(ii) Pyrheliometer: An instrument that measures beam radiation by using a
long and narrow tube to collect only beam radiation from the sun at
normal incidence.
(iii) A sunshine recorder measures the sunshine hours in a day.

SOLAR RADIATION DATA
• The radiation data are mostly measured on a horizontal surface.
• Typical records of global and defuse radiation versus solar time on a
horizontal surface for a clear day and partially cloudy day are shown in Fig.
• Daily radiant energy is obtained from the area under the corresponding
curve.
• Monthly average of the daily radiation is obtained by averaging over a
span of the corresponding month and expressed in kJ/m2.
• An alternative unit for expressing solar radiation is Langley per unit time,
where one Langley is equal to 1 calory/cm2.
• Thus, solar radiation data are presented in three ways:
• (i) Flow of energy per unit area per second, ( kJ/m2-s)
• (ii) Flow of energy per unit area per hour, (kJ/m2-h)
• (iii) Flow of energy per unit area per day, (kJ/m2-day)

Fig: Daily variation of global and diffuse radiation on typical
(a) clear and (b) cloudy days on horizontal surface

• The incident solar radiation is also a function of the orientation (or tilt,
due south in northern hemisphere) of solar collector from horizontal.
• A typical pattern of relative irradiation throughout a year for three tilt
angles equal to:
• (i) latitude,
• (ii) (latitude – 15°) and
• (iii) (latitude + 15°) is shown in Fig. 4.11.
• The radiation pattern indicates favouring of certain tilt during certain
periods of the year.
• Therefore, seasonal adjustment of tilt angle may result in enhanced
radiation collection.
• However, overall strategy changes from place to place and also on the
type of application.

Fig: Relative irradiation at tilted surfaces throughout a year

• Maximum solar radiation is received on a collector surface placed normal to incident
rays.
• But as the position of the sun in the sky changes throughout the day, the collector
has to adjust itself continuously to collect maximum radiation.
• Therefore, maximum energy can be collected if collector tracks the sun along two
axes.
• However, providing for 2-axis tracking is expensive and complicated.
• A compromising but less expensive option is to fix the collector at suitable tilt and
track the sun along 1-axis only.
• The most cost effective method with further compromise in the performance is to
have a fix orientation for collector and possibly with some arrangement for seasonal
adjustments only.
• For designing a solar system or for predicting the potential of any solar application
at a location, we need monthly average, daily solar radiation data (both global and
diffuse) on a horizontal and possibly at certain positions of tilt angle of the surface.
• These data are measured at certain measuring stations in a country (at present 51
locations in case of India) and computed for other locations.
• This record is produced in the form of charts and tables and an atlas is prepared to
help in solar systems design.
• Typical record of measured daily solar radiation data for New Delhi is shown in
Tables C1, C2 and C3.

SOLAR TIME (LOCAL APPARENT TIME)
• Solar time is measured with reference to solar noon, which is the time when the sun is crossing
observer’s meridian.
• At solar noon the sun is at the highest position in the sky.
• The sun traverses each degree of longitude in 4 minutes (as earth takes 24
• hours to complete one revolution).
• The standard time is converted to solar time by incorporating two corrections, as follows:
• where Lst and Lloc are the standard longitudes used for measuring standard time of the country
and the longitude of observer’s location, respectively.
• The (+ve) sign is used if the standard meridian of the country lies in western hemisphere (with
reference to prime meridian) and (–ve) if that lies in the eastern hemisphere.
• E is the correction arising out of the variation in the length of the solar day due to variations in
earth’s rotation and orbital revolution, and is called equation of time.
• The solar day, which is the duration between two consecutive solar noons, is not exactly of 24
hours throughout the year.
• E can be determined either by calculation using following equation (within an accuracy of half a
minute) or from the chart given in Fig.
• where B = (360/364)(n – 81)
• and n = day of the year, starting from 1st January

Figure 4.12 The equation of time as function of day of the year
SOLAR TIME (LOCAL APPARENT TIME)

SOLAR RADIATION GEOMETRY
(a) Latitude (Angle of Latitude), (φ) The latitude of a location on earth’s surface is
the angle made by radial line, joining the given location to the center of the
earth, with its projection on the equator plane as shown in Fig.(a).
• The latitude is positive for northern hemisphere and negative for southern
hemisphere.
(b) Declination, (δ) It is defined as the angular displacement of the sun from the
plane of earth’s equator as shown in Fig.(b).
• It is positive when measured above equatorial plane in the northern
hemisphere.
• The declination d can be approximately determined from the equation:
• where n is day of the year counted from 1st January.
(c) Hour Angle, (ω) The hour angle at any moment is the angle through which the
earth must turn to bring the meridian of the observer directly in line with sun’s
rays.

Fig: Latitude and declination angle

Fig: Variations in sun’s declination

Fig: Hour angle ω

• In other words, at any moment, it is the angular displacement of the sun
towards east or west of local meridian (due to rotation of the earth on its
axis).
• The earth completes one rotation in 24 hours.
• Therefore, one hour corresponds to 15° of rotation. At solar noon, as
sunrays are in line with local meridian, hour angle is zero.
• It is +ve in the forenoon and –ve in the afternoon.
• Thus at 06:00 hrs it is +90° and at 18:00 hrs it is –90° as shown in Fig.
• We adopt the convention of measuring it from noon based on LAT, being
+ve in the morning and –ve in the afternoon.
• It can be calculated as:

(d) Inclination Angle (Altitude), (α) The angle between sun’s ray and its
projection on horizontal surface is known as inclination angle, as shown in
Fig(16).
(e) Zenith Angle, (θz) It is the angle between sun’s ray and perpendicular
(normal) to the horizontal plane. (Refer Fig. (16))
(f) Solar Azimuth Angle (γs) It is the angle on a horizontal plane, between the
line due south and the projection of sun’s ray on the horizontal plane.
• It is taken as +ve when measured from south towards west. (Refer Fig.(16))
(g) Slope (Tilt Angle), (β) It is the angle between inclined plane surface, under
consideration and the horizontal.
• It is taken to be +ve for the surface sloping towards south. (Refer Fig.(17))
(h) Surface Azimuth Angle, (γ) It is the angle in horizontal plane, between
• the line due south (OS) and the horizontal projection of normal to the
inclined plane surface (OQ).
• It is taken as +ve when measured from south towards west. (Refer Fig.(17))

Fig(16) Solar inclination angle, solar azimuth angle and zenith angle

Fig(17): Surface azimuth angle and slope (tilt angle)

Fig(18): Angle of latitude, tilt angle, angle of incidence

SOLAR DAY LENGTH
• At sunrise the sunrays are parallel to the horizontal surface. Hence the
angle of incidence, θi = θz = 90°, the corresponding hour angle, ωs, from
Eq.:
• The hour angle, ωs at sunrise (or sunset) for horizontal surface is given by
Eq., which yields positive and negative values for ωs.
• The positive value corresponds to sunrise while the negative to sunset.
• The hour angle between sunrise and sunset is given by:
• Since 15° of hour angle is equivalent to one-hour duration, the duration of
sunshine hours, td or daylight hours is given by:
• The variation of td with latitude (f) for different days (n) of the year is
shown in Fig.(19).

Fig(19): Variation of sunshine hours, td with latitude, on certain days of the year
SOLAR DAY LENGTH

• The hour angle (ωst) at sunrise or sunset as seen by the observer on an
inclined surface facing due south (i.e. g = 0) will also be given by Eq. (4.11)
if the day under consideration lies between September 22 and March 21,
and the location is in the northern hemisphere.
• However, if the day under consideration lies between March 21 and
September 22, the hour angle at sunrise or sunset would be smaller in
magnitude than the value given by Eq. (4.11) and would be obtained by
substituting θi = 90° in Eq. (4.8).
• Thus:
• Therefore, in general, for any day of the year, in northern hemisphere, the
hour angle at sunrise or sunset on inclined surface may be given as:
SOLAR DAY LENGTH

EXTRATERRESTRIAL RADIATION ON HORIZONTAL
SURFACE

EMPIRICAL EQUATIONS FOR ESTIMATING TERRESTRIAL
SOLAR RADIATION ON HORIZONTAL SURFACE
• Since measurements of solar radiation often are not available at every
location of earth, attempts have been made by many researchers to
establish relationships linking the values of radiation (global or diffuse)
with meteorological parameters like number of sunshine hours, cloud
cover and precipitation etc.

• Monthly Average, Daily Global Radiation:

• Monthly Average, Daily Diffuse Radiation
• An empirical expression given below is suggested by Gopinath and Soler for
estimation of diffused radiation:
• The above expression was examined for radiation data available from 40 widely
spread locations all over the world in latitude range from 36° N to 36° S.
• However, when applied to Indian locations, the estimated value is found to be
significantly lower than the actual data.
• This is due the fact that the diffuse component is much larger in India.
• A more accurate estimation for Indian conditions, proposed by Garg and Garg,
is given below:

• Monthly Average, Hourly Global Radiation
• An empirical expression given below is suggested for estimation of
monthly average, hourly, global radiation :

• Monthly Average, Hourly Diffuse Radiation
• An empirical expression given below is suggested for estimation of
monthly average, hourly, diffuse radiation:

SOLAR RADIATION ON INCLINED PLANE SURFACE
• Total radiation incident on an inclined surface consists of three
components:
• (i) beam radiation,
• (ii) diffuse radiation and
• (iii) radiation reflected from ground and surroundings.
• It may be mentioned here that both beam and diffuse components of
radiation undergo reflection from the ground and surroundings.
• Total radiation on a surface of arbitrary orientation may be evaluated as:
• where rb, rd and rr are known as tilt factors for beam, diffuse and reflected
components respectively. The definitions and expressions for these factors
are given below:

Fig: Annual average of the daily radiation in kWh/m2 in India

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