Energy – Generation and Distribution

IES GS & Aptitude paper strategy
July 21, 2017
Energy Conservation
July 27, 2017
  1. Classification
    1. Conventional and Non-conventional
    2. Renewable and Nonrenewable
  2. Generation
    1. Global Status of power Generation
    2. Energy resources
    3. Generation Technologies
    4. Environmental pollution
  3. Transmission and Distribution
    1. Transmission & Distribution
    2. Storage
    3. Grids
  4. Challenges
    1. Availability and Accessibility
    2. Safety and Security
    3. Environmental sustainability
  5. Energy production and distribution in India
    1. India’s Energy mix
    2. Relation of Energy and Development
    3. Challenges
    4. Government Actions and Policies


The energy use occurs in two forms – primary energy and secondary energy. Primary energy is used for direct consumption like industrial heat generation or in internal combustion engines. When the energy sources are used to generate electricity, it becomes the secondary energy. The major energy source at present is the fossil fuels. Different energy resources can be classified as follows.

1.1 Conventional and Non-conventional

This classification is based on the pattern and use. Conventional are those in common use which have advantages of transportation easiness, availability and established technology to generate power.Whereas non-conventional fuels are the new entrants in the developing stages of technology and yet to be exploited at its full potential.

The fuels once nonconventional can become conventional in future. for eg., Nuclear power generation using nuclear fission was once an unconventional source, but now it has become a conventional source. Where as power generation using nuclear fusion is still unconventional.

1.2 Renewable and Nonrenewable

This classification is based on the replenishable nature of fuel resource. Also, the waste generated should be environmentally manageable.  Because of this criteria, the conventional nuclear energy is considered nonrenewable.


Electricity is the most versatile form of energy. Almost all energy resources other than that use in direct consumption, end up in the form of electrical energy.

2.1 Global Status of power Generation

The present global energy mix is as follows. The energy mix is the group of different primary energy sources from which secondary energy for direct use – usually electricity – is produced.

Trends visible in recent times are

  • Fossil fuel prices are falling
  • Renewable energy additions are at record high
  • Decoupling of energy demand growth and growth in major advanced economies. Ie, additional economic growth do not put pressure on energy demand.
  • Developing countries like China and India are diversifying energy mix and improving energy efficiency

2.2 Energy resources

The energy resources are those whose energy can be converted to useful heat or mechanical or electric power. As the humanity develops quest for energy also increases. This has led to discovery of a variety of energy resources.

The difference between different biofuels are summarised as follows,

Fuel Components How? Where?
Biomass Any organic matter Burning releases chemical energy in biomass as heat

In a direct combustion system, to generate hot gas and electricity

Example – Waste to Energy Plants

Biogas A mixture of methane and carbon dioxide Produced by bacterial degradation of organic matter Can be used as cooking fuel

And to generate electricity

Bioethanol Ethyl alcohol Through sugar fermentation process of starch rich biomass As a petrol substitute for road transport vehicles
Biodiesel Alkyl esters From vegetable oils and animal fats through transesterification Biodiesel can  blended with petroleum diesel and also as pure biodiesel fuel

The different generations of biofuels are

 Generation How? Example
First Produced directly from food crops Oils in biodiesel, Bioethanol through fermentation of sugarcane
Second Produced from non-food crops such as wood, organic waste, food crop waste and specific biomass crops Waste to energy plants

Biodiesel from jatropha seeds

Third Produced from specially engineered energy crops such as algae Algae based wide range of fuels such as diesel, petrol and jet fuel
Fourth Produced using the same processes as second generation biofuels.

But also captures and stores CO2 in the process.

Processes such as oxy-fuel combustion( burning a fuel using pure oxygen to produce a CO2 rich flue gas ready for sequestration)

2.3 Generation Technologies

The power generation can be either direct or indirect. In direct method, energy in any form is directly converted to electrical energy. In indirect method, energy from the fuel is transformed into another form(commonly kinetic energy of hot gas) to generate electricity. Some examples are shown in the following diagram.

Some important and latest generation technologies are discussed below.

A. Solar

The main technologies are Solar Photovoltaic (direct power generation) and solar thermal(indirect power generation). Technologies in this field are evolving very fast. 

Solar PV

Solar PV is the leading technology at present.

  • The most common solar PV technologies are crystalline silicon-based systems.
  • Thin-film modules are the latest established technology .
  • Concentrating PV, where sunlight is focused onto a smaller area has just entered full market deployment.They have very high efficiencies of up to 40%.
  • Other technologies, such as organic PV cells, are still in the research phase.

The comparison of crystalline silicon-based panels and Thin-film panels are given below

Thin film Panel

Silicon Panel

Module Efficiency at 25 degree C is about 13-19% Module Efficiency at 25 degree C is about 12%
Has lower Temperature Coefficients. So energy yield is higher at operating temperatures Has higher Temperature Coefficients. Energy yield decreases considerably with temperature rise
Only that part of the thin film panel that is not exposed to sunlight stops producing power Power production gets completely cut off even if a small part of the panel is covered by shade

Solar Thermal Plant

A concentrating solar power (CSP) plant comprises a field of solar collectors, receivers, and a power block, where the heat collected in the solar field is transformed into kinetic energy of steam, then to electricity.

B. Thermal Power Plants

Ultra Modern Super Critical Coal Based Thermal Power Technology 

Conventional coal-fired power plants, which make water boil to generate steam that activates a turbine, have efficiency of about 32%.  

Supercritical (SC) and ultra-supercritical (USC) power plants operate at temperatures and pressures above the critical point of water, i.e. above the temperature and pressure at which the liquid and gas phases of water coexist in equilibrium, at which point there is no difference between water gas and liquid water.


  • This results in higher efficiencies – above 45%
  • Thus Supercritical (SC) and ultra -supercritical (USC) power plants require less coal per megawatt-hour
  • Lower emissions (including carbon dioxide and mercury) because of low coal usage
  • Higher efficiency and lower fuel costs per megawatt

C. Ocean Energy

Waves, tides and currents can be used to generate electricity by capturing its kinetic energy. The temperature difference across ocean water layers can be harnessed using a developing technology called Ocean thermal energy conversion, or OTEC.

There are two types of OTEC technologies to extract thermal energy and convert it to electric power:

  • Closed cycle

In the closed cycle method, a working fluid, such as ammonia, is pumped through a heat exchanger and vaporized. This vaporized steam runs a turbine. The cold water found at the depths of the ocean condenses the vapour back to a fluid where it returns to the heat exchanger.

  • Open cycle

Here, the warm surface water is pressurized in a vacuum chamber and converted to steam to run the turbine. The steam is then condensed using cold ocean water from lower depths.

D. Geo-Thermal Energy

Ground Source Heat Pumps/ Geo-exchange Pumps

  • Ground Source Heat Pumps use the earth’s relatively constant temperature between 16 – 240C  at a depth of 20 feet to provide heating, cooling, and hot water for homes and commercial buildings
  • GSHP harvests heat absorbed at the Earth’s surface from solar energy
  • GHP’s is effective in all kind of climate zones

Geothermal energy from magma

  • Drilling to a depth of 4,659 metres (nearly 3 miles), engineers hope to access hot liquids under extreme pressure and at temperatures of 427 degrees C (800 F)
  • It will create steam that turns a turbine to generate clean electricity
  • If successful, the experimental project could produce up to 10 times more energy than an existing conventional gas or oil well
  • The project is called Iceland Deep Drilling Project (IDDP)

Fuel cells

E. Hydrogen Energy

  • A fuel cell is a device that generates electricity by a chemical reaction
  • Hydrogen is the basic fuel in the cell, it requires oxygen also


  • Hydrogen atoms enter a fuel cell at the anode and gets ionised as positive ions by losing electrons. 
  • Oxygen enters the fuel cell at the cathode and combines with electrons returning from the electrical circuit
  • The hydrogen ions travel through the electrolyte to form water combining with Oxygen ions
  • Thus the chemical reaction generates an electrical flow continuously. 


  • The fuel cell technology offers high conversion efficiency
  • It provides modularity, compactness and noise-free operations.  


  • It can be used in small power generating sets
  • Two and three wheeler (motorcycles) and also in heavy vehicles
  • Catalytic combustion systems for residential and industrial sectors 

F. Shale Gas

  • Shale Gas is the gas trapped in the sedimentary shale rock formations.
  • Shale gas is extracted by pumping high quantities of chemicals, water and sand into dense shale rock formations to release gas that is then pumped to the surface. This is called fracking.
  • Shale gas has gained widespread popularity in recent years following technological advances that make it commercially viable
  • In the USA shale gas production has shot up in 2012, creating disruptions in global petroleum market

G. Coal Bed Methane(CBM)

  • It is a natural gas found in coal seams
  • It mainly consists of Methane (CH4) with minor amounts of nitrogen, carbon dioxide and heavier hydrocarbons like ethane
  • Earlier the CBM was wasted and vented out into the atmosphere during mining
  • Now CBM is considered as a precious energy resource
  • Extraction requires drilling wells into the coal seams and removing water contained in the seam and release absorbed (and free) gas out of the coal

H. Syngas, Water gas and Producer Gas

Composition wise these gases are almost similar, but with slight differences

  • Syngas is a mixture of Carbon Monoxide and Hydrogen with possibility of having carbon dioxide content sometimes. It is the product of steam or oxygen gasification of organic material such as biomass. 
  • Water gas is a mixture of only Carbon Monoxide and hydrogen. It is produced using Lowe’s Gas Process, by passing steam over a red-hot carbon fuel such as coke

H2O + C → H2 + CO

  • Producer gas is a mixture of combustible (Hydrogen, Methane and Carbon Monoxide) and non-combustible (Nitrogen, Carbon dioxide) gases. Similar to syngas, producer gas is also produced by gasification of carbonaceous material such as coal or biomass.

I. Nuclear Energy

Most nuclear electricity is generated using just two kinds of reactors which were developed in the 1950s and improved since. New designs are coming forward and some are in operation. The energy released from continuous fission of the atoms of the fuel is harnessed as heat in either a gas or water, and is used to produce steam. The steam is used to drive the turbines which produce electricity (as in most fossil fuel plants).

Nuclear power plants in commercial operation or operable(IAEA data, end of 2015)

Reactor type Main countries Number GWe Fuel Coolant Moderator
Pressurised water reactor (PWR)

US, France, Japan, Russia, China
enriched UO2
Boiling water reactor (BWR)

US, Japan, Sweden
enriched UO2
Pressurised heavy water reactor (PHWR)

Canada, India
natural UO2
heavy water
heavy water
Gas-cooled reactor (AGR & Magnox)

natural U (metal),
enriched UO2
Light water graphite reactor (RBMK & EGP)


11 + 4
enriched UO2
Fast neutron reactor (FBR)

PuO2 and UO2
liquid sodium
  TOTAL 441 384      

Fast Breeder Reactors (FBRs) in India 

  • Fast reactors generally have an excess of neutrons that can breed more fuel from otherwise non-fissionable isotopes.
  • The most common breeding reaction is that on uranium-238 to produce plutonium-239 . 
  • Breeder reactors could, in principle, extract almost all of the energy contained in uranium or thorium, decreasing fuel requirements. 

India’s three stage nuclear programme envisages, construction of Fast Breeder Reactors (FBRs)  in Stage-II, fuelled by Plutonium produced in stage-I. 

KAMINI(Kalpakkam Mini reactor) was the first reactor in the world designed specifically to use uranium-233 fuel.

What is the progress now?

  • India have designed an Advanced Heavy Water Reactor (AHWR) which would  breed U-233 from Thorium. 
  • Construction of the pilot AHWR was envisaged in the 12th plan period. 2018 is now the target date. 

Advanced nuclear power systems

Generation IV reactors  are currently being researched for commercial applications by the Generation IV International Forum, motivated by a variety of goals including improved safety, sustainability, efficiency, and cost.

Nuclear Fusion Reactors

  • Nuclear fusion is a potentially revolutionary power source using process that fuels the Sun
  • Various projects are under development to achieve controlled nuclear fusion
  • The International Thermonuclear Experimental Reactor – The ITER Project
    • Is a collaboration of 35 nations to build the world’s largest tokamak, a magnetic fusion device
    • India is also a member of this project
    • Aims to begin the fusion operations(deuterium-tritium operation) by 2035
  • Tokamak Energy is a leading private fusion energy companies in the world and have recently announced its achievement of generating first plasma in the world

2.4 Environmental Pollutions

A. Thermal

The major share of energy generation worldwide is from fossil fuels. Burning of fossil fuels is the major source of air pollutants and greenhouse gas emissions.

The pollutants include

So the focus is now to shift to cleaner technologies and renewable energy sources for power generation.

B. Nuclear

The environmental damage from nuclear power plants is 2 fold – Danger of  Accidents and Issue of waste disposal


Accidents in the reactor core produces lot of heat which if not controlled can lead to a meltdown of fuel rods in the reactor core.

If a meltdown happens by accident

  • It will release large quantities of highly dangerous radioactive materials in the environment with disastrous consequences to the humans, animals and plants.
  • To prevent this type of accidents and reactor blow up, the reactors are designed to have a number of safety features.

Inspite of these safety measures three disasters in the nuclear power plants are noteworthy- namely at

  • ‘Three Mile Island’ in Middletown (U.S.A.) in 1979,
  • At Chernobyl (U.S.S.R.) in 1986 and
  • Fukushima Daiichi nuclear disaster(Japan) in 2011. 

Waste Management

Radioactive wastes are generated during various operations of the nuclear fuel cycle.

  • Mining, nuclear power generation, and various processes in industry, defense, medicine and scientific research produce byproducts that include radioactive wastes.
  • Radioactive waste can be in gas, liquid or solid form, and its level of radioactivity can vary.
  • The waste can remain radioactive for a few hours or several months or even hundreds of thousands of years.
  • Depending on the level and nature of radioactivity, radioactive wastes can be classified as follows,

The technology of vitrification

Why vitrification?

Before disposal, nuclear waste needs to be

  1. In solid form to minimise the volume
  2. Shielded to resist leaching to surroundings

The process involved are

  1. Identifying a suitable matrix material – such as cement, bitumen, polymers or borosilicate glass – that will ensure stability of the radioactive materials
  2. Immobilising the waste through mixing with the matrix material
  3. Packaging the immobilised waste in metal drums, metal or concrete boxes or containers, or copper canisters for disposal in deep geological formations

What is vitrification?

  • Vitrification process is essentially batch operation consisting of heating and fusing of pre-concentrated waste with the glass forming additives
  • Is carried out in melters based on induction heating
  • In general borosilicate glass is chosen as the matrix material as the glass is stable for thousands of years, which is more than the time required for the radioactive materials to decay

3. Transmission and Distribution

The most challenging issue in the power sector is – the generated power cannot be stored for future use, and it has to be distributed immediately. Most storage techniques available at present are highly inefficient. Thus transmission and distribution plays a major role. Managing power distribution is a balancing act, with the goal being to create a steady supply for consumers without overloading the system with too much power.

3.1 Transmission & Distribution

Transmission Distribution Grid
What? Bulk movement of electrical energy from a generating site, such as a power plant, to an electrical substation. Local wiring between high-voltage substations and customers Interconnected network for delivering electricity from suppliers to consumers.
How? At a generating plant, electric power is stepped up to several thousand volts by a transformer and delivered to the transmission line. At numerous substations on the transmission system, transformers step down the power to a lower voltage and deliver it to distribution lines.

Other method used is High Voltage DC (HVDC) transmission

Transformers step down the power to a lower voltage and deliver it to distribution lines It consists of generating stations that produce electrical power, high voltage transmission lines that carry power from distant sources to demand centers, and distribution lines that connect individual customers.

Transmission & Distribution Losses

The overall power losses between the power plant and consumers occurs in the range between 8 and 15%. Energy is lost as heat, due to resistance of the conducting wires, during the transmission. High voltage transmission is used to reduce the heat losses.

3.2 Storage

Energy storage is a technical challenge. Recently, strides made in battery technology are providing hopes for energy storage, which is vital to integrate renewable power especially solar and wind power to the network. The common methods used at present are

1.Water pumped to reservoirs

The water pumped to reservoirs using excess power can be used to generate hydroelectric power when required.

2.Battery storage

Battery storage is the most sought after technology. Rapid advancements in recent times have pulled down the cost .The two types of battery storage commonly used are

a).Solid State Batteries: 

  • Uses a range of electrochemical storage solutions, including advanced chemistry batteries and capacitors.

b).Flow batteries: 

  • These are batteries where the energy is stored directly in the electrolyte solution for longer cycle life, and quick response times.

3.3 Grids

Grids are the inter connectors of power to the consumers. The grid should be smart enough to handle the intermittency of power generated and consumer demand fluctuations . Advancements in information and communication technologies have made it possible.

1.Software aided smart grid

  • ‘Smartness’ is the digital technology that allows for two-way communication between the power utility and its customers, and the sensing along the transmission lines.
  • The Smart Grid will consist of controls, computers, automation, and new technologies and equipment working together, to respond digitally to the quickly changing electric demand.
  • Green energy corridor project is one such example

These grids are essential to integrate the renewable power generation to the supply system, as the renewable energy are mostly non-continuous in nature.

2. Micro and Nano Grids

The topology of the future electricity grid might be as a honeycomb having decentralised micro and nano grids in place of a large grid.

  • micro grid is composed of power generation system, energy storage facility and load management system.
  • It can cater 10 KW – 10 MW (power to 25,000 households). 
  • Nano grids comprises of a water pump and solar panels.

Advantages of Micro and Nano grids

  • Lower costs through resource sharing and controlling peak hour loads
  • complement SHS(solar home systems)
  • help with grid stability as renewable proportion increases in the generation mix
  • Practical solution to provide electricity to off grid and inaccessible areas

4. Challenges

The international Energy Agency has identified the following challenges in the power sector.

4.1 Availability & Accessibility

Energy is needed to meet the development objectives. There should be a reliable power supply for industrial development. The energy resources are not uniformly distributed in the world. Not only resources, but also technology is required to harness it is not available to all countries.

More than 1 billion people in the world(it means 1 in 5) do not have access to electricity. Reasons – non-availability and high prices

4.2 Safety and Security

There are treats of cyber attacks on the critical power infrastructure. 

4.3 Environmental sustainability

2/3rd of global GHGs comes from the energy sector. Actions has to be taken to curb the emissions, meeting at the same time, the energy demands for development.

5. Energy production and distribution in India

The energy scenario at present in India is marked by increasing energy deficit and increasing focus on renewable power.

5.1 India’s Energy mix

Fuel MW % of Total
Total Thermal 2,21,626 67.1%
 Coal 1,95,603 59.2%
 Gas 25,185 7.6%
 Oil 838 0.3%
Hydro (Renewable) 44,594 13.5%
Nuclear 6,780 2.1%
Other Renewable Energy Sources 57,260 17.3%
Total 330,261  

Other Renewable Energy Sources include Small Hydro Project, Biomass Gasifier, Biomass Power, Urban & Industrial Waste Power, Solar and Wind Energy. We can see that India is more dependent on thermal power, of which coal shares the major part.

5.2 Relation of Energy and Development

There is a positive correlation between energy access and the Human Development Index (HDI). The energy needed to meet development objectives is called lifeline energy.  It is benchmark at 2000-Watt (W) per capita. It is a basic level of energy which accounts for housing, mobility, food, consumption (manufactured goods) and infrastructure. Also reliable and quality power available 24X7 is important for industrial development. The per capita energy consumption in India has reached only 1075 kWh as of 2015-16.

5.3 Challenges

  1. The per capita energy consumption is only 1075 kWh against the benchmark of 2000KWh. It means we have to increase our energy production to give  at least the lifeline energy for all
  2. Nearly 96% villages in India are electrified but only 69% of homes have electricity connections
  3. The Power distribution companies are not performing well, creating bottlenecks between generation and supply
  4. The Aggregate Technical and Commercial (AT&C) Losses of transmission and distribution in India is very high (almost 25%)
  5. Concerns of pollution and the disposal of the large amount of ash from coal based power stations, which are the mainstay of India’s power generation
  6. The challenge of upgradation of grid network to accumulate the expected renewable power generation
  7. In World Bank “Ease of doing business” , ‘Getting Electricity’ is the one of these parameters, where India was lagging.

5.4 Government Actions and Policies

In order to address the above challenges, government of India has several programmes and policies as explained below

  1. Capacity Additions – including initiative for facilitating the development of a few Ultra Mega Power Projects of about 4,000 MW capacity each under tariff based competitive bidding route using super critical technology on build, own and operate basis. 
  2. 24×7 Power For All Scheme – to provide each household access to electricity, round the clock by 2019. Is a joint initiative with the states covering all segments of power sector i.e. Power generation, transmission and distribution, energy efficiency, health of Discom etc. 
  3. Pradhan Mantri Sahaj Bijli Har Ghar Yojana –“Saubhagya” is a scheme to ensure electrification of all willing households. The objective is to provide energy access to all by last mile connectivity and electricity connections to all remaining un-electrified households in rural as well as urban areas to achieve universal household electrification in the country. Poor households would be provided electricity connections free of cost. Saubhagya is a schematic support to address the issue of energy access.
  4. Integrated Power Development Scheme (IPDS) – Strengthening of sub-transmission and distribution networks in the urban areas
  5. Deendayal Upadhyaya Gram Jyoti Yojana (DDUGJY) – Strengthening of sub-transmission and distribution networks in the rural areas. It envisages creation of basic electricity infrastructure in villages / habitations, strengthening & augmentation of existing infrastructure, metering of existing feeders / distribution transformers / consumers to improve quality and reliability of power supply in rural areas. Besides this, last mile connectivity and free electricity connections are also provided to BPL households only identified by the States as per their list.
  6. National Grid – nationwide synchronous power grid, interconnecting all the five regional grids
  7. National Smart Grid Mission
  8. Ujwal DISCOM Assurance Yojana (UDAY) is the financial turnaround and revival package for electricity distribution companies of India (DISCOMs) to find a permanent solution to the financial troubles in the DISCOMs
  9. The biggest improvement in ease of doing business was seen in the area of ‘getting electricity’ where the ranking jumped to 26 from the last year’s 51st position due to various initiatives taken by the ministry
  10. Energy Efficiency Programmes – Ex – UJALA
  11. Programmes to reduce emissions -Ex- Pradhan Mantri Ujjwala Yojana
  12. Renewable Energy Projects


  1. ARUN SHARMA says:

    First of all thanks to you @Chanu Adapala sir and Annueja Peendli mam for helping the aspirsnts in a way no one is doing. \
    But I have a question in mind whether this much detail is necessary as you have provided in Energy – Generation and Distribution.
    Because there is a major difference in questions being asked in civils and ese and the material you are proving here is much better for civils aspirants.
    PLEASE HAVE YOU VIEWS on this .Thank you

    • aman says:

      question will be more depth:year by year the depth as of profensional working in the fields,not only for shake of academics

      if india decides to cut emmisions in international treaties it will be first ese engineers who will take the direction of work…

  2. IES GS says:

    Hi Arun Sharma,

    This topic is more technical in nature. In civils, there is no need of more technical details. The questions in IES prelims can go to the technical details, like the previous year questions about the waste water treatment. In this aspect, the pollution angle of energy is important, so is the nuclear waste management. Moreover IES paper may ask on recent technological developments.

    Definitely this material will be useful for civil service aspirants also.

  3. vishant sharma says:

    first of all thanks to all faculty members who are providing us such a good study material for GS .but 1 question arise in my mind that is this study material enough?,is it cover also latest changes which are going on regarding energy?,should i make short notes from this material?, can i get a 120 marks only by following your material which u r provinding to us? plz clear my all doubt .thanks

  4. IES GS says:

    Constant updates are required in any dynamic topic. We are covering the news updates on these topics through our daily news section. These articles are crisp enough to be used as a note. You can keep updating the notes.

  5. aman says:


  6. Mohd arif says:

    Sir plz provide current affairs

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