ET-332 Power Plant PDF

FOR DAE THIRD-YEAR ELECTRICAL TECHNOLOGY Developed by: (ACADEMICS WING) TEVTA PUNJAB, 96 H, GULBERG, LAHORE  PREFACE The world is currently facing a crucial moment in i...

FOR DAE THIRD-YEAR ELECTRICAL TECHNOLOGY Developed by: (ACADEMICS WING) TEVTA PUNJAB, 96 H, GULBERG, LAHORE  PREFACE The world is currently facing a crucial moment in its history, where energy consumption and its impact on the environment are becoming more and more pressing issues. The way we generate and consume energy has a significant impact on our planet, and it's up to us to ensure that we use it efficiently and responsibly. This book is an exploration of power plants and energy conservation. It aims to provide readers with an understanding of the different types of power plants, their workings, and their impact on the environment. Furthermore, the book focuses on energy conservation measures that can be implemented in homes, businesses, and industries to reduce energy consumption and lessen the burden on the planet. This book is intended for anyone interested in understanding the basics of power plants and energy conservation. Whether you are a student, a researcher, a policy-maker, or an ordinary citizen, this book will provide you with the knowledge and tools to make informed decisions and take responsible actions towards a sustainable future. Compiled by: Engr. Muhammad Faheem Akram Dharala (Instructor) Government College of Technology, Multan Engr. Amad Ali (Instructor) Government College of Technology, Multan Contents CHAPTER 1 SOURCES OF POWER........................................................................ 7 1.1 Introduction to different sources of power............................................ 7 1.2 Salient features of systems of power sources........................................ 7 1.2.1 The type and capacity of the power sources................................... 8 1.2.2 The configuration and interconnection of the power sources........ 8 1.2.3 The control and management of the power sources...................... 8 1.2.4 The integration and interaction with the load and the grid............ 8 1.3 Comparison of different sources, Thermal, Hydel, Nuclear, Solar, Tidal, Wind Magneto Dynamic and Geothermal.................................................... 8 1.3.1 Thermal Power................................................................................. 9 1.3.2 Hydropower (Hydel)....................................................................... 10 1.3.3 Nuclear Power................................................................................ 11 1.3.4 Solar Power.................................................................................... 13 1.3.5 Tidal Power..................................................................................... 14 1.3.6 Wind Power.................................................................................... 15 1.3.7 Magneto Hydrodynamic (MHD) Power......................................... 16 1.3.8 Geothermal Power......................................................................... 17 1.4 Solar Power System............................................................................... 19 1.4.1 Calculation of load for solar PV system design.............................. 20 1.4.2 Planning for installation of solar panel up to 3 KW....................... 21 1.4.3 Testing of solar power plant.......................................................... 23 1.5 Wind power system.............................................................................. 24 1.5.1 Parts of wind power plant.............................................................. 27 CHAPTER 2 THERMAL POWER STATION............................................................ 36 2.1 Introduction to thermal power station................................................. 36 2.2 Selection of fuels and site..................................................................... 37 2.2.1 Selection of Fuel............................................................................. 37 2.2.2 Selection of Site.............................................................................. 39 1|Page 2.3 Types of thermal power stations and their working............................. 40 2.3.1 Coal-fired power plants:................................................................ 40 2.3.2 Oil-fired power plants:................................................................... 41 2.3.3 Gas-fired power plants:.................................................................. 42 2.3.4 Combined Cycle Thermal Power Plants:........................................ 43 2.4 Parts of thermal power station and their working with schematic diagram....................................................................................................... 44 2.4.1 Coal and ash handling.................................................................... 44 2.4.2 Steam generating plant.................................................................. 45 2.4.3 Steam turbine................................................................................. 46 2.4.4 Alternator....................................................................................... 46 2.4.5 Feed Water..................................................................................... 46 2.4.6 Cooling arrangement..................................................................... 46 2.5 Boilers and their types.......................................................................... 47 2.5.1 Working principle of boiler............................................................ 47 2.5.2 Types of steam boiler..................................................................... 47 2.6 Steam turbine working principle and construction.............................. 50 2.6.1 Working principle........................................................................... 50 2.6.2 Construction of steam turbine....................................................... 50 2.7 Types of steam turbine......................................................................... 51 2.7.1 Impulse Turbine............................................................................. 51 2.7.2 Reaction Turbine............................................................................ 52 2.8 Selection and capacity of steam turbine............................................... 54 2.9 Construction of turbo generators......................................................... 55 2.9.1 Working Principle........................................................................... 55 2.9.2 Construction................................................................................... 55 2.9.3 Ratings............................................................................................ 56 2.10 Function and application of condenser in a steam turbine power station..................................................................................................................... 56 2.10.1 Function of Condensers............................................................... 56 2.10.2 Types of Condensers.................................................................... 56 2|Page  2.10.3 Applications of Condensers in Steam Turbine Power Stations:.. 58 2.11 Water circulation system in a thermal power station........................ 59 2.11.1 Boiler............................................................................................ 59 2.11.2 Turbine......................................................................................... 60 2.11.3 Condenser.................................................................................... 60 2.11.4 Feed water pump......................................................................... 60 2.11.5 Feed water heater........................................................................ 60 2.11.6 Economizer................................................................................... 61 2.12 Introduction to diesel engine power station...................................... 61 2.12.1 Major Components of a diesel power station............................. 62 2.12.2 Site Selection for diesel power plant:.......................................... 64 2.13 Working of a diesel Engine, two strokes, four strokes and their comparison................................................................................................. 65 2.13.1 Two Stroke Diesel Engine............................................................. 65 2.13.2 Four Stroke Diesel Engine............................................................ 67 2.13.3 Comparison of Two Stroke and Four Stroke Diesel Engines........ 72 2.14 Cooling system of diesel engine.......................................................... 72 CHAPTER 3 NUCLEAR POWER STATIONS.......................................................... 79 3.1 Introduction to Nuclear power station................................................. 79 3.2 Main parts of nuclear power station with schematic diagram............. 81 3.3 Principle of nuclear energy, atomic structure, atomic, number........... 83 3.3.1 Principle of nuclear energy............................................................ 83 3.3.2 Atomic Structure............................................................................ 83 3.4 Kinetic energy and isotopes, fuel (Nuclear).......................................... 85 3.4.1 Kinetic energy................................................................................. 85 3.4.2 Isotopes.......................................................................................... 86 3.4.3 Radio Activity................................................................................. 87 3.4.4 Half Life.......................................................................................... 87 3.4.5 Binding Energy and Mass Defect................................................... 88 3.4.6 Nuclear Fuel................................................................................... 89 3.5 Nuclear fission and fusion..................................................................... 90 3|Page  3.5.1 Nuclear Fusion................................................................................ 90 3.5.2 Nuclear Fission............................................................................... 92 3.6 Heavy water and its importance........................................................... 94 3.7 Nuclear reactor..................................................................................... 95 3.8 Types of a nuclear reactor.................................................................... 96 3.8.1 Boiling Water Reactor:................................................................... 97 3.8.2 Pressurized Water Reactor............................................................ 99 3.8.3 Heavy Water Cooled and Moderated type (CANDU) reactors.... 100 3.8.4 Gas Cooled Reactors.................................................................... 101 3.8.5 Liquid Metal Cooled Reactors...................................................... 103 3.8.6 Homogeneous Reactors............................................................... 104 3.8.7 Fast Breed Reactors..................................................................... 105 3.9 Site selection for nuclear power plant................................................ 105 3.10 Nuclear power stations in Pakistan................................................... 106 CHAPTER 4 HYDEL POWER STATION............................................................... 114 4.1 Introduction to Hydel Power station.................................................. 114 4.2 Classification of Hydel Power Station................................................. 115 4.2.1 Classification of hydroelectric power plants w.r.t head.............. 115 4.2.2 Classification of hydroelectric power plants w.r.t availability of water flow............................................................................................. 118 4.2.3 Classification of hydroelectric power plants w.r.t loading.......... 119 4.3 Merits & demerits of Hydel Power Station......................................... 120 4.4 Selection of site for Hydel Power Station........................................... 121 4.5 General arrangement and operation of Hydel Power Station............ 122 4.6 Types of Hydel turbines and their characteristic................................ 125 4.6.1 Impulse Turbines.......................................................................... 126 4.6.2 Reaction Turbines........................................................................ 128 4.7 Governing of Turbines......................................................................... 129 4.8 Comparison between turbines........................................................... 130 4.9 Hydro- electric generation in Pakistan................................................ 131 CHAPTER 5 GAS TURBINE POWER STATION................................................... 139 4|Page  5.1 Introduction to Gas Power station...................................................... 139 5.2 Construction & working of simple gas turbine................................... 141 5.2.1 Construction................................................................................. 141 5.2.2 Working of simple gas turbine..................................................... 145 5.2.3 Terms and Definitions.................................................................. 149 5.3 Layout of a gas turbine station........................................................... 150 5.4 Introduction to combined cycle power station.................................. 151 5.5 Gas turbine and combined cycle plants in Pakistan........................... 155 5.5.1 Gas Turbine Power Plants............................................................ 155 5.5.2 Combined Cycle Power Plants..................................................... 155 5.6 Environmental effects of Gas Turbine Plant and measures to improve the situation.................................................................................................... 156 5.6.1 Environmental Effects of Gas Turbine Plants............................... 156 5.6.2 Measures to Improve the Situation............................................. 156 CHAPTER 6 TARIFFS AND ECONOMICS............................................................ 164 6.1 Introduction to economics consideration........................................... 164 6.1.1 Cost of Generation....................................................................... 164 6.1.2 Fixed or capital cost..................................................................... 164 6.1.3 Running or operation cost........................................................... 166 6.2 Factors influencing cost of generation, load factor, demand factor, diversity factor.......................................................................................... 168 6.2.1 Some Important Terms................................................................ 171 6.2.2 Measures to reduce cost of electricity........................................ 172 6.3 Different load curves........................................................................... 173 6.4 Depreciation of plant cost and method of charging........................... 176 6.4.1 Straight line method.................................................................... 176 6.4.2 Sinking fund method.................................................................... 177 6.5 Types of Tariffs.................................................................................... 178 6.5.1 Objectives of tariff........................................................................ 179 6.5.2 Desirable Characteristics of a Tariff............................................. 179 6.5.3 Types of Tariff.............................................................................. 180 5|Page  6.6 Calculations on tariffs......................................................................... 184 6.7 Fundamentals of load management................................................... 190 6.7.1 Techniques of Power Load Management.................................... 192 CHAPTER 7 CONSERVATION OF ENERGY....................................................... 202 7.1 Introduction & necessity of energy conservation............................... 202 7.1.1 Necessity of Energy Conservation................................................ 204 7.2 Sources of energy loss and major Items of energy consumption....... 204 7.3 Ways to limit energy losses................................................................. 206 7.4 Power Factor....................................................................................... 210 7.4.1 Power Triangle............................................................................. 212 7.4.2 Causes of Low Power Factor..................................................... 213 7.4.3 Disadvantages of Low Power Factor............................................ 214 7.4.4 Power Factor Improvement......................................................... 215 7.4.5 Power Factor Improvement Equipment................................... 216 7.4.6 Importance of Power Factor Improvement............................ 220 7.5 Calculations of power factor improvement in the context of energy conservation............................................................................................. 221 6|Page CHAPTER # 01 Sources of Power CHAPTER 1 SOURCES OF POWER Chapter objectives: After studying this chapter, a student will be able to  Understand the Introduction of different sources of power.  Understand the difference between conventional, non- conventional, indigenous and non-indigenous sources of energy.  Understand the ccomparison of different sources, Thermal, Hydel, Nuclear, Solar, Tidal, Wind Magneto Dynamic and Geothermal.  Understand Solar Power System types, design and testing.  Wind Power System types, design and testing. 1.1 Introduction to different sources of power Electric power is the rate of doing work or transferring energy. It is measured in watts (W) or kilowatts (kW). Electric power sources supply energy to electric systems by moving the electrons in a circuit and thereby creating an electric current. This power is mainly divided into two categories being known as AC power and DC power. The most common sources for the transfer of electrical power are batteries and grid (mains) electricity. There are many sources of power that can be used to generate electricity, such as solar, wind, hydro, nuclear, geothermal, and tidal. These sources have different advantages and disadvantages in terms of cost, availability, environmental impact and reliability. In this chapter, we shall introduce the different sources of power and their salient features. 1.2 Salient features of systems of power sources The systems of power sources can be classified into two main categories: renewable and non-renewable. Renewable sources are those that can be replenished naturally or by human activities, such as solar, wind, hydro, biomass and geothermal. Non-renewable sources are those that are finite and cannot be replaced once they are used up, such as coal, oil, gas and nuclear. These sources are also categorized as indigenous and non-indigenous sources. 7|Page CHAPTER # 01 Sources of Power Indigenous sources are sources that are found within the local environment of a particular region or area and have been traditionally used by the population of that area to produce electricity. Examples of indigenous fuels include wood, charcoal, peat, and dung. Non-indigenous sources, on the other hand, are sources that are not typically found within the local environment of a particular region or area. These fuels are often imported from other regions or countries and effect the cost of power system. The salient features of power sources are: 1.2.1 The type and capacity of the power sources Different power sources have different characteristics, such as voltage, current, frequency, power factor, efficiency, reliability, and environmental impact. The type and capacity of the power sources determine the performance and cost of the system. 1.2.2 The configuration and interconnection of the power sources The power sources can be connected in series, parallel, or hybrid modes to achieve different objectives, such as voltage regulation, load sharing, fault tolerance, and redundancy. The configuration and interconnection of the power sources also affect the stability and security of the system. 1.2.3 The control and management of the power sources The power sources need to be controlled and managed to ensure optimal operation and coordination. The control and management functions include monitoring, protection, regulation, synchronization, dispatching, and load balancing. The control and management can be done locally or remotely, using wired or wireless communication technologies. 1.2.4 The integration and interaction with the load and the grid The system of power sources needs to be integrated and interact with the load and the grid to meet the demand and supply requirements. The integration and interaction involve aspects such as power quality, harmonics, voltage sag/swell, frequency deviation, islanding, grid support, and grid services. 1.3 Comparison of different sources, Thermal, Hydel, Nuclear, Solar, Tidal, Wind Magneto Dynamic and Geothermal. Changing one form of energy into a different form is called energy conservation. Total amount of energy remains same during this process. 8|Page CHAPTER # 01 Sources of Power Power generation is an energy conversion process that transforms the available source of energy into electrical energy. Figure 1.1. A Simple Energy Conservation Process The source of energy can be a fossil fuel, such as coal, oil or natural gas, a renewable resource, such as wind, solar or hydro, or a nuclear fuel, such as uranium or thorium. The process of power generation involves several steps, depending on the type of source and the technology used. In this section, we will compare the different power sources based on their salient features mentioned above. 1.3.1 Thermal Power Thermal power plants utilize heat to generate electricity. This heat is usually derived from the burning of fossil fuels such as coal, oil, or natural gas. These types of power plants are currently the primary source of electricity worldwide. However, they also contribute to greenhouse gas emissions and other environmental concerns. Thus, there is an increasing focus on alternative and renewable energy sources. Merits: a. High Reliability: Thermal power plants are highly reliable and have a high operational efficiency, ensuring uninterrupted power supply to the grid. b. Large Capacity: Thermal power plants can generate a large amount of electricity and are capable of meeting the power demands of both industrial and domestic consumers. c. Flexibility: Thermal power plants are highly flexible and can easily adapt to changes in power demand. 9|Page CHAPTER # 01 Sources of Power d. Cost-Effective: Thermal power plants are relatively cost-effective to build and operate compared to other power generation technologies. e. Low Maintenance Costs: Thermal power plants have low running and maintenance costs and require minimal downtime for maintena-nce. Demerits: a. Environmental Impact: Thermal power plants are known to emit large amounts of greenhouse gases, including carbon dioxide, which contributes to global warming and climate change. b. Water Consumption: Thermal power plants require large amounts of water for cooling purposes, which can lead to water shortages in areas with limited water resources. c. Land Use: Thermal power plants require a large amount of land, which can be a challenge in densely populated areas. d. Health Hazards: Thermal power plants can emit harmful pollutants such as sulfur dioxide, nitrogen oxides, and particulate matter, which can have negative health impacts on nearby communities. e. Fuel Dependence: Thermal power plants rely on fossil fuels such as coal, oil, and natural gas, which are finite resources and subject to price volatility in the global market. 1.3.2 Hydropower (Hydel) Hydropower or hydel power is generated from the energy of flowing water, by capturing its kinetic energy using turbines. Typically, dam projects are built to store this water for power generation. This type of power source is widely available, renewable, and emits comparatively fewer greenhouse gases. However, the construction of large hydropower projects can have significant land and aquatic ecosystem impacts. Merits: a. Renewable Energy: Hydroelectric power plants produce electricity using a renewable energy source - water, which means that it is sustainable, and there are no harmful emissions to the environment. 10 | P a g e CHAPTER # 01 Sources of Power b. Cost-Effective: Hydroelectric power plants have a lower cost of operation compared to thermal and nuclear power plants, which can save consumers money on their electricity bills. c. Large Capacity: Hydroelectric power plants can generate large amounts of electricity, making them an excellent option for meeting the power demands of both industrial and domestic consumers. d. Long Life Span: Hydroelectric power plants have a long life span, typically lasting up to 100 years, which makes them a good investment for long-term energy generation. e. Flood Control: Hydroelectric power plants can also help to control floods in river systems by regulating the flow of water. Demerits: a. Environmental Impact: The construction of hydroelectric power plants can have negative impacts on the environment and local ecosystems, such as altering the natural flow of rivers and streams and disrupting fish and wildlife habitats. b. Limited Site Availability: Hydroelectric power plants require specific topography, such as high rainfall and steep terrain, which can limit their availability in certain locations. c. Upfront Cost: The initial cost of building hydroelectric power plants can be relatively high compared to other power generation technologies. d. Dependence on Water Resources: Hydroelectric power plants rely on a steady and sufficient supply of water, which can be affected by droughts and changes in climate patterns. e. Sedimentation: Over time, sediment buildup in the reservoirs of hydroelectric power plants can reduce their capacity, leading to decreased efficiency in energy generation. 1.3.3 Nuclear Power Nuclear power plants generate electricity by harnessing the heat produced by nuclear fission reactions. These involve splitting heavy atomic nuclei to release a large amount of energy. Nuclear power is often described as a low-carbon energy source since it does not generate significant greenhouse gas emissions. Nevertheless, the handling and disposal of radioactive waste materials pose safety challenges. 11 | P a g e CHAPTER # 01 Sources of Power Merits: a. High Energy Density: Nuclear power plants have a very high energy density, meaning that they can generate a large amount of electricity using a small amount of fuel. b. Low Greenhouse Gas Emissions: Nuclear power plants emit very low amounts of greenhouse gases, making them a good option for reducing carbon emissions and mitigating climate change. c. Energy Security: Nuclear power plants can provide energy security by reducing dependence on imported fossil fuels and ensuring a reliable source of electricity. d. Low Operating Costs: Nuclear power plants have relatively low operating costs compared to other forms of energy production, such as natural gas or coal-fired power plants. e. Reliable Power: Nuclear power plants are highly reliable and can operate continuously for long periods, providing a stable source of electricity. Demerits: a. Risk of Nuclear Accidents: Nuclear power plants have the potential for catastrophic accidents, such as the Chernobyl disaster and the Fukushima Daiichi nuclear disaster, which can have devastating environmental and health consequences. b. Radioactive Waste: Nuclear power plants generate radioactive fuel waste that is hazardous to human health and the environment, which must be carefully managed and stored for thousands of years. c. High Capital Costs: The construction of nuclear power plants is very expensive, requiring large upfront capital investments, which can make it difficult for some countries to finance. d. Proliferation Risks: The technology used to generate electricity in nuclear power plants can also be used to produce nuclear weapons, creating a proliferation risk. e. Decommissioning Challenges: Nuclear power plants have a finite operational life, and the decommissioning process can be complex and expensive, requiring long-term management of radioactive materials. 12 | P a g e CHAPTER # 01 Sources of Power 1.3.4 Solar Power Solar power is derived from sunlight, which can be captured and converted into electricity in two main ways: directly using photovoltaic (PV) technology or indirectly through solar thermal systems. These power sources are renewable and produce minimal environmental impact. However, solar power generation is subject to the availability of sunlight, and the technology’s widespread deployment is limited by factors such as high costs and the need for large land areas. Merits: a. Renewable Energy: Solar power is green energy source. meaning that it is sustainable, and there are no harmful emissions to the environment. b. Low Operating Costs: Solar panels have low operating costs, and solar energy is essentially free, which can save consumers money on their electricity bills. c. Scalability: Solar power can be scaled up or down, making it suitable for both large and small-scale energy generation. d. Low Maintenance: Solar panels require minimal maintenance, and their lifespan can range from 20 to 30 years. e. Energy Security: Solar power can also provide energy security by reducing dependence on imported fossil fuels and ensuring a reliable source of electricity. Demerits: a. Intermittent Energy Production: Solar power is an intermittent energy source, meaning that it is affected by weather conditions and cannot produce electricity 24/7, which can make it difficult to meet peak energy demands. b. High Upfront Costs: The initial cost of installing solar panels can be high, making it challenging for some consumers to invest in solar energy. c. Land Use: Solar power requires a large amount of land to generate significant amounts of electricity, which can be a challenge in densely populated areas. d. Limited Efficiency: Solar panels have limited efficiency in converting sunlight into electricity, which means that they require large surface areas to generate significant amounts of electricity. 13 | P a g e CHAPTER # 01 Sources of Power e. Environmental Impact: The production of solar panels can have negative environmental impacts, such as the emission of greenhouse gases during manufacturing and the disposal of panels after their lifespan. 1.3.5 Tidal Power Tidal power is generated from the kinetic energy of moving water caused by the ocean’s tides. It is a predictable and renewable source of electricity. Tidal power can be generated using tidal stream generators, tidal barrages, or tidal lagoons. However, the technology is relatively expensive, and potential environmental impacts need to be carefully assessed. Merits: a. Renewable Energy: Tidal power is a renewable and green energy source, meaning that it is sustainable, and there are no harmful emissions to the environment. b. Predictable Energy Production: Tidal power is a predictable source of energy, as the tides are cyclical and can be accurately predicted, which allows for efficient energy production planning. c. High Energy Density: Tidal power has a very high energy density, which means that it can generate large amounts of electricity from a relatively small amount of space. d. Long Lifespan: Tidal power systems can have a lifespan of up to 75 years, making them a reliable source of energy. e. Low Operating Costs: Once installed, tidal power systems have low operating costs, which can save consumers money on their electricity bills. Demerits: a. Limited Availability: Tidal power can be generated in areas with large tidal fluctuations, which limits its availability and potential use. b. High Capital Costs: The installation of tidal power systems can be expensive, requiring significant upfront capital investments, which can make it challenging for some countries to finance. c. Environmental Impact: Tidal power systems can have negative environmental impacts, such as altering the natural flow of water, 14 | P a g e CHAPTER # 01 Sources of Power affecting marine ecosystems, and interfering with the migration patterns of marine animals. d. Limited Efficiency: Tidal power systems have limited efficiency in converting the energy of ocean tides into electricity, which means that large systems are required to generate significant amounts of electricity. e. Maintenance and Repair: Tidal power systems require regular maintenance and repair due to the harsh oceanic environment, which can increase operating costs and affect system reliability. 1.3.6 Wind Power Wind power generates electricity by harnessing the kinetic energy in wind using turbines. It is a clean and renewable source of electricity. Advancements in wind power technology have led to reduced costs, making it an increasingly viable alternative to conventional power sources. However, wind power is dependent upon wind conditions, which can be unpredictable, and the construction of wind farms can impact local ecosystems. Merits: a. Renewable Energy: Wind power is a renewable energy source, meaning that it is sustainable, and there are no harmful emissions to the environment. b. Low Operating Costs: Wind turbines have low operating costs, and wind energy is essentially free, which can save consumers money on their electricity bills. c. Scalability: Wind power can be scaled up or down, making it suitable for both large and small-scale energy generation. d. Energy Security: Wind power provide energy security by reducing dependence on imported fossil fuels and ensuring a reliable source of electricity. e. Land Use: Wind turbines require relatively little land compared to other renewable energy sources such as solar, allowing for their installation in a range of locations. Demerits: a. Intermittent Energy Production: Wind power is intermittent energy source, meaning that it is affected by weather conditions 15 | P a g e CHAPTER # 01 Sources of Power and cannot produce electricity 24/7, which can make it difficult to meet peak energy demands. b. Visual and Noise Pollution: Wind turbines can also generate noise pollution, which can be a concern for people living near them. c. High Upfront Costs: The initial cost of installing wind turbines can be high, making it challenging for some consumers to invest in wind energy. d. Environmental Impact: The construction of wind turbines can have negative environmental impacts, such as the disruption of wildlife habitats and the potential harm to migratory birds and bats. e. Land Use Conflicts: Wind turbines can sometimes conflict with other land uses, such as agriculture and wildlife conservation, which can limit their potential installation in some areas. 1.3.7 Magneto Hydrodynamic (MHD) Power MHD power generation is a technique that uses the motion of an ionized gas or liquid metal (the “plasma”) through a magnetic field to produce electricity it works on Faraday’s law of electromagnetic induction. The principle behind MHD generation is the conversion of the kinetic energy of the conductive fluid (or working fluid) into electrical energy. This technology yields high energy conversion efficiencies and requires minimal fuel usage, making it an attractive and clean energy source. A working fluid (such as a plasma) is passed through a duct or channel surrounded by a magnetic field. The magnetic field interacts with the moving charges in the working fluid, inducing an electric field perpendicular to both the magnetic field and the flow direction of the fluid. As the working fluid flows through the channel, the electric field induces an electric current in the fluid, which can be harnessed to generate electricity. The generated electricity can be extracted from the system through electrodes placed in contact with the fluid. However, technical challenges and costs remain significant barriers to its wide-scale deployment. Merits: a. High Efficiency: MHD systems have the potential for high conversion efficiency, as they can convert up to 50% of the energy in a fuel into electricity. 16 | P a g e CHAPTER # 01 Sources of Power b. Fuel Flexibility: MHD can operate on a range of fuels, including fossil fuels and nuclear energy sources, making it a versatile technology. c. Low Emissions: MHD systems have low emissions, making them a cleaner source of energy than conventional power generation technologies. d. Longevity: MHD systems have a long lifespan, and the materials used in their construction are durable and can withstand high temperatures. e. Minimal Maintenance: MHD systems require minimal maintenance, reducing the operating costs of the technology. Demerits: a. High Capital Costs: The installation of MHD systems can be expensive, requiring significant upfront capital investments, which can make it challenging for some countries to finance. b. Limited Availability: MHD systems are not yet widely available or commercialized, making it difficult to access the technology in some regions. c. Technological Challenges: The development of MHD technology requires overcoming significant technological challenges, such as the need to develop stronger magnets and better conductive fluids. d. Environmental Impact: While MHD systems have low emissions, the extraction and production of the fuels they use can have negative environmental impacts. e. Scalability: MHD systems are currently limited in their scalability, making them less suitable for large-scale energy production. 1.3.8 Geothermal Power Geothermal power is generated from the Earth’s natural heat stored in its interior. Hot water or steam extracted from underground is used to drive turbines, thus producing electricity. Geothermal power plants have minimal environmental impact and provide a consistent electricity supply. However, geothermal resources are limited to certain geographic locations, and the high costs of drilling and infrastructure can be prohibitive. Merits: 17 | P a g e CHAPTER # 01 Sources of Power a. Renewable Energy: Geothermal energy is a renewable energy source, meaning that it is sustainable and there are no harmful emissions to the environment. b. Low Operating Costs: Once installed, geothermal power plants have low operating costs, and geothermal energy is essentially free, which can save consumers money on their electricity bills. c. Scalability: Geothermal power can be scaled up or down, making it suitable for both large and small-scale energy generation. d. Energy Security: Geothermal energy can provide energy security by reducing dependence on imported fossil fuels and ensuring a reliable source of electricity. e. Environmental Benefits: Geothermal power plants have low emissions, and the use of geothermal energy can help reduce greenhouse gas emissions and other air pollutants. Demerits: a. Limited Resource Availability: Geothermal energy resources are not uniformly distributed, and suitable sites for geothermal power plants are limited. b. High Upfront Costs: The initial cost of drilling and installing geothermal power plants can be high, making it challenging for some consumers to invest in geothermal energy. c. Environmental Impacts: The construction and operation of geothermal power plants can have negative environmental impacts, such as the potential for groundwater contamination, land subsidence, and seismic activity. d. Land Use Conflicts: Geothermal power plants can sometimes conflict with other land uses, such as agriculture and wildlife conservation, which can limit their potential installation in some areas. e. Technology Limitations: Some geothermal resources have low temperatures and may require advanced technologies for efficient energy production, limiting the potential for their widespread use. A simple comparison of different power generation sources is given in table 1. 18 | P a g e CHAPTER # 01 Sources of Power Table 1. Comparison of Different Power Systems Source Renewable Cost Availability Environmental Reliability impact Solar Yes High Variable Low Low Wind Yes High Variable Low Low Hydro Yes Low Seasonal Moderate High Biomass Yes Low Constant Moderate High Geothermal Yes High Constant Low High Tidal Yes High Periodic Low Moderate Coal No Low Constant High High Oil No High Constant High High Gas No High Constant Moderate High Nuclear No High Constant Low High 1.4 Solar Power System A solar power system is a system that uses the energy from the sun to produce electricity or heat. There are two main types of solar power systems: photovoltaic (PV) and concentrated solar power (CSP). Photovoltaic systems convert sunlight directly into electric current using semiconductor materials that exhibit the photovoltaic effect. Concentrated solar power systems use mirrors or lenses and tracking devices to focus a large area of sunlight onto a small spot, where it is converted into heat that drives a turbine or engine. Both types of systems can be installed on rooftops, ground-mounted, or integrated into buildings or vehicles. The advantages of solar power systems include their renewable and clean nature, their potential to reduce greenhouse gas emissions and dependence on fossil fuels, and their decreasing costs and increasing efficiency over time. The challenges of solar power systems include their variability and intermittency depending on the weather and time of day, their need for storage or backup solutions, and their integration into the existing grid and energy markets. PV Solar panels have following different types. a. Monocrystalline solar panels: Made from a single crystal of silicon, these panels are highly efficient and can produce more electricity per 19 | P a g e CHAPTER # 01 Sources of Power square foot than other types of solar panels. They are also more expensive than other types of panels. b. Polycrystalline solar panels: These panels are made from multiple crystals of silicon and are less expensive than monocrystalline panels. They are slightly less efficient, but still a good option for residential and commercial installations. c. Thin-film solar panels: Made from a thin layer of semiconductor material, these panels are the least expensive and least efficient type of solar panel. They are lightweight and flexible, making them a good option for portable or off-grid applications. 1.4.1 Calculation of load for solar PV system design Process for the calculation of load for solar PV system design comprises off following steps. a. Determining the electrical load: This involves calculating the total amount of electrical energy required by the appliances, devices, and equipment that will be connected to the solar PV system. This can be done by reviewing the product specifications of each device and adding up their power consumption in Watts (W) or kilowatts (kW). b. Estimating daily energy consumption: Once the electrical load has been determined, the next step is to estimate the daily energy consumption. This is done by multiplying the total power consumption by the number of hours that each device or appliance is expected to run each day. c. Accounting for system efficiency: It's important to consider the efficiency of the solar PV system when calculating the load. This can be done by multiplying the estimated daily energy consumption by a factor of 1.3 to account for system losses and inefficiencies. d. Adjusting for climate conditions: The amount of solar energy that can be harvested by a solar PV system will depend on the climate conditions of the location. The average solar insolation (or solar irradiance) can be used to estimate the amount of energy that can be harvested by the solar PV system each day. This information can be obtained from publicly available solar maps or databases. e. Sizing the solar PV system: Based on the estimated daily energy consumption and the amount of solar energy that can be harvested, the size of the solar PV system can be calculated. This involves 20 | P a g e CHAPTER # 01 Sources of Power selecting the appropriate solar panel size, number of panels, and battery capacity to meet the estimated daily energy demand. 1.4.2 Planning for installation of solar panel up to 3 KW Main and first step for the solar system planning is calculation of load. Load of a house is given in Table 2 and we want to design a solar system for this load with a battery backup of 1 day. So, we shall calculate following three important things. a) Rating of Inverter. b) Battery capacity and connections. c) Rating of Solar Panels. After calculating these, we’ll decide how to connect batteries and solar panels. Table 2. Load and energy profile of a house Sr. Name of Quantity Operating Power Energy No Appliance Hours (W) (Wh) 1 Fridge 1 6 250 1500 2 Fan 4 6 300 1800 3 Led TV 1 5 50 250 4 Led Bulb 10 8 300 2400 5 Microwave oven 1 0.25 850 213 Total 1750 6163 a) Rating of inverter Inverter is always selected by keeping in view the peak load and multiply it with 1.3 to add the future load growth. Required inverter size for our proposed load will be Inverter Capacity = Peak load x 1.3 = 1750 x 1.3 = 2275 Watt Nearest suitable inverter available in market in 2.5 KW. b) Battery capacity and connections 21 | P a g e CHAPTER # 01 Sources of Power Batteries are selected keeping in view the supported battery voltage of inverter. Generally, 2.5KW inverters support 24V DC. Battery Capacity = Wh required x Backuptime in days System Efficiency x DOD x V 6163 x 1 0.85 x 0.8 x 24 =378Ah Where DOD represents the depth of discharge. Generally deep cycle batteries have 80 to 90% DOD and V represents the voltage of battery bank. So, our required battery capacity will be 400 Ah and we shall connect two 12V, 200 Ah batteries in series. c) Rating of solar panels There are several things to consider for the optimum selection of solar panels as like geographic location, solar peak hours, efficiency of solar panels and energy consumption of devices etc. Average solar peak hours per day in Pakistan are 8. Let’s calculate the capacity of solar panels. Solar Panel Capacity = Wh required Sun Peak Hours x Efficiency 6163 8 x 0.25 = 3082 W So, we shall use approximately 6 solar panels of 520 watt for this system. Now, we shall check the input voltage range of selected inverter. For example, a 2.5kW inverter has input voltage range of 145 V to 280 V while maximum voltage of 520 watt solar panel are 54 v. So, we shall make two parallel strings each comprising of three solar panels in series. 22 | P a g e CHAPTER # 01 Sources of Power Figure 1.2. Design of solar system 1.4.3 Testing of solar power plant Testing of a solar power plant is essential to ensure that the system operates efficiently and effectively, producing the desired amount of electricity. Here are some steps that are typically involved in testing a solar power plant. a) Pre-commissioning tests Before the solar power plant is commissioned, various tests need to be carried out to ensure that the plant is ready for operation. These tests include checking the wiring, measuring the voltage and current, and ensuring that all the components are functioning correctly. b) Performance testing Once the solar power plant is operational, it is essential to evaluate its performance. Performance testing involves measuring the power output of the solar panels, inverters, and other components to ensure that they are operating correctly. c) Environmental testing 23 | P a g e CHAPTER # 01 Sources of Power Solar power plants are exposed to various environmental conditions, including extreme temperatures, humidity, and wind. It is important to test the system's ability to withstand these conditions and continue to function optimally. d) Maintenance testing Regular maintenance of the solar power plant is necessary to ensure that it continues to operate efficiently. Maintenance testing involves checking the various components of the system and identifying any issues that need to be addressed. e) Monitoring and control Monitoring and control systems are essential for ensuring that the solar power plant operates efficiently. These systems enable operators to monitor the system's performance in real-time, detect any issues, and take appropriate action to address them. Overall, the testing of a solar power plant involves a combination of pre- commissioning tests, performance testing, environmental testing, maintenance testing, and monitoring and control. By carrying out these tests, operators can ensure that the system operates efficiently and effectively, producing the desired amount of electricity. 1.5 Wind power system A wind power system harnesses the power of wind to generate electricity. It typically consists of a wind turbine, a tower or pole to support the turbine, a generator, and a controller or inverter to convert the electrical output of the turbine to the appropriate voltage and frequency for use in homes or businesses. The wind turbine is designed to capture the kinetic energy of the wind and convert it into mechanical energy by rotating the blades of the turbine. The mechanical energy is then converted to electrical energy by the generator, which produces a current that can be used to power appliances, lights, and other electrical devices. Wind power systems come in various sizes, from small systems that can generate a few hundred watts to large systems that can generate several megawatts of power. They are typically installed in areas with high wind speeds, such as hilltops, ridges, or coastal regions. Wind power systems offer several advantages, such as being a clean and renewable source of energy, reducing reliance on fossil fuels, and reducing 24 | P a g e CHAPTER # 01 Sources of Power greenhouse gas emissions. However, they also have some limitations, such as the change of wind speed and direction, which can affect the efficiency and reliability of the system. Overall, wind power systems can be a cost-effective and sustainable option for generating electricity, especially in areas with high wind resources. Proper planning, installation, and maintenance are important to ensure the safe and efficient operation of the system. a) Horizontal-axis wind turbines (HAWT) HAWT is the most commonly used type of wind turbine. It consists of a rotor that has blades attached to a horizontal axis that rotates around a vertical mast. The rotor faces into the wind, and the blades spin like propellers. The rotational motion is transferred to a gearbox and a generator that converts the mechanical energy into electrical energy. HAWTs are suitable for large- scale applications, such as wind farms, as they can generate a significant amount of electricity with high efficiency. b) Vertical-axis wind turbines (VAWT) VAWTs have a rotor that spins around a vertical axis. They can be classified into two types: Savonius and Darrieus turbines. Savonius turbines have a curved, S-shaped rotor that resembles a cylinder cut in half. The curved blades catch the wind and rotate the rotor. Darrieus turbines have a straight rotor that consists of multiple airfoil-shaped blades that rotate around a central shaft. VAWTs are suitable for small-scale applications and urban areas, where space is limited. c) Offshore wind turbines Offshore wind turbines are installed in bodies of water, such as oceans or seas. They are designed to withstand harsh weather conditions and strong winds. Offshore turbines can be either HAWT or VAWT, but HAWT is more commonly used due to its higher efficiency. Offshore wind turbines can generate more energy than onshore turbines as the wind speed and consistency is generally higher over water bodies. 25 | P a g e CHAPTER # 01 Sources of Power Figure 1.3. Horizontal Axis Wind Turbines Figure 1.4. Vertical Axis Wind Turbines d) Hybrid wind turbines Hybrid wind turbines combine two or more types of wind turbines to enhance their efficiency and performance. For instance, a hybrid turbine can have a HAWT on top of a VAWT, where the HAWT operates in high wind speed conditions, and the VAWT operates in low wind speed conditions. Hybrid 26 | P a g e CHAPTER # 01 Sources of Power turbines can also have a solar panel or a battery system integrated with the turbine to provide a more stable power output. In conclusion, wind turbines come in various types and designs, each with its own advantages and limitations. The choice of wind turbine depends on factors such as wind speed, application, available space, and environmental conditions. 1.5.1 Parts of wind power plant A wind power plant consists of several components that work together to generate electricity from wind. In this response, we will discuss the major components of a wind power plant in detail: a. Wind Turbines The wind turbines are the most critical components of a wind power plant. They convert the kinetic energy of wind into mechanical energy that is used to rotate the turbine blades. Wind turbines can be categorized into two main types, Horizontal Axis Wind Turbines (HAWT) and Vertical Axis Wind Turbines (VAWT). HAWTs are more commonly used in wind power plants, as they are more efficient and generate higher electricity outputs. The number of wind turbines in a wind power plant can vary, depending on the capacity of the plant and the available wind resources. b. Tower The tower is the structure that supports the wind turbines. It is usually made of steel and can vary in height depending on the wind resources and the size of the wind turbines. The tower height can range from 30 meters to 150 meters, and the diameter can range from 3 to 6 meters. The tower must be strong enough to withstand the weight of the turbine and the rotational forces created by the wind. c. Foundation The foundation is the base on which the tower is erected. It must be strong enough to support the weight of the tower and the wind turbine. The foundation can vary in size and shape depending on the soil conditions and the tower height. The foundation can be a shallow or deep foundation, and it can be made of concrete or steel. d. Rotor Blades The rotor blades are the components that capture the kinetic energy of the wind and convert it into mechanical energy. The blades can vary in size and 27 | P a g e CHAPTER # 01 Sources of Power shape depending on the turbine capacity and the wind resources. The rotor blades can be made of various materials, such as fiberglass, carbon fiber, or wood. They are designed to be aerodynamically efficient and must withstand the stresses created by the wind. e. Gearbox The gearbox is a component that transfers the rotational energy from the rotor to the generator. It increases the rotational speed of the rotor to match the speed required by the generator. The gearbox is usually located inside the nacelle, which is the compartment at the top of the tower that houses the gearbox, generator, and other components. f. Generator The generator is the component that converts the mechanical energy into electrical energy. The generator is usually located inside the nacelle and can be either a synchronous or asynchronous generator. The generator output voltage is usually in the range of 690V to 33kV, depending on the capacity of the wind turbine and the grid requirements. g. Power Electronics The power electronics are the components that control the electrical output of the generator. They are responsible for regulating the voltage and frequency of the output to match the grid requirements. The power electronics can include components such as inverters, transformers, and switchgear. h. Control System The control system is responsible for monitoring and controlling the operation of the wind turbine. It includes sensors that measure the wind speed, direction, and temperature. The control system can adjust the pitch angle of the rotor blades to optimize the performance of the turbine based on the wind conditions. It also includes safety systems that can shut down the turbine in case of emergency or high wind speeds. i. Substation The substation is the component that connects the wind power plant to the grid. It includes transformers that step up the voltage of the generator output to match the grid voltage. The substation also includes switchgear that protects the plant from overloads and faults. The substation can be located on-site or off-site, depending on the distance to the grid connection point. 28 | P a g e CHAPTER # 01 Sources of Power Figure 1.5. Wind Power Plant 29 | P a g e CHAPTER # 01 Sources of Power Sample Multiple Choice Questions 1. Which of the following is not a renewable source of energy (a) Solar (b) Wind (c) Coal (d) Hydro 2. What is the main disadvantage of thermal power plants (a) They are not widely available (b) They emit significant greenhouse gases (c) They require large land areas (d) They have high installation costs 3. How is nuclear power generated (a) By harnessing the energy of water (b) By capturing sunlight (c) By burning fossil fuels (d) By nuclear fission reactions 4. What is the main advantage of tidal power (a) It is a predictable (b) It does not require large land areas (c) It produces no environmental impact d) It is not affected by weather conditions 5. What is a solar power system (a) System that uses energy from wind (b) System that uses energy from the sun (c) System that uses energy from water (d) System that uses energy from coal 6. What are the two main types of solar power systems (a) Wind power and hydro power (b) Photovoltaic and concentrated solar power (c) Geothermal power and biomass power (d) Nuclear power and fossil fuel power 7. What is the advantage of solar power systems (a) They are cheap and widely available (b) They are easy to install 30 | P a g e CHAPTER # 01 Sources of Power (c) They are renewable and clean (d) They are not affected by weather conditions 8. What is the disadvantage of solar power systems (a) They are expensive (b) Energy production is not sufficient (c) They are variable and intermittent (d) They are harmful to the environment 9. What are the types of PV solar panels (a) Monocrystalline and polycrystalline (b) Monocrystalline and thick-film (c) Polycromide and intracrystalline (d) Monocrystalline and amorphous 10. Which type of solar panel is the most efficient and expensive (a) Monocrystalline solar panels (b) Polycrystalline solar panels (c) Thin-film solar panels (d) Concentrated solar power panels 11. Which type of wind turbine is most commonly used in large-scale applications (a) Horizontal-axis wind turbines (HAWT) (b) Vertical-axis wind turbines (VAWT) (c) Offshore wind turbines (d) Hybrid wind turbine 12. What component of a wind power plant captures the kinetic energy of the wind and converts it into mechanical energy (a) Tower (b) Generator (c) Rotor blades (d) Gearbox 13. Which type of wind turbine is suitable for small-scale applications and urban areas with limited space (a) Horizontal-axis wind turbines (HAWT) (b) Vertical-axis wind turbines (VAWT) (c) Offshore wind turbines (d) Hybrid wind turbines 31 | P a g e CHAPTER # 01 Sources of Power 14. What component of a wind power plant is responsible for stepping up the voltage of the generator output to match the grid voltage (a) Generator (b) Control system (c) Power electronics (d) Substation 15. Which component of a solar power system focuses sunlight onto a small spot to produce heat (a) Photovoltaic panels (b) Mirrors or lenses in a CSP (c) Semiconductor materials (d) Solar tracking devices 16. What is the depth of discharge (DOD) of a typical deep cycle battery (a) 50-60% (b) 70-80% (c) 80-90% (d) 100% 17. What is the purpose of including an inverter in a solar power system (a) To convert sunlight into electric current (b) To focus sunlight onto a small spot (c) To convert direct current into alternating current (d) To store excess solar energy in batteries 18. What design feature allows thin-film solar panels to be suitable for portable or off-grid applications (a) High efficiency (b) Low cost (c) Lightweight and flexible (d) High power output per square foot 19. In wind power systems, what component is housed in the nacelle (a) Rotor blades (b) Tower (c) Foundation (d) Generator 20. What is MHD (a) Magnetohydrodynamic (b) Magnetomotive Force 32 | P a g e CHAPTER # 01 Sources of Power (b) Modern Hydrogen Dynamics (d) Mega Hydro Dam 21. All available fuels are source of (a) Coal (b) Thermal Energy (c) Nuclear Energy (d) Chemical Energy 22. MHD works on principle of (a) Fleming (b) Faraday (c) Edison (d) Tesla 23. To convert water energy into electric energy, _____ is used with generator (a) Steam Turbine (b) Wind Turbine (c) Water Turbine (d) Heat Exchanger 24. ________ power plants are installed far from load centers. (a) Hydro Electric (b) Thermal (c) Wind (d) Diesel 25. ________ is less for a nuclear power plant. (a) Age (b) Initial cost (c) Security (d) Per unit cost Answer to MCQ’s 1. c 2. b 3. d 4. a 5. b 6. b 7. c 8. c 9. a 10. a 11. a 12. c 13. b 14. d 15. b 33 | P a g e CHAPTER # 01 Sources of Power 16. c 17. c 18. c 19. d 20. a 21. b 22. b 23. c 24. a 25. d Sample Short Questions 1. What is electrical power? 2. Name some sources of power that can be used to generate electricity? 3. What are the salient features of systems of power sources? 4. Define hydroelectric energy? 5. Define nuclear power generation? 6. Define thermal power generation? 7. Define geothermal generation? 8. What are indigenous sources of energy? 9. What are non-indigenous sources of energy? 10. What is the difference between renewable and non-renewable energy? 11. What are the two main types of solar power systems? 12. How do photovoltaic systems convert sunlight into electricity? 13. What are concentrated solar power systems known for? 14. What advantages do solar power systems offer? 15. What challenges do solar power systems face? 16. Name the three types of PV solar panels. 17. What is the main difference between photovoltaic and concentrated solar power systems? 18. What factors are considered in the calculation of load for a solar PV system design? 19. What are the testing methods of solar power plant? 20. What are the main components of a wind power system? 21. What are the two main types of wind turbines? 22. What advantages do wind power systems offer compared to conventional power sources? 23. What is the main limitation of wind power systems? 24. What is the difference between horizontal-axis wind turbines and vertical-axis wind turbines? 34 | P a g e CHAPTER # 01 Sources of Power 25. Where are offshore wind turbines typically installed? 26. What are hybrid wind turbines, and why are they used? Sample Long Questions 1. Compare different sources of electrical power? 2. Write a detailed note on solar power generation? 3. What are the planning considerations for a solar power plant? 4. Describe different types of wind turbines in detail? 5. Write a note on construction of wind turbine? 35 | P a g e CHAPTER # 02 Thermal Power Station CHAPTER 2 THERMAL POWER STATION Chapter objectives: After studying this chapter, a student will be able to  Understand the Introduction to thermal power station.  Understand the types of thermal power stations and their working.  Understand the working of different parts of thermal power station and their working with schematic diagram.  Understand the types of boilers.  Understand the types, selection criteria and working of steam turbines.  Understand the cconstruction of turbo generators.  Understand the function and application of condenser in a steam turbine power station.  Understand the water circulation system in a thermal power station.  Understand the introduction of diesel engine power station.  Understand the working and construction of a diesel eengine, two strokes, four strokes and their comparison. 2.1 Introduction to thermal power station A thermal power station, also known as a coal-fired power station, is a type of power plant that generates electricity by burning coal to produce steam. The steam is then used to drive a steam turbine, which in turn drives a generator that produces electricity. Thermal power stations are one of the most common types of power plants in the world, and they provide a significant portion of the electricity used globally. The process of generating electricity in a thermal power station begins with the coal being delivered to the station and stored in coal bunkers. From there, the coal is transported to a coal pulverizer, which grinds the coal into a fine powder. The pulverized coal is then blown into the boiler, where it is burned at high temperatures to produce heat. This heat is used to boil water in the boiler, creating steam that is used to drive the steam turbine. 36 | P a g e CHAPTER # 02 Thermal Power Station The steam turbine is connected to a generator, which converts the mechanical energy from the turbine into electrical energy. The electricity generated by the generator is then transmitted through power lines to homes, businesses, and other users of electricity. Thermal power stations require large amounts of water for the steam generation process. The water is typically sourced from a nearby river, lake, or ocean and is treated to remove impurities before being used in the power plant. The process of cooling the steam after it has passed through the turbine also requires large amounts of water, which is typically returned to the source in a cooled state. One of the major environmental concerns associated with thermal power stations is the emission of greenhouse gases, primarily carbon dioxide, which contributes to global warming. Other pollutants, such as sulfur dioxide and nitrogen oxide, can also be emitted by the burning of coal and can contribute to acid rain and other environmental problems. In recent years, there has been a shift towards cleaner forms of energy, such as wind and solar power, as well as the development of technologies such as carbon capture and storage, which aim to capture and store carbon dioxide emissions from thermal power stations. Despite these developments, thermal power stations continue to play a significant role in meeting the world's energy needs, particularly in developing countries where access to electricity is limited. 2.2 Selection of fuels and site 2.2.1 Selection of Fuel The primary fuel used in thermal power stations is coal, which is burned to produce heat that is used to generate steam. However, other types of fuels can also be used, depending on the availability and cost of the fuel, as well as environmental considerations. Some of the fuels that can be used in thermal power stations include: a. Coal Coal is a fossil fuel that is formed from the remains of plants that lived millions of years ago. It is a black or brownish-black sedimentary rock that is primarily composed of carbon, along with small amounts of other elements such as sulfur, nitrogen, and oxygen. Coal is one of the most widely used fuels for 37 | P a g e CHAPTER # 02 Thermal Power Station power generation, accounting for about 38% of global electricity generation in 2020. Peat is considered very low grade coal which contains very high carbon content and not suitable to be used in power plants. There are four main types of coal that are commonly used in power generation, classified according to their degree of metamorphism, or the amount of heat and pressure they have been subjected to over time. These types are: Anthracite: Anthracite is the highest grade of coal, with a high carbon content and low moisture content. It is very hard and has a high heat output, making it an excellent fuel for power generation. Anthracite is relatively rare and expensive compared to other types of coal. Bituminous: Bituminous coal is the most common type of coal used in power generation, with a moderate carbon content and higher moisture content than anthracite. It is softer and more brittle than anthracite and is divided into sub- bituminous and bituminous coal depending on its carbon content. Bituminous coal is used in power plants that require a balance between heat output and cost. Subbituminous: Subbituminous coal has a lower carbon content and higher moisture content than bituminous coal. It is often brownish or black in color and has a dull, matte finish. Subbituminous coal is used in power plants that have lower efficiency requirements, such as in developing countries. Lignite: Lignite is the lowest grade of coal, with a low carbon content and high moisture content. It is often brown in color and has a woody texture. Lignite is typically used in power plants that have very low efficiency requirements, or as a backup fuel source. b. Natural Gas Natural gas is a clean-burning fuel that produces fewer emissions than coal. It is often used in combined-cycle power plants, where the exhaust heat from a gas turbine is used to generate steam for a steam turbine. c. Oil Oil can also be used as a fuel in thermal power stations, although it is less common than coal or natural gas. Oil-fired power plants are typically used as backup power sources or for peak demand periods. 38 | P a g e CHAPTER # 02 Thermal Power Station d. Biomass Biomass is a renewable fuel source that is derived from organic matter, such as wood chips, agricultural waste, or municipal solid waste. Biomass can be burned in a boiler to produce steam, which is then used to generate electricity. The choice of fuel used in a thermal power station depends on a number of factors, including cost, availability, and environmental impact. Coal remains the most common fuel used in thermal power stations, although there is increasing interest in using cleaner fuels such as natural gas and biomass. 2.2.2 Selection of Site Selecting the right site for a thermal power plant is a critical process that involves careful consideration of a variety of factors. Here are some of the key factors that are typically considered when selecting a site for a thermal power plant: a. Availability of fuel The primary fuel for a thermal power plant is coal, so the site should be located near coal mines or have easy access to a reliable supply of coal. b. Water availability Thermal power plants require large quantities of water for cooling purposes, so the site should be located near a reliable water source, such as a river or lake. c. Land availability The site should have sufficient land to accommodate the power plant and any associated infrastructure, such as transmission lines and substations. d. Environmental factors The site should be evaluated for any potential environmental impacts, such as air pollution, water pollution, and impacts on wildlife and habitats. e. Transportation infrastructure The site should have good transportation infrastructure, such as highways, railroads, and ports, to facilitate the transport of fuel and equipment to the site and the transport of electricity from the power plant to customers. f. Local community The site should be located in an area that is compatible with the local community and does not have significant negative impacts on the health, safety, or quality of life of nearby residents. 39 | P a g e CHAPTER # 02 Thermal Power Station g. Economic factors The site should be economically viable and have a low cost of production, including factors such as labor costs, taxes, and regulatory costs. Overall, selecting the right site for a thermal power plant is a complex process that requires careful evaluation of a wide range of factors. A comprehensive site selection study is typically conducted to evaluate potential sites and identify the most suitable location for the power plant. 2.3 Types of thermal power stations and their working 2.3.1 Coal-fired power plants: Figure 2.6. Coal Fired Thermal Power Plant Coal-fired power plants work by burning coal to produce heat, which is then used to generate steam. The steam turns a turbine connected to a generator, which produces electricity. To start the process, coal is first pulverized into a fine powder and then blown into the boiler, where it is burned to produce heat. The heat generated by the burning coal is used to convert water into steam, which is then directed to the turbine. The turbine spins the generator, 40 | P a g e CHAPTER # 02 Thermal Power Station which produces electricity. The steam is then condensed back into water and returned to the boiler to be heated again, completing the cycle. The electricity produced by the generator is sent to a transformer, which increases the voltage so it can be transmitted over long distances via power lines. Coal-fired power plants require a constant supply of coal, which is transported to the plant by rail or truck. They also require a source of cooling water, which is typically drawn from nearby lakes, rivers, or oceans. The cooling water is circulated through the power plant to absorb heat, and then released back into the environment. Coal-fired power plants generate large amounts of carbon dioxide and other pollutants, which contribute to climate change and air pollution. A typical coal fired power plant is given in figure 2.1. 2.3.2 Oil-fired power plants: Figure 2.7. Oil fired thermal power plant Oil-fired power plants work by burning oil to produce heat, which is then used to generate steam. The steam turns a turbine connected to a generator, which produces electricity. To start the process, oil is first stored in tanks and then pumped into the boiler, where it is burned to produce heat. The heat generated by the burning oil is used to convert water into steam, which is then directed to the turbine. The turbine spins the generator, which produces electricity. The steam is then condensed back into water and returned to the boiler to be heated again, completing the cycle. The electricity produced by the generator is sent to a transformer, which increases the voltage so it can 41 | P a g e CHAPTER # 02 Thermal Power Station be transmitted over long distances via power lines. Oil-fired power plants require a constant supply of oil, which is transported to the plant by tanker trucks or ships. They also require a source of cooling water, which is typically drawn from nearby lakes, rivers, or oceans. The cooling water is circulated through the power plant to absorb heat, and then released back into the environment. Oil-fired power plants generate fewer pollutants than coal-fired power plants but are still a significant source of greenhouse gases and other air pollutants. A typical oil fired power plant is given in figure 2.2. 2.3.3 Gas-fired power plants: Figure 2.8. Gas fired thermal power plant Gas-fired power plants work by burning natural gas to produce heat, which is then used to generate electricity. To start the process, natural gas is first extracted from underground wells and transported to the power plant via pipeline. At the power plant, the natural gas is burned in a boiler to produce heat. The heat generated by the burning natural gas is used to convert water into steam, which is then directed to a turbine. The turbine spins a generator, which produces electricity. The steam is then condensed back into water and returned to the boiler to be heated again, completing the cycle. The electricity produced by the generator is sent to a transformer, which increases the voltage so it can be transmitted over long distances via power lines. Gas-fired power plants require a constant supply of natural gas, which is transported to the plant via pipeline. They also require a source of cooling water, which is typically drawn from nearby lakes, rivers, or oceans. The cooling water is 42 | P a g e CHAPTER # 02 Thermal Power Station circulated through the power plant to absorb heat, and then released back into the environment. Gas-fired power plants generate fewer pollutants than coal-fired power plants and oil-fired power plants, making them a cleaner source of electricity. A typical gas fired power plant is given in figure 2.3. 2.3.4 Combined Cycle Thermal Power Plants: Figure 2.9. Combined cycle thermal power plant Combined cycle power plants work by using both gas turbines and steam turbines to generate electricity. The process begins by burning natural gas in a gas turbine, which produces hot exhaust gases. The hot exhaust gases are then directed to a heat recovery steam generator, where they heat water to produce steam. The steam is then directed to a steam turbine, which generates additional electricity. The steam is then condensed back into water and returned to the heat recovery steam generator to be heated again. The electricity produced by the gas turbine and steam turbine is sent to a transformer, which increases the voltage so it can be transmitted over long distances via power lines. Combined cycle power plants require a constant supply of natural gas, which is transported to the plant via pipeline. They also require a source of cooling water, which is typically drawn from nearby lakes, rivers, or oceans. The cooling water is circulated through the power plant to absorb heat, and then released back into the environment. Combined cycle power plants are highly efficient, as they capture waste heat from the gas turbine to produce additional electricity. They generate fewer pollutants than other types of power plants, making them a cleaner source of electricity. A typical combined cycle power plant is given in figure 2.4. 43 | P a g e CHAPTER # 02 Thermal Power Station 2.4 Parts of thermal power station and their working with schematic diagram Steam power station simply involves the conversion of heat of coal combustion into electrical energy, yet it embraces many arrangements for proper working and efficiency. The schematic arrangement of a modern steam power station is shown in figure 2.5.The whole arrangement can be divided into the following parts for the sake of simplicity: 1. Coal and ash handling 2. Steam generating plant 3. Steam turbine 4. Alternator 5. Feed water 6. Cooling arrangement 2.4.1 Coal and ash handling The coal is transported to the power station by road or rail and is stored in the coal storage plant. Storage of coal is primarily a matter of protection against coal strikes, failure of transportation system and general coal shortages. From the coal storage plant, coal is delivered to the coal handling plant where it is pulverized (crushed into small pieces) in order to increase its surface exposure, thus promoting rapid combustion without using large quantity of excess air. The pulverized coal is fed to the boiler by belt conveyors. The coal is burnt in the boiler and the ash produced after the complete combustion of coal is removed to the ash handling plant and then delivered to the ash storage plant for disposal. The removal of the ash from the boiler furnace is necessary for proper burning of coal. It is worthwhile to give a passing reference to the amount of coal burnt and ash produced in a modern thermal power station. A 100 MW station operating at 50% load factor may burn about 20,000 tons of coal per month and ash produced may be to the tune of 10% to of coal fired i.e., 2,000 to 3,000 tons. In fact, in a thermal station, about 50% to 60% of the total operating cost consists of fuel purchasing and its handling. 44 | P a g e CHAPTER # 02 Thermal Power Station Figure 2.5. Schematic arrangement of thermal power plant 2.4.2 Steam generating plant The steam generating plant consists of a boiler for the production of steam and other auxiliary equipment for the utilization of flue gases. a) Boiler: The heat of combustion of coal in the boiler is utilized to convert water into steam at high temperature and pressure. The flue gases from the boiler make their journey through super heater, economizer, and air pre- heater and are finally exhausted to atmosphere through the chimney. b) Super heater: The steam produced in the boiler is wet and is passed through a super heater where it is dried and superheated (steam temperature increased above that of boiling point of water) by the flue gases on their way 45 | P a g e CHAPTER # 02 Thermal Power Station to chimney. Superheating provides two principal benefits. Firstly, the overall efficiency is increased. Secondly, too much condensation in the last stages of turbine (which would cause blade corrosion) is avoided. The superheated steam from the super heater is fed to steam turbine through the main valve. c) Economizer: An economizer is essentially a feed water heater and derives heat from the flue gases for this purpose. The feed water is fed to the economizer before supplying to the boiler. The economizer extracts a part of heat of flue gases to increase the feed water temperature. d) Air preheater: An air preheater increases the temperature of the air supplied for coal burning by deriving heat from flue gases. Air is drawn from the atmosphere by a forced draught fan and is passed through air preheater before supplying to the boiler furnace. The air preheater extracts heat from flue gases and increases the temperature of air used for coal combustion. The principal benefits of preheating the air are: increased thermal efficiency and increased steam capacity per square meter of boiler surface. 2.4.3 Steam turbine The dry and superheated steam from the super heater is fed to the steam turbine through main valve. The heat energy of steam when passing over the blades of turbine is converted into mechanical energy. After giving heat energy to the turbine, the steam is exhausted to the condenser which condenses the exhausted steam by means of cold water circulation. 2.4.4 Alternator The steam turbine is coupled to an alternator. The alternator converts mechanical energy of turbine into electrical energy. The electrical output from the alternator is delivered to the bus bars through transformer, circuit breakers and isolators. 2.4.5 Feed Water The condensate from the condenser is used as feed water to the boiler. Some water may be lost in the cycle which is suitably made up from external source. The feed water on its way to the boiler is heated by water heaters and economizer. This helps in raising the overall efficiency of the plant. 2.4.6 Cooling arrangement In order to improve the efficiency of the plant, the steam exhausted from the turbine is condensed* by means of a condenser. Water is drawn from a natural source of supply such as a river, canal or lake and is circulated through the 46 | P a g e CHAPTER # 02 Thermal Power Station condenser. The circulating water takes up the heat of the exhausted steam and itself becomes hot. This hot water coming out from the condenser is discharged at a suitable location down the river. In case the availability of water from the source of supply is not assured throughout the year, cooling towers are used. During the scarcity of water in the river, hot water from the condenser is passed on to the cooling towers where it is cooled. The cold water from the cooling tower is reused in the condenser. 2.5 Boilers and their types A boiler is a closed vessel that heats a fluid (typically water). The fluid does not always boil. The heated or vaporized fluid exits the boiler and is used in a variety of processes or heating applications, including cooking, water or central heating, and boiler-based power generation. Boilers and most specifically steam boilers are an important component of thermal power plants. 2.5.1 Working principle of boiler The boiler operates on the principle that water is heated in a closed vessel and then converted into steam as a result of the heating. This steam has a lot of kinetic energy at high pressures. Water is fed to the boiler and then heated to its boiling point by using heat from the furnace. This water is converted into high-pressure steam as a result of heating. The generated steam is routed through the steam turbines. When high-pressure steam strikes the turbine, it causes it to rotate. A generator is connected to the turbine, and the generator begins to rotate along with the turbine, producing electricity. 2.5.2 Types of steam boiler Boilers are classified into several types based on several factors such as pressure and temperature, fuel type, form of heating, heating method and size/capacity etc. However, the most common fuel type is petrol, oil, or electricity to operate. Both gas and oil boilers work in the same way. Mainly tere are two types of boiler that are most important and these are a) Water tube boiler b) Fire tube boiler a) Water tube boiler A water tube Boiler is a type of pressure vessel used to create steam under pressure by passing hot water through it. It works by heating water above its 47 | P a g e CHAPTER # 02 Thermal Power Station normal boiling point which turns into vapor and then exits the boiler at higher pressure than when it was entered. Figure 2.6. Water tube boiler The main components of a water tube Boiler consist of tubes filled with water, a furnace where fuel is burned to heat up the water, and a drum connected to the top of the furnace containing air and other gases. Advantages of this type of boiler over fire-tube boilers include greater efficiency, easier access to parts, better control of flue gas temperature and composition, and improved safety features such as automatic blow down valves. However, they can be more expensive initially and require more frequent inspection and maintenance. La-Mont boiler, Benson boiler, Yarrow boiler and Wilcox boiler are some examples of water tube boilers. Advantages a. The tubes of these boilers are exposed outside the shell, any part inside the tubes can easily accessed without having to remove the entire unit from service. This makes repairs faster and cheaper. b. Automatic blow down valve systems help prevent explosions due to excessive build ups in pressure. c. The temperature of the exhaust gasses can be controlled precisely. 48 | P a g e CHAPTER # 02 Thermal Power Station d. Improved design for high pressure applications Disadvantages a. Water tubes are more prone to corrosion and scale formation than fire tubes. b. The large number of small diameter tubes in a water-tube boiler makes it difficult to maintain proper circulation if one or two tubes become blocked by debris or ash. 3. Due to the high pressure inside the boiler, any leakage of steam could cause serious safety hazards such as explosions or fires. c. These boilers have low efficiency as compared to fire tube boilers. b) Fire tube boiler Fire tube Boilers are one of the most common types of boilers available. Fire tube boilers consist of a series of small diameter tubes called fires into which fuel is burned to create high temperature gas flowing inside the tubes. In order to maximize energy output from the system, these tubes must be kept as long and straight as possible. Figure 2.7. Fire tube boiler To achieve this, these tubes may be supported by stay rods or a stay arm arrangement. As the gas flows through the tubes, it transfers its heat to the 49 | P a g e CHAPTER # 02 Thermal Power Station surrounding water, thus creating saturated steam. Fire tube boilers are typically designed to work under both low and high pressure conditions. Additionally, these boilers often feature automatic controls and safety devices to ensure proper operation and prevent any potential hazards. Overall, fire tube boilers offer many advantages including efficient use of space, easy maintenance, and versatility across various industries. Lancashire boiler, Cochran boiler, Velcon boiler and locomotive boiler are some examples of fire tube boilers. Advantages a. These are relatively low in cost. b. Their operation is easy. c. These can handle high pressures and temperatures. d. These boilers have flexibility in design. e. Efficiency of these boilers are high. Disadvantages a. These boilers have problem of water contamination due to ash deposits from combustion products. b. These have limited steam output compared to water tube boilers. c. Cleaning and maintenance of these boilers is difficult. 2.6 Steam turbine working principle and construction A steam turbine is a machine that converts thermal energy from pressurized steam into mechanical energy, which can be used to generate electricity or drive machinery. The steam turbine is an essential component of a power plant that uses steam as a working fluid to generate electricity. 2.6.1 Working principle The working principle of a steam turbine is based on the conversion of thermal energy into mechanical energy through the use of high-pressure steam. 2.6.2 Construction of steam turbine The construction of a steam turbine can vary depending on its type and size. However, the basic components of a steam turbine include a rotor, stator, and nozzles. The rotor is the rotating part of the steam turbine that converts the energy of the steam into mechanical energy. It is typically made of high- strength materials such as steel and is designed to withstand the stresses and strains associated with high-speed rotation. 50 | P a g e CHAPTER # 02 Thermal Power Station The stator is the stationary part of the steam turbine that contains a series of stationary blades. These blades guide the steam onto the rotor blades and are designed to optimize the energy transfer from the steam to the rotor. The stator also contains a series of fixed guide vanes that direct the steam flow into the rotor blades. The nozzles are the components that convert the high-pressure, high- temperature steam into a high-velocity jet. The steam is directed through the nozzles and onto the rotor blad