Towards Green Energy

1. Remake the table taking into account relation between entries in three columns.

2. Which fuel is used in thermal power plant? What are the problems associated with this type of power generation?

Answer:_ Thermal power plants use a variety of fossil fuels, such as coal, oil, and natural gas, to generate electricity. The fuel is burned in a boiler to heat water and create steam, which then drives a turbine to generate electricity.

One of the major problems associated with thermal power generation is the high level of greenhouse gas emissions, primarily carbon dioxide (CO2), produced during the burning of fossil fuels. These emissions contribute to climate change and air pollution. In addition to this, Thermal power plants also generate ash and other pollutants that can harm air and water quality. Moreover, the mining, transportation, and storage of fossil fuels can also have negative impacts on the environment and local communities. Another problem is the limited resources of fossil fuels.

3. Other than thermal power plant, which power plants use thermal energy for power generation? In what different ways is the thermal energy obtained?

Answer:- Other types of power plants that use thermal energy include:

• Combined Cycle Gas Turbine (CCGT) power plants, which use a combination of gas turbine and steam turbine technology to generate electricity.
• Concentrated Solar Power (CSP) plants, which use mirrors to concentrate sunlight to generate heat, which is then used to create steam to drive a turbine.
• Geothermal power plants, which use heat from the Earth’s interior to generate steam, which then drives a turbine to generate electricity.
• Biomass power plants, which use organic material such as wood, crops, and waste as a fuel source to generate heat and steam, which is then used to drive a turbine and generate electricity.

Thermal energy can be obtained in several ways:

• Burning fossil fuels such as coal, natural gas, and oil to generate heat, which is then used to create steam to drive a turbine.
• Concentrating sunlight with mirrors to create heat, which is then used to generate steam in a solar thermal power plant.
• Using the heat from the Earth’s interior in a geothermal power plant to generate steam, which then drives a turbine to generate electricity.
• Burning biomass such as wood, crops, and waste in a biomass power plant to generate heat, which is then used to create steam to drive a turbine.
• Heat recovery from industrial processes or waste heat from other sources like engines or cooling towers.
• Nuclear fission, in which the heat generated by the splitting of atoms is used to create steam and drive a turbine in a nuclear power plant.

4. Which type/types of power generation involve maximum number of steps of energy conversion? In which power generation is the number minimum?

Answer:- The type of power generation that involves the maximum number of steps of energy conversion is typically considered to be biomass power generation. This is because biomass, such as wood or crops, must first be grown, harvested, and transported to the power plant. Then it must be processed, such as by drying or chipping, before it can be burned to generate heat. This heat is then used to create steam, which drives a turbine to generate electricity.

On the other hand, the power generation with the minimum number of steps of energy conversion would be the direct conversion of the energy source into electricity, for example, Solar Photovoltaic (PV) or Hydroelectric power generation. In these cases, the energy source is directly converted into electricity with minimal or no conversion steps.

5. Solve the following crossword puzzle.

a. Maximum energy generation in India is done using….. energy.

b. …… energy is a renewable source of energy

c.Solar energy can be called…. energy.

d …. energy of wind is used in wind mills.

e. ….. energy of water in dams is used for generation of electricity.

Ans:_  

6. Explain the difference.

a. Conventional and Non-conventional Sources of energy.

Answer_ 

Conventional sources of energy include fossil fuels such as coal, oil, and natural gas. 

These energy sources are finite, meaning they will eventually run out, and they also release greenhouse gases when burned which contributes to climate change.

Non-conventional sources of energy, on the other hand, include renewable energy sources such as solar, wind, hydroelectric, geothermal, and biomass. 

These sources are considered non-conventional because they are not based on the consumption of finite resources and do not produce greenhouse gas emissions. T

hey are also considered sustainable because they can be replenished naturally.

b Thermal electricity generation and solar thermal electricity generation.

Answer:_ 

Thermal electricity generation is the process of generating electricity by burning fossil fuels, such as coal, natural gas, or oil, to heat water and create steam. The steam is then used to turn turbines, which generates electricity. Thermal power plants are widely used for electricity generation but they are also a major source of air pollution and carbon dioxide emissions.

Solar thermal electricity generation, on the other hand, is the process of generating electricity by using the heat from the sun to produce steam. The steam is then used to turn turbines and generate electricity. This process is considered a form of renewable energy because it does not involve the burning of fossil fuels and does not produce greenhouse gas emissions. It uses mirrors or lenses to concentrate sunlight and heat a fluid which then generates steam to drive the turbine.

In summary, the main difference between thermal electricity generation and solar thermal electricity generation is that the former uses fossil fuels to generate heat while the latter uses solar energy as the source of heat.

7. What is meant by green energy? Which energy sources can be called as green energy sources and why? Give example.

Answer:-  Green energy, also known as renewable energy, refers to energy sources that are derived from natural and replenishable resources, such as sunlight, wind, rain, and geothermal heat. These energy sources are considered “green” because they do not deplete finite resources or produce harmful emissions or pollutants.

Examples of green energy sources include:

• Solar energy: harnessing the power of the sun through solar panels or concentrated solar power plants.
• Wind energy: using wind turbines to generate electricity.
• Hydroelectric energy: using the movement of water to turn turbines and generate electricity.
• Biomass energy: using organic materials such as wood, crops, and waste to generate electricity or heat.
• Geothermal energy: using heat from the Earth’s core to generate electricity.

These sources of energy are considered green because they have very low or no carbon emissions, unlike fossil fuels which are major contributors to climate change. They are also sustainable and have a minimal impact on the environment.

For example, a solar power plant generates electricity by converting sunlight into electricity and does not produce any emissions or pollutants. This makes it a green energy source, which is considered to be environmentally friendly and sustainable.

8. Explain the following sentences.

a. Energy obtained from fossil fuels is not green energy

Answer:-  The sentence “Energy obtained from fossil fuels is not green energy” is referring to the fact that energy sources derived from fossil fuels, such as coal, oil, and natural gas, are not considered renewable or sustainable. These sources of energy are finite, meaning they will eventually run out, and their extraction and use can have negative impacts on the environment.

Fossil fuels are also considered to be non-green energy sources because when they are burned to generate electricity, they release greenhouse gases such as carbon dioxide into the atmosphere. These emissions contribute to climate change and have negative impacts on air quality and public health.

In contrast, green energy sources such as solar, wind, and hydroelectric are renewable, meaning they can be replenished naturally and do not deplete finite resources. They also do not produce harmful emissions or pollutants when they are used to generate electricity.

Therefore, energy obtained from fossil fuels is not considered to be green energy because it is not renewable, sustainable, and has negative environmental impact.

b. Saving energy is the need of the hour.

Answer:-  The sentence “Saving energy is the need of the hour” refers to the urgency and importance of reducing energy consumption in order to address current energy challenges.

The world’s population and economies are growing, and energy demand is increasing as a result. However, many conventional energy sources such as fossil fuels are finite and their extraction and use have negative environmental impacts.

Additionally, the burning of fossil fuels is a major contributor to climate change. Climate change poses significant risks to the environment, human health, and economic stability.

Saving energy refers to reducing the amount of energy consumed by using energy more efficiently, for example, through energy-efficient appliances and buildings, or by using renewable energy sources. By reducing energy consumption, we can reduce the amount of greenhouse gas emissions that contribute to climate change.

Moreover, saving energy can also help to reduce energy costs and improve energy security. It is therefore considered to be an important and urgent step that must be taken in order to address current energy challenges and build a more sustainable future.

9. Answer the following questions.

a. How can we get the required amount of energy by connecting solar panels?

Answer:_  There are several ways to connect solar panels in order to generate the required amount of energy. Some of the most common methods include:

1. Grid-tied solar systems: These systems are connected to the electrical grid and allow excess energy to be sent back to the grid for others to use. When the solar panels are not producing enough energy, the system can draw power from the grid to meet the energy demand.
2. Battery-based solar systems: These systems use batteries to store excess energy generated by the solar panels. This stored energy can then be used during times when the solar panels are not producing enough energy, such as at night or during periods of low sunlight.
3. Off-grid solar systems: These systems are not connected to the electrical grid and rely solely on the energy generated by the solar panels and stored in batteries. These systems are often used in remote locations where access to the electrical grid is not available.
4. Hybrid solar systems: These systems combine solar energy with other energy sources, such as wind or hydroelectric power, to provide a more reliable and consistent energy supply.

The required amount of energy will depend on the specific application and the energy consumption of the household or business. A professional solar installation company or an engineer can perform a site survey and energy consumption analysis to determine the size and number of solar panels needed to meet the energy demand.

Also, it’s worth mentioning that connecting more solar panels increases the amount of energy produced, but also increases the initial cost of the system.

b. What are the advantages and limitations of solar energy?

Answer:- Solar energy has many advantages, including:

• Renewable: Solar energy is a renewable resource and does not deplete finite resources like fossil fuels.
• Clean: Solar energy does not produce emissions or pollutants, making it a clean source of energy.
• Low maintenance: Solar panels require minimal maintenance and can last for many years.
• Cost-effective: The cost of solar energy has decreased significantly in recent years and is now competitive with other forms of energy.
• Versatile: Solar energy can be used for a wide range of applications, including powering homes and businesses, as well as for water heating, lighting, and transportation.

However, solar energy also has some limitations, including:

• Weather dependent: Solar panels require sunlight to generate electricity, so their output can be affected by weather conditions such as clouds and storms.
• Limited storage: Currently, the technology for storing solar energy on a large scale is not fully developed, so excess energy generated during the day may not be able to be stored for use at night.
• Initial cost: The initial cost of installing solar panels can be high, although the cost has been decreasing over the years and the payback period can be relatively short.
• Space requirement: Solar panels require a large amount of space, which can be a limitation for some applications, such as in urban areas.
• Limited availability: Solar energy is not always available in certain areas, such as at high latitudes or in areas with high levels of air pollution that can block sunlight.

Overall, solar energy is a promising source of renewable energy with many benefits, but also has some limitations that need to be considered.

10. Explain with diagram step-by-step energy conversion in

a. Thermal power plant

A thermal power plant converts heat energy into electrical energy. The basic principle of operation is to use fuel to heat water and create steam, which is then used to drive a turbine connected to a generator. The generator converts the mechanical energy of the turbine into electrical energy.

Here is a step-by-step explanation of the energy conversion process in a thermal power plant, with a diagram to illustrate the process:

1. Fuel (such as coal, natural gas, or oil) is burned in a combustion chamber to produce heat.
2. The heat is used to heat water in a boiler, creating steam.
3. The steam is then piped to a turbine.
4. The turbine is connected to a generator, which converts the mechanical energy of the steam into electrical energy.
5. The electrical energy is then distributed to the power grid and sent to homes and businesses.
6. The steam, after passing through the turbine, is cooled in a condenser, it turns into water again and is sent back to the boiler to start the process again.

Here is a simple Diagram representation of the energy conversion process in a thermal power plant:

[Insert Diagram]

Note that this is a simplified explanation of the process and there are many variations and additional components that can be used in a thermal power plant, such as air preheaters, economizers, and scrubbers, to improve the efficiency and environmental performance of the plant.

b. Nuclear Power Plant:_

Answer:- A nuclear power plant generates electricity by using the heat produced by nuclear reactions, typically nuclear fission. The basic principle of operation is to use nuclear fuel to generate heat, which is then used to produce steam, which is used to drive a turbine connected to a generator. The generator converts the mechanical energy of the turbine into electrical energy.

Here is a step-by-step explanation of the energy conversion process in a nuclear power plant, with a diagram to illustrate the process:

1. Nuclear fuel (typically uranium or plutonium) is loaded into the reactor and undergoes nuclear fission. This releases a large amount of heat energy.
2. The heat energy is used to heat water in a heat exchanger, creating steam.
3. The steam is then piped to a turbine.
4. The turbine is connected to a generator, which converts the mechanical energy of the steam into electrical energy.
5. The electrical energy is then distributed to the power grid and sent to homes and businesses.
6. The steam, after passing through the turbine, is cooled in a condenser and turns back into water. It is then pumped back to the heat exchanger to start the process again.
7. The used nuclear fuel is removed from the reactor and placed in a spent fuel pool for cooling. After a certain amount of time, it is moved into dry cask storage or reprocessed for reuse.

Here is a simple Diagram representation of the energy conversion process in a Nuclear power plant:

c. Solar thermal power plant

Answer:_

A solar thermal power plant generates electricity by using the heat from the sun to produce steam, which is then used to drive a turbine connected to a generator. The generator converts the mechanical energy of the turbine into electrical energy.

Here is a step-by-step explanation of the energy conversion process in a solar thermal power plant, with a diagram to illustrate the process:

1. Sunlight is collected and concentrated by mirrors (parabolic troughs, parabolic dishes, or a solar tower) onto a receiver.
2. The receiver absorbs the sunlight and converts it into heat energy.
3. The heat energy is used to heat a fluid (such as water or molten salt) in a heat exchanger, creating steam.
4. The steam is then piped to a turbine.
5. The turbine is connected to a generator, which converts the mechanical energy of the steam into electrical energy.
6. The electrical energy is then distributed to the power grid and sent to homes and businesses.
7. The steam, after passing through the turbine, is cooled in a condenser and turns back into the fluid. It is then pumped back to the heat exchanger to start the process again.
8. If the system uses molten salt as the heat-transfer fluid, it can store the thermal energy in the salt for later use. This allows the plant to continue generating electricity even when the sun isn’t shining.

Here is a simple Diagram representation of the energy conversion process in a Solar Thermal power plant:

d. Hydroelectric power plant

Answer:- A hydroelectric power plant generates electricity by using the kinetic energy of falling water to drive a turbine connected to a generator. The generator converts the mechanical energy of the turbine into electrical energy.

Here is a step-by-step explanation of the energy conversion process in a hydroelectric power plant, with a diagram to illustrate the process:

1. Water is collected from a river or other water source, and is directed into a dam or other structure to create a reservoir.
2. The water is then released from the reservoir and flows through a turbine, which is connected to a generator.
3. As the turbine spins, it converts the kinetic energy of the falling water into mechanical energy.
4. The mechanical energy is then converted into electrical energy by the generator.
5. The electrical energy is then distributed to the power grid and sent to homes and businesses.
6. After passing through the turbine, the water is released back into the river or other water source.

Here is a simple Diagram representation of the energy conversion process in a Hydroelectric power plant:

11. Give scientific reasons

a. The construction of turbine is different for different types of power plants.

Answer:_ The construction of a turbine is different for different types of power plants due to several scientific reasons:

1. Different types of power plants use different forms of energy, such as kinetic energy, heat energy, or nuclear energy, to drive the turbine. Each form of energy requires a specific design and construction of the turbine.
2. The energy source and the method of energy conversion also affect the turbine design. For example, a hydroelectric power plant uses the kinetic energy of falling water to drive the turbine, while a thermal power plant uses heat energy from burning fossil fuels to produce steam to drive the turbine.
3. The speed and direction of the energy source also play a role in the turbine design. A hydroelectric turbine, for example, is designed to work at a lower speed than a steam turbine, which is designed to work at a much higher speed.
4. The size of the turbine is also different for different types of power plants. For example, a hydroelectric turbine is usually smaller than a steam turbine, as the amount of water flowing through the turbine is limited.
5. Different types of power plants have different requirements for the turbine, such as efficiency, reliability, and cost. These requirements are met by the construction of turbine which are different for different types of power plants.
6. Different types of power plants have different environmental impacts, therefore the design of the turbine should also consider these impacts. For example, hydroelectric power plants can have an impact on fish populations and the ecosystem, while nuclear power plants have an impact on the environment and safety.

Overall, the construction of a turbine is different for different types of power plants because of the different energy sources, energy conversion methods, and environmental impacts. Engineers use the scientific knowledge of fluid mechanics, thermodynamics, materials science, and other disciplines to design the turbine that is most suitable for the particular type of power plant.

b. It is absolutely necessary to control the fission reaction in nuclear power plants.

Answer:_ It is absolutely necessary to control the fission reaction in nuclear power plants for several reasons:

1. Safety: Nuclear power plants generate electricity by harnessing the energy released from the fission of atoms. If the fission reaction is not controlled, it can lead to an uncontrolled chain reaction, which can cause a nuclear meltdown or an explosion. This could result in the release of radioactive materials and severe damage to the environment, as well as harm to people living nearby.
2. Efficiency: The efficiency of a nuclear power plant is highly dependent on the control of the fission reaction. An uncontrolled reaction can lead to the generation of too much or too little heat, which can affect the efficiency of the plant.
3. Power Output: The power output of a nuclear power plant is directly related to the rate of fission reactions. If the reaction is not controlled, the power output will be inconsistent, leading to fluctuations in the electricity supply.
4. Fuel: Nuclear power plants use nuclear fuel to generate electricity. The fuel is typically in the form of enriched uranium or plutonium. If the fission reaction is not controlled, more fuel will be consumed than necessary, leading to a higher cost of operation and a shorter lifespan for the fuel.
5. Radiation: The fission reaction in a nuclear power plant produces radioactive materials. If the reaction is not controlled, the radioactive materials produced will be more than necessary, leading to a higher risk of radiation exposure for people working in the power plant and for people living nearby.

To control the fission reaction in a nuclear power plant, various systems and safety measures are employed. These include control rods, which absorb neutrons and slow down or stop the reaction, as well as cooling systems, which remove the heat generated by the reaction. Additionally, all nuclear power plants are subject to strict regulations and oversight to ensure that they are operated safely and in compliance with regulations.

c. Hydroelectric energy, solar energy and wind energy are called renewable energies.

Answer:_  Hydroelectric energy, solar energy, and wind energy are all considered renewable energies.

1. Hydroelectric energy is generated by harnessing the kinetic energy of falling water. This energy is renewable because water is constantly replenished through the water cycle, making it a sustainable source of energy.
2. Solar energy is generated by harnessing the energy from the sun. The sun is a constant source of energy, making solar power a renewable energy source.
3. Wind energy is generated by harnessing the kinetic energy of wind. Wind is caused by the sun heating the Earth’s surface unevenly, creating pressure differences and wind. As the sun is a constant source of energy, wind energy is also considered a renewable energy source.

All three energy sources are not dependent on finite resources and they do not generate greenhouse gases and other pollutants, making them more environmentally friendly compared to fossil fuels. They also have relatively low lifecycle emissions, making them more sustainable. These renewable energy sources are also becoming increasingly cost-competitive with fossil fuels, making them more economically viable as well.

d. It is possible to produce energy from mW to MW using solar photovoltaic cells.

Answer:_ It is possible to produce energy from a few milliwatts to several megawatts using solar photovoltaic (PV) cells. Solar PV cells are devices that convert sunlight directly into electricity. They can be used in a variety of applications, ranging from small portable devices to large utility-scale power plants.

For small-scale applications, such as powering a small electronic device, a few milliwatts of power may be sufficient. This can be achieved by using a small number of solar PV cells in a portable device or a small solar panel.

For larger-scale applications, such as powering a home or a small community, several hundred watts to a few kilowatts of power may be required. This can be achieved by using a larger number of solar PV cells in a solar panel array.

For utility-scale applications, such as powering a large community or a small city, several megawatts to hundreds of megawatts of power may be required. This can be achieved by using a large number of solar PV cells in a solar power plant.

The amount of energy that can be generated using solar PV cells is dependent on the size of the solar panel array, the efficiency of the solar PV cells, and the amount of sunlight available. It is also possible to use a combination of different types of renewable energy sources to generate electricity.

12. Draw a schematic diagram of solar thermal electric energy generation.

13. Give your opinion about whether hydroelectric plants are environment friendly or not?

Ans:_ Hydroelectric power plants can be considered environmentally friendly in many ways. They do not produce air pollution or greenhouse gases, and they can have a low impact on aquatic ecosystems if properly managed. However, construction of large hydroelectric dams can have negative effects on local communities and wildlife. Additionally, the operation of hydroelectric dams can disrupt fish migration and change the downstream flow of water. Overall, it depends on the specific project and how it is managed, but hydroelectric power can certainly be a valuable source of clean, renewable energy. 

14. Draw neat and labelled diagrams.

a. Energy transformation in solar thermal electric energy generation.

b. One solar panel produces a potential difference of 18 V and current of 3A. Describe how you can obtain a potential difference of 72 Volts and current of 9 A with a solar array using solar panels.You can use sign of a battery for a solar panel

Answer:- We can obtain a potential difference of 72 V by forming a string of 5 solar panels in series. Now, to obtain a current of 9 A, connect 3 such identical strings in parallel. The same has been shown below.

15. Write short note on Electrical energy generation and environment.

Ans:- Electricity generation has a significant impact on the environment. The majority of electricity is generated from fossil fuels such as coal, natural gas, and oil, which release greenhouse gases and air pollutants when burned. This contributes to climate change and air pollution, which can have negative impacts on human health and the environment.

Renewable energy sources such as solar, wind, and hydroelectric power can generate electricity with minimal environmental impact. However, even renewable energy sources can have some negative effects, such as the construction of large hydroelectric dams which can displace communities and impact local wildlife.

In recent years, there has been a growing focus on transitioning to clean, renewable energy sources in order to reduce the environmental impact of electricity generation. This includes increasing the use of solar and wind power, as well as developing new technologies such as energy storage and advanced nuclear power.

Overall, the use of clean and renewable energy sources for electricity generation is a crucial step in reducing the environmental impact of human activities and protecting the planet for future generations.