17 Module 3: Infrastructure Civil Engineering: Societal & Global Impact

Intake - Gates on the dam open and gravity pulls the water through the penstock, a pipeline that leads to the
turbine. Water builds up pressure as it flows through this pipe.
Turbine - The water strikes and turns the large blades of a turbine, which is attached to a generator above it by
way of a shaft. The most common type of turbine for hydropower plants is the Francis Turbine, which looks like
a big disc with curved blades. A turbine can weigh as much as 172 tons and turn at a rate of 90 revolutions per
minute (rpm), according to the Foundation for Water & Energy Education (FWEE).
Generators - As the turbine blades turn, so do a series of magnets inside the generator. Giant magnets rotate
past copper coils, producing alternating current (AC) by moving electrons. (You'll learn more about how the
generator works later.)
Transformer - The transformer inside the powerhouse takes the AC and converts it to higher-voltage current.
Power lines - Out of every power plant come four wires: the three phases of power being produced
simultaneously plus a neutral or ground common to all three. (Read How Power Distribution Grids Work to
learn more about power line transmission.)
Outflow - Used water is carried through pipelines, called tailraces, and re-enters the river downstream.
The water in the reservoir is considered stored energy. When the gates open, the water flowing through the
penstock becomes kinetic energy because it's in motion. The amount of electricity that is generated is determined
by several factors. Two of those factors are the volume of water flow and the amount of hydraulic head. The
head refers to the distance between the water surface and the turbines. As the head and flow increase, so does the
electricity generated. The head is usually dependent upon the amount of water in the reservoir.

Advantages:
1. Once a dam is constructed, electricity can be produced at a constant rate.
2. If electricity is not needed, the sluice gates can be shut, stopping electricity generation. The water can be
saved for use another time when electricity demand is high.
3. Dams are designed to last many decades and so can contribute to the generation of electricity for many
years / decades.
4. The lake that forms behind the dam can be used for water sports and leisure / pleasure activities. Often
large dams become tourist attractions in their own right.
5. The lake's water can be used for irrigation purposes.
6. The build up of water in the lake means that energy can be stored until needed, when the water is released
to produce electricity.
7. When in use, electricity produced by dam systems do not produce green house gases. They do not pollute
the atmosphere.
Disadvanatges:
1. Dams are extremely expensive to build and must be built to a very high standard.
2. The high cost of dam construction means that they must operate for many decades to become profitable.

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3. The flooding of large areas of land means that the natural environment is destroyed.
4. People living in villages and towns that are in the valley to be flooded, must move out. This means that
they lose their farms and businesses. In some countries, people are forcibly removed so that hydro-power
schemes can go ahead.
5. The building of large dams can cause serious geological damage. For example, the building of the Hoover
Dam in the USA triggered a number of earth quakes and has depressed th
6. Although modern planning and design of dams is good, in the past old dams have been known to be
breached (the dam gives under the weight of water in the lake). This has led to deaths and flooding.
7. Dams built blocking the progress of a river in one country usually means that the water supply from the
same river in the following country is out of their control. This can lead to serious problems between
neighbouring countries.
8. Building a large dam alters the natural water table level. For example, the building of the Aswan Dam in
Egypt has altered the level of the water table. This is slowly leading to damage of many of its ancient

the changing water table level.

Tidal Energy
Tidal Energy, also known as Tidal Power is classified as an alternate energy or better known as the renewable
source of energy. It is one of the forms of hydropower energy that exercises energy of the oceanic tides to generate
electricity. In this article, study about tidal energy in India.
Tide is the periodic shift or movement of vast quantities of water resulting from the gravitational forces of the sun
ter bodies. These vertical shifts or movement of water is known as tides. In
normal course each day experiences two high tides and two low tides. High tide is a situation where the water of
the ocean bulges towards the shore i.e towards the moon because of the gravitational forces between moon and
Earth, then High Tide occurs. But when the gravitational force between the Earth and the Moon is at right angles
to each other, this gravitational force is weak and water flows in some other location i.e this is the time when the
sea is at its lowest level. Hence, this is the reason it is one of the most viable forms of energy generation this is
because it is sure that each day we
as compared to solar and winds energy.
Types of Tidal Energy Generation
Tidal Barrage
A Tidal Barrage as the name suggests uses tidal barrages (a low dam set-up) to generate electricity. It uses the
potential energy in the difference in height between high and low tide. When sea level rises and high tide begins
to come in the energy from this tide is channelized through the dams which has underwater tunnels that allows
the sea water to flow through them, as water passes through these tunnels, the turbine generators attached to these
tunnels whirl the sea water, converting the energy of this tide into mechanical energy, thereby generating tidal
electricity.
Tidal Stream Generator
This method of tidal energy generation exercises the kinetic energy of the flowing water to power turbines placed
beneath the water. Similar to wind power generation, where water flows across the rotor blades which rotates the
turbine and thus tidal streams are formed by the constant incoming and outgoing of the tide, thereby generating
tidal energy

Advantages of Tidal Energy Generation

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1. Tidal energy is the most sorted and renewable source of energy because the energy it produces has lower
-friendly and no waste by-products are
produced either
2. Tidal energy has the potential to produce a great deal of free and green energy. Hence, it -friendly
energy
3. Tidal energy is not expensive to be conducted and is easy to maintain compared to other forms of
renewable energy sources
4. Low visual impact as the tidal turbines is mainly if not totally submerged beneath the water.
5. Low noise pollution as any sound generated is transmitted through the water.
6. High predictability as high and low tides can be predicted years in advance and there is a definite surety
of high and low tides occurring twice a day respectively
7. Tidal barrages provide protection against flooding and land damage and tidal stream generators cause
lesser or no harm to the natural landscape
8. Large tidal reservoirs have multiple uses and can create recreational lakes and area
Disadvantages of Tidal Energy Generation
1. Although the occurrence of tides can be predicted tidal energy is not always a constant energy source
because the energy generated from the tides depends completely on the strength and flow of the motions
of the water, which itself is dependent on the gravitational effects of the celestial bodies- Earth, Moon,
and the sun.
2. Tidal Energy requires a suitable site, where the tides and tidal streams are consistently strong and can be
harnessed
3. In contrary to its installation and generation costs it should be able to withstand forces of nature thereby
resulting in additional investment, apt construction and maintenance costs. The cost involved to send the
generated power from the submerged devices to the land is high because it requires long underwater
cables for the transmission
4. Intermittent power generation only generates power ten hours a day during the outgoing and incoming
of the tides
5. Chances of increase in coastal erosion where the tides are concentrated.
6. If not taken properly it can create a mess in the form of accumulated silt, sediments and pollutants within
the tidal barrage from rivers and streams flowing into the basin as it is unable to flow out into the sea.
7. Danger to marine animals like fish and other sea-life as they might get stuck in the barrage or get sucked
by the force of tidal turbine blades.
8. Many types of advanced tidal energy generation techniques like dynamic tidal power and tidal lagoon
still cannot be put in action because of the complexities attached to tidal energy generation
Tidal Energy in India
As of March 2017, India announced of its 7500 Km long coastline, where the height of high tide was recorded
over 5 mtrs higher than the low tide which can essentially capture the potential tidal power. The Ministry of New
and Renewable Energy estimated that the country can produce 7000 MW of power in the Gulf of Khambhat in
Gujarat, 1200 MW of power in the Gulf of Kutch in Gujarat and about 100 MW of power in the Gangetic delta
of Sunderbans in West Bengal.
Wave Energy
Wave power is the capture of energy of wind waves to do useful work for example, electricity generation, water
desalination, or pumping water. A machine that exploits wave power is a wave energy converter (WEC).
Wave power is distinct from tidal power, which captures the energy of the current caused by the gravitational pull
of the Sun and Moon. Wave-power generation is not a widely employed commercial technology compared to
other established renewable energy sources such as wind power, hydropower and solar power. However, there
have been attempts to use this source of energy since at least 1890 mainly due to its high power density.

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Difference between Tidal energy and wave energy

Tidal Energy Wave Energy
1. Harnessed from the rise and fall of sea levels. 1. Harnessed from waves moving along the
2. Caused by the gravitational pull of the moon surface of the ocean.
and sun on the Earth 2. Caused by wind
3. Intensity is affected by location and position 3. Intensity is affected by wind strength Often
of the Earth referred to as wave power
4. Types of tidal energy include kinetic and 4. Types of wave energy include kinetic energy
potential energy
5. Harnessed using barrages, dams, tidal fences 5. Harnessed using offshore and onshore
and tidal turbines systems
6. More reliable since it is based on the 6. Less reliable since it is based on the effect of
gravitational pull of the moon and sun the strength of the wind on the surface of the
7. Discontinuous source of energy that is water
generated for about 6 12 hours at a time 7. Continuous source of energy
8. Can disrupt migrating routes of birds and 8. Effect on surrounding environments,
boating pathways and result in large amounts ecosystems and communities are low
of fish kill 9. Extremely high start-up costs to design and
9. High construction costs but low develop the technology required
maintenance costs

Solar Energy
Solar power is the conversion of energy from sunlight into electricity, either directly using photovoltaic (PV),
indirectly using concentrated solar power, or a combination. Concentrated solar power systems
use lenses or mirrors and solar tracking systems to focus a large area of sunlight into a small beam.

Photovoltaic cells convert light into an electric current using the photovoltaic effect. Photovoltaic were initially
solely used as a source of electricity for small and medium-sized applications, from the calculator powered by a
single solar cell to remote homes powered by an off-grid rooftop PV system. Commercial concentrated solar
power plants were first developed in the 1980s. As the cost of solar electricity has fallen, the number of grid-
connected solar PV systems has grown into the millions and utility-scale photovoltaic power stations with
hundreds of megawatts are being built. Solar PV is rapidly becoming an inexpensive, low-carbon technology to
harness renewable energy from the Sun. The current largest photovoltaic power station in the world is
the Pavagada Solar Park, Karnataka, India with a generation capacity of 2050 MW

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Concentrated solar power (CSP), also called "concentrated solar thermal", uses lenses or mirrors and tracking
systems to concentrate sunlight, then use the resulting heat to generate electricity from conventional steam-driven
turbines. A wide range of concentrating technologies exists: among the best known are the parabolic trough,
the compact linear Fresnel reflector, the dish Stirling and the solar power tower. Various techniques are used
to track the sun and focus light. In all of these systems a working fluid is heated by the concentrated sunlight, and
is then used for power generation or energy storage. Thermal storage efficiently allows up to 24-hour electricity
generation.
A parabolic trough consists of a linear parabolic reflector that concentrates light onto a receiver
positioned along the reflector's focal line. The receiver is a tube positioned along the focal points of the
linear parabolic mirror and is filled with a working fluid. The reflector is made to follow the sun during
daylight hours by tracking along a single axis. Parabolic trough systems provide the best land-use factor
of any solar technology. The Solar Energy Generating Systems plants in California and Acciona's Nevada
Solar One near Boulder City, Nevada are representatives of this technology.
Compact Linear Fresnel Reflectors are CSP-plants which use many thin mirror strips instead of parabolic
mirrors to concentrate sunlight onto two tubes with working fluid. This has the advantage that flat mirrors
can be used which are much cheaper than parabolic mirrors, and that more reflectors can be placed in the
same amount of space, allowing more of the available sunlight to be used. Concentrating linear Fresnel
reflectors can be used in either large or more compact plants.
The Stirling solar dish combines a parabolic concentrating dish with a Stirling engine which normally
drives an electric generator. The advantages of Stirling solar over photovoltaic cells are higher efficiency
of converting sunlight into electricity and longer lifetime. Parabolic dish systems give the highest
efficiency among CSP technologies. The 50 kW Big Dish in Canberra, Australia is an example of this
technology.
A solar power tower uses an array of tracking reflectors (heliostats) to concentrate light on a central
receiver atop a tower. Power towers can achieve higher (thermal-to-electricity conversion) efficiency
than linear tracking CSP schemes and better energy storage capability than dish Stirling
technologies. The PS10 Solar Power Plant and PS20 solar power plant are examples of this technology.

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Advantages:
1. Solar power is pollution free and causes no greenhouse gases to be emitted after installation
2. Reduced dependence on foreign oil and fossil fuels
3. Renewable clean power that is available every day of the year, even cloudy days produce some power
4. Return on investment unlike paying for utility bills
5. Virtually no maintenance as solar panels last over 30 years
6. Creates jobs by employing solar panel manufacturers, solar installers, etc. and in turn helps the economy
7. Excess power can be sold back to the power company if grid intertied
8. Ability to live grid free if all power generated provides enough for the home / building
9. Can be installed virtually anywhere; in a field to on a building
10. Use batteries to store extra power for use at night
11. Solar can be used to heat water, power homes and building, even power cars
12. Safer than traditional electric current
13. Efficiency is always improving so the same size solar that is available today will become more efficient
tomorrow
14. Aesthetics are improving making the solar more versatile compared to older models; i.e. printing,
flexible, solar shingles, etc.
15. Federal grants, tax incentives, and rebate programs are available to help with initial costs
Disadvantages
1. High initial costs for material and installation and long ROI
2. Needs lots of space as efficiency is not 100% yet
3. No solar power at night so there is a need for a large battery bank
4. Some people think they are ugly (I am definitely not one of those!)
5. Devices that run on DC power directly are more expensive
6. Depending on geographical location the size of the solar panels vary for the same power generation
7. Cloudy days do not produce much energy
8. Solar panels are not being massed produced due to lack of material and technology to lower the cost
enough to be more affordable
9. Solar powered cars do not have the same speeds and power as typical gas powered cars
10. Lower production in the winter months
Nuclear Power
Nuclear power plants have risen in numbers over the years. There are over 400 nuclear power plants across the
world as of 2019. Currently, more than 14%
Nuclear reactions are of two types Nuclear Fission and Nuclear Fusion. We use Nuclear Fission to generate

-effectively.
In nuclear power plants, this heat emitted from the reactions is used to turn water into superheated steam. This
steam is then used to turn a turbine which is connected to a generator. As the turbine spins, the generator begins
to produce energy.
Nuclear fission is the process of splitting an atom. When an atom is split, it releases a massive amount of energy.
Nuclear power plants that we use today harness this power and convert it into electrical energy.

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Advantages
1. Since the requirement of fuel is very small, so the cost of fuel transportation, storage etc. is small.
2. Nuclear power plant needs less space as compared to any other power station of the same size.
Example: A 100 MW nuclear power station needs 38 - 40 acres of land whereas the same capacity coal
based thermal power plant needs 120-130 acres of land.
3. This type of power plant is very economical to produce large electric power.
4. Nuclear power plant can be located near load centre because bulk amount of fuel (like water, coal) is
not required.
5. Nuclear power is most economical to generate large capacities of power like 100 MVA or more. It
produces huge amount of energy in every nuclear fission process.
6. Using a small amount of fuel, this plant produces large electrical energy.
7. This plant is very reliable in operation.
8. Since, the large number of nuclear fuel is available in this world. So, a nuclear power plant can
generate electrical energy thousands of years continuously.
9. Nuclear Power Plant is very neat and clean as compared to a steam power plant.
10. The operating cost is low at this power plant but it is not affected for higher load demand. Nuclear
power plant always operates a base load plant and load factor will not be less than 0.8.

Disadvantages
Though nuclear power plant has above advantages, but there are some disadvantages of nuclear power plant too,
1. Initial installation cost is very high as compared to the other power station.
2. Nuclear fuel is very much expensive and it is difficult to recover.
3. Capital cost is higher in respect of other power station.
4. Good technical knowledge is required to operate such type plant. So, salary bill and other maintenance
cost will be higher to operate such of a plant.
5. There is a chance to spread of radioactive pollution from this type of plant.
6. Nuclear Reactor does not response efficiently with the fluctuating load demand. So, it is not suited for
varying the load.
7. Cooling water requirement is twice than a coal based steam power plant.
Wind Energy
The wind is a clean, free, and readily available renewable energy source. Each day, around the world, wind

increasingly important role in the way we power our world in a clean, sustainable manner.
Wind turbines allow us to harness the power of the wind and turn it into energy. When the wind blows, the turbine's
blades spin clockwise, capturing energy. This triggers the main shaft of the wind turbine, connected to a gearbox
within the nacelle, to spin. The gearbox sends that wind energy to the generator, converting it to electricity.
Electricity then travels to a transformer, where voltage levels are adjusted to match with the grid.

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Advantages of Wind Energy

1. Clean & Environment friendly Fuel source:

combustion of fossil fuel. It does not produce atmospheric emissions that cause acid rain or green house
gases (carbon dioxide (CO2) or methane (CH4)). Noise and visual pollution are both environmental

2. Renewable & Sustainable: Winds are caused by heating of atmosphere by the sun, earth surface
irregularities and the rotation of the earth. For as long as the sun shines the wind blows, the energy
reserves.
3. Cost Effective:

depending upon the wind resource and th

4. Industrial and Domestic Installation: Wind turbines can be built on existing farms or ranches where
most of the best wind sites are found. Wind turbines uses only a fraction of the land which causes no
trouble in work for the farmers and rancher, providing landowners with additional income paid by the
owners of the wind power plants. Many landowners opt to install smaller, less powerful wind turbines in
order to provide part of a domestic electricity supply.
5. Job Creation: Jobs have been created for the manufacture of wind turbines, the installation and
maintenance of wind turbines and also in wind energy consulting. According to the Wind Vision Report,
wind has the potential to support more than 600,000 jobs in manufacturing, installation, maintenance,
and supporting services by 2050.

Disadvantages of Wind Energy

1. Fluctuation of Wind and Good wind sites: Wind energy has a drawback that it is not a constant energy
source. Although wind energy is sustainable and will never ru
can cause serious problems for wind turbine developers who will often spend significant time and money
investigating whether or not a particular site is suitable for the generation of wind power. For a wind
turbine to be efficient, the location where it is built needs to have an adequate supply of wind energy.
2. Noise and aesthetic pollution: Wind turbines generate noise and visual pollution. A single wind
turbine can be heard from hundreds of meters away. Although steps are often taken to site wind turbines
away from dwellings. Many people like the look of wind turbines, others do not and see them as a blot
on the landscape.
3. Not a profitable use of land: Alternative uses for the land might be more highly valued than electricity
generation.
4. Threat to wildlife: Birds have been killed by flying into spinning turbine blades. However it is believed
that wind turbines pose less of a threat to wildlife than other man made structures such as cell phone
masts and radio towers. Most of the problems have been resolved or greatly reduced through
technological development or by properly siting wind plants.

Geothermal energy

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