SUSTNABL.com

Hydro Power energy

1

Hydro Power energy

SUSTNABL.com

Hydro Power energy

3

Index

Title Page Number

Chapter 1 - What is wind energy 3

Chapter 2 - Transforming Wind into Energy 7

Chapter 3 - Wind farms 13

Chapter 4 -Wind power capacity and production 15

Chapter 5 -The use of wind power 18

Chapter 6 - Advantage and disadvantage of wind power 21

Chapter 7 - Wind Energy in India 24

References 25

SUSTNABL.com

Hydro Power energy

4

Chapter 1 - What is the meaning of Hydro Power

Hydropower or water power (from the Greek: ύύύύ, “water” ) is power derived from the energy of falling water or fast run-ning water, which may be harnessed for useful purposes. Since ancient times, hydropower from many kinds of water-mills has been used as a renewable energy source for irriga-tion and the operation of various mechanical devices, such as gristmills, sawmills, textile mills, trip hammers, dock cranes, domestic lifts, and ore mills. A trompe, which produces com-pressed air from falling water, is sometimes used to power other machinery at a distance.

In the late 19th century, hydropower became a source for generating electricity. Cragside in Northumberland was the first house powered by hydroelectricity in 1878 and the first commercial hydroelectric power plant was built at Niagara Falls in 1879. In 1881, street lamps in the city of Niagara Falls were powered by hydropower.

Since the early 20th century, the term has been used al-most exclusively in conjunction with the modern develop-ment of hydroelectric power. International institutions such as the World Bank view hydropower as a means for economic development without adding substantial amounts of carbon

SUSTNABL.com

Hydro Power energy

5

to the atmosphere, but in some cases dams environmental issues.

History

In India, water wheels and watermills were built ; in Imperial Rome, water powered mills produced flour from grain, and were also used for sawing timber and stone; in China, water-mills were widely used since the Han dynasty In China and the rest of the Far East, hydraulically operated “pot wheel” pumps raised water into crop or irrigation canals.

The power of a wave of water released from a tank was used for extraction of metal ores in a method known as hushing. The method was first used at the Dolaucothi Gold Mines in Wales from 75 AD onwards, but had been developed in Spain at such mines as Las Médulas. Hushing was also widely used in Britain in the Medieval and later periods to extract lead and tin ores.[4] It later evolved into hydraulic mining when used during the California Gold Rush.

In the Middle Ages, Islamic mechanical engineer Al-Jazari described designs for 50 devices, many of them water pow-ered in his book, The Book of Knowledge of Ingenious Me-chanical Devices, including devices to serve wine, clocks and five devices lift water from rivers or pools, though three

SUSTNABL.com

Hydro Power energy

6

are animal-powered and one can be powered by animal or water. These include an endless belt with jugs attached, a cow-powered shadoof and a reciprocating device with hinged valves.

In 1753, French engineer Bernard Forest de Bélidor pub-lished Architecture Hydraulique which described vertical- and horizontal-axis hydraulic machines. By the late nineteenth century, the electric generator was developed by a team led by project managers and prominent pioneers of renewable energy Jacob S. Gibbs and Brinsley Coleberd and could now be coupled with hydraulics. The growing demand for the In-dustrial Revolution would drive development as well.

At the beginning of the Industrial Revolution in Britain, wa-ter was the main source of power for new inventions such as Richard Arkwright’swater frame.[8] Although the use of water power gave way to steam power in many of the larger mills and factories, it was still used during the 18th and 19th centu-ries for many smaller operations, such as driving the bellows in small blast furnaces (e.g. the Dyfi Furnace) andgristmills, such as those built at Saint Anthony Falls, which uses the 50-foot (15 m) drop in the Mississippi River.

In the 1830s, at the early peak in US canal-building, hydro-power provided the energy to transport barge traffic up and

SUSTNABL.com

Hydro Power energy

7

down steep hills using inclined plane railroads. As railroads overtook canals for transportation, canal systems were mod-ified and developed into hydropower systems; the history of Lowell, Massachusetts is a classic example of commercial development and industrialization, built upon the availability of water power.

Technological advances had moved the open water wheel into an enclosed turbine or water motor. In 1848 James B. Francis, while working as head engineer of Lowell’s Locks and Canals company, improved on these designs to create a turbine with 90% efficiency. He applied scientific principles and testing methods to the problem of turbine design. His mathematical and graphical calculation methods allowed confident design of high efficiency turbines to exactly match a site’s specific flow conditions. The Francis reaction turbine is still in wide use today. In the 1870s, deriving from uses in the California mining industry, Lester Allan Pelton developed the high efficiency Pelton wheel impulse turbine, which uti-lized hydropower from the high head streams characteristic of the mountainous California interior.

Hydraulic power-pipe networks

Hydraulic power networks used pipes to carrying pressur-ized water and transmit mechanical power from the source

SUSTNABL.com

Hydro Power energy

8

to end users. The power source was normally a head of wa-ter, which could also be assisted by a pump. These were ex-tensive in Victorian cities in the United Kingdom. A hydraulic power network was also developed in Geneva, Switzerland. The world famous Jet d’Eau was originally designed as the over-pressure relief valve for the network.[11]

Compressed air hydro

Where there is a plentiful head of water it can be made to generate compressed air directly without moving parts. In these designs, a falling column of water is purposely mixed with air bubbles generated through turbulence or a venturi pressure reducer at the high level intake. This is allowed to fall down a shaft into a subterranean, high-roofed chamber where the now-compressed air separates from the water and be-comes trapped. The height of the falling water column main-tains compression of the air in the top of the chamber, while an outlet, submerged below the water level in the chamber allows water to flow back to the surface at a lower level than the intake. A separate outlet in the roof of the chamber sup-plies the compressed air. A facility on this principle was built on the Montreal River at Ragged Shutes near Cobalt, Ontario in 1910 and supplied 5,000 horsepower to nearby mines.

SUSTNABL.com

Hydro Power energy

9

Hydropower types

Hydropower is used primarily to generate electricity. Broad

categories include:• Conventional hydroelectric, referring to hydroelectric

dams.• Run-of-the-river hydroelectricity, which captures the ki-

netic energy in rivers or streams, without a large reservoir and sometimes without the use of dams.

• Small hydro projects are 10 megawatts or less and often have no artificial reservoirs.

• Micro hydro projects provide a few kilowatts to a few hun-dred kilowatts to isolated homes, villages, or small industries.

• Conduit hydroelectricity projects utilize water which has already been diverted for use elsewhere; in a municipal wa-ter system, for example.

• Pumped-storage hydroelectricity stores water pumped uphill into reservoirs during periods of low demand to be re-leased for generation when demand is high or system gener-ation is low.

SUSTNABL.com

Hydro Power energy

10

Chapter 2 - Hydro electricity

Hydroelectricity is the term referring to electricity generat-ed by hydropower; the production of electrical power through the use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy, account-ing for 16 percent of global electricity generation – 3,427 ter-awatt-hours of electricity production in 2010, and is expected to increase about 3.1% each year for the next 25 years.

Hydropower is produced in 150 countries, with the Asia-Pa-cific region generating 32 percent of global hydropower in 2010.China is the largest hydroelectricity producer, with 721 terawatt-hours of production in 2010, representing around 17 percent of domestic electricity use.

The cost of hydroelectricity is relatively low, making it a com-petitive source of renewable electricity. The average cost of electricity from a hydro station larger than 10 megawatts is 3 to 5 U.S. cents per kilowatt-hour. It is also a flexible source of electricity since the amount produced by the station can be changed up or down very quickly to adapt to changing ener-gy demands. However, damming interrupts the flow of rivers and can harm local ecosystems, and building large dams and reservoirs often involves displacing people and wildlife. Once a hydroelectric complex is constructed, the project produces

SUSTNABL.com

Hydro Power energy

11

no direct waste, and has a considerably lower output level of the greenhouse gas carbon dioxide (CO2) than fossil fuel powered energy plants.

Conventional (dams)

Most hydroelectric power comes from the potential energy of dammed water driving a water turbine and generator. The power extracted from the water depends on the volume and on the difference in height between the source and the wa-ter’s outflow. This height difference is called the head. A large pipe (the “penstock”) delivers water from the reservoir to the turbine.

Pumped-storage

This method produces electricity to supply high peak de-mands by moving water between reservoirs at different ele-vations. At times of low electrical demand, the excess gener-ation capacity is used to pump water into the higher reservoir. When the demand becomes greater, water is released back into the lower reservoir through a turbine. Pumped-storage schemes currently provide the most commercially import-ant means of large-scale grid energy storage and improve the daily capacity factor of the generation system. Pumped storage is not an energy source, and appears as a negative

SUSTNABL.com

Hydro Power energy

12

number in listings.

Run-of-the-river

Run-of-the-river hydroelectric stations are those with small or no reservoir capacity, so that only the water coming from upstream is available for generation at that moment, and any oversupply must pass unused. A constant supply of water from a lake or existing reservoir upstream is a significant ad-vantage in choosing sites for run-of-the-river. In the United States, run of the river hydropower could potentially provide 60,000 megawatts (80,000,000 hp) (about 13.7% of total use in 2011 if continuously available).

Tide

A tidal power station makes use of the daily rise and fall of ocean water due to tides; such sources are highly predict-able, and if conditions permit construction of reservoirs, can also be dispatchable to generate power during high demand periods. Less common types of hydro schemes use water’s kinetic energy or undammed sources such as undershot wa-terwheels. Tidal power is viable in a relatively small number of locations around the world. In Great Britain, there are eight sites that could be developed, which have the potential to generate 20% of the electricity used in 2012.

SUSTNABL.com

Hydro Power energy

13

Sizes, types and capacities of hydroelectric facilities

Large facilities

Large-scale hydroelectric power stations are more com-monly seen as the largest power producing facilities in the world, with some hydroelectric facilities capable of generat-ing more than double the installed capacities of the current largest nuclear power stations.

Although no official definition exists for the capacity range of large hydroelectric power stations, facilities from over a few hundred megawatts are generally considered large hy-droelectric facilities.

Currently, only four facilities over 10 GW (10,000 MW) are in operation worldwide, see table below.

Rank Station Country LocationCapacity

(MW)

1.Three

Gorges Dam

China 30°49ύ15ύN 111°00ύ08ύE

22,500

SUSTNABL.com

Hydro Power energy

14

Small

Small hydro is the development of hydroelectric power on a scale serving a small community or industrial plant. The definition of a small hydro project varies but a generating ca-pacity of up to 10 megawatts (MW) is generally accepted as the upper limit of what can be termed small hydro. This may be stretched to 25 MW and 30 MW in Canada and theUnited States. Small-scale hydroelectricity production grew by 28% during 2008 from 2005, raising the total world small-hydro capacity to 85 GW. Over 70% of this was in China(65 GW), fol-lowed by Japan (3.5 GW), the United States (3 GW), and India (2 GW).

2.Itaipu Dam

BrazilParaguay

25°24ύ31ύS 54°35ύ21ύW

14,000

3.Xiluodu

DamChina

28°15ύ35ύN 103°38ύ58ύE

13,860

4. Guri Dam Venezuela07°45ύ59ύN 62°59ύ57ύW

10,200

SUSTNABL.com

Hydro Power energy

15

Pico hydroelectricity in A micro-hydro facility in Vietnam Mondulkiri, Cambodia

Pico hydroelectricity in Mondulkiri, CambodiaSmall hydro stations may be connected to conventional

electrical distribution networks as a source of low-cost re-newable energy. Alternatively, small hydro projects may be built in isolated areas that would be uneconomic to serve from a network, or in areas where there is no national elec-trical distribution network. Since small hydro projects usually have minimal reservoirs and civil construction work, they are seen as having a relatively low environmental impact com-pared to large hydro. This decreased environmental impact depends strongly on the balance between stream flow and power production.

Micro

Micro hydro is a term used for hydroelectric power instal-lations that typically produce up to 100 kW of power. These

SUSTNABL.com

Hydro Power energy

16

installations can provide power to an isolated home or small community, or are sometimes connected to electric power networks. There are many of these installations around the world, particularly in developing nations as they can provide an economical source of energy without purchase of fuel. Micro hydro systems complement photovoltaic solar energy systems because in many areas, water flow, and thus avail-able hydro power, is highest in the winter when solar energy is at a minimum.

Pico

Pico hydro is a term used for hydroelectric power genera-tion of under 5 kW. It is useful in small, remote communities that require only a small amount of electricity. For example, to power one or two fluorescent light bulbs and a TV or ra-dio for a few homes. Even smaller turbines of 200-300W may power a single home in a developing country with a drop of only 1 m (3 ft). A Pico-hydro setup is typically run-of-the-riv-er, meaning that dams are not used, but rather pipes divert some of the flow, drop this down a gradient, and through the turbine before returning it to the stream.

Underground

An underground power station is generally used at large

SUSTNABL.com

Hydro Power energy

17

facilities and makes use of a large natural height difference between two waterways, such as a waterfall or mountain lake. An underground tunnel is constructed to take water from the high reservoir to the generating hall built in an underground cavern near the lowest point of the water tunnel and a hor-izontal tailrace taking water away to the lower outlet water-way.

Calculating available power

Main article: HydropowerA simple formula for approximating electric power produc-

tion at a hydroelectric station is: , where• is Power in watts,• is the density of water (~1000 kg/m3),• is height in meters,• is flow rate in cubic meters per second,• is acceleration due to gravity of 9.8 m/s2,• is a coefficient of efficiency ranging from 0 to 1. Efficien-

cy is often higher (that is, closer to 1) with larger and more modern turbines.

Annual electric energy production depends on the avail-able water supply. In some installations, the water flow rate can vary by a factor of 10:1 over the course of a year.

SUSTNABL.com

Hydro Power energy

18

Chapter 3 - How Does Hydroelectric Pow-er Work?

Hydroelectric power, also known as hydroelectric energy or simply hydroelectricity, supplies about 20% of the entire world’s electricity needs – About 88% of the total electricity that is generated from renewable energy sources. In this arti-cle I’m going to explain how hydroelectric power plants work.

Where Does Hydroelectric Energy Come From?

Hydroelectric energy can be defined as a form of hydro-power where the motion of running water (kinetic energy) is converted into electricity.

The water cycle is driven directly by solar energy. When the sun heats the water in the ocean, some of the water on the surface is vaporized. The water vapor rises and when it reach-es higher layers of air and is cooled, the water falls down in the form of rain, hail or snow. The water flows in streams and rivers, finally reaching the sea where it again evaporates.

What is Hydroelectricity?

Hydroelectric energy is potential energy that is converted to

SUSTNABL.com

Hydro Power energy

19

kinetic energy through the forces of gravitation, which again comes from solar energy, driving the water cycle around. To answer the question, hydroelectric energy is the result of heat energy from the sun and the gravitational forces from the earth.

How Hydroelectric Power Plants WorkBy letting the water flow through turbines on their way to

the sea, we can harness some of the kinetic energy of water to produce electricity. The flow and head determines the po-tential energy of a waterfall.

The head is the height difference between the water level in the inlet and outlet from the power plant. From the intake reservoir, the water flows down to the power station, and then into the turbine wheel.

Tidal PowerThere are several ways to generate electricity other than

the conventional hydroelectric power plant. Tide power is a form of hydroelectricity that looks very promising. The basic gist of how tide power works is this:

Tidal power is the result of the moon and the sun’s gravi-tational influence on the ocean. Height differences between high and low tides create tidal currents in coastal areas, and

SUSTNABL.com

Hydro Power energy

20

these currents can be strong enough to drive turbines.

How Much Does Hydroelectric Power Cost?

The cost of hydroelectric power is dependent on a lot of factors. An important factor is that hydroelec-tric power requires no fuel. This results in almost no fluctuations in costs when costs of other en-ergy sources such as oil and gas go up or down.

Hoover Dam, built in the 1930’s, is lo-cated in the Black Canyon area of Colorado River. This facility is capable of generating 2,074MW and came with a price tag of $49 million.

These plants have long lives and don’t require a lot of op-erators to function. Hydroelectric power plants are in most cases able to generate cheaper electricity than other alterna-tives. So why don’t we just mass-produce these power plants across the globe? The answer is that suitable reservoirs are limited.

SUSTNABL.com

Hydro Power energy

21

Chapter 4 – Tools that generate hydro pow-er

So just how do we get electricity from water? Actually, hy-droelectric and coal-fired power plants produce electricity in a similar way. In both cases a power source is used to turn a propeller-like piece called a turbine, which then turns a met-al shaft in an electric generator, which is the motor that pro-duces electricity. A coal-fired power plant uses steam to turn the turbine blades; whereas a hydroelectric plant uses falling water to turn the turbine. The results are the same.

Take a look at this diagram (courtesy of the Tennessee Val-ley Authority) of a hydroelectric power plant to see the details:

SUSTNABL.com

Hydro Power energy

22

The theory is to build a dam on a large river that has a large drop in elevation (there are not many hydroelectric plants in Kansas or Florida). The dam stores lots of water behind it in the reservoir. Near the bottom of the dam wall there is the water intake. Gravity causes it to fall through the penstock inside the dam. At the end of the penstock there is a turbine propeller, which is turned by the moving water. The shaft from the turbine goes up into the generator, which produces the power. Power lines are connected to the generator that carry electricity to your home and mine. The water continues past the propeller through the tailrace into the river past the dam. By the way, it is not a good idea to be playing in the water right below a dam when water is released!

This diagram of a hydroelectric generator is courtesy of U.S. Army Corps of Engineers.

As to how this generator works, the Corps of Engineers ex-plains it this way:

“A hydraulic turbine converts the energy of flowing water into mechanical energy. A hydroelectric generator converts this mechanical energy into electricity. The operation of a generator is based on the principles discovered by Faraday. He found that when a magnet is moved past a conductor, it causes electricity to flow. In a large generator, electromag-

SUSTNABL.com

Hydro Power energy

23

nets are made by circulating direct current through loops of wire wound around stacks of magnetic steel laminations. These are called field poles, and are mounted on the perim-eter of the rotor. The rotor is attached to the turbine shaft, and rotates at a fixed speed. When the rotor turns, it causes the field poles (the electromagnets) to move past the conductors mounted in the stator. This, in turn, causes electricity to flow and a voltage to develop at the generator output terminals.”

Pumped storage: Reusing water for peak elec-tricity demand

Demand for electricity is not “flat” and constant. Demand goes up and down during the day, and overnight there is less need for electricity in homes, businesses, and other facilities. For example, here in Atlanta, Georgia at 5:00 PM on a hot Au-gust weekend day, you can bet there is a huge demand for

SUSTNABL.com

Hydro Power energy

24

electricity to run millions of air conditioners! But, 12 hours lat-er at 5:00 AM …not so much. Hydroelectric plants are more ef-ficient at providing for peak power demands during short pe-riods than are fossil-fuel and nuclear power plants, and one way of doing that is by using “pumped storage”, which reuses the same water more than once.

Pumped storage is a method of keeping water in reserve for peak period power demands by pumping water that has already flowed through the turbines back up a storage pool above the powerplant at a time when customer demand for energy is low, such as during the middle of the night. The wa-ter is then allowed to flow back through the turbine-genera-tors at times when demand is high and a heavy load is placed on the system.

The reservoir acts much like a battery, storing power in the form of water when demands are low and producing maxi-mum power during daily and seasonal peak periods. An ad-vantage of pumped storage is that hydroelectric generating units are able to start up quickly and make rapid adjustments in output. They operate efficiently when used for one hour or several hours. Because pumped storage reservoirs are rela-tively small, construction costs are generally low compared with conventional hydropower facilities.

SUSTNABL.com

Hydro Power energy

25

Chapter 5- How to calculate the hydro pow-er generated

A hydropower resource can be evaluated by its available power. Power is a function of the hydraulic head and rate of fluid flow. The head is the energy per unit weight (or unit mass) of water. The static head is proportional to the difference in height through which the water falls. Dynamic head is related to the velocity of moving water. Each unit of water can do an amount of work equal to its weight times the head.

The power available from falling water can be calculated from the flow rate and density of water, the height of fall, and the local acceleration due to gravity. In SI units, the power is:

where• P is power in watts• ύ is the dimensionless efficiency of the turbine• ύ is the density of water in kilograms per cubic metre• Q is the flow in cubic metres per second• g is the acceleration due to gravity• h is the height difference between inlet and outlet in me-

tres

To illustrate, power is calculated for a turbine that is 85% ef-ficient, with water at 1000 kg/cubic metre (62.5 pounds/cubic

SUSTNABL.com

Hydro Power energy

26

foot) and a flow rate of 80 cubic-meters/second (2800 cu-bic-feet/second), gravity of 9.81 metres per second squared and with a net head of 145 m (480 ft).

In SI units: which gives 97 MW

In English units, the density is given in pounds per cubic foot so acceleration due to gravity is inherent in the unit of weight. A conversion factor is required to change from foot lbs/second to kilowatts:

which gives 97 MW (130,000 horsepower)

Operators of hydroelectric stations will compare the total electrical energy produced with the theoretical potential en-ergy of the water passing through the turbine to calculate effi-ciency. Procedures and definitions for calculation of efficiency are given in test codes such as ASME PTC 18 and IEC 60041. Field testing of turbines is used to validate the manufacturer’s guaranteed efficiency. Detailed calculation of the efficiency of a hydropower turbine will account for the head lost due to flow friction in the power canal or penstock, rise in tail wa-ter level due to flow, the location of the station and effect of varying gravity, the temperature and barometric pressure of the air, the density of the water at ambient temperature, and

SUSTNABL.com

Hydro Power energy

27

the altitudes above sea level of the forebay and tailbay. For precise calculations, errors due to rounding and the number of significant digits of constants must be considered.

Some hydropower systems such as water wheels can draw power from the flow of a body of water without necessarily changing its height. In this case, the available power is thek-inetic energy of the flowing water. Over-shot water wheels can efficiently capture both types of energy.

The water flow in a stream can vary widely from season to season. Development of a hydropower site requires analysis of flow records, sometimes spanning decades, to assess the reliable annual energy supply. Dams and reservoirs provide a more dependable source of power by smoothing season-al changes in water flow. However reservoirs have significant environmental impact, as does alteration of naturally occur-ring stream flow. The design of dams must also account for the worst-case, “probable maximum flood” that can be ex-pected at the site; a spillway is often included to bypass flood flows around the dam. A computer model of the hydraulic basin and rainfall and snowfall records are used to predict the maximum flood.

SUSTNABL.com

Hydro Power energy

28

Hydropower sustainability

As with other forms of economic activity, hydropower proj-ects can have both a positive and a negative environmental and social impact, because the construction of a dam and power plant, along with the impounding of a reservoir, cre-ates certain social and physical changes.

A number of tools have been developed to assist projects.

Most new hydropower project must undergo an Environ-mental and Social Impact Assessment. This provides a base line understand of the pre project conditions, estimates po-tential impacts and puts in place management plans to avoid, mitigate, or compensate for impacts.

The Hydropower Sustainability Assessment Protocol is an-other tool which can be used to promote and guide more sustainable hydropower projects. It is a methodology used to audit the performance of a hydropower project across more than twenty environmental, social, technical and economic topics. A Protocol assessment provides a rapid sustainability health check. It does not replace an environmental and social impact assessment (ESIA), which takes place over a much longer period of time, usually as a mandatory regulatory re-

SUSTNABL.com

Hydro Power energy

29

quirement.

The World Commission on Dams final report describes a framework for planning water and energy projects that is in-tended to protect dam-affected people and the environment, and ensure that the benefits from dams are more equitably distributed.[14]

IFC’s Environmental and Social Performance Standards define IFC clients’ responsibilities for managing their environ-mental and social risks.[15]

The World Bank’s safeguard policies are used by the Bank to help identify, avoid, and minimize harms to people and the environment caused by investment projects.[16]

The Equator Principles is a risk management framework, adopted by financial institutions, for determining, assessing and managing environmental and social risk in projects

Chapter 6 - Hydroelectric Energy Pros and Cons

20% of the world’s electricity consumption in 2006 was generated with hydroelectricity (generating electricity from

SUSTNABL.com

Hydro Power energy

30

hydropower), the most used renewable energy source in the world. We all know that hydroelectricity is both renewable and green, but what are the other advantages this technolo-gy offer? Are there any disadvantages?

Advantages of Hydroelectric Energy

1. Renewable

Hydroelectric energy is renewable. This means that we cannot use up. However, there’s only a limited number of suitable reservoirs where hydroelectric power plants can be built and even less places where such projects are profitable.

2. Green

Generating electricity with hydro energy is not polluting itself. The only pollution occurs during the construction of these massive power plants.

3. Reliable

Hydroelectricity is very reliable energy. There are very little fluctuations in terms of the electric power that is being by

SUSTNABL.com

Hydro Power energy

31

the plants, unless a different output is desired. Countries that have large resources of hydropower use hydroelectricity as a base load energy source. As long as there is water in the magazines electricity can be generated.

4. Flexible

As previously mentioned, adjusting water flow and output of electricity is easy. At times where power consumption is low, water flow is reduced and the magazine levels are being conserved for times when the power consumption is high.

5. SafeCompared to among others fossil fuels and nuclear ener-

gy, hydroelectricity is much safer. There is no fuel involved (other than water that is).

Disadvantages of Hydroelectric Energy

1. Environmental Consequences

The environmental consequences of hydropower are re-lated to interventions in nature due to damming of water, changed water flow and the construction of roads and power

SUSTNABL.com

Hydro Power energy

32

lines.

Hydroelectric power plants may affect fish is a complex in-teraction between numerous physical and biological factors. More user interests related to exploitation of fish species, which helps that this is a field that many have strong opinions on.

Fish habitats are shaped by physical factors such as water level, water velocity and shelter opportunities and access to food. Draining would be completely devastating to the fish. Beyond this, the amount of water may have different effects on the fish in a river, depending on the type and stage of the lifecycle. Not all unregulated river systems are optimal in terms of fish production, because of large fluctuations in flow.

2. Expensive

Building power plants in general is expensive. Hydroelec-tric power plants are not an exception to this. On the other hand, these plants do not require a lot of workers and main-tenance costs are usually low.

3. Droughts

Electricity generation and energy prices are directly related

SUSTNABL.com

Hydro Power energy

33

to how much water is available. A drought could potentially affect this.

4. Limited Reservoirs

We have already started using up suitable reservoirs for hy-droelectric power plants. There are currently about 30 major power plants that are expected to generate more than 2.000 MW under construction. Only one of these projects was start-ed in the last two years.

Chapter 7 - Top Countries in using Hydro power

As the world attempts to stall climate change by cutting emissions and dependence on fossil fuels, energy from re-newable sources has become an integral part of global strat-egies. But hydroelectric power, despite being an important energy source in many nations around the world, is often overlooked.

The 2012 data in the chart below is taken from the US En-ergy Information Administration

SUSTNABL.com

Hydro Power energy

34

(EIA), which provides independent national and interna-tional energy statistics.

China produces the most electricity from hydroelectric power, some 856.4 billion kilowatt hours a year – more than double the amount produced by Brazil, in second place. The top three is completed by Canada, which produces 376.7 bil-lion kilowatt hours a year.

Alongside the United States, in fourth, there are also plac-es for Norway, Sweden, India, Venezuela and Japan, showing the geographical dispersion of hydroelectric power produc-tion.

SUSTNABL.com

Hydro Power energy

35

Reference

https://en.wikipedia.org/wiki/Hydropower

http://energyinformative.org/how-does-hydroelectric-pow-er-work/

http ://energyinformat ive .org/hydroelectr ic-ener-gy-pros-and-cons/

https://en.wikipedia.org/wiki/Hydroelectricity#Generating_methods

https://www.weforum.org/agenda/2015/10/which-coun-tries-produce-the-most-hydroelectric-power/

http://water.usgs.gov/edu/hyhowworks.html