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Hydro-Power

Alternative Energy Project                                                                                                                                                Emily C., Michael Y., Tim M., Tim M.                                                                                                                                                                                                 2012-2013

Hydro-Power

tim1

Article:

Hydropower actually brought electricity, jobs and inexpensive power during the Great Depression. Many of the large projects were directed with hydropower, but that all slowed to a halt after the second World War, when the atomic age started. For more information about this, the article below explains the great ideas that were once used, and are starting to be used again. http://www.scientificamerican.com/article.cfm?id=time-to-think-hydropower

 

How it works:

tim2

Electrical generation through hydro-power converts energy through several states. First stored energy (water) is converted to kinetic energy (moving the water) then converted to electrical energy. In order to obtain the stored energy, a dam of some sort must be built in front of an elevated water source (lake, river). The dam’s purpose is to build up water behind it, creating a stored energy. Now that stored energy is obtained, it must be converted to kinetic energy. That is obtained by releasing the held water into the dam’s intake via the popular force known as gravity. The water then takes a trip from the intake through the penstock and into the turbines. Water passing through will rotate the massive turbines which are connected to a generator.                                                                                http://save-our-resources.wikispaces.com/Hydroelectricity

 

The generator consists of a number of electromagnets called a rotor, which rotates inside a coil of copper wire. The combination of the spinning magnets and the wound coil of metal create antim3 alternating electric current that can finally be harnessed and transferred to the transformer, stepping up the voltage of the current and passed though power lines and into homes.

The remaining water exits the dam through the outflow and into a lower part of the water source.

 

 

 

 

 

http://users.owt.com/chubbard/gcdam/html/hydro.html

Types:

There are a number of methods and variation in producing hydro-electrical energy.

–          Conventional Dams

  • The most common method of using water as an electrical source, see above explanation for electric production

–          Pump-Storage

http://upload.wikimedia.org/wikipedia/commons/9/9a/Pumpstor_racoon_mtn.jpg

  • This method uses the exact same format as the convention dam except for a few differences.
  • Instead of taking water from the elevated source, running it through the dam, and dumping it to the lower source, where it leaves the system, the water in the lower source is pumped back into the higher source. So water is just being moved from one source to the other. Disregarding water evaporation, this method is extremely efficient in producing energy while using a set amount of water.

–          Run-of-the-River

http://en.wikipedia.org/wiki/File:Chief_Joseph_Dam.jpg

  • This method uses the same format of electrical production as the conventional method
  • This method contains little to no water storage
  • Any water storage is called pondage
  • This method takes advantage of the seasonal flow of rivers

–          Tide

http://en.wikipedia.org/wiki/File:SeaGen_installed.jpg

  • This method uses the same format of electrical production as the conventional method
  • Instead of two water reservoirs (high and low), this method uses the ocean
  • This method relies on the periodic tides moving water in and out of the turbines to produce electricity.

History:

Hydroelectricity operates based off of the ancient concept of hydropower – power generated from harnessing the kinetic energy of falling water. It’s a concept that has been around for a very long time, and has been used by people like the ancient Greeks to perform simple tasks such as grinding flour using an invention called the water wheel. The water wheel works by converting the kinetic energy of the flowing water into mechanical energy, causing the waterwheel to spin, much like how a gust of wind can cause a pinwheel to spin. This ancient water wheel acts very similarly to the modern hydropower plant. In the late 19th century, shortly after the invention of the dynamo – the earliest electrical generator that converted mechanical energy into electrical energy via electromagnetic induction to convert mechanical rotations into direct current electricity through a commutator – hydropower became a good way to generate electricity. The first hydropower plant was built at Niagara Falls in 1879, and many other countries soon followed suit including the United States, China, Brazil, and 140+ more. Today, hydro electrical power is the most widely used source of alternative energy production, accounting for approximately 16 percent of global electricity consumption in 2010.

Efficiency:

Hydroelectricity operates based off of the ancient concept of hydropower – power generated from harnessing the kinetic energy of falling water. It’s a concept that has been around for a very long time, and has been used by people like the ancient Greeks to perform simple tasks such as grinding flour using an invention called the water wheel. The water wheel works by converting the kinetic energy of the flowing water into mechanical energy, causing the waterwheel to spin, much like how a gust of wind can cause a pinwheel to spin. This ancient water wheel acts very similarly to the modern hydropower plant. In the late 19th century, shortly after the invention of the dynamo – the earliest electrical generator that converted mechanical energy into electrical energy via electromagnetic induction to convert mechanical rotations into direct current electricity through a commutator – hydropower became a good way to generate electricity. The first hydropower plant was built at Niagara Falls in 1879, and many other countries soon followed suit including the United States, China, Brazil, and 140+ more. Today, hyroelectrical power is the most widely used source of alternative energy production, accounting for approximately 16 percent of global electricity consumption in 2010.

Societal Implications:

As with all sorts of different energy convention, hydroelectric dams can be useful and efficient but also a setback in other aspects. Hydroelectric dams are useful in Canada as the geography allows for abundance of waterways. But there are hidden, small font price tags that come with the efficient technology. So here are the facts. The dams release fewer emissions and are entirely renewable unlike the common use of oil and gas. However the dams require its water supply to be held back like a reservoir or a steady flow of water must lead towards the dams, and areas where animals reside may no longer have its steady water flow as the water is backed up. Lower water levels will lower the ability for certain water organisms to continue living there. The lower water level also leads to warmer water temperature which could damage certain types of fish such as salmon. Of course in order for the hydroelectric facilities to have a frequent supply of water to run its energy, upstream areas must also be submerged by water coming in from other waterways. This annihilates the ecologically vibrant areas such as lowlands, marshes and swamps. Another notable offense from the use of this technology is the disturbance of fish migrating areas. Fish often need to swim upstream the dams in order to get to their mating locations and reproduce. However, the dams make it impossible for the fish to do so. Therefore, hydroelectric dams must put in place fish ladders or manually catch the fish and release them on the opposite side. The larger the hydroelectric facility the more damage it does environmentally. In order for these large hydroelectric dams to be put in place, areas of nature must be cleared before starting construction. The trees and living organisms become submerged underneath and release methane and carbon into the air. Roads that continue towards the dam from the cities are also needed. It is not just the dam that takes away the environment but everything that connects to it. Construction of these dams must be able to withstand harsh weather conditions, as the destruction of any such dam would cause extreme environmental concerns and danger to nearby living areas. Such was exactly what happened in Banqiao in 1975. The dam built by the Chinese broke under a harsh typhoon that year. Not only were there thousands of causalities and affected, but the environmental damage was difficult to restore. The risk of building these dams and continuing the project, only to have it fail is not a price to pay by the environment. Therefore, using hydroelectricity dams are efficient, but are they worth it? If so, then it is sure hoped that they will consider and find a solution to most if not all the environmental concerns that comes with it.

References:

–          Atlantica Centre for Energy. (n.d.). Hydroelectric. Retrieved December 25, 2012, from   http://atlanticaenergy.org/hydroelectric

–          Bonsor, K. Howstuffworks. (n.d.). How hydropower plants work. Retrieved December 25, 2012  http://science.howstuffworks.com/environmental/energy/hydropower-plant1.html

–          David Suzuki Foundation. (n.d.). Hydroelectricity. Retrieved December 25, 2012, from   http://www.davidsuzuki.org/issues/climate-change/science/energy/hydropower/

–          Lund, K. Agriculture and Rural Development. (2002). Hydroelectric power. Retrieved December  25, 2012, from http://www1.agric.gov.ab.ca/$department/deptdocs.nsf/all/eng4431

–          Ministry of Energy, Mines and Natural Gas and Responsible for Housing. (n.d.). What is  hydroelctricity?. Retrieved December 25, 2012, from http://www.empr.gov.bc.ca/EPD/Electricity/supply/hydro/Pages/default.aspx

–          Nuclear Technology Exploring Possibilities. (n.d.). Hydroelectricity. Retrieved December 25    2012, from http://curriculum.cna.ca/curriculum/cna_world_energy_res/hydro-         eng.asp?bc=Hydroelectricity

–          Perlman, H. The USGS Water Science School. (2012). Hydroelectric power: how it works.      Retrieved December 25, 2012, from http://ga.water.usgs.gov/edu/hyhowworks.html

–          Practical Action. (n.d.). Micro-hydro power. Retrieved December 25, 2012, from  http://practicalaction.org/energy/micro_hydro_expertise?utm_source=S000&utm_medium=PPC&utm_campaign=C10105&gclid=CN7H66rEtrQCFcN_Qgod2zAA6g

–          Technology and Inventions. (2009). Hydro-electricity. Retrieved December 25, 2012, from   http://www.kidcyber.com.au/topics/hydroelec.html

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Hydroelectric Dams

Hydroelectric Dams

By Aryan G, and Bayan H

Hydroelectricity is the term referring to electricity generated by hydropower; the production of electricabayan1l power through the use of the gravitational force of falling or flowing water. It is the most widely used form of renewable energy, accounting for 16 percent of global electricity generation – 3,427 terawatt-hours of electricity production in 2010. The cost of hydroelectricity is relatively low, making it a competitive source of renewable electricity. The average cost of electricity from a hydro plant larger than 10 megawatts is 3 to 5 cents per kilowatt-hour. Hydro is also a flexible source of electricity since plants can be ramped up and down very quickly to adapt to changing energy demands.

The theory is to build a dam on a large river that has a large drop in elevation. 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 carries electricity to your home and mine. The water continues past the propeller through the tailrace into the river past the dam.

 

Generator:

A hydraulic turbine converts the energy of flowing water into mechanical energy. bayan2A 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, electromagnets 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 perimeter 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 electricity 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. bayan3Hydroelectric plants are more efficient at providing for peak power demands during short periods 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 power plant at a time when customer demand for energy is low, such as during the middle of the night. The water is then allowed to flow back through the turbine-generators 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 maximum power during daily and seasonal peak periods. An advantage 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 relatively small, construction costs are generally low compared with conventional hydropower facilities.

Cost of Hydroelectric Energy:

Hydroelectric is less than half the cost of fossil fuel derived electricity. It also has no fuel cost.

Advantages of Hydroelectric Energy:

1. Renewable

Hydroelectric energy is renewable. This means that we cannot use it all up. As long as the sun and gravity exist there will be a water cycle and a constant flow of water running the hydroelectrically power plant.  However, there are 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 friendly to the atmosphere in the way that it does not pollute the atmosphere. Other forms of energy such as fossil fuels will pollute the atmosphere and increase co2 levels. Hydro electricity is environmentally friendly in the sense of producing a clean form of renewable energy.

3. Reliable

Hydroelectricity is very reliable energy. There are very little fluctuations in terms of the electric power that is being by 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 the sun and water exist 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 water behind the dam is being conserved for times when the power consumption is high.

5. Safe

Compared to among others fossil fuels and nuclear energy, 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 related to interventions in nature due to damming of water, changed water flow and the construction of roads and power lines.

Hydroelectric power plants may affect fish is a complex interaction 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.

Also, many species of fish are migratory, using the major rivers as their conduits, and dams cut them off from their spawning areas. Beyond that, the flooding destroys large swaths of habitat, replacing it instead with a new biome. Many animals lose their lives and habitats due to the flooding of the land beside the reservoir.

2. Expensive

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

3. Droughts

Electricity generation and energy prices are directly related to how much water is available. A drought could potentially affect this. If there is no water or fluid source there will be no form of electricity generated. So a drought condition is not ideal for running a hydro electric power plant.

 Conclusion:

Overall hydro electricity has its positive and negative effects on our lives and the surrounding environment. It’s a form of renewable energy that runs on the water cycle and gravitational potential energy which causes turbines to spin and generate electricity. This form of energy is much more resourceful than fossil fuels because fossil fuels are non renewable source of energy and is constantly increasing the levels of co2 in the atmosphere whenever it is consumed. Hydro electricity is a cleaner form of energy and it can be used as long as the sun exists. And from the data it is clear that hydro electricity cost much less than other forms of energy. However the negative effects are that the development of hydro electric dams floods the surrounding lands and the animals inhabiting that area loss their homes. This flooding of the land also destroys many ecosystems. Also hydro electrical dams can only work in places where there is water. In extremely dry places where there is drought it is not the ideal condition for a hydro electric generator because it strictly consists of the flow of fluid to generate power. It is also extremely expensive to build and operate. Overall hydro electrical power plants have their ups and their downs, and it’s up to society as a whole to decide whether or not hydro electrical dams are for the good.

Sources:

http://en.wikipedia.org/wiki/Hydroelectricity

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

http://answers.yahoo.com/question/index?qid=20090310133846AATM2VC

http://www.colorado.edu/geolsci/courses/GEOL3520/Hydropower.pdf

http://www.wellhome.com/blog/the-pros-and-cons-of-hydropower/

http://www.worldwatch.org/node/9527

http://www.guardian.co.uk/environment/2010/jan/22/wave-tidal-hydropower-water

http://www.internationalrivers.org/environmental-impacts-of-dams

http://energyinformative.org/hydroelectric-energy-pros-and-cons/

http://en.wikipedia.org/wiki/File:Ren2008.svg

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The Generator Effect: Hydro-electric Dam

Author: Ricky B.

The origins of the Hydro-electric dam: The dam was first used for fishing but when they found out they could use it to do work, they integrated it to grind wheat into flower. Then in the 1700s they started making the water wheel turn a series of gears to turn a large blade to cut lumber and also for pumping irrigation water.OLYMPUS DIGITAL CAMERA

Then in 1882 in Appleton, Wisconsin  they made the first hydro-electric dam that generated a total of 12.5 kilowatts of power, this was a revolution to their former knowledge. It could provide enough energy to power 250 lights at maximum. At this point they still used a simple engine but 20 years later they came up with the hydraulic reaction turbine, which created large advancements in the hydroelectric energy field. So much so the in the early 1900s hydroelectric dams were producing 40% of all the electricity in the USA. In 2001 90,000 mega watts of power could be produced from hydro-electric dams.

 

Hydro-electric power: It is the power generated from a spinning turbine that is spun when the water fallricky2s onto the turbine or passes around the turbine to spin it creating electricity. As you can see in the photo potential energy from the weight of water falling through a vertical distance is converted to electrical energy. The amount of electric power P that can be generated is given by the equation below, where Q is the volume flow of water, h is the height through which the water falls, and k is a constant equal to 0.102 when Q is in cubic meters and h is in meters (SI units). The formula for electricity of the hydro electric dam is P = Qh/k (kW units).  This unit is a key part to how they know how to build the dam and how to operate the wicket gates to make sure that the turbine gets enough water and not too much Water so that the damn floods. It is also used to calculate the amount of power they can achieve with a certain amount of water or how much water they need to create the required power.

 

The Hydro power generator: The water flows through the dam then hits the turbine turns a shaft which rricky3otates a series of magnets past copper coils and a generator to produce electricity. There is a part of the turbine called the Kaplan Head which is the part associated with the adjustable blade which improves the efficiency of the pump to counteract the variations in water flow and energy demands.

The rotor is a series of magnets that is turned by a shaft that spins inside the stator (which is the stationary coil of wires) which is where the magnetic field is created. This is all controlled by a series of gates called the wicket gates that provide the water flow to the turbine with gets everything to go.

 

 

 

 

The key Aspects to the Hydro-electric power:  The key aspects to the hydroelectric dam are the water cycle and the force of gravity. Water that evaporates from a river or lake turns into clouds.ricky4 The water in these clouds that came from a water source will then fall back down to earth. Some of the water that evaporated from a lake or the ocean will fall onto a higher elevation than the lake or ocean that it originally was in. This increase in elevation is directly related to the energy that is created through hydro-electric power. Water evaporates and rises in altitude, while the whole hydroelectric process relies on water falling, and losing elevation.

The second major aspect is gravity because the water is falling onto the turbine to cause it to spin. A hydroelectric dam capitalizes on gravity. In order to subtract the gravitational force from the water and cause an energy transfer, a hydroelectric dam blocks the flow of water from a higher elevation to a lower elevation. The physical dam actually lets a small amount of water pass through the dam, but this amount is blocked by a turbine. The turbine is the primary object that utilizes the gravitational force of the water. This is the only reason that the hydro-electric dam works to create a load of electricity.ricky5

Advantages of Hydropower:

1. 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. Long lasting energy because dams do not break easily.

4. The lake that forms behind the dam can be used for recreation activities.

5. The lake’s water can be used for irrigation purposes.

6. The buildup of water in the lake means that energy can be stored until needed, when the water is released to produce electricity.

7. It is not bad for the environment.

Disadvantages of Hydropower:

1. Dams are extremely expensive to build and must be built to a very high standard.

2. It blocks the river for decades at a time and blocks the environment for very long time.

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 dams can be made.

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 caved in the earth’s surface at the Hoover Dam.

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).

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.

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 has also happened in many other places were the dams mess up the water flow so then many minerals are not displaced which leads to problems for farmers.

References:

http://library.thinkquest.org/17658/hydro/hydphysicsht.html

Think quest, (unknown ), used Jan 3, 2013

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

Howard Perlman, (2012), used Jan 3, 2013

http://curriculum.cna.ca/curriculum/cna_world_energy_res/hydro-eng.asp?bc=Hydroelectricity

Unknown, (2007), used Jan 3, 2013

http://science.howstuffworks.com/environmental/energy/hydropower-plant.htm

Kevin Bonsor, (unknown) used Jan 3, 2013

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Mechanism of Hydroelectric Power

June 8, 2012 by ElectarL, PeterX, RyanW, SandraS

There are many ways to generate electricity in modern day. One of them is to use the gravitational force of falling water, which is also known as hydroelectricity. Hydroelectricity occurs in a dam, where the falling water is used to generate enough force to turn a turbine that is connected to an electricity generator. With this action, potential energy of water is transformed into mechanical energy and then into electrical energy. This is both an efficient and green way of generating electricity: it is not as hard as the geothermal electricity because people do not have to find a perfect area to generate it; and it is also not as polluting as the nuclear power plants are. Therefore, hydroelectricity is much greener than the nuclear power plants which generate electricity, and much easier to generate than the geothermal electricity. Now, how exactly does a dam actually work to generate electricity?

A dam is built where there is a natural source of water in a valley and it is used to hold the water and create pressure so that the water can produce more electrical power. The gravitational potential energy stored in the water is used to turn generators and create electricity. Electrical generators are turned by massive turbines, which are within tunnels in the dam wall—water flows through the tunnels with great pressure due to the great height, at which is kept in the dam. If there is a greater volume of water or there is a very large difference between the water level and where it flows out, then more power comes out of the water as it has greater potential energy. For example: Hydro power generation works well in mountainous countries as the water can be stored at very high pressures. The dam wall increases with width as you go down towards the base this is because the water pressure gets greater as depth increases. This difference in height of the water is called the head.

The generator contains two main parts: the rotor and the stator. The rotator is the part    which rotates and the wire has a huge magnet inside of it; and the stator is the part which is covered in copper. The electrical current is created when the rotor spins around the copper wire on the stator. This is the charge which is then used as electricity.

 Some countries that use hydroelectric power:

China is the largest producer of hydroelectricity depending on the Yangtze River., followed by Canada, Brazil, and the United States.

Egypt also uses hydroelectricity depending on the River Nile, which the longest river in the world (6695 km). The Nile River is often associated with Egypt; it actually touches Ethiopia, Zaire, Kenya, Uganda, Tanzania, Rwanda, Burundi and Sudan, as well as Egypt. President Gamal Abdel Nasser decided to make use of it and built High Dam in Aswan, Egypt in 1954 to produce hydroelectric power.

 

 

ADVANTAGES

  • Renewable energy source: hydroelectricity uses the energy of running water, without reducing its quantity, to produce electricity. Therefore, all hydroelectric developments, of small or large size, whether run of the river or of accumulated storage, fit the concept of renewable energy
  • Hydroelectricity makes it feasible to utilize other renewable sources: the flexibility and storage capacity of hydroelectric power plants make them more efficient and economical in supporting the use of intermittent sources of renewable energy, such as solar energy or Aeolian energy
  • A fundamental instrument for sustainable development: Hydroelectric enterprises that are developed and operated in a manner that is economically viable, environmentally sensible and socially responsible represent the best concept of sustainable development. That means development that today addresses people’s needs without compromising the capacity of future generations for addressing their own needs” (World Commission on the Environment and Development, 1987)
  • Increases the stability and reliability of electricity systems: the operation of electricity systems depends on rapid and flexible generation sources to meet peak demands, maintain the system voltage levels, and quickly re-establish supply after a blackout. Energy generated by hydroelectric installations can be injected into the electricity system faster than that of any other energy source. The capacity of hydroelectric systems to reach maximum production from zero in a rapid and foreseeable manner makes them exceptionally appropriate for addressing alterations in the consumption and providing ancillary services to the electricity system, thus maintaining the balance between the electricity supply and demand
  • Hydroelectricity helps fight climate changes: The hydroelectric life cycle produces very small amounts of greenhouse gases (GHG). In emitting less GHG than power plants driven by gas, coal or oil, hydroelectricity can help retard global warming. Although only 33% of the available hydroelectric potential has been developed, today hydroelectricity prevents the emission of GHG corresponding to the burning of 4.4 million barrels of petroleum per day worldwide
  • Water can be stored, waiting to be used in peak times
  • Hydropower plays a major role in reducing greenhouse gas emissions; hydroelectric power plants don’t release pollutants into the air. They very frequently substitute the generation from fossil fuels, thus reducing acid rain and smog. In addition to this, hydroelectric developments don’t generate toxic by-products

Disadvantages

  • Hydrology dependent (precipitation)
  • In some cases, inundation of land and wildlife habitat
  • In some cases, loss or modification of fish habitat
  • Fish entrainment or passage restriction
  • In some cases, changes in reservoir and stream water quality
  • In some cases, displacement of local populations
  • Building the dam is expensive and time taking
  • The dam will change the habitat and landscape upstream, as much more land will be submersed
  • The land below the dam is also affected as the flow of water is reduced .
  • Silt can build up in the dam as the water slows down it does not have enough energy to carry the sand and silt which it was

In conclusion, Hydroelectricity is a very unique way of generating energy. It is one of the most used systems around the world. Also, it is a renewable energy source which is very helpful to our planet and it is something that will never end unlike natural gas and fossil fuels. Therefore, many of the countries and many more in the future will choose it over a lot of the other ways to generate electricity. All in all, it is a very cost efficient and green way to generate something that us human beings need in our daily lives!

References

Author: Attic Designs (2008), Used on June 3, 2012

http://www.ancient-egypt-online.com/river-nile-facts.html

Author: Think Quest (unknown), Used on June 3, 2012

http://library.thinkquest.org/06aug/01335/hydroelectric.htm

Author: Unknown (2006), Used on June 3, 2012

http://ga.water.usgs.gov/edu/wuhy.html

Author: Unknown (2006), Used of June 3, 2012
http://ga.water.usgs.gov/edu/hydroadvantages.html

Author: Unknown (unknown), Used of June 3, 2012

http://www.mbarron.net/Nile/envir_nf.html

Author: BBC News (2006), Used on June 3, 2012

http://news.bbc.co.uk/2/hi/asia-pacific/5000092.stm

River Nile Facts

River Nile facts you always wanted to know.

Author: Attic Designs(2008, Used on June 3, 2012

www.ancient-egypt-online.com

http://upload.wikimedia.org/wikipedia/commons/thumb/a/a4/Water_turbine.jpg/220px-Water_turbine.jpg

http://a3.att.hudong.com/28/32/01000000000000119093213306528.jpg

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Hydroelectricity

June 6, 2012

Hydroelectricity

By Lina L., Nora L., Felicia Y., and Jason J.

      

Hydroelectric power is the process of using potential energy of a body of water to transfer into kinetic energy. The kinetic energy can then easily be converted into electricity through rotary turbines. The water from the reservoir at the top of the dam has gravitational potential energy due to its elevation with respect to the turbine. As it flows down the penstock, the gravitational potential energy of water has been converted into kinetic energy and is thus high pressure as it arrives at the turbines.

The water flows through the wicket gate to the turbine, where the kinetic energy of the water pushes the blades of the turbine, causing the turbine to spin. The turbine is connected to the rotor of the generator via the turbine generator shaft. The rotor is attached to large electromagnets located within coils of copper wire called the stator. As the rotor spins, the large magnets of the stator spin by association within stationary loops of copper wire. According to the principles of magnetic flux and Lenz’s Law, which states that a magnetic flux (change in magnetic field) through a circuit will produce a current in a wire loop whose magnetic field will counteract the magnetic flux, an electric current is induced in the copper wire coils.  As the North pole of the magnetic moves closer to the wire loop, there is increasing flux and a current is induced in the wire loop such that a North pole is developed to oppose the North pole of the magnet (refer to Figure 1). As the South pole of the magnet moves away from the wire loop, there is decreasing flux and the induced current in the wire loop develops a North pole to attract the South pole of the magnet (refer to Figure 2).

Figure 1. Induced current in wire loop as North pole of a magnet moves toward the wire loop.

Figure 2. Induced current in wire loop as South pole of a magnet moves away from the wire loop.

The electricity produced by the generator is stepped up in voltage by step-up transformers in which the number of wire loops on the secondary coil is greater than the number of loops on the primary coil. The high voltage electricity is carried in transmission lines to substations where the voltage is decreased via step-down transformers (number of loops on secondary coil is less than the number of loops on the primary coil) and distributed to homes and businesses.

Figure 3. Transformer utilizing the design of Faraday’s Apparatus.

Hydro-plant is a very convenient way to produce electricity for daily life. It is not like fossil fuels that people will eventually use it up one day because hydroelectricity is renewable. After all, the electricity comes from water pressure on turbines.  Dams could be freely controlled by the people. If the electricity is not needed, the sluice gate could be shut, and open it until electricity is needed. For the saved water that was again opened, a larger amount of power could then be produced responding to a high demand of electricity. Furthermore, people could use this large but limited potential energy fuel on other scientific purposes: scientists could use this abundant potential energy to develop a better transportation system or construction. Using fuel energy to create electricity could be recognized as a waste of labor and money when hydro-plant could also create electricity with less labor work and costs.  In addition, hydro-plant reduces on the number of human labors and the payments to the workers because all the work is being done by the motion of water automatically. In this way, the companies could earn much a meaningful amount of money without hiring too many laborers for the hydro-plant compared to the fossil fuels companies. Using hydro-plant is also a method to save the limited amount of our fossil fuel in the world.

However, according to Uganda’s standard of living, there are up to ninety percent of their citizens don’t have regular electricity for their living. The lack of access to electricity restricts the people’s interaction in the community. Thus, it is a deadly result to the country because less people have opportunity to work, so fewer stimulation of economy for the country is demonstrated. Therefore, one of the fastest and easiest ways to solve these citizens’ struggles is to create the Bujagali dam.

Although hydroelectric dams are an efficient source of clean and renewable energy, the significantly detrimental impacts left on its surroundings cannot be ignored. While hydroelectricity requires a rapid flowing stream of water, the dam itself also takes up a large area of space, disrupting surrounding ecosystems and even local communities. At the same time, the construction of dams is extremely costly and time consuming. The Bujagali Dam itself is 30 meters in height, costing approximately $826 million to build over the span of 5 years while disrupting surrounding communities greatly.

Perhaps the most significant issue surrounding hydroelectric dams are the negative impacts made to the surrounding environment of the dam. The construction of the dam essentially introduces a large foreign block of concrete and metal to the surrounding ecosystem, disrupting the habitats of countless organisms. For example, rivers where salmon run occurs every year are made unavailable for salmon due to the construction of dams, severely reducing the salmon population annually.  With the construction of dams around rivers all over the world, the biodiversity of organisms inhabiting river ecosystems have been decreased significantly in a similar manner due to the changes made to their chemical, biological and physical processes. In the case of the Bujagali Dam, the main concern lies with Lake Victoria, the world’s largest tropical lake. As water levels are drained by the running of the dam, water supplies will be depleted from not only the local communities but the vast collection of organisms depending on the lake to survive as well. Although the Ugandan government promises to regulate the volume of water drained from the lake, the damage done to the delicately balanced ecosystem of the world’s largest tropical lake will be irreversible.

Another commanding issue to hydroelectric dams is the potential of flooding. As the power source comes from a rapidly flowing stream of water, a large reservoir of water needs to be stored in the dam. However in the case of these dams becoming damaged or collapsing due to poor construction or maintenance, the resulting flood can cause severe environmental and social consequences. An example of this is the collapse of the Teton Dam in Idaho on June 5, 1976. As farmlands and towns were completely drowned, a total of 14 lives were lost while leaving costs of approximately $1 billion.

Although hydroelectricity is an efficient alternative to fossil fuels as a mean to generate electricity, there are many associated that cannot be ignored. While all dams leave a lasting detrimental impact on river ecosystems, the potential of flooding poses as an alarming threat to all those situated near the dams. With these implications, many alterations must be made to the hydroelectricity generating system before it can be considered to be the perfect alternative to fossil fuels.

References

Dams and Salmon – Why Some Dams Must Go! (n.d.). In The Pacific Coast Federation of

Fishermen’s Associations. Retrieved June 4, 2012, from http://www.pcffa.org/dams.htm

Hydroelectric power water use (2012). In U.S. Geological Survey. Retrieved June 4, 2012, from http://ga.water.usgs.gov/edu/wuhy.html

Green, A. (2012, February 21). Uganda’s Power Drive Stills Rapids at the Headwaters of the Nile.

National Geographic. Retrieved May 26, 2012, from http://news.nationalgeographic.com/news/energy/2012/02/120221-hydroelectric-power-nile-dam-in-uganda/

Hydroelectricity Pros and Cons (2012). In Buzzle. Retrieved June 4, 2012, from

http://www.buzzle.com/articles/hydroelectricity-pros-and-cons.html

– (n.d.).

In Bujagali Hydropower Project. Retrieved June 4, 2012, from http://www.bujagali

energy.com/default.htm

Industrial archaeology review, Volumes 10-11. Oxford University Press. 1987. pp. 187.

ESHA(1998), Layman’s handbook on how to develop a small hydro site.

Joycec, S. (2011). Dams – The Advantages and Disadvantages. In Environment, Health and

Safety Online. Retrieved June 4, 2012, from http://www.ehso.com/ehshome/energydams.htm

Walter, J. (2012). Forces and fields 2 PowerPoint. Sir Winston Churchill High School, AB.

Retrieved May 26, 2012 from https://d2l.cbe.ab.ca/d2l/lms/content/home.d2l?ou=185572.

 Images:

Sylvester, A. G. (n.d.). Teton Dam Failure. Retrieved June 4, 2012, from

http://www.geol.ucsb.edu/faculty/sylvester/Teton_Dam/welcome_dam.html

Walter, J. (2012). Forces and fields 2 PowerPoint. Sir Winston Churchill High School, AB.

Retrieved May 26, 2012 from https://d2l.cbe.ab.ca/d2l/lms/content/home.d2l?ou=185572.

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Hydroelectric dams

Alternative Energy Project

June 8, 2012

Yong K, Tim H

 

Title: Hydroelectric dams

 
 Introduction

In now days, we used fossil fuels to produce energy; however, as the technology develops, the use of fossil fuels becomes less desirable, the world will need alternative energy sources and uses for the next generation. There are many technology that produces the energy without fossil fuels, like wind farm, nuclear power plants, hydroelectric dams. However, we are going to focus on the topic of hydroelectric dams. As it proves that the hydroelectric dams are efficient to produce the energy, number of hydroelectric dams is increasing. And we expect the benefits from the hydroelectric dams. However, hydroelectric dams are not always benefits to everything. Therefore in our blog, we are going to talk about how the hydroelectric dams work advantages and disadvantages of the hydroelectric dams.

Explanation of hydroelectricity

First what is hydroelectricity? Hydroelectricity is the electricity gained by the harnessing the power of water flowing down from the high level. Hydroelectricity is timeless and renewable resource. In this case, water is acts as power source. Therefore as the water flowing down from the high level, the huge generators convert the potential energy into electrical energy. Potential energy converted into mechanical energy and then into electrical energy. So this method of converting energy applies to the hydroelectric dams. Water usually stored in dams is led down through large pipes or tunnels to lower levels, and in the course of the fall, the water rotates the turbines. The mechanical energy produced is converted to electricity by the generator connected to it.

 

Basic concept of physic related to hydroelectricity

As I briefly explained about the production of electricity by hydroelectricity, the actual process behind hydroelectric power, it relies on some of the basic laws of physics. First basic law of physics is gravity. Gravity is the central force that causes a object to fall in elevation. For example, whenever we throw a object vertically upwards, it is going to fall down. This is the basic laws of gravity. In the hydroelectric dams, water that is high in elevation falls to a lower elevation because of gravity. Dams stored amount of water in high elevation, and as they remove the blocks, the water accelerates toward the earth because of gravity. Water accelerates downwards and spins the turbines, therefore generator produces the energy. The simple physic equation is

F = ma, F = m * dv / dt

The second concept of physics in hydroelectric dams is water cycle. As the characteristic of water, it will evaporates and form a clouds. The water in these clouds will fall back down to earth some point. As they fall back down to earth, some of the water that evaporated from a lake or the ocean will fall onto a higher elevation than their original position. Therefore it increase in elevation and related to the energy of hydroelectric dams.

 Advantages and Disadvantages

The advantages of the hydroelectric dams are firstly it is renewable and does not require any fuel. For example the fossil fuels costs are increasing rate every year. Therefore hydroelectric dams save cost of fuels to produce electricity. Secondly, operating cost and little maintenance is low. Operating labor cost is low and dams work automated and have few personnel on site during normal operation. Thirdly, no greenhouse gas emissions or air pollution. This is huge advantages of the hydroelectric dams. When ever we burn fossil fuel to produce, it creates air pollution, but for hydroelectric dams, it helps environment, and reduce global warming. Lastly, hydro plants have long life around 50-100 years. When we compare to nuclear power plant, it is much longer.

Disadvantages of the hydroelectric dams are firstly, environmental, dislocation and tribal rights. Hydroelectric dams occupies large area in the river therefore it is going to affect the daily life of tribal who live close to river. For example, in Brazil, because of the dams, tribal are losing their hunting ground, and destroying their lands. Secondly, wildlife and fishes get affected. As the hydroelectric dams block the middle of the river, therefore it changes the flow of the river completely, and forms its river characteristic. Thirdly, large dams have increased the potential of earthquakes. And lastly, hydroelectric dams cannot be built anywhere. Hydroelectric dams can only be built in particular place.

Conclusion

In conclusion Hydroelectricity is very useful and renewable resource helps envrionment. The importnace of hydroelectricity is growing and becomes bigger parts of production of energy. It contains advantages and disadvanges however, as use of electricity increase, hydroelectricity will play significant role in the future.

Reference

John Vidal,(2010) hydroelectric dams pose threat to tribal peoples, report warns. Retrieved from the Internet on June 8th 2012 :

http://www.guardian.co.uk/environment/2010/aug/09/hydroelectric-dams-tribal-people

E.W Humphrys (2012) hydroelectricity . Retrieved from the Internet on June 8th 2012 :

http://www.thecanadianencyclopedia.com/articles/hydroelectricity

Author Unknown. (2011) Hydroelectric Energy Advantages and Disadvantages. Retrieved from Internet on June 8th 2012 :

http://www.greenworldinvestor.com/2011/04/04/hydroelectric-energy-advantages-and-disadvantages/

Author Unknown (1998) The Physics of Hydroelectric Power . Retrieved from Internet on June 8th 2012: http://library.thinkquest.org/17658/pdfs/hydrophysics.pdf

Ice in Grand Coulee Dam [Online Picture]. Retrieved from the Internet on June 8th 2012 : http://www.worldtourismplace.com/grand-coulee-dam-hydroelectric-dams-in-the-united-states/ice-in-grand-coulee-dam/

Hydropower [Online Picture]. Retrieved from Interent on June 8th 2012 :

http://www.window.state.tx.us/specialrpt/energy/renewable/hydro.php

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Alternative Energy Source – Hydroelectric Energy

By Phoebe C and Vicky K

As the use of fossil fuels becomes less desirable, the world will need alternative energy sources and uses. Hydroelectric power is a form of energy and more importantly, a renewable resource. For hydroelectric power to be produced, dams must be created. A dam is a man-made structure built across a river and energy is produced as the water passes through the dam. The theory is to build a dam on a large river that has a large drop in elevation. The dam stores lots of water behind it in the reservoir. Near the bottom of the dam wall there is the water intake, and 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 turbine thus converts the energy of flowing water into mechanical energy. The shaft from the turbine goes up into the generator, which 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, electromagnets 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 perimeter of the rotor. The rotor is attached to the turbine shaft, and rotates at a fixed speed. When the rotor turns, it causes the filed 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.

There is another type of hydropower plant, called the pumped-storage plant that more efficiently meets the peak electricity demand. 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 power plant at a time when customer demand for energy is low, such as during the middle of the night. The water is then allowed to flow back through the turbine-generators 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 maximum power during daily and seasonal peak periods. An advantage 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 relatively small, construction costs are generally low compared with conventional hydropower facilities.

Hydroelectric facilities have many characteristics that favor the preservation of environment: first of all, the power plants do not use up limited non-renewable resources to make electricity; they do not cause pollution of air, land or water; they have low operating costs and are highly reliable. As an added benefit, reservoirs have scenic and recreation value for campers and water sports enthusiasts. Dams add to domestic water supplies, control water quality, provide irrigation for agriculture, and avert flooding. Dams can actually improve downstream conditions by allowing mud and other debris to settle out. However, some dams have shown to have negative effects on the environment. Species that use rivers to spawn are often hurt by dams. In the Pacific Northwest Region, sockeye salmon and trout populations have dropped from 16 million to 2.5 million since hydroelectric plants were built on the Columbia River. But more advanced facilities are emerging: facilities now can incorporate features that aid fish and wildlife, such as salmon runs to protect certain species.

As we learn to live in harmony as part of the environment, we must seek the best alternatives among all ecologic, economic, technological and social perspectives. The longer we delay the balanced development of our potential for hydropower, the more we unnecessarily use up other vital resources.

Bibliography

How Stuff Works: How Hydropower Plants Work. Retrieved on June 4, 2011 from the internet: http://science.howstuffworks.com/environmental/energy/hydropower-plant1.htm

Hydroelectric Energy: Hydroelectric Power Plants. (2010). Retrieved on June 4, 2011 from the internet: http://hydroelectric-energy.blogspot.com/2010/08/itaipu-dam.html

Solar Power Notes: Hydroelectric Power. (2009). Retrieved on June 4, 2011 from the internet: http://www.solarpowernotes.com/renewable-energy/hydroelectric-power/hydro-power-plant.html

USGS Science for a Changing World: Hydroelectric power: How It Works. Retrieved on June 4, 2011 from the internet: http://wwwga.usgs.gov/edu/hyhowworks.html

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