Hydroelectricity is the type of electricity which is basically generated by the use of water. The hydropower plant uses water only as its major raw material for power generation. Water down a stream is collected in a reservoir on the upstream or in dam. This water flows from the reservoir or the dam. This water has potential energy (stored energy). The water then moves through a special pipe referred to as the penstock. In this pipe, the water actually builds a lot of pressure and moves under gravity up to the turbines. Inside this pipe, the water has kinetic energy, since it is in motion. This water is made to flow via bottlenecks created in the penstock, thus increasing its speed.
When the turbines rotate, they consequently make the generator to rotate. The most commonly used turbine is referred to as the Francis Turbine. Statistics as per the Foundation Water and Energy Education, FWEE show that turbines can weigh as much as 172 tons. Therefore, the more the volume of the water, the higher the amount of electricity can be harnessed from the water. Also, the higher the hydraulic head, the higher the amount of current can be produced.
Inside the hydropower plant generator are giant magnetic and copper coils. The generator has various parts, namely; the shaft, excitor, rotor and the stator. Static copper coils are also utilized in the process, and they cut the magnetic fields for the magnets rotating past them. When the turbines rotates, it causes the excitor to move and send an electric current to the rotor, which is a series of electromagnets that spins past the massive tightly- wounded coils of copper cables.
The electric current is created by stator (a magnetic field) formed in the interaction between the copper wires and the electromagnets. This current comes as a result of movement of electrons, which eventually causes that current-an alternating current is commonly known as AC current. This AC current is converted to super high voltage current. This current is then transmitted to the high-voltage power lines. The power produced is in three phases, and one neutral phase. Therefore, the power lines from the power house where the power is generated will always be four. Since the power is at a high voltage, it goes directly to the step-down transformer, where it is lowered to make it safe for consumer consumption.
During this time when the climate change is on the top of global agenda, people all over the world have shifted their focus on the hydroelectricity, since it doesn’t produce greenhouse gases which bring about global worming. There are also scores of other benefits which go hand in hand with the establishment of a hydropower plant. These are among others; water provision to neighboring people, aquiculture, and recreation facility of the dam water etc.
There are various methods of electricity generation. They include conventional, where the potential energy is water. Water is used to move the turbines. The second is the generator pumped –storage hydroelectricity, in which there is use of two reservoirs-which are at different elevations. The third is the use of run-of-the-river hydropower plants which are built in cases where the reservoirs are too small to hold plenty of water, and finally, use of the tide. In the final method, there is use of the tides which causes the rise and the fall of water.
Hydropower plants also vary in sizes, as well as the amounts of power they generate. The higher the amount of power generated, the more the people and businesses will be supplied by the electricity. The first category is the large and specialized types. These include; for example, Three Gorges Dam which has 22500 mega watts (China). Itaipu dam has 14000 mega watts (Brazil) and Guri dam, which has 102000 mega watts.
There are other small hydroelectricity power plants which are used on small scale for the purpose of small communities, and generate at least 10 mega watts. Micro hydropower plants are those that produce about 100 kilo watts. They provide power to isolated people. Pico hydroelectric power plants; these generate about 5 kilowatts. These are applied where there are low requirements for power. This is mostly for powering televisions and radios in small homes. The source of water to power them is run-of-the-river, so, no dams are used but pipes which run the water to the turbines but by gravity.
Hydropower in U.S
Hydroelectricity power generates about 12 per cent of the U.S electricity. It has the capacity to supply “28 million” people in the country (DOE). This is from about 2000 power plants. Hydropower In the recent past, the U.S. has increased the use of hydroelectric power to over 300 million kilo watts-hours. Most of the U.S hydroelectric power is generated in three states i.e. Washington, California and Oregon and they contribute to about 31 per cent of the U.S. hydropower.
The largest dam, and consequently the largest hydroelectric power are from the West, although there are several other smaller ones scattered across the country. The largest hydropower plant in the U.S. is called the Grand Coulee Power Station. It is built along river Colombia in Washington State. This power station can produce over 6800 megawatts. It is among the world largest hydropower stations.
Hydroelectric power use in other parts of the world
The world biggest hydroelectric power plant is known as Itaipu power plant. This dam is built in the border of two countries i.e. Brazil and Paraguay. Therefore, it is shared between the two countries since they jointly own it. Itaipu dam can produce as much as 12300 mega watts of power. The world’s second largest hydroelectric power plant is known as the Guri power plant. It is built along Caroni River which is in Bolivar, a state in Venizuela.
It generates around 10200 mega watts of power. Tucurui is located in Brazil and generates a total of 8370 mega watts, making it the second largest hydroelectric power generation plant in Brazil after Itaipu. Other major dams in the world include; Churchhil Falls Hydroelectric power Station. It is found in Canada and generates 5428 mega watts of power. Bratsk hydroelectric power plant is found in Russia. It is located at Angara River and produces 4500 mega watts of power.
The Cost of Making the Hydropower Plant over Other Sources of Renewable Energy
It is very expensive to construct a hydroelectric power plant. This is because the water and the land requirement are huge. There are also a number of environmental concerns, which are aired against the construction of these plants. This is the reason as to why in the U.S, there is a tendency of moving towards small scale hydroelectric power plants which are basically meant for single but small communities. Nevertheless, after the reservoir is built and the power house is installed, the hydropower generation can out-rival other sources of electricity in terms of its cost. This is simply as a result of hydroelectric power having extremely low cost of operation and maintenance.
This source of power generation has over 100 years of service life. However, the cost of power generation will depend majorly on the size of the plant. The size of the generator used will affect the power output of that particular generator. In essence, if a plant is small with for instance one generator, it will require as much number of people to operate and maintain for every kilo watt of power generated as a plant with two or more generators. So, it is expensive for smaller power plants than bigger ones.
For this reason, it is vivid that the larger the hydroelectric power plant, the cheaper it is to generate electricity and vice versa. People who live near the power plant can heck their living from the dam water but in various ways, hence improving their living standards. They get electricity at a lower cost than those who use electricity generated from other source of energy such as nuclear energy, gas turbines, fossil fuels for instance coal, methane etc. The high cost of these raw materials which are actually non renewable, inflates the cost of electricity generation, which implies that the consumer will obviously get it at a sky-rocketed price.
When compared to the other forms of electricity generation such as fossil fuels (coal and or oil) and nuclear power, it is very clear that hydroelectric power generation cost is actually one third or around 33 per cent of these other forms of power generation methods. This implies that, the hydroelectric power generation is cheaper compared to the fossil fuels and the nuclear energy. The gas turbine, which has cheaper initial cost, is actually 75 per cent more costly as compared to hydroelectric power generation method; this is simply because of its operational cost, which is so huge. The ever sky rocketing prices of the fuels used to run these power generation plant is the only cause of the huge difference in the cost of production of electricity using other method other than the hydroelectric power generation.
The Average Output of Energy That is Given off per Plant per Year
The output of a power plant will generally depend on the size of the generator used. For instance, the average generator of about 76000 kilo watts will result to an average maximum out put of 76000×24(one day)×30 (one month)×12(one year) which translate to 656640000 kilo watts per year. It is possible to operate at full or smaller load capacity according to the amount of water in reservoir.
Advantages of hydroelectric power
To start with, this electricity from water is highly reliable, as long as there is enough water for the power plant. Also, the site where the plant is built is studied for as.many as 50 years before the project is rolled down. A lot of feasibility study is done thoroughly before the establishment of the project. The site must also pass the environmental assessment test before the recommendations are passed for the establishment of the actual project. This is all meant to ensure reliability of the project. The issue of technology is also very vital for such a vital project. This must be proven and of high standards to avoid failure and unnecessary losses after the project has started.
The efficiency must also be very high to make sure that there is quality and up to standard supply of electricity all the times, and also presence of high quality services all the times. This is to make sure that the project will never stall once it is rolled out. The quality of electricity generated is also assessed on whether there is breakdown of equipment as a result lack of maintenance. A good plant should also adjust variation of the load changes in different seasons.
The reservoir is also used as a flood control measure. There is also the benefit of it being used as a recreational facility. This is where the dam can be used for swimming as a sporting activity. The reservoir can also be used for aquiculture. Fish farming and other marine life can be brought to the dam hence improving the living standards of the people living near it.
The dam created upstream is a good reservoir for water. This has many advantages as its uses. It can be used for water provision for human consumption. People living near the hydropower plants derive their water for domestic use from these dams. The hydroelectricity generation does not bring along with wastes which bring about air pollution hence resulting to acid rains as well as greenhouse gases which are the cause of the global warming
Disadvantages of hydroelectricity
The high initial cost of equipment and facilities is the major disadvantage of this power source. The giant generators and transformers used come with huge cost. The man-power required is also experience with the current technology making it very expensive. The water precipitation and massive evaporation makes it difficult to ensure the right water levels all the times. The fluctuation of water levels affect the quality and quantity of electricity generated.
The water in the dam has got changes in its actual temperature hence affecting and other wildlife near the dam. There is also changes in water levels which also has negative impact on the aquatic life i.e. both flora and fauna. There is need for a “balance” between freshwater maintenance and electricity production (EPR). There is also the problem of silting which causes unwarranted problems to the fish and other organisms which use the dam as their natural habitat.
So many people are displaced from the area where the reservoir is built. Their life is definitely affected negatively. Because of the financial risks perceived, dams are “less attractive” as investments compared with “other power projects” (Hildyard; cited in SIRTE, 30). With “great requirement” for electricity realized in communities (Kumar, 1), the impacts of it on environment have been investigated (see Pirker). Bano has noted “drought” vulnerabilities emanating from activities of hydropower plants (p. iii).
As Does hydroelectric power plants help reduce the number of C02 Emission in years (10, 20, 30, 40) compared to the total Co2 emission we’re giving off
Hydroelectric power plant don’t emit carbon dioxide, neither do they emit other green house gases such as methane, although “extremely low” CO2 may be produced during the plant construction, but it is just but a negligible fraction, which has just but meager negative environmental impact (World Commission on Dams). Carbon dioxide emission in power plants is a major issue because it accounts for a “quarter” of generated carbon dioxide gas in the U.S. (ScienceDaily) and contributes to rise of global temperatures that were estimated to reach 5 – 20% “by the end of the next century” (Atsushi; cited in SIRTE, 5).
Generally, hydroelectric power plant produces the least of greenhouse gases as compared to any other source of energy. The second electricity source with more greenhouse gases emission but slightly above hydroelectricity is the wind power. At the third position is nuclear energy. The forth one is the solar photovoltaic, which produces a huge volume of green house gases.
What are the market value or market industries for hydro power plant?
The biggest and the most prominent hydroelectric pants suppliers and service provider in the whole world is known as the Alstom. The company has over one hundred years of experience in the hydropower industry. The Alstom turbines and power generators spread to every corner of the world and this contributes to over 25 per cent of the power generation in recent time. For a new hydropower plant, one would need a wide range of equipment such as turbines, generators, and control and protection systems, lifting equipments among others.
Works Cited
Atsushi, Iimi. “Estimating Global Climate Change Impacts on Hydropower Projects: pplications in India, Sri Lanka and Vietnam.” Policy Research Working Paper, 4344, 2007.
Bano, Mehdi. Hydropower and climate change. 2006. Web.
Department of Energy. “Hydropower.” 2009. Web.
EPR. “Improving Water Forecasting for Better Hydropower Production.” n.d. Web.
Hildyard, Nicholas. Dams on the Rocks – The Flawed Economics of Large Hydroelectric Dams. 1998. Web.
Kumar, Slariya. The Role of Hydroelectric Power Projects in the Climate Change: A Case study of Ravi basin in Himachal Pradesh. 2010. Web.
Pirker, Otto. Climate Change & Hydropower Consequences and challenges. 2007. Web.
ScienceDaily. “Carbon Dioxide Emissions From Power Plants Rated Worldwide.” 2007. Web.
SIRTE. “Ministerial conference on Water for agriculture and energy in africa: The challenges of climate change.” 2008. Web.
World Commission on Dams. “Does Hydropower Reduce Greenhouse Gas Emissions?” 2000. Web.