Introduction
Energy can be found anywhere in the world, and it stays that way, “it cannot be created or destroyed” from the law of conservation of energy. However, every energy can be converted, for example, a kinetic energy can be converted to an electrical energy and when a dynamite explodes it is the chemical energy from the dynamite converted into kinetic energy. This is concept is used by people to generate electricity. Classically, conservation of mass is very different with conservation of energy. Special relativity showed that “mass can be converted into energy and vice versa,” by the formula, E=mc2.
In this world, there are many ways certain energy can be converted into electricity. One of them, are from the two-third elements on the earth, which is water. Hydroelectric power means that collecting energy from the falling water or the flow of water. It is known as a clean technique for generating energy, since it does not leave any waste. Hydro-powered generators have been found for over 135 years ago. The earliest innovations was found in China between 202 BC and 9 AD. Trip hammers, devices that is used to pound grain, break ore stones, and conventional paper-making, were powered by a vertical water wheel.
Source: http://www.survivopedia.com/basic-physics-that-saves-your-life/
The size of hydro plants today produce a massive energy ranging from hundred kilowatts to several hundred kilowatts. Sometimes there are larger ones that produce up to 10,000 megawatts that supply electricity for tens of millions of people. Nowadays, over 80 percent of the electricity produced by renewable resources are hydro-generated. Hydro-powered generator produces less carbon dioxide emissions and cost less than fossil fuel-powered. Hydropower contributes to about 20% of the total energy generated to the world. It was studied by World Wide Fund that by 2050, another 370 giga watts of any size hydroelectric capacity is able to be developed without any impacts.
The Process
An example of process in hydro-powered generator is a dam. Parts of the Hydroelectric plant is a dam that holds and collect water so that it rise to a certain level, a turbine that rotates by the falling of water , converting potential energy to mechanical energy, a generator that converts the mechanical energy to electric energy, and lastly transmission lines that distributes all the electricity products to the society.
Firstly, an artificial lake is made behind the dam and the force from the water from a height spins the turbine and the water flows back to the river on the other side of the dam. Secondly, the turbine is connected to the generator, the electricity is produced from the spinning of electromagnets inside the generator’s wire coil that creates a flow of electrons. The fall of water that keeps the turbine spinning, results in keeping the electromagnets spin. An electric charge is developed in the stator while the rotator and its magnetic field rotate.
Source: http://www.wvic.com/content/how_hydropower_works.cfm
Important Factors
The amount of electricity that is produced by the plant depends on these two factors: the height of the level when the water falls and the amount or mass of the water that falls. The power of the water increases as the higher the water falls, which depends on the size of the dam. Scientists states that, “the falling of water is directly proportional to the distance it falls,” which means that if the water fell twice the height, the power is also doubled. A formula that can be used to calculate the amount of power generated by the water is,
P = (Height of Dam) x (River Flow) x (Efficiency)/ 11.8
P = Electric Power (kilowatts)
Height of Dam = Distance when the water fall
River Flow = Water that flows through the river in cubic feet per second
Efficiency = An older dam might have an efficiency of 60% (0.60) and newer dam would have 90% (0.90)
11.8 = This converts the unit from feet and seconds to kilowatts
To convert it to energy annually, use the following formula
E = P x (24 hours a day) x (365 days a year)
Environmental Impact
Large dams have various and numerous impact towards the environment biologically and chemically. It disrupts the river ecosystems, causing a blockage on fish migrations and in some cases or some species the dam separates their spawning and rearing habitat. Sometimes, there are more predator fish in one side, resulting in the decrease in number of some species. Chemically, the physical property of the dam also affects the river ecosystem, such as the change in temperature, the substance of the dam’s materials are sometimes not suitable for the aquatic plants and animals in the river. The alteration flowing of water also affects the aquatic life in someway, because some species depends on the quantity and the timing of river flows. Some fishes were also killed from the blades of the turbine.
However, there are some disagreement on the impact of hydroelectric impact, when it is installed, hydro-powered generator do not emit any harmful gas or waste, that is why hydroelectric plant is more preferable than coal, nuclear, or gas powered- generator. The method is also being innovated and improved making less negative impacts every time, such as fish ladders.
Advantages
When the reservoir or dam is built, it is considered that energy is free. There are no waste or pollution created by this generator. Rather than wind, solar and geothermal power, hydro-powered is more reliable. It is known that hydro-powered generator can rise to full power in a very short time.
Disadvantages
Unfortunately, in order to create a dam that big, a large number of money is needed. A large dams caused problems to the ecological systems in river. A suitable and efficient site is difficult to find. Quality of the water is affected.