Hydroelectric Power: The Renewable Energy Source
For centuries, human have been relying solely on the use of fossil fuel to produce energy. To anticipate the exhaustive use of fossil fuel that has hit the highest point and issued the fear of energy source shortage in the next decades, it is urgent to investigate the closest and renewable potentials to cover the advanced needs of energy.
One of the most popular sources that have been thoroughly investigated and mechanically tested is the use of hydroelectric power. Hydroelectric power plant utilizes natural power from the flowing water, which is channeled into a turbine. The flowing water holds enormous energy to spin the turbine and operate generators. Human can get endless supply of electricity from dams, rivers, waterfalls, or artificial channels.
Unlike the fossil fuel, flowing-water power doesn’t run out as long as the water cycle is kept undamaged. This renewable energy source does not limit energy consumption to the earth content and applies easily on many types of water sources. In this way human obtain enough supply without having to destroy the environment for another oilrigs.
Hydropower also has more benefits and less pollution impact as created by another form of power plant. Hydropower plants produce lower gas emissions to the atmosphere than diesel or fossil fuel power plants do. It does not produce liquid waste either. On the other hand, hydropower plants enable the surrounding population to control the water level, reduce the flood risk, obtain regular irrigation schedule for their plantations and enough electricity (Coface Environmental Guidelines, 2002. p. 2)
Hydroelectric plant can be developed in large basis, such as at dams and water reservoirs, as well as in small scale use, for example for home and farms (National Renewable Energy Laboratory, -. par. 2, 4).
Large plants are built on dams and water reservoirs. The system utilizes the high-head hydro principle, which generates energy from the water stream. Water molecules contain potential energy, when after acceleration of its fall from the top of the dam is converted into kinetic energy, which then spins the turbine (Ordal, 2002. par. 2).
Many outsized dams use the high head standard. The higher the source of water, the higher kinetic energy it will create. As a result, many dams were built in towering construction, like Hoover Dam, Colorado, and most power plants in Norway.
Dam as the main construction is built to collect water from nearby streams. It can be a single block of a giant river, or take up input from several waterways. Dams are usually built with extremely high construction that allows the collected water to reach elevated level of the water surface, which makes it an artificial lake.
Down above the bottom of the dam, a channel is connecting the dam with the turbine pipe, secured with the control gate. When the control gate opens, water comes into the penstock channeling to the turbine and spins it. The turbine rotation activates the magnetic power in the generator and produces alternating current (AC) power. The power goes to the transformer and distributed later as the electricity. Meanwhile, the excess of water from the process exits through the outflow passage, into the normal stream or river on the other side of the dam (Bonsor, 2003. par. 6-12). The water storage at the dam is known as impoundment hydropower.
There is also another type of hydropower that pumps water from the lower to upper reservoir. The technique allows the plant to control the water consumption in the plant. When there is a great of electricity, the water is flowed back to the lower reservoir to turn the turbine (U.S. Department of Energy Hydropower Program, 2001. p. 3).
As for national scale, governments need to allocate serious investment to fund reservoirs development and facilities to integrate the power and electricity resulted. In the U.S., hydroelectric power use is taking about 7% of total energy source (Electric Power Monthly, as cited in U.S. Department of Energy Hydropower Program, 2001. p. 5). China also has moved on with the newest project of the Three Gorges Dam. The dam would be taking 400 miles for the reservoir only (Ordal, 2002).
However this technology sometimes does not work under specific circumstances. Norway, for example, ranked the sixth from the top hydroelectric generating countries in 1998. The country depends much on the hydroelectric stations that provide it economical source of electricity for its people. Once the government realized that they had trouble during the dry year, the electricity cost had increased to 400%. The prolonged dry season had left the dams empty that only limited sources of stored energy left, causing extreme hikes on electricity cost. It might cost 2-3 times higher than usual for the people to keep their houses warm and businesses to stay open.
Although reported to be efficient and satisfying, the development of large dams and utilization of powerful turbines have created superfluous effects that have traumatized the adjacent environment. (U.S. Department of Energy Hydropower Program, 2001. p. 7).
The main consideration is, such huge construction and landscape alteration required to build a dam will affect the organisms living in the streams and the natural platform of the neighboring areas. Dam construction will at least destroy the farms and villages, forcing the inhabitants to relocate; which costs very high.
The other obvious concern is about the threatened fish lifecycle in the river. The powerful movement of the water into the penstock and the turbine rotation has been proven of killing fishes in the rivers. The gravitation force draw fishes into the penstock, and the sharp blades of the turbine instantly bash them into pieces or leave them injured.
In North America, the dam operation is reported in endangering young fishes life, as the fishes are sucked into the pipes and smashed onto the wall, while others are killed for increasing water pressure inside the unit (Stoner, 2002. par. 7). Moreover, it is important to consider that the barrier effect of the dam building most likely blockade the natural salmon journey to the spawning site. Some dams have implemented ladder structures for the salmons to make their way through their home, however this method has been reported ineffective.
The U.S. Department of Energy recently introduced the new Advanced Turbine Technology to reduce the violent effect of the hydropower plant to the fishes. The new turbine has less blades and noise, and allows water to pass with less shocking effect to the fishes carried in the water. The design allows the turbine to produce more energy, around 6% greater than the conventional one (Stoner, 2002).
From the previous study, the advanced turbine technology reduces fish mortality to less than 2%, while on the current turbine system may reach 5-30%. Moreover, the turbine also retains the Dissolved Oxygen level to 6 mg/L, which meets the standard water quality for the existence of the organisms (U.S. Department of Energy Hydropower Program, 2001. p 7). The quality of this instrument is yet to be tested to find out whether it fulfills the need of environmentally friendly hydropower plant.
Bonsor, Kevin. “How Hydropower Plants Work.” 2003. How Stuff Works. 5 Mar. 2003. http://people.howstuffworks.com/hydropower-plant.htm
Coface Environmental Guidelines. “Hydroelectric Power Stations and Large Dams.” November 2002. Coface Consulting. 5 Mar. 2003. http://www.coface.com/_docs/barragesgb.pdf
National Renewable Energy Laboratory. “Introduction to Hydroelectric Power.” Clean Energy Basic. National Renewable Energy Laboratory. 5 Mar. 2003. http://www.nrel.gov/clean_energy/hydroelectric_power.html
Ordal, David. “Technology: How Hydro Actually Works.” 2002. Hydro Power. Department of Physics and Astronomy Pomona College. 5 Mar. 2003. http://www.physics.pomona.edu/faculty/prof/tanenbaum/phys17s99/hydro/technology.htm
Stoner, Mark. “Hydropower: Environmental Effects.” 2002. Hydro Power. Department of Physics and Astronomy Pomona College. 5 Mar. 2003. http://www.physics.pomona.edu/faculty/prof/tanenbaum/phys17s99/hydro/environmental.htm
US Department of Energy Hydropower Program. “Hydropower Partnership With The Environment.” 2001. U.S. Department of Energy Hydropower Program. 5 Mar. 2003. http://hydropower.inel.gov/facts/01-GA50627-01-brochure.pdf