Water is a natural resource found on the earth’s surface, below the surface and in the atmosphere as vapor. Water is sometimes referred to as an infinite source since it is replenished naturally through the hydrologic cycle. The hydrologic cycle involves the evaporation, condensation and precipitation of water as rain across the earth’s atmosphere. Water contains potential energy which is only felt or experienced once the water is in motion. For instance, a stream with fast moving water, rainfall or ocean waves possess sufficient kinetic energy that can be converted into a form more suitable for human use, electricity. This essay will
There are various methods that the water energy can be harnessed to generate electricity and this include the hydro-electric dam, wave power and tidal power (Soyka et al. 164). Hydro-electric dams are the most commonly used water energy to electrical energy conversion methods globally. When a strong structure barring the flow of water is constructed across a river, it is referred to as a dam. Once the dam is constructed, the man-made lake that results behind it is referred to as a reservoir. As the water behind the dam rises to form a reservoir, the potential energy accumulates which is finally exhibited by the water that spill-over after the reservoir is. In order to control the amount of water in the reservoir and hence the energy stored within, spillways are included in the dam, where in-excess water can flow out.
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The conversion of water energy to electrical energy in a hydro-electric dam involves the dam itself alongside the reservoir, a turbine, a generator and transmission lines. The dam and the reservoir are crucial in storing the potential energy. A structure referred to as the penstock allows the water from the dam to flow to the turbine in the power station in a lower ground. The potential energy in the water is converted into kinetic energy in the penstock which is the converted to mechanical energy in driving the turbine at high speeds. The turbine then transmits the mechanical energy to the generator which converts the energy into electrical energy. According to the law of conservation of energy, energy is neither lost nor created but converted to other forms. Therefore, the final electric energy may not be an equivalent of the potential energy in the dam since conversions to other forms of energy occurs through the process. The transmission lines finally transmit the generated electricity for domestic use. Hydro-electric power is the most preferred form of renewable energy where by 2016, there was about 1,064 GW of installed hydro-electric capacity globally (“Hydropower”).
Wave power is a form of electrical energy harnessed from oceans and lakes. Once the wind blows over a water surface, waves are formed. The waves formed are focused into a narrow channel which increases their strength and height in such that they are able to spin the specific turbines which in turn generate electricity through a generator. Another approach of harnessing the wave energy is through channeling the waves to another reservoir similar to a dam, where a turbine elevated lower than the reservoir is driven in a similar case to the hydro-electric power. The World Energy Council (WEC) estimates that the wave power could generate more than 2 million megawatts globally if properly harnessed (Phillips).
The tidal power is another form of water energy that is harnessed to useful electric energy. The rise and fall of the ocean levels are referred to as tides and are caused by the gravitational effects between the earth and the moon. Huge tidal turbines are placed in areas with excessive tidal movements. The tidal turbines are placed underwater in an offshore station where the surging and ebbing of the sea tides transmit kinetic energy to the turbine, which in turn generate electricity through the generator (Chudnovsky 393). The tidal power capacity is estimated exceed 120 million megawatts globally (“Estimate Of Global Potential Tidal Resources”).
- “Estimate Of Global Potential Tidal Resources”. Tidal Energy Today, 2015, http://tidalenergytoday.com/2015/02/17/estimate-of-global-potential-tidal-resources/.
- “Hydropower”. Worldenergy.Org, 2016, https://www.worldenergy.org/data/resources/resource/hydropower/.
- Chudnovsky, Bella H. Transmission, Distribution, And Renewable Energy Generation Power Equipment. 2nd ed., Boca Raton, Fl, CRC Press, 2017.
- Phillips, Ari. “Blue Is The New Green: How Oceans Could Power The Future”. Thinkprogress, 2014, https://thinkprogress.org/blue-is-the-new-green-how-oceans-could-power-the-future-b8923ca372cf.
- Soyka, Peter Arnim et al. Drive Growth Through Sustainable Business Practices (Collection). 1st ed., Upper Saddle River, N.J., Ftpress Delivers, 2013.
