Power in the Present
At present we use the movement and enrgy from natural sources to move a generator creating electricity. We use water to make electricity in three main ways:
The basic principle of hydroelectric power is to pass water from a high place, through a water turbine and power generator. The power comes from the gravitational potential energy which is stored in the water; this is because the water is raised by being dammed then ‘falls’ through the turbine. The amount of energy produced depends upon the height the water has to fall and also the amount that passes through the turbine.
After the hydroelectric power station has been built, there are no extra costs for fuel, as in nuclear or coal fired power stations. Money is still required to pay for labor and maintenance but this is the same in other types of power station. Hydroelectric power still gives out some carbon dioxide and methane due to anaerobic respiration taking place in the large reservoir, this comes from plant material that has not been cleared before building the dam. This however mostly occurs in tropical environments. The main disadvantage comes from the need to flood large areas of land when the river is initially dammed. This disrupts the ecosystems of near by animals, and may require humans also to be relocated.
We all know the importance of water in the desert, but in las vegas this has another meaning. The famous attractions, involving large ammounts of neon lights, and ammount of tourists visiting the area mean a large ammount of power is required. This power coems from a hydroelectric power station nearby, called 'lake mead'.
Tidal power is a variation of hydroelectric power and comes in two main forms. The first uses kinetic energy in flowing water, rivers, tides and open currents and the second uses potential energy, similarly to hydroelectric power, but using the differing heights of low and high tides. A barrage can be set up blocking of a section of water. The water level then changes outside the barrage and then cause the water to move the turbines, in flowing water the turbines would constantly be moving and generating electricity.
The power source is highly efficient converting 80% of the potential energy in the water into electricity. The barrages have a large effect on the environment resulting in changes in the eco system. By cutting off the water it moves less than it would normally, meaning more plants will grow changing the food chains, the salt levels in the water would change which could be deadly to animals and also the pollution would be unable to spread out to other water harming animals stuck behind the barrier.
Wave power is currently not used much as a power source, with the first 'wave farm' being set up in 2006. The basic idea is that an object is put on a wave and will 'bob' up and down. This kinetic energy can then be used to move the mechanics inside of the wave power device. The electricity can then be sent to the shore via under water cables. The problems with this type of energy is that the cost of creating the 'wave power device' to be able to survive the sea condition often makes the idea un-economically viable.
Google Definition Turbine
Google Definition Ecosystem
Google Definition Barrage
Wikipedia Article Hydroelectricity
Wikipedia Article Tidal Power
Wikipedia Article Wave Power