LOWER SIXTH - KGP SCHEDULE, WEEKS 2-9 - ENERGY
MODULE 1 THE DYNAMICS OF CHANGE
10.2 PEOPLE AND THE ENVIRONMENT -POPULATION AND RESOURCES
RENEWABLE ENERGY - HEP
NON-RENEWABLE ENERGY -OIL
   
HYDRO-ELECTRIC POWER
∑ Hydroelectricity is the worlds most used renewable resource as it contributes around 20% of the world's electricity. The next biggest renewable contributor to the world's energy is geothermal power, which contributes a mere 0.30% of the world's energy.
∑ Most of this energy comes form large-scale river projects such as the Aswan Dam, (Egypt,), the AtatÚrk dam, (Turkey) and the Tennessee Valley Authority complex, (USA). The first hydroelectric dam was built using the power generated from the Niagara Falls in 1958
∑ The largest hydroelectric dam is the Itaipů on the Parana River on the border of Paraguay and Brazil in South America. Its generating capacity is 12,600 MW, which is nearly 2% of the capacity for all Hydroelectric, dams.
∑ However only 20% of the world's potential hydroelectric power is actually exploited world wide, although that figure is much higher in LEDC's where approximately 75% is exploited. So it is up to the MEDC's to employ large schemes to maximise the potential energy form hydroelectric dams. The world's output of energy from hydroelectricity is rising by two or three percent every year.
∑ The large-scale schemes required to maximise the potential of hydropower are often very unpopular with local inhabitants as they spoil the local scenery and often cause a lot of rehousing. However they are very beneficial for governments as they provide a constant source of electricity, they do not emit much Carbon Dioxide or other pollutants and the running overheads are low. However the installation costs are very high so that is the main worry for governments especially those of LEDC's, so there is considerable involvement in the World Bank in these matters.
∑ Hydroelectricity is generated by the water falling on and turning turbine blades. The size of the turbine depends on the 'head'. The head is the distance the water falls into the turbines so the head is therefore its potential energy. The relationship between the dam's capacity and the head is as follows; Power increases as the size of the head increases. In mountain schemes (like, for example, the KaprunOberstife in Austria) the head depends on the difference between catchment area and the powerhouse. The water flowing down to the turbines through the pipes is known as penstock.
∑ These dams often cause untold damage to the environment as they seriously disrupt the natural ecological cycle of the area. Also many of the fish in the reservoir get killed in the turbines and a lot of habitat is removed to make way for the dam. Another consideration, especially for the warmer countries is the amount of water lost every year from evaporation from the large open reservoirs.
∑ Hydroelectricity does not have to always be on a large scale it can also be used to serve small communities in rural areas. Small-scale hydroelectric power, (capacity below 10MW) can be used on local rivers to generate the power needed to run a small village.
∑ Overall hydroelectric power is the most economically viable and efficient method of renewable source and one that should be used more readily in the future.
RENEWABLE ENERGY - HEP
NON-RENEWABLE ENERGY -OIL