The rapid depletion of fossil fuels has given serious warning that the era of using conventional energy is coming to an end. Due to the energy shortage, a need to find replacement of fossil fuels has appeared. Moreover, problems such as various pollution and serious climate change have occurred, which makes renewable and less pollution energy source alternative choices. Therefore, three options can be suggested to solve the problem with the depletion of natural sources. These options could be wind power, geothermal energy and solar power, which will replace fossil fuels in the future. This essay will evaluate these there renewable energy sources by using the following criteria: availability, cost, practicality, and environmentally friendlness.
On one hand, fierce pollution and global warming affect human beings health. The burning ash of coal and mine contaminates the air gravely, as Sawin (2003) has pointed that almost 80% of CO2 emissions are from fossil fuels burning. In addition, these emissions partly lead to global warming which can be appear in the form of glaciers melting. West Antarctic ice sheets and Greenland are thawing in a surprising speed, and sea level is raised by 12m (Brown, et al, 2008). Unavoidably, glaciers are shrinking every day and in danger of disappearing. On the other hand, the exhaustion of natural energy sources becomes the public concentration. The consumption rate of oil is enormous, which can reach about 1,000 barrels per second in 2005 (Seitz,2008). Middleton (2008) argues that unless the exceeding consumption of fossil fuels is controlled, oil will disappear in just 30-40 years while gas will be used up in only 50-60 years. Population growth, continuing industrialization and urbanization are also the causes of fast consumption.
One way to solve these tough problems is wind power, which will replace fossil fuels by virtue of its low cost and abundance. The volume of demand of wind energy has increased significantly owing to its characteristic of widely spread, clean, inexhaustible, and cheap. The tremendous potential of wind energy can be demonstrated from a worldwide survey done by a Stanford team of Cristina Archer and Mark Jacobson(Brown, 2008), which of the survey is if harnessing one fifth of the word’s available wind energy, 7 fold of electricity used now will be provided. According to Aruvian’s R’search (2009), in Denmark, wind power provided 20% of the whole country’s electricity in 2007. Apart from availability, cost should also be considered. Since wind farm is usually located in remote places, its cost of building is low while purchasing modern wind generate equipment is getting cheaper and cheaper, too. However, only the low cost cannot lead to the widely achievements of wind power, which is largely due to its practicality. The geologic limitation determines that not every place can enjoy modest average wind speeds about 4.9 to 5.6m/second (measured at 10m height) like Denmark, which has huge offshore wind resources and sea territory (Aruvian’s R’search, 2009). Furthermore, both Sinden(2005) and Boyle (2007) agree that the unpredictable wind could not make turbines generating proper amount of electricity possible in the most time. As a result, wind power’s practicality still need to be advanced. Arguably, wind power has a negative effect on ecology. Migrating flocks prefer strong wind; therefore the wind blades can possibly kill birds and bats when rolling. The US Fish and Wildlife Services stated that each wind turbine may kill up to 37 birds annually in Europe (Brown, 2008). However, this situation can be overcome by promoting the facilities and careful locating in case birds are in risky zones again.
The second renewable source is geothermal energy, which is the most successful energy to replace conventional ones. Geothermal energy can generate electricity, space heat and...