VIEWS: 18 PAGES: 3 POSTED ON: 9/24/2011
Name ________________ What are the pros and cons of different sources of energy? The three different kinds of energy-sources have their own pros and cons. In this part we give a few of them. Nuclear power For the generation of nuclear power, a little bit of uranium (an element) from the earth can be used to make a whole lot of energy. This is a very good thing. It’s an advantage because the earth has enough uranium to last a long time. A very big disadvantage is that the uranium, is very radio-active. Also the used rods and other materials used in nuclear power plants stay radio- active for hundres of years. The nuclear power plant Chernobyl exploded leaking radioactive material to the surrounding city polluting the environment and making the entire city a waste zone. People could no longer live there. Fossil energy The big advantage of fossil energy is that, to generate the energy from the raw material is easy and cheap. Disadvantage is that during the process of combustion a lot of toxic materials comes into the air which causes extra pollution of the atmosphere, these materials also increase the effect of global warming. Another disadvantage of fossil energy is that the supply of fossil fuels is not endless. The current supply is for approximately 50 years. That is why the USA wants to trail for oil and natural gas in Alaska. If the USA does this, there are big consequences for the environment. Alternative energy The advantage of alternative energy is that the energy source is endless and doesn't give any pollution. Wind, biomass, geothermal, solar and hydroelectric are some examples. Still, there are not many alternative energy forms, because for instance the technique to transform sun-beams into electric energy is very expensive. Wind Power Wind energy harnesses the power of the wind to propel the blades of wind turbines. The rotation of turbine blades is converted into electrical current by means of an electrical generator. In the older windmills, wind energy was used to turn mechanical machinery to do physical work, like crushing grain or pumping water.Wind towers are usually built together on wind farms. Now, electrical currents are harnessed by large scale wind farms that are used by national electrical grids as well as small individual turbines used for providing electricity to isolated locations or individual homes. In 2005, worldwide capacity of wind-powered generators was 58,982 megawatts, their production making up less than 1 of world-wide electricity use. Pros Wind power produces no pollution that can contaminate the environment, Since no chemical processes take place, like in the burning of fossil fuels, in wind power generation, there are no harmful by-products left over. Since wind generation is a renewable source of energy, we will never run out of it. Farming and grazing can still take place on land occupied by wind turbines which can help in the production of biofuels. Wind farms can be built off-shore. Cons Wind power is intermittent. Consistent wind is needed for continuous power generation. If wind speed decreases, the turbine lingers and less electricity is generated. Large wind farms can have a negative effect on the scenery. Solar Power Solar energy is used commonly for heating, cooking, the production of electricity, and even in the desalination of seawater. works by trapping the sun's rays into solar cells where this sunlight is then converted into electricity. Additionally, solar power uses sunlight that hits solar thermal panels to convert sunlight to heat water or air. Other methods include using sunlight that hits parabolic mirrors to heat water (producing steam), or simply opening a rooms blinds or window shades to allow entering sunlight to passively heat a room. Pros Solar power is a renewable resource. As long as the Sun exists, its energy will reach Earth. Solar power generation releases no water or air pollution, because there is no chemical reaction from the combustion of fuels. Solar energy can be used very efficiently for practical uses such as heating and lighting. The benefits of solar power are seen frequently to heat pools, spas, and water tanks all over. Cons Solar power does not produce energy if the sun is not shining. Nighttime and cloudy days seriously limit the amount of energy produced. Solar power stations can be very expensive to build. Geothermal Energy Literally, geothermal means, "earth heat." Geothermal energy harnesses the heat energy present underneath the Earth. Hot rocks under the ground heat water to produce steam. When holes are drilled in the region, the steam that shoots up is purified and is used to drive turbines, which power electric generators. Pros If done correctly, geothermal energy produces no harmful by-products. Once a geothermal plant is build, it is generally self-sufficient energy wise. Geothermal power plants are generally small and have little effect on the natural landscape. Cons If done incorrectly, geothermal energy can produce pollutants. Improper drilling into the earth can release hazardous minerals and gases. Geothermal sites are prone to running out of steam. Hydroelectric Energy Hydroelectric power comes from the potential energy of dammed water driving a water turbine and generator. Another variation is to make use of water's kinetic energy or undammed sources such as tidal power. Hydro power works by harnessing the gravitational descent of a river that is compressed from a long run to a single location with a dam or a flume. This creates a location where concentrated pressure and flow of water can be used to turn turbines or water wheels. These can then drive an electric generator. This can be compared to past days when a water wheel would drive a mill. Electric generators powered by hydro power can be run backwards as a motor to pump water back up for later use. Pros Water can be accumulated above the dam and released to coincide with peaks in demand. So, unlike other types of power stations, hydroelectric power stations can promptly increase to full capacity. Electricity can be generated constantly, because there are no outside forces, unlike other forms of alternative energy, which affect the availability of water. Hydroelectric power produces no waste or pollution since there is no chemical reaction to produce power. Water used for hydro power can be reused. Cons Dams can be very expensive to build. There needs to be a sufficient, and powerful enough, supply of water in the area to produce energy.