Methods Of Producing Electricity PDF

FOSSIL FUELS  Boiler Turbine Generator Grid FUEL Chemical Heat Kinetic Electrical energy energy energy energy Facts The fossil fuels are coal, oil and natural gas. They are fuels beca...

FOSSIL FUELS  Boiler Turbine Generator Grid FUEL Chemical Heat Kinetic Electrical energy energy energy energy Facts The fossil fuels are coal, oil and natural gas. They are fuels because they release heat energy when they are burned. Fossil Fuels were formed from the remains of living organisms millions of years ago. About three-quarters of the electricity generated in the UK comes from power stations fuelled by fossil fuels.  Advantages A major advantage of fossil fuels is their capacity to generate huge amounts of electricity in just a single location. Fossil fuels are very easy to find. When coal is used in power plants, they are very cost effective. Coal is also in abundant supply. Transporting oil and gas to the power stations can be made through the use of pipes making it an easy task. Power plants that utilize gas are very efficient. Power stations that make use of fossil fuel can be constructed in almost any location. This is possible as long as large quantities of fuel can be easily brought to the power plants.  Disadvantages Fossil fuels are non-renewable energy resources. They are limited and they will eventually run out one day. Fossil fuels release carbon dioxide when they burn, which adds to the greenhouse effect and increases global warming. Of the three fossil fuels, for a given amount of energy released, coal produces the most carbon dioxide and natural gas produces the least. Coal and oil release sulfur dioxide gas when they are burnt, this then causes breathing problems for living creatures and contributes to acid rain. NUCLEAR POWER STATIONS Fuel rods of uranium and plutonium Facts The main nuclear fuels are uranium and plutonium, both of which are radioactive metals. Nuclear fuels are not burned to release energy. Instead, heat is released from changes in the nucleus. Just as with power stations burning fossil fuels, the heat energy is used to boil water. The kinetic energy in the expanding steam spins turbines, which drive generators to produce electricity Advantages Unlike fossil fuels, nuclear fuels do not produce carbon dioxide. Disadvantages Like fossil fuels, nuclear fuels are non-renewable energy resources. If there is an accident, large amounts of radioactive material could be released into the environment. Nuclear waste remains radioactive and is hazardous to health for thousands of years. It must be stored safely. BIOFUELS Facts Biofuels are fuels produced from plant material. For example, bioethanol is produced from plant sugar and biodiesel is produced from plant oils. Unlike fossil fuels, biofuels are renewable resources. In addition, their use may lead to an overall reduction in emissions of carbon dioxide because the growing plants absorb carbon dioxide from the atmosphere.  Advantages Are cheaper than fossil fuels. Many governments are now offering tax incentives to buy greener cars that run on biofuels (ethanol being one example). Are considered ‘carbon neutral’ by some people. Reduces carbon emissions by 50-60%. Reduce dependence on foreign oils. Oil fluctuates in price rapidly, so changing to biofuels will help buffer against the change. Emit less particulate pollution than other fuels, especially diesel. Are renewable sources of energy as you can just keep producing more. Ethanol is very inexpensive to produce. Can help prevent engine knocking. Disadvantages Setting aside land to grow biofuels means that there is less land to grow food. It is also possible that food prices will rise as a result. More land must be set aside to make biofuels. Natural habitats (flora and fauna) may be lost as a result. There are better solutions- such as using hydrogen fuel cells. Not many gas stations have biofuels available at the moment. This discourages people from buying cars that are not reliant only on gas. Burning corn may release high concentrations of nitrous oxide into the air, which is a greenhouse gas. WIND Facts Wind turbines (modern windmills) turn wind energy into electricity. The wind is produced as a result of giant convection currents in the Earth's atmosphere, which are driven by heat energy from the sun. This means that the kinetic energy in wind is a renewable energy resource: as long as the sun exists, the wind will too. Wind turbines have huge blades mounted on a tall tower. The blades are connected to a nacelle or housing that contains gears linked to a generator. As the wind blows, it transfers some of its kinetic energy to the blades, which turn and drive the generator. Several wind turbines may be grouped together in windy locations to form wind farms. Advantages Wind is free, wind farms need no fuel. Produces no waste or greenhouse gases. The land beneath can usually still be used for farming. Wind farms can be tourist attractions. A good method of supplying energy to remote areas. Wind power is renewable. Winds will keep on blowing, it makes sense to use them. Disadvantages The wind is not always predictable - some days have no wind. Suitable areas for wind farms are often near the coast, where land is expensive. Some people feel that covering the landscape with these towers is unsightly. Can kill birds - migrating flocks tend to like strong winds. However, this is rare, and we tend not to build wind farms on migratory routes anyway. Can affect television reception if you live nearby. Can be noisy. Wind generators have a reputation for making a constant, low, "swishing" noise day and night, which can annoy people. WAVE Facts The water in the sea rises and falls because of waves on the surface. Wave machines use the kinetic energy in this movement to drive electricity generators. Advantages Wave power is a renewable Energy Source. Wave Energy Is a Clean Fuel. Wave Energy is Environmentally Friendly - it doesn't destroy the environment. There is plenty of it. Tides/Waves are always predictable. You can always produce a significant amount of energy. You don't need fuel so it doesn't cost that much. Waves are free and will not run out so the cost is in building the power station. Disadvantages It can cost a lot of money and requires further research. If the whole tidal/wave energy scheme does get popular real estate will be losing money for beach front houses since they will be using the beaches for the tidal/wind farms. It depends where you put it for the costs so not much good financially May interfere with mooring and anchorage lines commercial and sport fishing. Waves can be big or small so you may not always be able to generate electricity. You need to find a way of transporting the electricity from the sea onto the land. HYDROELECTRIC Facts To make electricity this way, the water is held in a reservoir, behind the dam. The water close to the control gates is where the intake is, and when the control gates open, the water rushes through the penstock and turns the turbine. After the water does so, it goes through the outflow into the river. The turbine spins the generator, and the electricity goes to the transformer in the powerhouse. Then the transformer transforms the electricity into a usable form, and the electricity travels through the power lines and goes to homes and businesses. Advantages Once a dam is constructed, electricity can be produced at a constant rate. If electricity is not needed, the sluice gates can be shut, stopping electricity generation. Dams are designed to last many decades and so can contribute to the generation of electricity for many years. The lake that forms behind the dam can be used for water sports and leisure / pleasure activities. Often large dams become tourist attractions in their own right. The build up of water in the lake means that energy can be stored until needed, when the water is released to produce electricity. When in use, electricity produced by dam systems do not produce green house gases. They do not pollute the atmosphere.  Disadvantages Dams are extremely expensive to build and must be built to a very high standard. The flooding of large areas of land means that the natural environment is destroyed. People living in villages and towns that are in the valley to be flooded, must move out. The building of large dams can cause serious geological damage. Although modern planning and design of dams is good, in the past old dams have been known to be breached. This has led to deaths and flooding. Dams built blocking the progress of a river in one country usually means that the water supply from the same river in the following country is out of their control. Building a large dam alters the natural water table level. SOLAR  Facts Solar cells are devices that convert light energy directly into electrical energy. Larger arrays of solar cells are used to power road signs in remote areas. Solar panels do not generate electricity, but rather they heat up water. They are often located on the roofs of buildings where they can receive heat energy from the sun. Cold water is pumped up to the solar panel, there it heats up and is transferred to a storage tank. A pump pushes cold water from the storage tank through pipes in the solar panel. The water is heated by heat energy from the sun and returns to the tank. In some systems, a conventional boiler may be used to increase the temperature of the water. Advantages Solar energy is a renewable energy resource There are no fuel costs. No harmful polluting gases are produced. Disadvantages Solar cells are expensive and inefficient, so the cost of their electricity is high. Solar panels may only produce very hot water in very sunny climates, and in cooler areas may need to be supplemented with a conventional boiler. Although warm water can be produced even on cloudy days, neither solar cells nor solar panels work at night. GEOTHERMAL  Grid turbines 7Km Facts Several types of rock contain radioactive substances such as uranium and plutonium. Radioactive decay of these substances releases heat energy, which warms up the rocks. In volcanic areas, the rocks may heat water so that it rises to the surface naturally as hot water and steam. Here the steam can be used to drive turbines and electricity generators. This type of geothermal power station exists in places such as Iceland, California and Italy.... Hot rocks In some places, the rocks are hot, but no hot water or steam rises to the surface. In this situation, deep wells can be drilled down to the hot rocks and cold water pumped down. The water runs through fractures in the rocks and is heated up. It returns to the surface as hot water and steam, where its energy can be used to drive turbines and electricity generators Advantages Geothermal energy is a renewable energy resource and there are no fuel costs. No harmful polluting gases are produced. Disadvantages Most parts of the world do not have suitable areas where geothermal energy can be exploited.