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1、Integrated Science Renewable and Nonrenewable energy sourcesIntroduction of sources of energy Non-Renewable Fossil Fuels NuclearRenewable Wind Solar Tidal Hydropower 5. GeothermalNon-Renewable energy sources:1.Fossil FuelsWhat are fossil fuels ? A fuel is any substance used as a source of energy, in
2、cluding heating, transport, electricity generation and other uses. Most of the worlds energy is provided by the burning of fossil fuels (化石燃料). Coal, Oil and Gas are called “fossil fuels”because they are natural combustible substances formed originally from dead plants and animals. The major fossil
3、fuels are coal (煤), petroleum (石油) and natural gas (天然氣). Fossils fuels are non-renewable (非再生能 源) energy sources. This is because fossil fuels take millions of years to form. Once they are used up they can never be replaced.World Fuel Resources Petroleum or OilNatural GasCoalPower reserves130 billi
4、on tonnes158 billion cubic metres950 billion tonnesTotal used in 19902.2 billion tonnes1.5billion cubic metres2.2 billion tonnesFrom the above table, the present worlds estimated oil reserves may be used up in the next 50 to 60 years.Coal Coal is the plants ,that grew in swampy areas about 300 milli
5、ons ago, died to form layers of decaying material. Heat, pressure and the action of bacteria changed the decaying plants into coal.How it works: Coal is crushed to a fine dust and burnt. How is coal used? Today, about 70 % of the total coal mined is burned in power station. Coal Education (http:/www
6、.coaleducation.org/) Petroleum1.How was petroleum formed? Petroleum was formed from small sea animals and plants that lived millions of years ago. After they died, heat; pressure; and the action of bacteria changed the remains into oil. The oil formed was then trapped as small drops inside the pores
7、 of rocks. Petroleum (http:/www.petroleum.co.uk/) How is petroleum used? The thick crude oil that comes from the ground is a complex mixture of compounds. It is necessary to separate the compounds. The separated substances have two main uses: as sources of useful fuels. e.g. petrol as raw materials
8、to make other products. e.g. plastics, detergents. Products Made from a Barrel of Crude Oil Natural Gas Natural gas is found together with oil and sometimes with coal. The gas consists mainly of methane CH4.Natural Gas (http:/www.naturalgas.org/) Source : www.naturalgas.org In some countries, the ga
9、s is carried by pipes to homes and factories for heating and cooking. HOW NATURAL GAS IS STORED AND DELIVERED How is petroleum used?The advantage and disadvantages of using fossil fuelAdvantages Very large amounts of electricity can be generated in one place using coal, fairly cheaply. Transporting
10、oil and gas to the power stations is easy. Gas-fired power stations are very efficient. A fossil-fuelled power station can be built almost anywhereDisadvantages Pollution Burning any fossil fuel produces carbon dioxide, which contributes to the “greenhouse effect“, warming the Earth. Burning coal pr
11、oduces more carbon dioxide than burning oil or gas. It also produces sulphur dioxide, a gas that contributes to acid rain. We can reduce this before releasing the waste gases into the atmosphere.Mining coal can be difficult and dangerous. Strip mining destroys large areas of the landscape.Non-Renewa
12、ble energy sources:2.Nuclear EnergyWhat are Nuclear Power? Nuclear power is generated using Uranium, which is a metal mined in various parts of the world. Some military ships and submarines have nuclear power plants for engines. Nuclear power produces around 11% of the worlds energy needs, and produ
13、ces huge amounts of energy from small amounts of fuel, without the pollution that youd get from burning fossil fuelsHow it works Nuclear power stations work in pretty much the same way as fossil fuel-burning stations, except that a “chain reaction“ inside a nuclear reactor makes the heat instead.The
14、 reactor uses Uranium rods as fuel, and the heat is generated by nuclear fission. Neutrons smash into the nucleus of the uranium atoms, which split roughly in half and release energy in the form of heat. Carbon dioxide gas is pumped through the reactor to take the heat away, and the hot gas then hea
15、ts water to make steam. The steam drives turbines which drive generators. Modern nuclear power stations use the same type of turbines and generators as conventional power stations. Advantages Nuclear power costs about the same as coal, so its not expensive to make. Does not produce smoke or carbon d
16、ioxide, so it does not contribute to the greenhouse effect. Produces huge amounts of energy from small amounts of fuel. Produces small amounts of waste.Disadvantages It is very, very dangerous. It must be sealed up and buried for many years to allow the radioactivity to die away. It is reliable,but a lot of money has t
