Physics 1 Revision Lesson 4 Generating electricity

Generating electricity power stations and the national grid

Power stations make electrical energy from fossil fuels or nuclear fuel Fuels are burnt in the boiler which releases heat energy The steam is used to drive huge turbines (big fans) This heats water changing it into high pressure steam The turbines are attached to a generator which spins around making electricity Electrical energy is then fed onto the National grid and out to our home - where it powers our TV’s etc

Once electricity is made it must be transported around the country Overland cables Underground cables Over ground cablesUnder ground cables   CheaperNot safe from weatherSafe from weatherExpensive Faults can be easily located and quickly repaired Can’t transport electricity over water Can transport electricity under water Faults can’t be easily located and quickly repaired Flexible to adapt to changes in network demand. EyesoreUnseenNot Flexible to adapt to changes in network demand. Prone to short-term interruptions Less disturbance to land than underground installation More reliableInstallation causes land disturbance

Electricity is distributed from power stations to consumers along the National Grid The voltage is ‘stepped up’ when it leaves the power station to reduce the current - this reduces the amount of energy loss The voltage is then ‘stepped down’ before it reaches our homes Power station Step up transformer Step down transformer Homes

Generating electricity Non Renewable energy sources

Fossil fuels are found underground and take millions of years to form They are non renewable they cause pollution and global warming Advantages of fossil fuelsDisadvantages of fossil fuels Readily availableNon renewable Easily transportedCauses pollution & acid rain Low fuel costCauses global warming due to increasing the amount of CO2 Low building costsInefficient Short start up timesHave to dig to find them

Nuclear fuels use energy from splitting an atom to make electrical energy They don’t produce any pollution They do produce dangerous radioactive waste Advantages of nuclear fuelsDisadvantages of nuclear fuels Cheap to run once builtExpensive to build Conserves fossil fuelsNon renewable No sulphur dioxide emissionsProduces radioactive waste No carbon dioxide emissionsExpensive to shut down Safe under normal conditionsLinks with cancer Small amount of fuel used so less transport needed Risks of distaster

Generating electricity Renewable energy sources

Biofuels are made form plants and use the chemical energy in plants to make electrical energy They are cheap They require a lot of land Advantages of BiofuelsDisadvantages of Biofuels Low fuel costNeed a lot of space to grow the crops Less pollutants put in the atmosphere Growing bio fuels takes up valuable farm land and can lead to a loss of habitats RenewableThe fertilisers used to grow biofuel cops can be harmful to the environment Short start up timesVehicles need to be adapted to run on biofuels

Wind turbines use kinetic energy and turn it into electrical energy Advantages windDisadvantages wind RenewableNeeds a lot of space Clean energy- no pollution More than one needed On windy day can produce a lot of electricity Eye sore Can be noisy Expensive to build Needs a windy day to generate electricity

Water can be used to make electricity, by making a turbine spin Wave turbine- use the kinetic energy from waves going up and down Tidal turbines- use the kinetic energy from tides coming in and out of land Hydroelectric dams- use the kinetic energy of falling water These can be used in remote locations were it is difficult to put in electricity cables from a power station

Solar panels may contain water that is heated by radiation from the Sun. This water may then be used to heat buildings or provide domestic hot water Solar panels are often used to make small amounts of energy to light up road signs etc.  No pollution Cheap once installed Only works on sunny days Expensive to buy

Geothermal power stations use the thermal energy from hot volcanic rocks deep underground to make electrical energy  No pollution Renewable Expensive to build power station Eye sore

Key words and statements

Renewable energy sources Non renewable energy sources Global warming Clean energy Power stations National grid Step up transformers Step down transformers Increase in temperature due to the increasing levels of carbon dioxide gas. Energy that does not produce any pollution or waste Energy sources that will not run out How energy is distributed to homes from the power station Energy sources that will run out one day. Voltage is increased through this device so that current is reduced in order to decrease energy loss through cables Voltage is decreased through this device before the electricity reaches our homes Where different energy forms are converted into electrical energy. Usually via a turbine Generating electricity

Renewable energy sources Non renewable energy sources Global warming Clean energy Power stations National grid Step up transformers Step down transformers Increase in temperature due to the increasing levels of carbon dioxide gas. Energy that does not produce any pollution or waste Energy sources that will not run out How energy is distributed to homes from the power station Energy sources that will run out one day. Voltage is increased through this device so that current is reduced in order to decrease energy loss through cables Voltage is decreased through this device before the electricity reaches our homes Where different energy forms are converted into electrical energy. Usually via a turbine Generating electricity

Biofuels are… Solar power is… Geothermal power is… Wind power is… Fossil fuels are… Nuclear fuels are… Over ground cables are… Underground cables are… Are more reliable, but faults cant be fixed easily Readily available and can be transported easily, but cause pollution, acid rain and global warming Renewable, but requires a large power station to built on top of volcanic sites which can be an eyesore Renewable, but will only work high up and on windy days. cheap, and renewable, but they require a lot of valuable land to grow crops on Expensive to install and will only work on sunny days, but is rebewable Expensive to build and produce radioactive waste but don’t release any pollutant gasses Cheap but can be affected by weather Generating electricity

Biofuels are… Solar power is… Geothermal power is… Wind power is… Fossil fuels are… Nuclear fuels are… Over ground cables are… Underground cables are… Are more reliable, but faults cant be fixed easily Readily available and can be transported easily, but cause pollution, acid rain and global warming Renewable, but requires a large power station to built on top of volcanic sites which can be an eyesore Renewable, but will only work high up and on windy days. cheap, and renewable, but they require a lot of valuable land to grow crops on Expensive to install and will only work on sunny days, but is rebewable Expensive to build and produce radioactive waste but don’t release any pollutant gasses Cheap but can be affected by weather Generating electricity