Coal Electricity Generation When it nears our homes, businesses and schools, In the case of Yallourn the material at the surface the electricity is converted to safer level of 240 of the mine, known as overburden, is removed by volts (at the distribution substation), which is used the use of Bucket Wheel Excavators or Dredgers EnergyAustralia Coal Electricity Generation Coal is a fossil fuel which is a natural substance, to power all our electrical appliances including to reveal the coal. The coal is then dug up, using Every hour at the EnergyAustralia Yallourn power and is one of the world’s most important sources televisions, game consoles, fridges, toasters bucket wheel excavators or large dozers and station, 2,200 tonnes of brown coal are used to of energy that is used to generate around 37% and washing machines. loaded on to conveyer belts which transport the boil water into superheated steam to drive the of electricity worldwide. How is coal formed? coal to the coal bunkers which provide around four turbine generators. These turbines have a 20 hours of coal storage for the power station. combined capacity of 1,480 megawatts of electricity Coal is a type of rock formed millions of years As areas of the mine are depleted of coal, the and generate approximately 10,500 gigawatt hours ago from plant and mineral materials in swampy land is rehabilitated so it can fulfil a new purpose. areas. Over time, sediments covered these materials, Rehabilitation typically includes reducing the slope forming heavy rock layers. This forced the plant of the steeper mine walls and capping over coal material to decompose into a spongy material called surfaces. Once this is done, indigenous vegetation peat. As the water and gasses were squeezed out can be introduced into the area which will generally by the heavy rock layers, above the peat was heated include plants, trees and grasses. In some cases, * How is coal converted to electricity? Coal is burnt in power stations to generate electricity. Generally, brown coal is first ground into a powder which allows it to burn more quickly. The powdered coal is burnt at a high temperature of around 1100 degrees Celsius. The heat converts into steam. per annum. This is enough to supply electricity to around 2 million homes. Useful links at great temperatures in the earth and coal began rehabilitation can also involve man made lakes. Powerworks The high-pressure steam is passed into the turbine, to form, first as brown coal (lignite) and then harder The revegetation of depleted mines can provide http://www.powerworks.com.au which is connected to a generator which is in turn black coals. The coal formed in layers called seams. a potential habitat for wildlife in the region. Brown coal is a relatively young coal at around connected to the electricity grid. World Coal Association When the steam is passed into the turbine it 30 million years old compared to black coal Coal to the Power Station http://www.coal.org causes the turbine shaft to rotate at high speeds which is 10 to 20 times older. The brown coal From the mine, the coal is carried through crushers CSIRO (the speed is usually fixed at 3000 rotations per seam at Yallourn is around 100m in depth and into the short-term boiler bunkers of each of the http://www.csiro.au minute). This energy is converted into electricity by there are other seams lower down. The brown generating units. The coal is then delivered to the the generator and passed into the electricity grid. coal is characterised by being relatively high in pulverised fuel mill to be crushed into a powdered At our Yallourn power station in the LaTrobe Valley moisture content (60 to 70%) but very low in consistency. In conjunction with the crushing, hot in Victoria, the electricity generated is passed through ash and sulphur as compared to black coal. gases drawn from the furnance. The mill, acting a transformer which converts the voltages (a unit of measure for electricity) to a level appropriate How is coal mined? for the transmission lines. The transmission line At the EnergyAustralia power station, brown coal The heat from the coal combustion is transferred transports the power to the networks where is mined in the adjacent open cut mine. Open cut into the boiler surfaces thereby generating steam EnergyAustralia Pty Ltd the voltage is lowered at a zone substation to an simply means that coal is mined at the surface, to be delivered to the turbine. appropriate level for industrial and commercial use. rather than by using underground methods. *Source: Australia Coal Association ABN 99 086 014 968 Locked Bag 14060 Melbourne VIC 8001 Energy Information Sheets as a large fan, then delivers the pulverised fuel (powdered coal) into the furnace where it ignites. A Typical Coal Fired Power Station F A J K L E D B C I G H A Conveyor D Boiler G Ash Systems J Turbine B Coal pulveriser E Precipitator C Furnace F Stack H Cooling pond I Condenser K Generator L Substation Transformer Energy Information Sheets EnergyAustralia Pty Ltd ABN 99 086 014 968 Locked Bag 14060 Melbourne VIC 8001