The discovery of electricity
How power stations work
Several energy sources are used for electricity generation in Victoria. Around 97 per cent* of Victoria’s electricity is generated from brown coal. The remainder comes from natural gas, oil, water, wind and solar. In a fuel-burning power station, the heat energy of coal, oil or gas is fi rst converted to mechanical energy before it is transformed into electrical energy. The fi rst conversion is 1 carried out by means of steam. Fuel is burned in a boiler and the heat produces steam under pressure. The steam is allowed to expand through nozzles in a steam turbine. After expansion, the steam has a high speed and its mechanical energy is transferred to the turbine shaft, which is caused to rotate at high speed. The shaft fi nally turns the electro-magnet of the generator and the generator changes the mechanical energy into electrical energy.
*Source: Electricity Gas Australia 2005.
The discovery of electricity fact sheets reviewed and updated with print the assistance of STAV Publishing friendly Thermal power stations The power stations in the
Hazelwood Power Station It is then blown into the furnace. There it is mixed with air and burns at a high temperature. The boiler itself consists of a large number of tubes in which water is changed to steam by the heat of the furnace. After passing through a large steam drum, the steam is further heated in super heaters to a temperature of 550 degrees Celsius. Now the steam enters a cycle where it’s used and re-heated. The electricity is produced by turbine-driven generators. The high pressure steam drives the turbine, providing the driving force for the generator. The steam fi rst enters the high pressure end of the turbine. It’s then re-heated, so that its temperature is raised again.
STEAM DRUM
TO ELECTRICITY BOILER DISTRIBUTION COAL SYSTEM CONVEYOR
STEAM TRANSFORMER
COAL DREDGER COOLING BUNKER TURBO-GENERATOR TOWER
DUST COLLECTOR
COOLING WATER PULVERISER CONDENSER
print friendly From there it’s fed to the low pressure end of the turbine. On leaving the turbine, it fl ows to the condenser where it comes in contact with the cool water pipes within the condenser. This converts the steam back into water or condensate. The condensate is then pumped back through a series of heaters, returning once more to the boiler and ultimately to the steam drum as steam. This, then, is the constant cycle of water to steam via the boiler, turbine, condenser and steam heaters. In some instances, the cooling water within the condenser is returned to a pond or tower, where it’s cooled before being re-used. Wherever fuel is burned to provide energy, there is a release of combustion by-products into the atmosphere. For solid fuel fi red furnaces, gases and dust particles leaving the furnace enter electrostatic precipitators. This equipment traps more than 97 per cent of the dust in exhaust gases. The clean gases are then projected high into the atmosphere through a tall chimney stack. This way they are diluted to harmless amounts before returning to ground level. The solid ash waste collected is removed to an ash pond.
Gas The metropolitan power station, Newport, west of Melbourne has a natural gas-fi red boiler, with oil fi ring available in the event of a gas failure. Newport operates on basically the same principle as a brown coal power station, using steam to drive its turbine. Different types of gas stations which use a gas turbine for generation are located at Bairnsdale, Somerton and the Latrobe Valley – Jeeralang “Valley Power”. Laverton is due to be commissioned in 2006. One of the advantages of gas turbines in their ability to be started up and give maximum power in a very short time (a few hours) which is very useful to meet “peak” loads, or provide power in emergencies. However, gas turbines are more costly to run and less effi cient than brown coal stations, which take longer to respond to changes in load.
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Tunnels, canals, channels and pipelines convey the water from the storage to the turbines in the power stations. The water fl ows through a turbine which drives an electric generator usually mounted on a vertical shaft above the turbine. The power stations are situated where they can take advantage of the greatest fall of water as at the bottom of a deep and steep-sided valley or gorge or at the foot of a mountain range. Some hydro-electric stations are located primarily to operate in conjunction with irrigation and water supply schemes, so that water for electricity generation is not always available. Hydro-electric plants controlled in this way are not a substitute for steam power stations but save the burning of fuels in these stations when water for power is available. However, some are designed for both hydro-electric generation and irrigation, and “peak load” power is always available.
Solar, wind and wave power Click on these links for information about solar, wind and wave power.
print friendly Further information La Trobe Valley: history of power generation
How power stations work General information:
Newport Power Station (history):
Sustainable energy: Hydro:
Fossil fuel power:
Wind power: development
Wind power:
Wave power:
Solar power:
Hydro power:
Renewable versus non-renewable energy
print 5 friendly How power stations work
Several energy sources are used It is then blown into the furnace. There it is Wherever fuel is burned to provide energy, for electricity generation in Victoria. mixed with air and burns at a high there is a release of combustion by-products Around 97 per cent* of Victoria’s temperature. into the atmosphere. For solid fuel fi red electricity is generated from brown coal. furnaces, gases and dust particles leaving The boiler itself consists of a large number The remainder comes from natural gas, the furnace enter electrostatic precipitators. of tubes in which water is changed to steam oil, water, wind and solar. This equipment traps more than 97 per cent by the heat of the furnace. of the dust in exhaust gases. The clean In a fuel-burning power station, the After passing through a large steam drum, gases are then projected high into the heat energy of coal, oil or gas is fi rst the steam is further heated in super heaters atmosphere through a tall chimney stack. converted to mechanical energy before it to a temperature of 550 degrees Celsius. This way they are diluted to harmless is transformed into electrical energy. The amounts before returning to ground level. fi rst conversion is carried out by means Now the steam enters a cycle where it’s The solid ash waste collected is removed to of steam. used and re-heated. The electricity is produced by turbine-driven generators. The an ash pond. Fuel is burned in a boiler and the heat high pressure steam drives the turbine, produces steam under pressure. The providing the driving force for the generator. Gas steam is allowed to expand through The metropolitan power station, Newport, nozzles in a steam turbine. After The steam fi rst enters the high pressure end west of Melbourne has a natural gas-fi red expansion, the steam has a high of the turbine. It’s then re-heated, so that its boiler, with oil fi ring available in the event of speed and its mechanical energy is temperature is raised again. a gas failure. Newport operates on basically transferred to the turbine shaft, which From there it’s fed to the low pressure end the same principle as a brown coal power is caused to rotate at high speed. The of the turbine. On leaving the turbine, it station, using steam to drive its turbine. shaft fi nally turns the electro-magnet fl ows to the condenser where it comes in Different types of gas stations which use a of the generator and the generator contact with the cool water pipes within the gas turbine for generation are located at changes the mechanical energy into condenser. electrical energy. Bairnsdale, Somerton and the Latrobe Valley This converts the steam back into water – Jeeralang “Valley Power”. Laverton is due *Source: Electricity Gas Australia 2005. or condensate. The condensate is then to be commissioned in 2006. pumped back through a series of heaters, One of the advantages of gas turbines in Thermal power stations returning once more to the boiler and their ability to be started up and give The power stations in the
The discovery of electricity fact sheets reviewed and updated with the assistance of STAV Publishing