of electricity The discovery Victoria s brown coal

Transcription

1 The discovery of electricity Victoria s brown coal The discovery and use of coal has been one of the major factors in helping develop our highly industrialised society. Coal made it possible to make iron and steel, power the steam engines of the industrial revolution, and today provides most of the steam for electricity generation. Most of these changes have happened in the past 200 years, but the coal which made them possible fi rst started forming between 20 and 300 million years ago. Essentially, all coals have been produced by the transformation of decaying vegetable matter by geological and chemical processes acting together over long periods of time. 1 The discovery of electricity fact sheets reviewed and updated with the assistance of STAV Publishing

2 Generally speaking, the older the coal, the better its quality. Black coal has a lower moisture content and is easier to burn than the younger brown coals. Victoria has little usable black coal, and has had to turn to the brown coal deposits in the Latrobe Valley as one of its main sources of fossil fuel. Here, the poorer quality is partly compensated for by its very thick seams close to the surface, which make it easy and comparatively cheap to dig in large volume. Today, about 75 per cent of the State s electricity generation relies on the brown power of the Gippsland fi elds. 2 Latrobe Valley brown coal has a very complicated make up with many fossilised remains mixed in with the decomposed material. The recognisable remains are mainly fossil woods (trunks, branches and stems), fossil leaves, bark, fruit, seeds, spores and pollen grains, and resin. Some of the fossils are so well preserved that scientists have been able to learn from them a lot about the early history of Australia. Some of the trees identifi ed in the coal have not grown in Victoria for millions of years. Among the trees identifi ed are Kauri, Celery Top Pine, King Billy Pine, Brown Pine, Sheoak and Banksia.

3 History of brown coal The fi rst records of the use of brown coal in Victoria date back to 1857 but the deposits were not explored in detail until the early 1900s, when Dr H Herman, the State Director of Geological Survey, began a broad survey of brown coal resources. The great Morwell Coal Mining Company did produce coal from the bank of the Latrobe River in the 1890s, and made about 2000 tonnes of briquettes. But in those days the new fuel could not compete with black coal, and the company was wound up in Other coal was mined at Lal Lal, near Ballarat, but it also could not compete with other fuels. Later investigations have shown that there are economic deposits of brown coal in Victoria at Anglesea, Bacchus Marsh and in the Latrobe Valley. The Latrobe Valley deposits are best suited to large scale mining. 3

4 Latrobe Valley coal fields Latrobe Valley brown coal is young (20 to 50 million years old) and relatively soft. From Yallourn eastwards the coal belt is practically continuous for 50 kilometres, and for much of the distance is between 8 and 16 kilometres wide. Of the proved and estimated reserves of million tonnes, some million tonnes can be won at present day costs by the open cut method. In the most favourable areas coal seams ranging in thickness from 60 to 140 metres are covered by an easily removed layer of sand and clay averaging about 15 metres deep. Boring at one point has shown the coal bed, only 27 metres below the surface, to be 250 metres thick. <Fossil fuels Activity> COAL SEAMS IN THE LATROBE VALLEY In its raw state the brown coal is a low-grade fuel comprising two-thirds water. But by using special burning techniques it can be used effi ciently in power stations near the coal fi elds. The Latrobe Valley coal fi elds produce most of Victoria s electricity, as well as about 300,000 tonnes of briquettes each year for use in homes and industry. 4

5 Production of electricity On June 24,1924, power began fl owing down transmission lines to Melbourne. Horse drawn rail trucks were fi rst used in the open cut to carry the coal to the power station bunkers. Today, giant bucket wheel and bucket chain dredgers win the coal in large quantities and it is carried by conveyor belts to the power stations. Bucket wheel dredgers up to 12 storeys high and bucket chain dredgers 28 metres long dig up to tonnes each of coal a day. Conveyors carry the coal out of the cut to bunkers at the power station. Other conveyors then take it into the power station boilers as it is required. On the way it is crushed and partly dried before being blown into the boilers as a, fi ne powder. The Latrobe Valley fi eld is one of the largest single brown coal fi elds in the world. Because the coal seams are so thick, it has been able to develop large open cuts with high capacity dredgers and conveyor systems. Brown coal boilers need three to four times as much fuel to produce the same amount of electricity as black coal boilers. This is because of the high moisture content and low fuel value of brown coal. So the boiler plants where the coal is burnt are much larger than black coal boilers, with hundreds of kilometres of water and steam tubing. The chemical and moisture content vary throughout the coal fi eld. This makes it necessary to design each boiler and operating technique differently for power stations based on different parts of the coal fi eld. 5 More information Fossil fuels < Latrobe Valley power trail <

6 Fossil Fuels Activity When the world ran out of fossil fuels Write a story or construct a series of cartoons based on the topic When the world ran out of fossil fuels 6 Your story or cartoons should have: a minimum of 5 key scientific facts or concepts about alternatives to fossil fuels a clear explanation of the scientific principles involved a maximum of 750 words for a story; or 5 annotated cartoons a list of references used. Activity written by Michaela Patel on behalf of STAV Publishing.

7 Victoria s brown coal The discovery and use of coal has been one of the major factors in helping develop our highly industrialised society. Coal made it possible to make iron and steel, power the steam engines of the industrial revolution, and today provides most of the steam for electricity generation. Most of these changes have happened in the past 200 years, but the coal which made them possible fi rst started forming between 20 and 300 million years ago. Essentially, all coals have been produced by the transformation of decaying vegetable matter by geological and chemical processes acting together over long periods of time. Generally speaking, the older the coal, the better its quality. Black coal has a lower moisture content and is easier to burn than the younger brown coals. Victoria has little usable black coal, and has had to turn to the brown coal deposits in the Latrobe Valley as one of its main sources of fossil fuel. Here, the poorer quality is partly compensated for by its very thick seams close to the surface, which make it easy and comparatively cheap to dig in large volume. Today, about 75 per cent of the State s electricity generation relies on the brown power of the Gippsland fi elds. Latrobe Valley brown coal has a very complicated make up with many fossilised remains mixed in with the decomposed material. The recognisable remains are mainly fossil woods (trunks, branches and stems), fossil leaves, bark, fruit, seeds, spores and pollen grains, and resin. Some of the fossils are so well preserved that scientists have been able to learn from them a lot about the early history of Australia. Some of the trees identifi ed in the coal have not grown in Victoria for millions of years. Among the trees identifi ed are Kauri, Celery Top Pine, King Billy Pine, Brown Pine, Sheoak and Banksia. History of brown coal The fi rst records of the use of brown coal in Victoria date back to 1857 but the deposits were not explored in detail until the early 1900s, when Dr H Herman, the State Director of Geological Survey, began a broad survey of brown coal resources. The great Morwell Coal Mining Company did produce coal from the bank of the Latrobe River in the 1890s, and made about 2000 tonnes of briquettes. But in those days the new fuel could not compete with black coal, and the company was wound up in Other coal was mined at Lal Lal, near Ballarat, but it also could not compete with other fuels. Later investigations have shown that there are economic deposits of brown coal in Victoria at Anglesea, Bacchus Marsh and in the Latrobe Valley. The Latrobe Valley deposits are best suited to large scale mining. Latrobe Valley coal fields Latrobe Valley brown coal is young (20 to 50 million years old) and relatively soft. From Yallourn eastwards the coal belt is practically continuous for 50 kilometres, and for much of the distance is between 8 and 16 kilometres wide. Of the proved and estimated reserves of million tonnes, some million tonnes can be won at present day costs by the open cut method. In the most favourable areas coal seams ranging in thickness from 60 to 140 metres are covered by an easily removed layer of sand and clay averaging about 15 metres deep. Boring at one point has shown the coal bed, only 27 metres below the surface, to be 250 metres thick. In its raw state the brown coal is a lowgrade fuel comprising two-thirds water. But by using special burning techniques it can be used effi ciently in power stations near the coal fi elds. The Latrobe Valley coal fi elds produce most of Victoria s electricity, as well as about 300,000 tonnes of briquettes each year for use in homes and industry. Production of electricity On June 24,1924, power began fl owing down transmission lines to Melbourne. Horse drawn rail trucks were fi rst used in the open cut to carry the coal to the power station bunkers. Today, giant bucket wheel and bucket chain dredgers win the coal in large quantities and it is carried by conveyor belts to the power stations. Bucket wheel dredgers up to 12 storeys high and bucket chain dredgers 28 metres long dig up to tonnes each of coal a day. Conveyors carry the coal out of the cut to bunkers at the power station. Other conveyors then take it into the power station boilers as it is required. On the way it is crushed and partly dried before being blown into the boilers as a, fi ne powder. The Latrobe Valley fi eld is one of the largest single brown coal fi elds in the world. Because the coal seams are so thick, it has been able to develop large open cuts with high capacity dredgers and conveyor systems. Brown coal boilers need three to four times as much fuel to produce the same amount of electricity as black coal boilers. This is because of the high moisture content and low fuel value of brown coal. So the boiler plants where the coal is burnt are much larger than black coal boilers, with hundreds of kilometres of water and steam tubing. The chemical and moisture content vary throughout the coal fi eld. This makes it necessary to design each boiler and operating technique differently for power stations based on different parts of the coal fi eld. More information Fossil fuels < Latrobe Valley power trail < The discovery of electricity fact sheets reviewed and updated with the assistance of STAV Publishing