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ATAR Integrated Science Year 12 > Impact of Electricity Generation > Flashcards

Flashcards in Impact of Electricity Generation Deck (58)
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1

coal process 1-3

1. Coal is pulverised in to a fine power. 2. Coal is then mixed with hot air and blown into the firebox, in the boiler. The coal-air mixture provides combustion and a large amount of heat. 3. Highly purified water is pumped through pipes inside the boiler. This water turns into steam, by the heat from the combustion. This steam reaches pressure up to 625.0289 kg/cm and reaches temperatures up to 537ºC.

2

coal process 4-5

4. The high pressure in the pipes pushes against a series of blades, this results in the turbine shaft turning. The turbine shaft is connected to the generator, where magnets spin within wire coils and produce electricity. 5. After completing work and turning the turbine, steam is drawn into a large chamber. In the chamber millions of litres of cool water in pipes are used to cool the steam, converting it back into water, which can be used again in the plant.

3

gas power process

1. Air from outside, is taken in and pressurised (pressure is increased). 2. Natural Gas is added to the stream of air. This gas-air mixture combusts. 3. Combustion cause expansion in the chamber, the expansion causes a turbine to spin. The turbine is connected to a generator, inside the generator are magnets, which spin with movement of the turbine, this causes electrons to flow from one place to another, creating an electric current. 4. In some gas power stations (combined cycles), the heat energy that would typically be wasted, is used in a separate chamber to heat water, turning it to steam which spins a turbine, generating electricity.

4

how much coal power is used

Coal is used to power about 37% of the world’s electricity.

5

nuclear power station process

1. In the reactor neutrons collide with uranium atoms, causing them to split, this causes a large release of energy in the form of heat and radiation. This is known as nuclear fission. 2. As neutrons continue to collide with other uranium atoms, more heat and radiation is released. This process is known as a nuclear chain reaction. 3. This heat energy produced, is used to heat a water source, producing steam. 4. This steam is then used to power a turbine. The movement of this turbine is used to generate electricity. 5. The steam is then cooled using cold water source, this results in the steam condensing, turning back to water. The water is then returned to the original source (lake, river etc.) or reused in the nuclear power process.

6

safety measures

time distance shielding disposal

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time

The more time spent near radiation sources the greater the radiation received. Limiting exposure time, reduces the dose received. › Radiation Badges, are created for this purpose. These badges monitor the dose of radiation being received by individuals, indicating when an individual should remove themselves from exposure to the radiation, when they have exceeded a certain dose.

8

distance

The closer an individual to the source of radiation the greater radiation received. The dose of radiation significantly decreases the dose of radiation received.

9

shielding

Barriers made of substances including, lead, concrete and water provide protection from specific rays of radiation (gamma rays and x-rays). Placing a barrier/shield between radiation source, greatly reduce/eliminate the radiation dose received. › Barriers include lead aprons, and concrete walls.

10

disposal

When fuel is removed from a reactor it is usually stored in large concrete cylinders, which are placed under water for up typically 2 to 5 years. This period allows waste to cool. The used forced is then transferred and stored, and eventually moved to a place for permanent disposal.

11

exposure to radiation (8)

- Skin Burns. Radiation burns are different to normal burns, the body responds to radiation differently causes cell mutations and possible cancer. - Radiation sickness/acute radiation syndrome. › Nausea and vomiting begin within hours of exposure. › Diarrhoea, headaches and fever follow the nausea. - Mutations. These changes to the DNA. DNA determines all body functions; these mutations can result in serious complications. An example of a mutation is cancer. - Cancer (long term). - Cardiovascular Disease (long term). - Can cause change to germline DNA, which can be inherited and result in serious deformities in offspring (small head/brain size, poorly formed eyes, slow growth or sever learning difficulties). As the dose of radiation increases the risk/chance of getting cancer increases.

12

what is temperature of earth effected by

The atmospheric composition – the greenhouse gases including nitrous oxide, carbon dioxide, ozone, methane and water vapour.

13

the greenhouse gas effect

The greenhouse effect is the natural process of gases in the atmosphere trapping heat energy from the sun, without them the Earth would be too cold to support life.

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the enhanced greenhouse effect

The enhanced greenhouse gas effect is that human’s activity increasing the concentrations of the gases, trapping more of the energy warming the earth further and at a faster rate so organisms do not have time to adapt.

15

greenhouse gases

A gas in the atmosphere that absorbs infrared radiation and emits some back towards the Earth, instead of just letting it pass right through to space. include carbon dioxide, methane, nitrous oxide, water vapour.

16

carbon dioxide

› Burning fossil fuels. › Deforestation.

17

methane

› Burning fossil fuels. › Livestock. › Methane is 20% more potent (better at trapping radiation, compared to CO2).

18

nitrous oxide

› Fertilisers. › Combustion- car exhausts.

19

water vapour

› Not directly impacted on by human activity but increase in other greenhouse gases increase temperature which increases evaporation rates and water vapour.

20

draw the diagram for greenhouse gas effect

21

efficiency of coal

Average of around 33-35% efficiency rate. (Only about 35% of the usable energy in coal is converted to electricity).

22

efficiency of gas

Combined gas cycles convert up to 50% if the input gas to electricity.

23

efficiency of nuclear

More efficient than burning fossil fuels. 8000 times more efficient than oil/coal. Nuclear produces a huge amount of energy for little input.

24

cost advantages of coal

- Cheaper and more affordable than other energy sources. - Coal is abundant, therefore cheaper to source and also easy to extract. - Cheap to transport

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cost advantages of gas

- Not as expensive as other fossil fuels. - Burns cleanly, little clean-up for pollution or transportation of waste.

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cost advantages of nuclear

- Cheap production costs. - Cheaper production cost compared to oil, gas and coal. - Uranium is cheap to transport.

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cost disadvantages of coal

- Extra costs for the removal of waste products. - Greenhouse gas emissions effect environment, more money is put towards saving he environment.

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cost disadvantages of gas

- Needs to be handled carefully as it can possibly combust. - Installation of pipes and other infrastructure is expensive.

29

cost disadvantages of nuclear

- Cheap production price is overshadowed by the cost for removal/disposal of the nuclear waste. This also includes its transportation and maintenance over time. - Added cost of mining uranium. - Very expensive clean-up process if radiation is leaked. - Infrastructure is expensive.

30

base load supply of coal

Reliable, has a great ability to supply power demand as both base power and off-peak power. This supports grid system avoiding black outs