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Flashcards in Impact of Electricity Generation Deck (55)
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1

how much coal power is used worldwide

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

2

coal power stations 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.

3

coal power stations 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.

4

Gas power stations 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.

5

nuclear power stations 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.
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 need to be considered for nuclear power

time
distance
shielding
removal

7

time as a measure

The more time spent near radiation sources the greater the radiation received. Limiting exposure time, reduces the dose received.

8

distance as a measure

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 as a measure

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.

10

removal as a measure

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 high levels of radiation can cause (7)

- 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, 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).

12

as dose of radiation increases...

risk/chance of getting cancer increases.

13

what is the temperature of the earth effected by

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

14

the greenhouse 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.

15

the enhanced greenhouse gas 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.

16

what are 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.

17

examples of greenhouse gases

Carbon Dioxide
› Burning fossil fuels.
› Deforestation.
Methane
› Burning fossil fuels.
› Livestock.
Nitrous Oxide
› Fertilisers.
› Combustion- car exhausts.
Water Vapour
› Not directly impacted on by human activity but increase in other greenhouse gases increase temperature which increases evaporation rates and water vapour.

18

societal impacts of electricity generation

health impacts
decrease in recreational area
pollution of water used in consumption

19

environmental impacts of electricity generation

resource extraction disturbing natural ecosystems
production of wastes
increase in Greenhouse gas emissions

20

health impacts

- Nuclear health impacts discussed earlier.
- The smoke/ash produced by coal stations can impact those nearby with particular conditions such as asthma.

21

decrease in recreational area

- Land clearing for infrastructure for power stations, mines and waste storage, take away space for recreational activities of the community.

22

pollution of water used in consumption

- Both nuclear and fossil fuel power plants use water to generate electricity, water as a finite resource is already placed under a lot of pressure from other human activities.
- Resource extraction can cause sedimentation and eutrophication decreasing the availability of the source for possible consumption

23

resource extraction disturbing natural ecosystems

Fossil fuels and uranium must be mined or extracted from the earth. This extraction can result in;
› Deforestation.
› Extinction of species.
› Soil Erosion.
› Water Pollution.
› Desertification.

24

production of wastes

- Both coal and nuclear power plants produce waste.
- Nuclear waste was discussed earlier. It is a lengthy process that needs to be taken seriously due to the impact of any leaks of radioactive material.
- Coal, leaves behind waste, that does not serve much purpose. This waste fills land fill creating pollution.

25

increase in greenhouse gas emissions.

- Both gas and coal power stations contribute to greenhouse gas emissions of methane and carbon dioxide.
- The burning of these fossil fuels to produce electricity increases the earth’s temperature, which effects organisms breeding and nesting habits, puts food and water sources at risk. Can increase drought and flooding in some areas.

26

efficiency of coal

Average of around 37% efficiency rate.

27

efficiency of gas

Average of 33% energy conversion.

28

efficiency of nuclear

More efficient than burning fossil fuels. 8000 times more efficient than oil/coal

29

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

30

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.