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Energy uses: 1.1
Summary of energy
resources: generating
electricity methods, advantages, disadvantages
Doc Brown's GCSE level Physics exam study revision notes
INDEX physics notes: Energy 1.
Comparing resources, uses, issues, trends, renewables, non-renewables
1.1 Summary of energy
resources and methods of generating
electricity
This is also Electricity section 7.
See also
'National Grid' power supply, small scale
supplies, transformers
Know and understand that in some power stations an
energy source is used to heat water.
Energy sequences we use to generate electricity
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chemical energy store (fossil fuel) or
nuclear energy store ===> heat energy (steam) ===> kinetic energy (turbine blades)
===> electrical energy (generator)
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OR renewable energy stores:
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sunlight == solar panel ==> electrical
energy
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The figures for the UK electricity generation
for 2017 are: Natural gas 40%, coal 7%,
renewables (wind, solar, hydroelectric) 30%, nuclear 21% and 2% from
other sources. This is part of a good trend as we become less
reliable on fossil fuels.
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Appreciate that various energy sources can be used to generate the electricity we need.
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Appreciate the need to
carefully consider the advantages and disadvantages of using each energy source before
the decision to decide which
energy sources would be best to use in any particular situation.
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Know that electricity is distributed via the
National Grid.
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You are expected to use your skills, knowledge and understanding to:
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Be able to evaluate different methods of generating electricity,
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you should be able to evaluate
different methods of generating electricity given data including start-up
times, costs of electricity generation and the total cost of generating
electricity when factors such as building and decommissioning (removing
everything of an old power station) are taken into
account.
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You must also be able to consider the reliability of different
methods.
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There are other general issues
such as environmental impact - pros and cons for the local community (eg
jobs versus environmental damage, visual impact), how long will it take to
build?, at what cost versus eventual power output?, planning delays etc.
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Ideally you would want to site a
large fossil fuel/nuclear power station as near as possible to the
major/bulk users AND in the case of coal, near a coal mine, since power line
transmission involves wasted energy (see National Grid section).
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Large scale tidal and river/lake
hydroelectric schemes and geothermal power plants all need very specific
geographical locations.
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For safety reasons, nuclear
power plants are sited in remote locations, often near the coast.
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Small scale power generation
with solar cells and wind turbines can be sited anywhere, but larger wind
farms need to be in a windy area eg on low hills or out at sea.
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Knowledge of the actual values
of start-up times and why they are different is not needed, but you must
appreciate that the implications of such differences in start-up times are
important.
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Be able to evaluate ways of matching supply with demand, either by increasing supply or decreasing demand,
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you should be aware of the fact that, of
the fossil fuel power stations, gas-fired have the shortest start-up time.
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Power station generator start up
times: Nuclear >> coal fired > gas-fired
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By coincidence (or maybe not?),
this order is also paralleled by the capital costs, decommissioning costs,
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you should also be aware of the advantages of pumped storage systems in
order to meet peak demand, and as a means of storing energy for later use.
See the section on hydroelectricity.
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compare the advantages and disadvantages of overhead power lines and underground cables.
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Know and understand that the
flow of water and wind can be
used to drive turbines directly.
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 Know that
renewable energy sources used in
this way include, but are not limited to, wind, waves, tides and the falling
of water in hydroelectric schemes and all involve converting FREE kinetic
energy into electrical energy using a generator.
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None of these schemes needs
a fuel, or produces any kind of chemical pollution on the site, and all are
'green' in terms of not consuming fossil fuels ie carbon dioxide, but they
may have quite an environmental impact. All these methods can contribute to
National Grid of electricity supply.
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Know and understand that
small-scale production of
electricity may be useful in some areas and for some uses, eg
hydroelectricity in remote areas, solar cells for roadside signs, remote
telephone kiosks.
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You should know and
appreciate that using different energy
resources has different effects on the environment and these effects include:
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the release of substances into the atmosphere,
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the production of waste
materials,
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noise and visual pollution,
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the destruction of wildlife
habitats.
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Also, you should know and
understand that carbon capture and storage is a rapidly evolving technology.
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To prevent carbon dioxide building up in the atmosphere we can catch and
store it.
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Know that some of the best natural containers are old oil and gas
fields, such as those under the North Sea.
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The idea is to capture the
carbon dioxide from fossil fuel burning before it is released into the
atmosphere and pump it to some suitable storage location.
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Is it possible to feed the
carbon dioxide to algae from which to derive a biofuel?
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There are other ways to reduce
carbon dioxide, principally by reducing electricity demand, so less fossil
fuel is burned. You can reduce electricity demand in the home by insulation,
better designed and more energy efficient appliances like washing machines,
low energy light bulbs, turning off all devices/appliances not in use.
INDEX physics notes: Energy 1.
Comparing resources, uses, issues, trends, renewables, non-renewables
Keywords, phrases and learning objectives
on energy resources
Be able to compare and discuss the use of various energy resources
in methods of
generating electricity, including their advantages and disadvantages.
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INDEX physics notes: Energy 1.
Comparing resources, uses, issues, trends, renewables, non-renewables
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Non-renewable
energy sources
Renewable
energy sources