Energy
resources, uses and trends
IGCSE AQA GCSE Physics Edexcel GCSE Physics OCR GCSE
Gateway Science Physics OCR GCSE 21st Century Science Physics
Doc Brown's school physics revision notes: GCSE
physics, IGCSE physics, O level physics, ~US grades 8, 9 and 10
school science courses or equivalent for ~14-16 year old students of
physics
Energy resources and their uses - a general survey and trends
Comparing biofuels, renewables and non-renewables
(includes
Electricity section 7. methods of generating
electricity)
Sub-index for this
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(a)
Summary of energy
resources and methods of generating
electricity
(b)
Energy resources and their uses - a general survey and global trends
(c)
Comparing renewables and non-renewables
(d)
Summary of typical uses of energy - fuels, electricity
etc.
(e)
More on comparing biofuels, renewables and non-renewables
(f)
More on trends in the
use of energy store resources
(g)
Quick summary comparison of advantages and disadvantages of
energy resources
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(a)
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
chemical energy store (fossil fuel) or
nuclear energy store ===> heat energy (steam) ===> kinetic energy (turbine blades)
===> electrical energy (generator)
OR renewable energy stores:
sunlight == solar panel ==> electrical
energy
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.
-
Appreciate that various energy sources can be used to generate the electricity we need.
-
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.
-
Know that electricity is distributed via the
National Grid.
-
You are expected to use your skills, knowledge and understanding to:
-
evaluate different methods of generating electricity,
-
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.
-
You must also be able to consider the reliability of different
methods.
-
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.
-
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).
-
Large scale tidal and river/lake
hydroelectric schemes and geothermal power plants all need very specific
geographical locations.
-
For safety reasons, nuclear
power plants are sited in remote locations, often near the coast.
-
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.
-
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.
-
evaluate ways of matching supply with demand, either by increasing supply or decreasing demand,
-
you should be aware of the fact that, of
the fossil fuel power stations, gas-fired have the shortest start-up time.
-
Power station generator start up
times: Nuclear >> coal fired > gas-fired
-
By coincidence (or maybe not?),
this order is also paralleled by the capital costs, decommissioning costs,
-
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.
-
compare the advantages and disadvantages of overhead power lines and underground cables.
-
Know and understand that the
flow of water and wind can be
used to drive turbines directly.
-
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.
-
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.
-
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.
-
You should know and
appreciate that using different energy
resources has different effects on the environment and these effects include:
-
the release of substances into the atmosphere,
-
the production of waste
materials,
-
noise and visual pollution,
-
the destruction of wildlife
habitats.
-
Also, you should know and
understand that carbon capture and storage is a rapidly evolving technology.
-
To prevent carbon dioxide building up in the atmosphere we can catch and
store it.
-
Know that some of the best natural containers are old oil and gas
fields, such as those under the North Sea.
-
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.
-
Is it possible to feed the
carbon dioxide to algae from which to derive a biofuel?
-
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.
|
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(b)
Energy resources and their uses - a general survey and trends
Energy use
and global trends

The first thing to point out is the
exponential rise in the world's human population AND the
corresponding exponential demand and use of energy - the graphs are
rather s good match!
The rise in energy demand is due to two
reasons:
(i) Increase in population.
(ii) Under-developed countries are
becoming increasingly developed, particularly as regards technology and
consumer goods - so an ever increasing demand for electricity.
The economies of China and India are
growing at an enormous rate and they still rely a lot on fossil fuelled
power stations.
Both points (i) and (ii) are
illustrated by the three graphs above.
The two graphs below show the use and
trends of various energy resources, coal, oil, natural gas, nuclear and
renewables.
The units are not particularly
important, but the trends are very important.
World energy
consumption 1965-2015
Actual +
predicted energy trends 2015-2040
The graph above, follows on from the one
above, by moving from actual world energy consumption to from 1990 to 2015
to the predicted energy demands to the year 2040.
All the trends are upward except for
coal, but in terms of fossil fuel burning, the switch is often from coal o
natural gas - this reduces pollution as methane burns more cleanly than
coal, BUT, it is still contributing to rising carbon dioxide levels!
In
2018 CO2 level reached 408 ppm
See my GCSE chemistry revision notes
on
Levels of CO2 in atmospheres, global warming, climate change
and
reducing our carbon footprint from fossil fuel burning
It might seems surprising but most of our
available energy resources, at some point rely on the energy of the Sun.
This includes fossil fuels (coal, oil,
gas, peat), biofuels, wind, wave, hydroelectric and direct solar radiation
energy.
(Can you deduce the Sun connection in
each case?)
A much smaller % of our energy comes from
other resources such as geothermal energy (hot rocks or steam), tidal energy
(thanks to the Moon) and nuclear energy.
All of these energy sources have both
advantages and disadvantages.
Fossil fuels have a high energy
concentration of chemical energy - but have climate change and pollution
issues.
The use of fossil fuels has the
greatest environmental impact:
- causing global warming
and its consequences e.g. melting ice, rising sea levels, weather
patter changes etc.
- polluting acidic gases like
sulfur dioxide that cause acid rain that damages plant life
ill-health in us.
Fossil fuels are more concentrated than
biofuels from plants and animals, so a greater mass is needed to release the
same amount of chemical energy.
Renewable energy resources should be our
preference, but they are not always reliable e.g. wind turbines and solar
panels.
Wind turbines and solar panel energy
outputs are dependent on the weather and no sunlight at night.
They cannot supply energy (converted
to electrical energy) all the time.
The methods, advantages and
disadvantages are discussed in detail on
Renewable energy (1) Wind power and
solar power, advantages and disadvantages gcse physics notes
Renewable energy (2) Hydroelectric power and
geothermal power,
advantages and disadvantages
Renewable energy (3) Wave power and tidal barrage power,
advantages and disadvantages
gcse physics
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sub-index
(c)
Comparing renewables and non-renewables
INTRODUCTION
Generally speaking the world-wide demand for
energy, in particular, electrical energy is continually increasing.
This is due to the population increasing and
increasing electricity demands from the ever increasing technology in our homes
e.g. computers - often left on all day!
We do need to use as far as is practicable
sustainable e.g. renewable energy resources we can use long-term, without
running out, and are constantly replenished without harm to the environment.
Its very much in the hands of governments to
promote sustainable and renewable energy resources including sponsoring research
into energy technology - all of which takes time and money!
For any particular use of an energy resource
you have to weigh up the benefits versus the drawbacks and risks.
Which energy resources are readily
available?
What is their cost and reliability?
What is their impact on the environment?
What employment will a power generation
plant bring to a community?
Limits to the use of fossil fuels and global warming are critical problems for
this century.
Physicists
and engineers are working hard to identify ways to reduce our energy usage.
Most energy resources are used to generate
electricity and include both renewables like wind/solar power and, at the
moment, and historically, mainly fossil fuels like gas, oil and coal.
The second biggest use of energy resources is
powering transport systems and heating buildings - domestic or industrial.
Finite
non-renewable energy resources
- fossil fuels (coal, oil, natural gas, peat) and
nuclear materials
Fossil Fuels
The fossil fuel energy resources coal, oil
and gas are non-renewable and will all run out one day in the future.
It has taken millions of years of years to form
fossil fuels from once living materials but we are consuming them at a vast rate
and contributing to global warming.
Energy store changes for fossil
fuel power station:
chemical potential energy store
(in fossil fuel)
==> thermal energy store of steam
(thermal energy store transfer from hot gases of furnace to water)
==> kinetic energy store of
turbine (mechanical energy transfer)
==> kinetic energy store
of generator (mechanical energy transfer)
==> electrical energy
output (to power line system)
Burning fossil fuels damages the environment
but we have become very dependant on them for our energy needs.
There will be plenty of fossil fuels
for hundreds of years, but the rate at which we burn them, far exceeds
the long geological time needed to form them!
Therefore we need other energy
sources in the long-term anyway, AND, minimising the impact of these
'new' renewable sources on our environment - the 'biosphere'!
Another problem in reducing our
'carbon footprint' is the large quantities of fossil fuels we use to
heat our homes (in the UK).
Four out of five homes are heated
by natural gas and many other homes will use kerosene central
heating oil. Its going to be difficult to replace this situation
with other energy resources.
Gas and oil from the North Sea
fields is running out and we have to import gas from Norway.
BUT, the cost of renewable energy is
falling all the time.
Nuclear fuels like uranium and plutonium are also finite resources and
uranium ores will all be exploited in the future - assuming nuclear power
develops on a large scale.
Energy store changes for nuclear
power station:
nuclear
potential energy store (in uranium or
plutonium fuel rods)
==> thermal energy store of steam
(thermal energy store transfer from hot gases of furnace to water)
==> kinetic energy store of
turbine (mechanical energy transfer)
==> kinetic energy store
of generator (mechanical energy transfer)
==> electrical energy
output (to power line system)
Nuclear power stations take a long
time to build, but fossil fuel power stations are much simple and faster
to build.
There is also the VERY costly problem
of dealing with dangerous radioactive nuclear waste and the safe
dismantling (decommissioning) of a nuclear reactor.
With nuclear power stations there is
always the risk of a major catastrophe, the latest being the Fukushima
nuclear power station in Japan in 2011. The accident was initiated
primarily by the tsunami following the Tōhoku earthquake, but it
demonstrated the vulnerability of such power plants to natural
disasters. An earthquake could have been just as easily been the cause.
These non-renewable energy sources are
reliable, particularly for large demands of electricity.
There are plenty of fossil fuel
resources to meet current energy demands.
Such power plants can respond quickly
to changes in demand, from peak time demands, to rapidly growing
countries like India and China with their huge populations of consumers
and resulting energy demands.
However, there is a big cost to the
environment in terms of pollution and 'greenhouse' warming of our
planet. Acid rain, global warming, oil spillages, ugly open cast coal
mines can all be minimised if not eliminated all together.
For more on pollution see ...
Fossil fuel air pollution -
incomplete combustion, carbon monoxide & soot particulates
Fossil fuel air pollution - effects of sulfur oxides
and nitrogen oxides
Pollution, Accidents
and Economic Aspects of the Petrochemical Industry
and
Greenhouse
effect, global warming, climate change,
carbon footprint
Renewable
energy resources
Renewable energy resources rely on sunlight, wind, wave power, hydro power, biofuel, tidal
power and geothermal - they are not perfect, but renewable sources of energy
usually do less harm to the environment.
Renewable resources, theoretically,
will never run out (infinite) because the energy is renewed as it is
being used e.g. the wind blows frequently, tides and waves are always on the
move.
Renewables include solar power (direct sunlight), wind, hydro-electricity,
water waves, tidal movement (tides), geothermal energy and biofuels.
These have
several advantages over non-renewables e.g. infinite - shouldn't run out, less
damaging to the environment.
However, there are some disadvantages e.g. some are
not suitable for large scale power production AND they can be unreliable e.g.
wind speed and intensity of sunlight can be very variable.
For more details see
Renewable energy (1) Wind power and
solar power, advantages and disadvantages (gcse physics notes)
Renewable energy (2) Hydroelectric power and
geothermal power,
advantages and disadvantages
(gcse physics)
Renewable energy (3) Wave power and tidal barrage power,
advantages and disadvantages
(gcse physics notes)
See also
Biofuels & alternative fuels,
hydrogen, biogas, biodiesel (gcse chemistry revision notes)
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sub-index
(d)
Summary of typical USES OF ENERGY
Energy for Transport
Non-renewable fuels like petrol, diesel or heavy fuel oil are all
derived from the fossil fuel oil and are burned directly in internal combustion
engines e.g. in cars, lorries, diesel locomotives, ships etc.
Coal was once used
extensively to fire steam locomotives, but these have completely replaced by
diesel and electric traction in most countries.
Although
electric traction is 'greener', much of the electricity used in trains or cars
is still generated from burning coal or oil. It would be much better if the
electricity was all produced from renewable energy sources.
However, it is now possible to make
renewable
biofuels that can be used
directly in motor vehicles or using a mixture of biofuel and petrol, though only
the biofuel component is renewable.
Express mainline trains and local
electric trams is the
direction we should be heading.
Energy for heating
and lighting
Historically most homes and factories would
be heated from non-renewable energy sources like coal and some domestic heating from wood.
Many homes in Europe are
now
centrally heated from natural gas or oil (e.g. the UK uses gas directly from the North Sea gas
fields or piped gas from Norway).
The gas (mainly methane, CH4) is
burned in open fires or boilers to make hot water for pumping round the house,
office or factory in central heating system. Oil is burned in special boilers -
the most efficient being the more modern condensing types which are more
efficient - higher % of input energy converted to useful thermal energy
to heat your home.
You can use solar panels to heat up
water - pipes with a dark matt surface can be used to absorb the Sun's
infrared radiation (thermal radiation) increasing the thermal energy
store of the water. It can be piped to a hot water storage tank or
through radiators in the house.
Wood stoves are growing in popularity and
wood can be considered renewable - but the smoke is quite polluting!
Electric heaters are obviously cleaner for
cooking and heating and night storage heaters offer efficiency for the consumer,
but, its still a matter of how the electricity is generated, still mainly from
non-renewables sources BUT increasingly less so.
Storage heaters are good by
using cheaper off-peak electricity, but unless the electricity comes from
non-renewable sources, its only a partial answer.
Solar water heaters capture sunlight energy
(infrared radiation) directly to heat up water that can be pumped to a storage
tank or radiators.
A geothermal energy source uses either hot
water pumped from deep underground to the surface OR using a heat pump system
which is rather like a refrigerator working in reverse.
Electricity is needed for heating and
lighting in homes, shops and many work premises.
Electrical energy for industry
Huge amounts of (mainly) electrical
energy are needed to power factory production lines and industrial chemical plants.
Very little can be manufactured without a
supply of electrical energy to run machines and provide electric lighting
for all types of industry.
Most industrial usage of electricity is
derived from large scale power line distribution - pylons on the skyline!
In the UK it is referred to as the
National Grid System
See
The 'National Grid' power supply, environmental
issues, use of transformers
gcse
physics revision notes
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and sub-index
(e) More on comparing biofuels, renewables and non-renewables
ENERGY FLOW:
chemical/nuclear
energy (fuel) => heat energy (steam) => kinetic energy (turbine blades)
=> electrical energy (generator)
Non-renewable
energy resources
The
non-renewable fossil fuels (coal, oil and gas) which are burned to heat water or air.
Fossil fuels do provide a cost
effective energy resource that can readily produce large quantities of
thermal energy - most of which is converted into electrical energy for
general home and industry use, fuels for domestic use in the home and
road and rail transport.
The cost of building fossil fuel
power stations is quite high, BUT they can be built relatively
quickly, fuel is relatively cheap and running costs are relatively
low.
Fossil fuel power plants are very
reliable and can respond to periods of high electricity demand -
they are rarely short of stocks of oil, natural gas or coal - but
these may run out many decades in the future.
The burning of fossil fuels leads to all sorts of
pollution and environmental impact
issues.
The carbon dioxide produced by combustion is a
'greenhouse gas' implicated in global warming and climate change.
See
Greenhouse
effect, global warming, climate change,
carbon footprint from fossil fuel burning
In the
smoke are acidic gases like sulfur dioxide and nitrogen oxides which are
harmful to our health as air pollutants, and, by forming 'acid rain' wreak
havoc with ecosystems (particularly aquatic ones and trees) and cause extra
corrosion of stone and metal structures.
It is possible to remove most of
the sulfur from oil hydrocarbons before their use, and smoke from power
stations can be treated with an alkali to remove acidic gases.
See
Fossil fuel air pollution - effects of sulfur oxides
and nitrogen oxides
There are
other environmental issues eg the 'high price' dangers of coal mining, ugly
open-cast coal mines, oil pipelines/tankers and oil spillage effects on
wildlife.
See
Pollution, Accidents
and Economic Aspects of the Petrochemical Industry
In the UK, old coal/oil fired
power stations are being replaced with cleaner less polluting gas fired
power stations which have faster start up times - much easier to respond to
higher/lower power demands.
Non-renewable fossil fuel power
stations do provide a stable and reliable electricity supply, unlike some
renewable energy resources which are distinctly unreliable eg wind power and
solar power which depend on the weather.

The
non-renewable nuclear fuels uranium and plutonium provide energy from nuclear fission
(splitting atomic nuclei).
In principle and general design, a
nuclear power station is similar to a fossil fuel power station.
However, the initial source of the
energy store is nuclear energy, not chemical potential energy.
Inside a nuclear reaction, uranium or
plutonium atoms undergo fission to release nuclear energy.
See
Nuclear Fission Reactions, nuclear power
as an energy resource
The thermal energy generated from the
nuclear energy store is used to heat
water or carbon dioxide gas, either way, the hot fluid is used to make steam
via a heat exchanger for safety reasons to drive turbines and generators.
Good points
Nuclear power plants do not emit
greenhouse or harmful polluting gases into the atmosphere.
They, in most cases, reliable
sources of 'bulk' electricity production.
There is enough nuclear fuel
around to meet current nuclear power station demands - but building
new nuclear power plants is controversial in some countries e.g.
Iran, for fear of more countries developing nuclear weapons.
There are unfortunately some
serious issues with nuclear power.
Environmental issues include how do we store, and where do we put,
dangerous
radioactive waste from nuclear power stations?
Some waste is highly
radioactive for a short time, but other waste is still radioactive for
thousands of years - this is a really big problem.
Disasters such as the
Chernobyl nuclear power plant explosion in Russia have long term effects
on people and the local flora (plants) and fauna (animals) - the local
population in the nearest town and villages had to be relocated to safe
areas.
Nuclear power
stations are very expensive and may take over a decade to build and involve the most complicated
technology of any means of power production.
Safety standards must be
exceptionally high and very costly.
The availability of uranium ores,
and plutonium made in nuclear reactors, is quite limited (finite)
and the production of suitable nuclear fuel rods is very expensive.
As well as costly to build, they
are very expensive to decommission, e.g. the central core of a
disused nuclear reactor is full of radioactive material and much of
the surrounding structure will also be contaminated with harmful
radioisotopes.
See
Properties of radioactive
nuclear emission & symbols - dangers of radioactive emissions
Fossil and nuclear fuelled power
stations are reliable and there is plenty of coal, oil, natural gas,
uranium and plutonium to power them.
They are also capable of responding to
high demand situations.
Its particularly easy to increase the amount of
fossil fuel burning to make more steam to drive the generators.
This is one
of the main reasons why changing to renewable energy stores will not happen
quickly. Fossil fuels are a finite resource and would run out in the
long-run, but there still huge deposits available of coal, oil an natural
gas.
The cost to extract fossil fuels and
build power stations is relatively low, but nuclear power plants are VERY
costly to build and technically much more demanding to produce a safe
operation.
Nuclear power plants are also very costly to
decommission at the
end of their useful life - you have to deal with a lot of radioactive waste
from the reactor core and surrounding construction materials - its costing
billions of pounds in the UK to clean up the oldest nuclear power
stations.
Renewable Biofuels
Renewable biofuels that can be burned to heat water
to make steam to drive a turbine and generator.
The basic idea is to have an
alternative combustible material instead of coal, oil or natural gas.
Bio-fuels from bio-mass are used to
power electricity generator or motor vehicles.
BUT, not every example is large
scale, on decaying, animal dung generates methane gas which on burning
can be used for cooking or very small scale electricity generation.
Biofuels are a renewable energy stores
made from plant materials or animal waste.
They can be gases, liquids or solids and
all can be burned to create steam to drive turbines and electricity
generators.
Biomass, like woodchips, can be burnt on
a large scale to make steam to drive turbines and generators to produce
electricity.
Energy store changes for biomass
power station:
chemical potential energy store
(in woodchip fuel)
==> thermal energy store of steam
(thermal energy store transfer from hot gases of furnace to water)
==> kinetic energy store of
turbine (mechanical energy transfer)
==> kinetic energy store
of generator (mechanical energy transfer)
==> electrical energy
output (to power line system)
Biofuels are renewable
energy sources and come in a variety of forms eg woodchips (trees or waste
from timber products), alcohol (ethanol
from fermenting sugar cane), biodiesel (from vegetable oil) and
biogas (methane from anaerobic digestion of sewage waste) and are all
derived from plant materials eg crops or bacterial digestion/decay of waste
organic material.
They are 'reasonably' reliable through
the yearly (or more) growing seasons and crops take a short time to grow,
BUT, they cannot respond quickly to high demand without a huge pre-arranged
store of fuel - dependant on how much crop is grown, harvested and processed
- not quite as fast as 'harvesting' fossil fuels from oil wells or coal
mines!
Bio-fuels when first produced are
somewhat 'impure' are quite costly to refine into quality fuels.
Reducing our carbon footprint or just
maintaining a sort of 'neutrality' maybe?
The theoretical 'carbon neutral' idea behind using
biofuels is that the carbon dioxide released on burning is re-absorbed by
plants and utilised in photosynthesis to create the next fuel crop.
In other words, you try to match the
rate of crowing a biofuel crop, with the rate you burn it as a fuel.
Issues and criticisms of renewable
biomass fuel production
But,
even though this sounds fine in principle, there are still environmental
issues eg in Brazil and other countries, huge areas of ecological valuable
natural rain forest (loss of plant and animal species rich habitats) are being cut down to grow
crops for biofuels.
Also, the cost of refining biofuels is very
high - technology and energy costs - renewable rarely means 'cheap'.
AND you are still producing carbon
dioxide to contribute to global warming - no good, especially if we are
burning biomass at faster rate than it grows back!
There is also 'cash crop' criticism of
biofuel production because of water and land demands limiting space for food
production - often affecting poorer countries.
There is a lack of farmland for
growing suitable biofuel crops.
Unfortunately, one solution, in some countries,
is large areas
of indigenous forest are being cleared in order to grow plant material for
biofuels. This leads to loss of rich wildlife habitats affecting many
species in their ecosystems.
Also, clearing vegetation in this way, releases (i) methane
and (ii) carbon dioxide adding to the emissions from burning fossil fuels
(ii) and from cattle (i).
The animals that create dung
biomass, also produce methane gas, a powerful greenhouse gas, whose,
albeit minute, concentration is steadily rising - in fact large
tracts of forest are being cut down in favour of rearing huge herds
of beef cattle.
For more see ...
Biofuels & alternative fuels,
hydrogen, biogas, biodiesel (GCSE chemistry revision notes)
Other notes on renewable energy resources
These do not run out, the energy store
is being constantly replenished - renewed!, but there both
advantages and disadvantages to their use. For detailed discussions read
the following pages ...
Renewable energy (1) Wind power and
solar power
Renewable energy (2) Hydroelectric power and
geothermal power
Renewable energy (3) Wave power and tidal power
Biofuels & alternative fuels,
hydrogen, biogas, biodiesel
You can't say renewable energy stores do
no harm to the environment, but they are less damaging than non-renewable
energy resources such as burning fossil fuels.
Two major problems that can beset some
non-renewable energy stores is there inability to cope with high demand
situations and unreliability.
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(f) More on trends in the
use of energy store resources
The industrial revolution in Europe was powered by fossil
fuels, mainly coal until the mid-20th century.
In the 20th century, and into the 21st century, populations
have increased and the demands for electricity are ever increasing in our
'consumer' societies.
However, with increased home insulation and more efficient
electrical appliances, demand has levelled off in the UK, and may actually
fall in the future.
Apparently UK demand for electricity
has fallen by 9% from 2011 to 2017.
A slowing economy, mild weather and energy-efficient appliances are
among possible reasons for decline
The move away
from fossil fuels
Much of electricity generation in the UK was based on
fossil fuels (oil and natural gas), but not anymore.
The figures for electricity
generation in the UK for 2017: 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.
You should also appreciate that fossil fuels from oil
and gas power most road vehicles e.g. petrol and diesel and be burn
kerosene in central heating system boilers.
BUT, renewable energy resources can be used to fulfil
these energy needs too.
Biofuels can power vehicles, different kinds of
solar panels can heat water for domestic use or heat the house or
produce electricity - which can be used directly or fed into the
National Grid system.
Overall in countries such as the UK
there is an encouraging trend towards a greater use of renewable energy
resource, particularly from non-polluting wind turbines.
There is a small upward trend in
nuclear power, but nuclear power stations are not growing in popularity
due to:
(i) Huge capital cost and takes
many years to build.
(ii) They create highly
radioactive nuclear waste that can remain dangerous for thousands of
years.
(iii) Danger of a major accident
releasing radioactive materials into the environment leading to
long-term contamination.
See also
Nuclear Fission Reactions, nuclear power
as an energy resource - 'pros and cons' discussed
Reasons for the
increasing use of renewable energy sources
The increasing use of renewable energy resources is
driven by several factors ...
The highly polluting effects of burning fossil
fuels on people and the environment
See Fossil fuel air pollution -
incomplete combustion, carbon monoxide & soot particulates
and Fossil fuel air pollution - effects of sulfur oxides
and nitrogen oxides
Climate change caused by increased levels of
CO2 in the atmosphere - global warming.
See
Greenhouse
effect, global warming, climate change,
carbon footprint
People power - many
people, either as individuals, or members of organisations like
'Friends of the Earth' believe that use of renewables is better for
our planet - and environmental science agrees with this view.
Governments of countries:
This has put pressure on governments to introduce strategies
and targets to reduce our impact on the 'biosphere' - we live in
that narrow 'delicate' band on the Earth's surface!
Governments must weigh up
ethical, social and economic issues when deciding on their
energy policy - they must consider the well-being of future
generations.
Resources should be truly
renewable like wind power, solar and hydro power generation.
How to power generation
plants affect people as well as providing much needed jobs.
The best 'green' technology
with the smallest 'carbon footprint' may not be the cheapest -
though the more they are developed, the cheaper it becomes.
Energy providers
are being encouraged, often with financial grants, to build plants
powered by renewable energy resources.
They are responding to public
pressure demanding cleaner, less-polluting electricity production
and help reduce the effects of climate change.
Road vehicle manufacturers are
responding by doing increasing research on electric cars.
Some
commercial electric cars are available (but NOT cheap!) and city
commuter routes are using electric buses.
Hybrid cars have also been
developed that are powered by both fossil fuel petrol and electricity
(hopefully from a renewable source) - a useful
intermediate strategy, but they are very expensive to buy.
As a regular user,
compliments to York city 'Park and Ride' scheme which uses some
(if not all?) electric buses.
BUT, the electricity needs to
come from a non-polluting, non-climate changing source!
What inhibits an
even greater increase in renewables? ...
... despite all the scientific
evidence concerning the damage to our environment from using
non-renewable energy resources and the advantages of using renewable
sources of energy ...
Technological change and time factors
We are hardly ignorant of the
effects of air pollution and global warming, but things don't change
fast!
Although we have made amazing technological advances
very rapidly, it takes time to translate this into mass use of
cleaner technologies using renewables.
We need to improve the
reliability of renewable power sources.
e.g. car makers have developed electric cars and
hybrid vehicles that combine the use of petrol and electricity.
Although their popularity is increasing, they are
more costly than conventional petrol/diesel cars.
Research and development is ongoing, but is costly
and takes time and so dependable non-renewable energy resources will
be used for some time.
In fact there is a case that some
non-renewable power stations should be retained as an emergency
backup to the bulk demand of electricity.
Investment and cost factors
To develop the technology and build new renewable energy power plants is costly
and not initially profitable, since fossil fuels are still more cost
effective to meet our huge electricity demands.
Somebody has to pay to switch to
renewable energy sources e.g. paying more through our electricity
bills.
Government taxes can be used to
provide initial subsidy grants, these can be relaxed as the
renewable power industry grows larger and more efficient. Should we
be forced to go 'renewable' as much as possible? BUT paying more on
our electricity or tax bills is NOT very popular, and yet it clashes
with most peoples belief that we should look after our environment -
we are a very enigmatic species!
Adapting business to be 'greener'
has its own extra costs and not all companies can afford all the
changes desirable, but governments use carbon credits and grants to
try to offset the extra investment needed.
Lack of public support, but
decreasing fortunately
People object to industries on their doorstep e.g.
wind farms can meet strong local opposition.
Making personal changes in life-style do not come
easily to many of us and they might be more expensive options.
At the moment, the cost of renewable electricity is
higher than that generated from fossil fuels - are you prepared to
pay more for YOUR environment?
As mentioned already, hybrid cars are more costly,
as are solar panels - but pay back time is not unreasonable,
including reducing energy requirements in the home ...
See
More on methods of reducing heat transfer eg in a house
- payback time
and
Conservation of energy,
energy transfers, efficiency - calculations
Lack of reliability compared to fossil fuels
Fossil fuel non-renewable power
still provide the most reliable power sources, and so,
unfortunately still needed.
It cannot be denied that the sun doesn't always
shine to give a high light intensity for solar panels and the wind
doesn't always blow strong enough to turn the turbine blades.
This situation could be helped if there was a
cheaper way to store electrical energy for high peak demands.
At the moment, and I would think always, we must
rely on a variety of sources and hopefully at any given time, enough
electrical energy is produced to meet demand.
TOP OF PAGE and
sub-index
(g)
Quick summary
comparison of advantages and disadvantages of energy resources
(mainly for
electricity production)
Summarises many of the energy resource uses
described e.g.
Stage 1 includes fossil fuels, wind, tidal,
geothermal, biomass, sunlight, nuclear, hydroelectric.
Stage 2 is often kinetic energy e.g. from very hot
moving steam, or cold water/wind flow.
Stage 3 is often a turbine driven by steam of wind.
Stage 4 is usually an electrical generator.
ENERGY RESOURCE for heat or electricity |
Examples of
ADVANTAGES |
Examples of
DISADVANTAGES |
COAL from the remains of buried and decayed plant remains |
relatively cheap, suitable for big power big stations |
very polluting from smog and acid rain, non-renewable fossil fuel (115 years left?), carbon dioxide produced |
BIOMASS from plant growth e.g. oils, sugar, wood or from animal dung |
renewable from plant and animal resources, can use waste material, less demand on non-renewable resources |
pollution can be high but does recycle carbon dioxide, no good for big power stations |
WIND,
the heat from Sun warms air, causes movement |
renewable, no fuel costs, little pollution, less demand on non-renewable sources, no carbon dioxide produced |
unreliable due to variable wind speed, no good large scale |
SUNLIGHT infrared radiation
for heat |
renewable, no fuel costs, little pollution, less demand on non-renewable resources, no carbon dioxide produced |
unreliable due to variable sunlight intensity |
ENERGY RESOURCE for heat or electricity |
Examples of ADVANTAGES |
Examples of
DISADVANTAGES |
NATURAL GAS
from the remains of buried and decayed marine organisms |
reasonably cheap for medium to large scale power stations, quick start up, efficient, convenient to pipe |
medium
pollution, carbon dioxide adds to global warming, non-renewable
(90 years left?) |
SUNLIGHT for
electricity directly using visible light sensitive solar
cells |
renewable, no fuel costs, no pollution, less demand on non-renewable resources, good for remote locations |
unreliable, no good for large scale power |
NUCLEAR power from unstable atoms disintegrating |
suitable for large scale power stations, no carbon dioxide to add to global warming |
toxic
radioactive waste, accidents potentially very serious, very
costly to build and dismantle, non-renewable |
HYDROELECTRIC power from rainwater stored behind dam |
renewable, no fuel costs, no pollution, no demand on non-renewable resources, fast start up and increase power, no carbon dioxide produced |
very
costly to build, disruption or removal of wildlife habitat or
farmland, limited suitable valley locations |
ENERGY RESOURCE for heat or electricity |
Examples of
ADVANTAGES |
Examples of
DISADVANTAGES |
WAVE POWER from the up-down movement due to wind |
renewable, no fuel costs, no pollution, no demand on non-renewable resources |
unreliable, storm damage |
CRUDE OIL from the remains of buried and decayed marine
organisms | lots of it at the moment, relatively cheap, ok for big power big stations, easy to pipe around |
polluting from smog and acid rain, non-renewable fossil fuel (80 years left?), adds to global warming |
TIDAL BARRAGE from the mass movement of water due to gravity pull of the moon |
renewable, no fuel costs, little pollution, less demand on non-renewable resources, no carbon dioxide produced |
very costly to build, disruption of wildlife habitat, limited suitable estuary locations, cannot generate power when tides are turning (about 10 useful hours?) |
GEOTHERMAL from hot rocks underground in active/recent volcanic regions |
renewable energy resource, no fuel costs, little pollution, no carbon dioxide |
limited suitable locations |
TOP OF PAGE and
sub-index
Energy resources, and
transfers, work done and
electrical power supply revision notes index
Types of energy & stores - examples compared/explained, calculations of
mechanical work done and power
Chemical *
Elastic
potential energy *
Electrical
& electrostatic
*
Gravitational potential
energy
Kinetic
energy store *
Nuclear
energy store *
Thermal
energy stores *
Light energy *
Sound energy
Conservation of energy,
energy transfers-conversions, efficiency - calculations and
Sankey diagrams gcse physics
Energy resources: uses, general survey & trends,
comparing renewables, non-renewables, generating electricity
Renewable energy (1) Wind power and
solar power, advantages and disadvantages gcse physics revision
notes
Renewable energy (2) Hydroelectric power and
geothermal power,
advantages and disadvantages
gcse physics
Renewable energy (3) Wave power and tidal barrage power,
advantages and disadvantages
gcse physics
See also
Renewable energy - biofuels & alternative fuels,
hydrogen, biogas, biodiesel gcse chemistry notes
Greenhouse
effect, global warming, climate change,
carbon footprint from fossil fuel burning gcse chemistry
The absorption and emission of radiation by
materials - temperature & surface factors including global warming
The Usefulness of Electricity gcse
physics electricity revision notes
and
The 'National Grid' power supply, mention of small
scale supplies, transformers gcse
physics notes
IGCSE physics revision
notes on energy resources uses KS4 physics Science notes on energy
resources uses GCSE physics guide
notes on energy resources uses for schools colleges academies science physics course tutors images
pictures diagrams for energy resources uses science physics revision notes on
energy resources uses for revising physics modules physics topics notes to help on understanding of
energy resources uses university courses in technical science
careers in physics jobs in the industry
technical laboratory assistant
apprenticeships technical internships in engineering physics USA US grade 8 grade 9 grade10
physics AQA
physics science GCSE
notes on energy resources uses Edexcel GCSE physics science notes on
energy resources uses for OCR 21st century
physics science OCR GCSE Gateway physics science
notes on energy resources uses WJEC gcse science CCEA/CEA gcse
science O level physics notes on energy resources uses IGCSE physics revision
notes on comparing biofuels renewables non-renewables KS4 physics Science notes on
comparing biofuels renewables non-renewables GCSE physics guide
notes on comparing biofuels renewables non-renewables for schools colleges academies science physics course tutors images
pictures diagrams for comparing biofuels renewables non-renewables science physics revision notes on
comparing biofuels renewables non-renewables for revising physics modules physics topics notes to help on understanding of
comparing biofuels renewables non-renewables university courses in technical science
careers in physics jobs in the industry
technical laboratory assistant
apprenticeships technical internships in engineering physics USA US grade 8 grade 9 grade10
physics AQA
physics science GCSE
notes on comparing biofuels renewables non-renewables Edexcel GCSE physics science notes on
comparing biofuels renewables non-renewables for OCR 21st century
physics science OCR GCSE Gateway physics science
notes on comparing biofuels renewables non-renewables WJEC gcse
science CCEA/CEA gcse science O level physics notes on comparing
biofuels renewables non-renewables
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