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Energy uses: 1.2
Energy resources and their typical uses - a general global survey and global trends
in energy use - population increase and move away from reliance on fossil fuels
Doc Brown's Physics exam study revision notes
INDEX physics notes: Energy 1.
Comparing resources, uses, issues, trends, renewables, non-renewables
1.2A.
Energy resources and their typical uses - a general global survey and global trends
in energy use - population increase and move away from reliance on fossil fuels
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, the latest figure in 2023 is 425
ppm and rising steadily
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
Renewable energy (2) Hydroelectric power and
geothermal power,
advantages and disadvantages
Renewable energy (3) Wave power and tidal barrage power,
advantages and disadvantages
1.2B.
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.
INDEX physics notes: Energy 1.
Comparing resources, uses, issues, trends, renewables, non-renewables
Keywords, phrases and learning objectives
on energy resources
Be able to describe and discuss the use of energy resources uses
in terms of global trends in
energy, noting the rise in population producing increased energy
demands.
Be able to discuss, describe and give reasons for
the move away from reliance on non-renewable fossil
fuels and the trend to develop non-renewable energy sources.
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INDEX physics notes: Energy 1.
Comparing resources, uses, issues, trends, renewables, non-renewables
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