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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

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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!

doc b oil notes

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.

non-renewable fossil fuel coal oil gas diagram electricity power generation turbine generator transformer power lines

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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