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GCSE Physics revision notes: Comparing energy resources, uses and trends

World energy consumption by energy source resource oil petroleum gas coal renewables nuclear gcse physics uses of energy transport mainline express electric trains

Energy resources, uses and trends

Energy resources and their uses - a general survey and trends

Comparing biofuels, renewables and non-renewables

(includes Electricity section 7. methods of generating electricity)

Doc Brown's Physics Revision Notes Suitable for GCSE/IGCSE Physics/Science courses or their equivalent

Sub-index for this page

Summary of energy resources and methods of generating electricity

Energy resources and their uses - a general survey and global trends

Comparing renewables and non-renewables

Summary of typical uses of energy - fuels, electricity etc.

More on comparing biofuels, renewables and non-renewables

More on trends in the use of energy store resources



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.

  • Know that the steam produced drives a turbine that is coupled to an electrical generator.

  • 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.

  • Energy resources (more detailed notes on other pages):

    • Non-renewable energy sources

      • These energy resources are finite and will run out eventually, there are major associated environmental issues BUT at the moment, most of our useful energy is derived from them. These are historically, and to the present day, the major energy sources for large power stations - but the use of fossil fuels is steadily decreasing.

      • e.g. Coal (mainly carbon), crude oil (certain hydrocarbon fractions), natural gas (mainly methane) and nuclear fuels (based on the metals uranium and plutonium).

    • Renewable energy sources

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 understand that while small-scale production can be locally useful because it is sometimes uneconomic to connect such generation to the National Grid.

  • 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?

        • I do know that carbon dioxide from a fermentation process is fed into greenhouses to promote growth of crops like tomatoes! Can we do it on a bigger scale?

    • 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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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!

doc b oil notes 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.

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 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

 

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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.

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

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.

gcse physics diagram of nuclear power station electricity generation non-renewable reactor fuel rods heat echanger

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 notes)

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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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.

gcse physics uses of energy transport mainline express electric trains  gcse physics uses of energy transport electric tram systems metro metrolinks around city

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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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

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

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.

 

gcse physics diagram of nuclear power station electricity generation non-renewable reactor fuel rods heat echanger

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.

renewable biomass energy store fuel diagram electricity power generation turbine generator transformer power lines

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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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.

 

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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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