Energy Resources (AQA GCSE Combined Science: Trilogy: Physics): Revision Note

Energy Resources

• Energy resources are large stores of energy that can be used to generate electricity and heat homes and businesses

• Electricity is generated in very similar ways, no matter what energy resource is used

• A turbine is turned, which turns a generator, which generates electricity

• The element that differs is how the turbine is made to turn

Energy from water

• Water can be used to turn turbines in the case of hydroelectric dams, tidal barrages and tidal turbines 

• Energy in the kinetic store of the flowing water is transferred to the kinetic store of the turbine and then to the kinetic store of the generator and transferred electrically to the National Grid

Hydroelectric dam

A hydroelectric dam transfers energy from the gravitational potential energy store of the water to its kinetic energy store mechanically to turn a turbine

Energy from fossil fuels

• Fossil fuels can be combusted to heat water, and the steam produced can be used to turn turbines

• Energy from the chemical store of the fuel is transferred to the thermal store of the water, which is then transferred to the kinetic store of the turbine, and then transferred to the kinetic store of the generator and then transferred electrically to the National Grid

The energy transfers involved in the production of electricity from fossil fuels

Energy from nuclear fuel

• Nuclear fuel can also be used to heat water to produce steam to turn turbines

• The energy transfers involved in electricity generation from a nuclear power plant are:

Nuclear store of fuel → thermal store of water → kinetic store of turbine → kinetic store of generator

Energy from geothermal sources

• Geothermal energy is another way to produce the steam that turns the turbines

• Water is pumped down to the hot rocks and returns through a fissure as steam

Cold water is heated by the rocks and returned as hot water or steam which can be used to turn turbines to generate electricity

Summary of energy resources

• Generating energy reliably requires the use of a range of different energy resources, as listed in the table below:

Energy Resources Table

Renewable Energy Resources

• Some electricity drawn from the National Grid is generated from non-renewable resources, and some is generated from renewable resources

Renewable energy

• A renewable energy resource is defined as:

An energy resource that is being (or can be) replenished as it is used

• Renewable resources include:

  • Solar energy

  • Wind

  • Bio-fuel

  • Hydroelectricity

  • Geothermal

  • Tidal

  • Water waves

Non-renewable energy

• A non-renewable energy resource is finite, so there is a limited supply

• Non-renewable energy resources include:

  • Fossil fuels (coal, oil and natural gas)

  • Nuclear fuel

Coal, oil and natural gas are examples of fossil fuels

Uses of Energy Resources

• The three main uses of energy resources include:

  • Transport

  • Electricity generation

  • Heating

Types of energy resources

Transport

• The majority of vehicles in the world are powered by petroleum products such as petrol, diesel and kerosene

  • These resources all originate from crude oil, which is a fossil fuel

• A growing number of vehicles are now being powered by electricity

  • The advantage of this is that while the vehicle is being driven, it produces zero carbon emissions

  • The disadvantage is that when the vehicle is being charged, it is connected to the National Grid, which currently uses a combination of renewable and non-renewable energy sources

• Vehicles can also be powered by biofuel

  • The advantage of biofuel is that it is a renewable resource

  • However, the claim that biofuels are carbon-neutral is largely controversial

  • Biofuels emit carbon dioxide when burned, so they are not in the list of resources that emit no carbon dioxide (nuclear and solar do not emit carbon dioxide when generating electricity)

Electricity Generation

• Electricity plays a bigger role in people's lives than ever before

• With more than 8 billion people in the world, this means the demand for electricity is extremely high

• To keep up with this demand, a combination of all the energy resources available is needed

• On the downside, the majority (84%) of the world's energy is still produced by non-renewable, carbon-emitting sources

  • This has an enormous negative impact on the environment

  • Currently, scientists are working hard to develop more and more efficient ways to produce electricity using more carbon-neutral energy resources

Pie chart of global energy consumption

Heating

• Most homes in cold countries are fitted with central heating systems

• These utilise natural gas in order to heat up water which can be pumped around radiators throughout the home

  • Unfortunately, gas is a non-renewable energy resource

• In geologically active countries, such as Iceland, they are fortunate to be able to heat their homes using geothermal energy