Energy Resources (Edexcel GCSE Physics: Combined Science)

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

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

• A renewable energy resource is defined as

An energy source that is replenished at a faster rate than the rate at which it is being used

• As a result of this, a renewable energy resource is one that will not run out
• Renewable resources include:
  • Solar energy
  • Wind
  • Bio-fuel
  • Hydroelectricity
  • Geothermal
  • Tidal
• Non-renewable energy resources include:
  • Fossil Fuels (coal, oil and natural gas)
  • Nuclear fuel

• 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

• 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

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

• 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

• 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

• 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

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

Energy Resources Table

• Each energy resource has various advantages and disadvantages associated with it
• A renewable energy resource is one that is replenished at a faster rate than the rate at which it is being used
  • As a result of this, renewable energy resources will not run out

• A reliable energy resource is one that can produce energy at any time
• Non-reliable resources can only produce energy some of the time (e.g. when it’s windy)

• The table below shows a comparison of the advantages and disadvantages of the different energy resources:

Comparison of Different Energy Resources Table

• 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

Electricity Generation

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