StudyDeck

Energy types

Exam code: 2217
Written by: Ashika|Reviewed by: Caroline Carroll|Updated 2 July 2026

Specification link

This page covers section 10.4.1 of the CIE O Level specification.

  • 10.4.1 - Types of energy:

    • Renewable: biomass, geothermal, hydroelectric power (HEP), solar, tidal, wave, wind

    • Non-renewable: fossil fuels (coal, gas, oil), nuclear

    • Fuelwood, which can be either renewable or non-renewable.

Energy production

Energy production

  • Energy sources are needed to power technology, transport, factories, homes

  • The amount of energy used globally varies from place to place

  • Each country has it's own energy mix

  • This will depend on several factors including the availability of:

    • fossil fuels

    • sunlight

    • rivers suitable for dams

    • steady wind speeds

    • coastal access

  • Energy production also relies upon a country's investment in infrastructure and government subsidies

Renewable energy sources

Renewable energy sources

  • Renewable energy sources are infinite and will not run out. They include:

    • hydroelectric

    • wave/tidal

    • wind

    • solar

    • geothermal

    • biomass/waste

  • Once in place, except for biomass/waste, they do not produce any greenhouse gas emissions

  • Greenhouse gases may be emitted in the production, construction and transport of the equipment

Increase in renewable energy

  • Renewable energy is increasingly important in the global energy mix

  • This is due to:

    • Non-renewable fossil fuels will at some point run out and so they need to be replaced with another energy source

    • The use of non-renewable fuels is damaging to the environment.

      • Fossil fuels, when burnt, release greenhouse gases and the sulphur dioxide released causes acid rain

      • Mining and drilling for fossil fuels can destroy habitats and damage the surrounding environment

    • Increasing awareness of the impact of using fossil fuels has resulted in international pressure to reduce their use

    • Countries wanting to reduce their reliance on imports of energy sources and improve their energy security

Non-renewable energy sources

Non-renewable energy sources

  • Over 80% of the world's energy is provided by fossil fuels (coal, oil and gas)

    • 33% oil

    • 27% coal

    • 24% gas

  • Fossil fuels are fuels formed from the remains of living organisms (plants/animals)

    • These are non-renewable as they cannot be replaced at a speed that keeps up with consumption

  • It is estimated that based on current use and availability, gas and oil will run out by 2080

Pie chart showing energy sources: oil 33%, gas 24%, coal 27%, nuclear 4%, hydroelectric 6%, and other renewables 5%.
World energy mix
  • The use of nuclear and renewable energy is growing but non-renewable fossil fuels still dominate energy production

  • It is predicted that the use of gas and oil will continue to increase over the next 30 years

    • Fossil fuels are expected to still provide over 75% of the world's energy by 2040

Nuclear

Nuclear

  • Nuclear fuel has the potential to provide large amounts of energy

  • It is often used countries who do not have their own supplies of fossil fuels such as France 

  • Nuclear fuel can be reused and is used in small amounts

  • This means that although non-renewable it is not likely to run out in the near future

World map showing nuclear electricity production share in 2021. Colour-coded by percentage, with a key indicating no data, no nuclear, and 10%-60% levels.
Share of electricity production from nuclear.
  • In 2019, approximately 4% of the global primary energy supply was from nuclear power

  • There are 439 active nuclear reactors across the world

  • Most of these are in just five countries:

    • USA (92)

    • France (56)

    • China (54)

    • Russia (37)

    • Japan (33)

Fuelwood

Fuelwood

  • It is estimated that between 2 and 3 billion people across the world rely on fuelwood for heating and cooking

    • This is usually because they do not have access to other forms of energy

  • Approximately 13% of the world's population does not have access to electricity

    • This is mostly an issue in LICs within Sub-Saharan Africa and Asia

  • Fuelwood is often included as a biofuel but the wood is not usually grown specifically for use in heating and cooking

  • The reasons for this include

    • It is free 

    • It does not require technology 

    • That it can be renewable if the trees are replaced

    • No high-technology equipment is needed to use the fuel

  • If new trees are planted this is a renewable energy source

  • If the trees are not replaced it is a non-renewable energy source