What are Fossil Fuels? (SL IB Environmental Systems & Societies (ESS))

What are Fossil Fuels?

• Fossil fuels include:
  • Coal
  • Natural gas (mostly methane) which is used in domestic boilers and cookers
  • Crude oil which is refined into petrol, diesel, and other fuels

• Fossil fuels are formed from the remains of plants and animals
  • Chemical energy stored in fossil fuels originally came from sunlight
  • Energy from the sun was transferred to chemical energy stores within plants through photosynthesis (plants use energy from sunlight to make food)
  • Animals ate the plants and the energy was then transferred to their chemical store

Fossil fuels include coal, oil and natural gas

Advantages of Fossil Fuels

• The current systems of transport and electricity generation used by human societies rely heavily on fossil fuels, which are generally readily available on a daily basis
• In the past fossil fuels have been reliable for large scale energy production (although this is changing as supplies deplete and prices rise)
• Efficient - fossil fuels typically have a high energy density (they produce a large amount of energy per kilogram)

Disadvantages of Fossil Fuels

• It takes millions of years for fossil fuels to form
  • This is why they are considered to be a non-renewable energy resource

• The increasing demand for a decreasing supply causes prices to increase
  • Fossil fuels are predicted to completely run out within the next 200 years

• Burning fossil fuels pollutes the atmosphere with harmful gases such as:
  • Carbon dioxide which contributes to the greenhouse effect
  • Sulphur dioxide which produces acid rain
  • Both carbon and sulphur can be captured upon burning preventing it from being released into the atmosphere but this is expensive to do

• Oil spills can occur during transport of fossil fuels, which damage the environment and wildlife over very large areas
• Prices fluctuate rapidly
• Supplies can be affected by conflict and political disagreements (e.g. the war in Ukraine)

Uses of Fossil Fuels

• Fossil fuels are mainly used for:
  • Transport
  • Generating electricity
  • Heating

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

Electricity Generation

• Fossil fuels, such as coal and oil, are used to produce energy on-demand when energy is needed
  • This is done by burning the materials when the energy is required
  • When coal is burned, it produces thermal energy
• This is used to boil water creating steam
• Steam is forced around the system and this turns a turbine
• The turbine turns coils in a magnetic field in the generator
  • This generates electricity
• The electricity is transferred through a step-up transformer and is carried out of the system by electrical lines
• The steam within the turbine will cool and condense and then be pumped back into the boiler to repeat the process

Electricity generation of coal through a power station

Heating

• Heating systems in cold countries vary depending on the region and availability of resources
• In some countries, central heating systems are commonly used and often rely on fossil fuels such as natural gas, fuel oil, coal, or coke for heating purposes
  • These systems typically heat up water, which can then be pumped around radiators throughout the home

• However, it's important to note that not all countries rely on central heating systems or use gas as the principal fuel for heating
  • In regions where natural gas is less common or unavailable, alternative heating methods may be used, such as electrical heating or district heating systems
  • Electrical heating is common in some countries like Japan, where it is often powered by nuclear energy rather than fossil fuels
  • In certain areas, renewable energy sources such as geothermal heating or solar heating systems may also be employed as sustainable alternatives

Pie chart of global energy sources used in 2019

Energy Demand

• The demand for energy across the globe is rising
• Population growth and development are the two main causes of the increase in energy demand:
  • The higher demand for food leads to more intensive farming, which requires more energy for machines, light and heat
  • Increasing industry requires energy for heating, lighting and machinery
  • There is more transport all of which requires energy in the form of petrol, diesel or electricity
  • Urbanisation increases with the development increasing domestic appliances, heating, lighting
  • Increased wealth means people buy more appliances and technology which require energy

World energy demand