Hydrogen vs Fossil Fuels (Edexcel GCSE Chemistry: Combined Science)

Hydrogen as a fuel

• Hydrogen is used in rocket engines and in fuel cells to power some cars and buses
• It reacts with oxygen in an exothermic reaction:

2H₂ + O₂ →2H₂O

• Hydrogen has a series of advantages and disadvantages regarding its use as a fuel
• Advantages:
  • It releases more energy per kilogram than any other fuel (except for nuclear fuels)
  • It does not pollute as it only produces water on combustion, no other product is formed

• Disadvantages:
  • Expensive to produce and requires energy for the production process
  • Difficult and dangerous to store and move around (usually stored as liquid hydrogen in highly pressurised containers)
  • The production of hydrogen process releases carbon dioxide 

• A fuel is a substance which when burned, releases heat energy
• This heat can be transferred into electricity, which we use in our daily lives
• Most common fossil fuels include coal, natural gas and hydrocarbons such as methane and propane which are obtained from crude oil
• The main constituent of natural gas is methane, CH₄
• Most of the world's energy supply still comes from fossil fuels:

Over 80% of the world's energy supply still comes from fossil fuels