Development of New Energy Resources (Cambridge International IGCSE Environmental Management)

Hydrogen as an energy source

Why hydrogen can be used as an energy source

• Hydrogen is a fuel that burns easily, releasing large amounts of energy
• When hydrogen burns, it produces water vapour instead of carbon dioxide, so it can be a low-carbon energy source

Blue hydrogen fuel

• Blue hydrogen—hydrogen fuel made from natural gas

• Natural gas is reacted with steam in a process called steam methane reforming

  • This produces hydrogen gas and carbon dioxide

• Carbon dioxide is captured and stored using carbon capture and storage (CCS)

• Hydrogen can then be used as a clean fuel for vehicles, heating or electricity generation

Green hydrogen fuel

• Green hydrogen—hydrogen fuel made using renewable energy

• Electricity from solar, wind or hydropower is used for electrolysis

  • Electrolysis is the splitting of water into hydrogen and oxygen using electricity

• Produces no carbon emissions during production

• Hydrogen can be stored and used when needed, helping balance renewable energy supply

Ground source heat pumps

Ground source heat pumps: transfer of heat from the ground for heating

• Pipes are buried underground, where the temperature stays fairly constant

• A liquid (water mixed with antifreeze) flows through the pipes

  • The liquid absorbs heat from the ground

• The pump transfers this heat into a building’s heating system

• Provides low-carbon heating for homes, schools and offices

• Works well in places with enough outdoor space for underground pipes

How a ground source heat pump works

Exam Hint For heat pumps, always include the phrase 'transfer of heat'. Examiners look for this because heat pumps move heat rather than create it. Missing this wording can lose marks.

Air source heat pumps

Air source heat pumps: transfer of heat from the air for heating

• A fan draws in outside air, even on cold days

• A refrigerant fluid absorbs heat from the air

• A compressor then compresses the air, increasing its temperature

• The heat is then transferred indoors

  • Can heat radiators, underfloor heating, or hot water

• Easier to install than ground source systems because they stay above ground

• More effective in mild climates where air temperatures stay higher

How an air source heat pump works