8.5 - Fuels
Hydrogen as an alternative to petrol
Hydrogen is a non-hydrocarbon fuel that burns in oxygen, releasing large amounts of energy with water as the only product.
The reaction
hydrogen + oxygen → water
2H2 + O2 → 2H2O
Advantages of hydrogen
- No pollutants at point of use - Only water is produced, with no carbon dioxide or particulates.
- Renewable source - It can be obtained from water, unlike crude oil which is finite.
Disadvantages of hydrogen
- Requires an expensive, specially built engine.
- Manufacturing requires energy (for example electricity for the electrolysis of water), which is often generated by burning fossil fuels that release carbon dioxide.
- Storage is difficult - As a gas at room temperature, it requires large, heavy, pressurised tanks.
- Safety risk - It's highly flammable and forms explosive mixtures with air.
- Lack of refuelling infrastructure compared to petrol.
Key points to remember
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