Energy Density
- A fuel is anything that can be burned to produce heat, which can be used for an engine to work
- The energy that an amount of fuel can provide is an important consideration for the modern world
- When this is compared by volume of fuel, it is known as energy density
- Energy density is a measure of the amount of energy per unit volume of a fuel
- Energy density is measured in J m-3
- Different fuels contain different amounts of energy, which make them suitable for certain uses e.g. petrol for running vehicles
- Some examples are:
Energy Density Table
| Fuel | Energy density / MJ L−1 |
| coal | 38 |
| liquid hydrogen | 9 |
|
methane (natural gas) |
0.3 |
| diesel | 39 |
| biodiesel | 33 |
| vegetable oil | 30 |
| wood | 3 |
- 1 L (litre) is 0.001 m3
- This means that we can get more energy per unit volume of coal than we can wood
- Fuels are chosen for specific uses based on a number of factors, including energy density, safety of use and pollutants released in combustion