Energy Density
- A fuel is anything that can be burned to produce heat, which can be used for an engine to work
- The amount of energy that a fuel can provide for the amount of fuel used is an important consideration for the modern world
- When this is compared by volume is known as energy density
- Energy density is a measure of the amount of energy per unit volume of a fuel
- It 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 of Fuels Table
| Fuel | Energy density / MJ L−1 |
| coal | 72 |
| crude oil | 37 |
| diesel | 36 |
| sugar | 26 |
| 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
- This is why coal is burnt for fuel, whilst wood isn't - there isn't enough energy from it for it to be of use for practical purposes such as an engine or turning a turbine
