Energy Density

From Cornburning

The term 'energy density' refers to the energy contained in a fuel per unit weight; figures are usually quoted in GJ/tonne. The energy density of fossil fuels is considerably higher (up to three times) than that of biomass fuels such as pellets or wood chips.

Moisture content has a drastic effect on energy density for all biomass materials. Wood pellets below 10% moisture (as stipulated by the British BioGen code of good practice), have an energy density of around 16.8 GJ per tonne. Wood chips can vary from 14.3 GJ/tonne at 25% moisture to 9.5 GJ/tonne at 50% moisture, making wood chips a more un-predictable form of fuel.