David Anderson – 2016 Parliamentary Question to the Department for Energy and Climate Change
The below Parliamentary question was asked by David Anderson on 2016-03-24.
To ask the Secretary of State for Energy and Climate Change, whether her Department holds data on the amount of heat a tonne of biomass gives off when burned compared to a tonne of coal; and if she will make a statement.
Andrea Leadsom
The Department annually publishes the Digest of United Kingdom Energy Statistics (DUKES). Appendix A of DUKES contains data on the calorific value of fuels:
https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/447648/ DUKES_2015_Annex_A.pdf.
The gross calorific value of dry biomass fuels, (the DUKES values have been corrected for moisture content), vary between 10 gigajoules per tonne (GJ/t) for poultry litter and 24 GJ/t for meat and bone meal. A typical dry wood based fuel has an energy content close to 19 GJ/t. Treatments such as torrefaction or charcoal production increase the energy density of biomass derived materials. However these manufactured biomass fuels are not commonly used for heating in the UK.
A tonne of coal can also vary in heat content, depending on the rank of the coal, but lies between 24 GJ/t for bituminous coal as used in the pulp, paper and printing industries and 34 GJ/t of fuel for anthracite used in households. Typical bituminous house coal has a gross heat content of 30 GJ/t.
These values represent the maximum heat available from a fuel in a laboratory test. The useful heat provided by combustion of that fuel to the business or home will depend on the efficiency of the combustor in which it is burnt and the design of the energy distribution system. The combustor efficiency can range from an open fire which may provide 20% of the energy in the fuel as useful heat, to modern condensing wood pellet boilers with gross efficiencies around 90%.
