Inventory of Carbon & Energy methodology for timber

Contents

Summary

This methodology represents embodied energy, fossil-derived carbon dioxide (CO2), biogenic CO2 and CO2e emissions associated with the use of timber. The data and calculation methodology is sourced from the Inventory of Carbon & Energy (ICE), version 2.0 life cycle dataset, produced in conjunction with the University of Bath.


The methodology

Emissions model

The methodology is based on factors which describe the quantities of energy and fossil-derived CO2 which are 'embodied' within unit quantities of timber. By multiplying a quantity of timber by these factors, an estimate of the embodied energy and emissions associated with that quantity can be calculated.

In addition, this methodology provides factors for the biogenic CO2 emissions which are associated with quantities of timber. These emissions represent CO2 which is derived from the combustion of recently produced organic material (e.g. biogas and biofuels, timber off-cuts). These emissions are differentiated from fossil-associated CO2 emissions (e.g. from coal, natural gas, oil) because they represent the return of CO2 to the atmosphere which was only recently removed through biological processes (i.e. photosynthesis). In most cases, these emissions are not considered to represent a net addition of CO2 into the atmosphere and therefore not regarded as a contributor to atmospheric warming.

This methodology permits users to choose whether biogenic CO2 emissions are neutral or otherwise.

Model data

Embodied energy and emissions vary between different types of timber. This methodology represents 11 different types of timber (e.g. Hardboard, Laminated veneer lumber) with each type represented by four data values:

  • embodied energy per unit mass (MJ/kg)
  • embodied fossil CO2 per unit mass (kg/kg)
  • embodied biogenic CO2 per unit mass (kg/kg)
  • embodied CO2e per unit mass (kg/kg)

In addition, each material is described by a life cycle analysis boundary, indicating the stages in the material life cycle which are represented by the energy and CO2 factors, and in most cases author notes on the sourcing of the data.

Activity data required

Embodied energy and emissions are directly proportionate to the mass of timber used, which therefore must be available in order to calculate.

Calculation and results

Embodied energy and emissions are calculated by multiplying the specified quantity of timber used by the available factors. Four values are returned representing the embodied energy, as well as fossil CO2, biogenic CO2 and CO2e emissions attributable to the specified quantity of timber.

Note: CO2e quantities incorporate fossil-CO2 as well as the effects of other greenhouse gases, but do not include biogenic CO2 emissions.


Related methodologies

Several other methodologies sourced from the ICE database are also available. The bulk of the ICE database represents several hundred distinct materials, embodied emissions and energy of which can be calculated on the basis of mass or area.

In addition, there exist several methodologies which provide data and calculations specific to particular types of materials: concrete and windows.

Details of the sources of data for the ICE database are also available.


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