Quality based energy contents and carbon coefficients for building materials: A systems approach

Abstract

This paper describes a computerised relational database management system to represent and calculate (i) the energy inputs to a building material or element up to the point of utilisation or construction and (ii) the carbon emitted to the atmosphere up to that point. All building elements, materials and “primitive” raw materials are placed in an aggregation–decomposition hierarchy. The process analysis carried out here captures around 90% of the embedded energy in a product. The database can handle multiple sources of data and perform calculations to give the average, maximum and minimum embedded energies, which are also classified according to fuel type (i.e. biomass, fossil fuel and electricity) and process stage (i.e. production energy, transport energy for raw materials and energy embedded in raw materials). The embedded energy requirements are also calculated on the basis of the lowest quality energy, namely biomass energy (“bio-equivalent” basis), in addition to the more conventional basis of tonnes of oil equivalent. Timber was found to be the preferred option and steel the least desirable, with concrete in between, from an energy consumption and carbon emission point of view.