What is embodied energy?
One definition is: "The quantity of energy required by all the activities associated with a production process, including the relative proportions consumed in all activities upstream to the acquisition of natural resources and the share of energy used in making equipment and other supporting functions. i.e. direct plus indirect energy." (Treloar, 1994).
History of the project
In 1983 NZERDC published Energy Cost of Houses and Light Construction Buildings. This publication has since been used world-wide as a reference document on embodied energy. The investigation was completely redone in 1995: the published document is available here.
In 1997 BRANZ contracted the CBPR to extend and improve the results of the 1995 work and to develop a computer database to enable the efficient handling and updating of embodied energy information. A number of deficiencies had been identified with the 1995 investigation. The goal of the 1997 study was to rectify these deficiencies, providing a system by which an enhanced set of embodied energy coefficients for New Zealand building materials could be routinely maintained and expanded.
To be able to use Embodied Energy information effectively it is normally represented as a table of coefficients so that different materials can be easily compared. (Please note: the data for this table for fibreglass insulation is based on our best estimate from international data because the local manufacturer refused to supply the necessary information.)
The New Zealand Building Industry Advisory Council (BIAC) standard house was used for this study to determine the total energy embodied in the materials of a typical house, using the data from the table of coefficients.
What we can do at present is work out how many MJ of energy is required to build the BIAC house. This enables us to answer questions like: 'if we insulate – how long does it take to get back the energy "invested" in insulation in energy savings?' For a copy of the full report, email the CBPR. The next stage is to collect data so we can examine other environmental impacts of buildings for example, what is the CO2 load on the atmosphere the chemical contamination of our waterways resulting from particular building material choices.
Deficiencies—the need for further research
The collection of data for all environmental impacts of New Zealand building materials will be a large task, and the database of New Zealand materials now collated into SimaPro may be tackled as resources permit.
The example SimaPro "project" described in Volume I, Section 4 of the final report shows, for a standard house, how embodied energy data might be used by industry. A report on say, CO2 production or ozone depleting emissions would look the same, and would be as easy to use as this energy report.
The system developed for routine collection of embodied energy data was a database. The commercial program SimaPro fits most of the criteria in data specification developed in the 1997 study. The SPOLD format used by SimaPro has an added advantage; it provides an internationally recognised format for the collection and exchange of data on all environmental impacts, not just embodied energy.
A database specification was developed for the collection and processing of embodied energy information. The commercial program SimaPro fits most of the criteria in this specification. The SPOLD format used by SimaPro provides an internationally recognised format for the collection and exchange of data on all environmental impacts, not just embodied energy.
The program itself is in use around the world: ATHENA, Canada; BRE, UK; Eco-Quantum, Netherlands; Franklin Life Cycle Inventory, USA; Sintef environmental building, Norway. The advantages afforded by its user-friendly interface, SPOLD structured data format, encompassing of other environmental impacts and industry acceptance far outweigh the limitations of the program identified in the implementation of the New Zealand embodied energy database.