Embodied Energy Tool (ICE)

I am currently undergoing a Masters in Environmental Systems and for my thesis I am investigating the embodied energy (EE) of the Passive House concept. I am still at the research stage of my thesis. I am currently looking into embodied energy assessment tools used for calculating the EE of buildings.

The first one I choose to look at is the ICE (Inventory of Carbon & Energy) created at the University of Bath. The ICE tool is an inventory database of the embodied energy and embodied carbon of building materials. The data has been collected from secondary resources in the public domain, including journal articles, Life Cycle Assessments (LCA's), books, conference papers ...etc.

The embodied energy of materials can be calculated using different boundary conditions based on the stages of its life cycle. Cradle to Grave boundary condition represents the primary embodied energy of the material over its entire life cycle from extraction, manufacturing, transportation, maintenance to disposal after its end of life use. Most materials in the ICE database are calculated from Cradle to Gate, a boundary condition which means the energy required for the processes of material extraction, manufacturing and transportation of the materials up until it is ready to leave the factory gate is only considered. A reason for using Cradle to Gate is because the energy consumed after the materials leaves the factory gate is site specific and can vary depending on distance to site and method of installing the material. Cradle to Site condition considers the energy consumed until the material has reached the point of use (i.e. the building site).

The problem with calculating embodied energy of materials is the uncertainty of the accuracy of figures used and the sources of those figures. The accuracy of information used is dependent on the reliability of the literature sources used which isn't always accurate. The specification of the data can be inconsistent when the boundary conditions are not specified in the literature and when the author’s reporting on the scope of the study is incomplete.

The ICE database however, applies five criteria when selecting the embodied energy and carbon values of the individual materials to ensure consistency of data. These criteria are:

1. Compliance with Approved Methodologies/Standards,

2. System Boundaries,

3. Origin of Data,

4. Age of the Data,

5. Embodied Carbon. 

Consistency is a vital element when calculating embodied energy of a building to ensure accurate and relevant results. When using the values from the inventory in your own calculations it is important to understand the criteria and particularly the boundary conditions applied to each material to ensure relevance to your own study.