Embodied Carbon

Carbon emissions from the built environment come from two main sources: (1) embodied carbon in the construction materials and processes, and (2) operational carbon when the built environment is occupied. As stated by Hammond and Jones (2008) of University of Bath in UK, embodied carbon of a building material can be defined as the total carbon released over its life cycle. This would normally include raw material extraction, manufacturing and transportation. Ideally the boundaries would be set from the extraction of raw materials until the end of the products lifetime, known as "Cradle-to-Grave".

Energy and carbon analysis of buildings typically focuses on the consumption of operational energy as well as operational carbon emission, due to the larger share in the total life cycle energy and carbon emission. However, embodied energy and carbon have attracted much attention recently. It has been shown that embodied energy and carbon can greatly influence the life cycle energy consumption and carbon emission of contemporary buildings.

Embodied carbon values are region-specific. However, estimation of embodied carbon in the construction materials used in Hong Kong still relies heavily on overseas data, which may not be applicable to the construction industry in Hong Kong. A local carbon inventory database for construction materials will be a good reference for property developers, architects, engineers, contractors, procurement officers, and material suppliers to optimize their design, construction, and logistic approaches to minimize carbon emission. The database will also help promote a low carbon construction industry by providing a basis for selection of green materials, development of carbon labels, and prediction and estimation of building facility carbon footprint.