I recently ran across some unknown terminology in connection with buildings, that being embodied energy. From an Australian Government publication:
Embodied energy is the energy consumed by all of the processes associated with the production of a building, from the mining and processing of natural resources to manufacturing, transport and product delivery. Embodied energy does not include the operation and disposal of the building material, which would be considered in a life cycle approach. Embodied energy is the ‘upstream’ or ‘front-end’ component of the life cycle impact of a home.
Apparently the importance of embodied energy is somewhat controversial, which surprises me as it seems to be a measurable quantity that can be characterized as to source and impact on the environment, although in some cases the characterization will change over time or location. Lloyd Alter on Treehugger.com presents some thoughts on the subject:
Embodied energy, the energy “baked in” to materials, is a controversial subject. Some experts do not think it very important, since adding a little embodied energy in the form of insulation will save many times as much energy over the life of the building. Others believe that a long life cycle is far more important, so if more durable materials have a little more embodied energy, so be it. Most don’t even bother thinking about it at all. (More explaining on TreeHugger here) …
In Dhaka, the capital city of Bangladesh, the embodied energy and carbon from making bricks and tile is “responsible for 58% of the capital city’s air pollution — much more than cars, power generation and other industries combined.”
Brick kilns are a major source of air pollution not just in Bangladesh but across South Asia and China, together accounting for 75% of the global consumption of clay bricks. More than one trillion bricks are produced annually in these countries, resulting in 1.4% of global GHG emissions. To avoid the continued compulsive use of such resource-intensive building materials, actionable change must occur. [Prashant Kapoor]
He also explains why the more efficient the building is, the bigger the problem becomes. “The reality is that as energy consumption is driven down, the relative importance of embodied energy increases.”
I think Lloyd misstates the scenario – it’s not a bigger problem. It hasn’t grown in absolute numbers. Simply, as the operational efficiencies of running a building improve, the embodied energy becomes a larger and larger target.
And it is important, because as the human population continues to increase, more buildings will be constructed, and thus embodied energy needs to be carefully analyzed as to its character (i.e., source) and how its use will improve the building.
