Embodied Energy in Garden Design
What is embodied energy?
The energy consumed through the extraction, transport, manufacturing of products
How does it effect material Choice?
Using a material with a lower embodied energy sounds like a good thing. Though it is not always as simple as that, there are a few questions to ask:
How long will the material last for?
How long will it stay in fashion?
How much of it is needed to do the job?
Commonly embodied energy is calculated in MJ/Kg. This does not necessarily give you a good comparison of materials as they can be used in diverse ways to create the same object. To make a screen wall, two different materials we could use are timber and concrete. To build a concrete wall we need to we need to build a solid wall of perhaps around 150mm in thickness and provide a strip footing across the length of the wall of concrete. However, to build a timber screen we might place posts at around 2.4 metres apart with only a footing around the post. We would then run rails between the posts and then clad the rails. The amount of material needed is significantly higher in the concrete wall. On top of that the weight per cubic metre of the material is significantly higher as well. A heavy timber might be around 1 tonne per cubic meter, while a cubic meter of concrete might be more like 2.4 tonnes per cubic metre. So even though both materials have an embodied energy of approximately 2Mj/Kg, the embodied energy of the concrete wall will be significantly higher.
Lesson Outline
What is embodied energy?
How does it effect material Choice
Presentations
Definitions