The embodied energy of a material refers to the total energy
required to produce that material, including the collection of
raw materials (see Figure 2). This includes the energy of the
fuel used to power the harvesting or mining equipment, the
processing equipment, and the transportation devices that
move raw material to a processing facility. This energy
typically comes from the burning of fossil fuels, which are a
limited, non-renewable resource. The combustion of fossil
fuels also has severe environmental consequences, from
localized smog to acid rain. The greater a material’s embodied
energy, the greater the amount of energy required to produce
it, implying more severe ecological consequences. For example,
the processing of wood (harvested in a sustainable fashion)
involves far less energy and releases less pollution than the
processing of iron, which must be extracted from mined ores.
A revision of a manufacturing process that saves energy will
reduce the embodied energy of the material. Conventional
materials with a high embodied energy can often be replaced
by a material with low embodied energy, while using conventional
design and construction techniques.