Embodied energy

Figure 1. It takes about 1 gigajoule of energy (1 billion joules) to build a typical smartphone - known as the phone's embodied energy.[1]

Embodied energy is the energy that is consumed in order to build a given usable object. This includes the energy from material extraction, refining, processing, transporting, and fabricating.[2] It is named as such because it is as if this energy is "embodied" within the item itself. Embodied energy also comes along with idea of embodied carbon, which is the associated CO2 footprint that is emitted during the object's creation.

Embodied energy is found within all types of objects, including things like cell phones, appliances, homes, buildings, and furniture. The embodied energy of a given object can be analyzed by knowing what materials are contained within an object, and how much of that given material there is. The amount of energy needed to produce a certain material such as aluminum, steel, or concrete is known and can be used to calculate the embodied energy within an item.[3]

Embodied Energy of Objects

The idea of embodied energy is important to help analyze the energy savings of a particular object. For example, if a proposed wind turbine is promised to be more energy efficient in its operation but requires tremendous amounts of energy in its materials and assembly, it might not be worth the effort. From this knowledge of an object's embodied energy, the environmental impact associated with it may also be estimated.

The embodied energy within a given raw material is typically measured in an "energy per unit mass" scale, such as megajoules per kilogram. For the table below the values are an aggregate of all of the energy within the objects, so there is no mass unit included, rather it is the amount of energy in the entire object.

Item Embodied energy (MJ/functional unit)[4][5]
Hair dryer 79
Coffee maker 184
LCD monitor 963
Smartphone 1,000
PC tower 2,085
Washing machine 3,900
Laptop 4,500
Refrigerator 5,900
Digital copier 7,924
Cell tower 100,000

Raw materials

Item Embodied energy (MJ/kg)[3]
Cadmium 17
Iron 20-25
Lead 25-50
Copper 30-90
Mercury (liquid) 90-180
Nickel 180-200
Aluminum 190-230
Magnesium 270-350
Silicon (electronics-grade) 1,000-1,500
Silver 1,500
Zirconium 1,600
Platinum 190,000
Gold 310,000

For Further Reading


References

  1. Pexels [Online], Available: https://www.pexels.com/photo/hand-apple-iphone-smartphone-3510/
  2. Circular Ecology. (Accessed September 12, 2015). Embodied energy and carbon [Online], Available: http://www.circularecology.com/embodied-energy-and-carbon-footprint-database.html#.VfSnOPlVikp
  3. 3.0 3.1 UNEP. (August 19, 2015). Environmental Risks and Challenges of Anthropogenic Metals Flows and Cycles [Online]. Available: https://d396qusza40orc.cloudfront.net/metals/3_Environmental_Challenges_Metals-Full%20Report_36dpi_130923.pdf#96
  4. N. Duque Ciceri, T.G. Gutowski, and M. Garetti. (Accessed September 13, 2015). A Tool to Estimate Materials and Manufacturing Energy for a Product [Online], Available: http://web.mit.edu/ebm/www/Publications/9_Paper.pdf
  5. B. Raghavan and J. Ma at UC Berkeley. (Accessed September 13, 2015). The Energy and Emergy of the Internet [Online], Available: http://conferences.sigcomm.org/hotnets/2011/papers/hotnetsX-final56.pdf

Authors and Editors

Jordan Hanania, Kailyn Stenhouse, Jason Donev
Last updated: September 3, 2018
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