Editing Embodied energy (section)

===Standards===
The SBTool, UK [[Code for Sustainable Homes]] was, and USA LEED still is, a method in which the embodied energy of a product or material is rated, along with other factors, to assess a building's [[environmental impact assessment|environmental impact]]. Embodied energy is a concept for which scientists have not yet agreed absolute universal values because there are many variables to take into account, but most agree that products can be compared to each other to see which has more and which has less embodied energy. Comparative lists (for an example, see the University of Bath ''Embodied Energy & Carbon Material Inventory''<ref name="ICE Database">G.P.Hammond and C.I.Jones (2006) ''[http://www.circularecology.com/embodied-energy-and-carbon-footprint-database.html Embodied energy] and [[carbon footprint]] database'', Department of Mechanical Engineering, University of Bath, United Kingdom</ref>) contain average absolute values, and explain the factors which have been taken into account when compiling the lists.

Typical embodied energy units used are MJ/kg (mega[[joules]] of energy needed to make a kilogram of product), t{{CO2}} (tonnes of [[carbon dioxide]] created by the energy needed to make a kilogram of product). Converting MJ to t{{CO2}} is not straightforward because different types of energy (oil, wind, solar, nuclear and so on) emit different amounts of carbon dioxide, so the actual amount of carbon dioxide emitted when a product is made will be dependent on the type of energy used in the manufacturing process. For example, the Australian Government<ref>[http://www.cmit.csiro.au/brochures/tech/embodied/ CSIRO on embodied energy: Australia's foremost scientific institution] {{webarchive|url=https://web.archive.org/web/20060225154902/http://www.cmit.csiro.au/brochures/tech/embodied/ |date=2006-02-25 }}</ref> gives a global average of 0.098 t{{CO2}} = 1 GJ. This is the same as 1 MJ = 0.098&nbsp;kg{{CO2}} = 98 g{{CO2}} or 1&nbsp;kg{{CO2}} = 10.204 MJ.