Embodied energy
As embodied energy the amount of energy is referred to, which is required for production, transportation, storage, sale and disposal of a product. This is because all precursors are considered to extraction of raw materials and energy use of all existing production processes added. If necessary to produce machines or infrastructure devices, usually also the energy required for their manufacture and maintenance is included pro rata " embodied energy " of the final product in the. The " product" can also be a service. Embodied energy is thus the indirect energy requirements by buying a consumer product, in contrast to the direct energy requirements associated with its use.
Orders of magnitude
The Federal Statistical Office of Germany has calculated that in 2003, the average energy intensity of all goods excluding energy goods 4.5 MJ / EUR. That is, in macro-economic means causes each euro that a consumer spends, about one kilowatt-hour ( = 3.6 MJ) of " embodied energy " (other than direct purchase of energy).
Depending on the product group, the energy intensity varies greatly. The following groups were in 2003, according to the Federal Statistical Office loaded the most indirect energy requirement: Aviation ( 25.7 MJ / EUR ), other traffic ( 16.3 MJ / EUR ) and chemical products ( 11.8 MJ / EUR ).
Examples
Individual products
Difficulties in calculating
The process chain is quite complex for most products, so you have to make simplifying assumptions in the calculation of gray energy. Specific figures for the amount of embodied energy of a product are correspondingly uncertain, depending on the source or calculation method different and often controversial. In addition, the concept of embodied energy is not defined exactly what inter alia to in the occurrence of demarcation problems expressed such as:
- Is it useful to flip the energy needs of the canteen to the generated products?
- If all the products are transported by road, also a part of the energy needs of the hospitals where the injured are treated after traffic accidents, are assigned?