Energy balance (environment)

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An energy balance calculates the consumption of primary and final energy . It thus forms a basis for the assessment of production processes, processes and supply systems. With the energy balance, the energy consumption is shown in terms of quantity, so that the effort can be assessed and energy losses can be identified. The energy balance forms a basis for the economical use of energy .

In the case of sustainable production methods, the energy balance characterizes the entire effort involved in manufacturing, operating and further processing ( disposal or recycling ) of products. It is not only the energy consumption during production, e.g. B. a refrigerator, but also the energy and resources required for production and disposal ( gray energy ).

For power plants , the energy balance from production and operation of the plant is given as a so-called harvest factor or the energy payback time.

Germany

Annual energy balances have been carried out for the Federal Republic of Germany since 1971 - looking back to 1950 - by the Arbeitsgemeinschaft Energiebilanzen e. V. created.

Examples

Energy equivalents
Energy source Amount of energy
natural gas 7.8 kWh / m³
oil 10.0 kWh / l
Beech wood 4.0 kWh / kg
Spruce wood 4.5 kWh / kg
  • For both engines and heating systems , the key figure for the energy balance is their efficiency .
  • In buildings, the heating energy is compared to the heat losses due to inadequate thermal insulation .
  • For building heating, energy sources can be compared using the energy equivalents. The energy balance from the extraction of the raw materials to their availability by the consumer must be taken into account. In the production of spruce, z. B. (only) between 1.1% and 4.2% of the energy contained in the raw material is used to make it available on the forest road - but it is usually still a long way to the consumer.
  • In crude oil production , only the ratio of energy used to energy gained is considered for the harvest factor . From an environmental point of view, however, the energy losses caused by the flaring of the associated gases must be included.

literature

  • Torsten Marheineke: Life cycle analysis of fossil, nuclear and regenerative power generation technologies . July 2002, 222 pages.

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