Daily work in energy research shows that topics and terms are sometimes not clear or easy to understand. In the ENERGY EXPLAINED series published by the Fraunhofer Institute for Systems and Innovation Research ISI, scientists explore complex issues from the practice of energy research and offer a vivid and concise introduction to the respective topics.

  • Primary energy factors

    Primary energy is energy that is available as an energy source in its natural form. However, before it can be used, primary energy is usually converted into final energy in one or more steps. The primary energy factor plays a crucial role in this context:

    • Formally, a primary energy factor describes the ratio between primary energy use and final energy supply and thus the efficiency of the final energy supply.
    • Against the background of the limited availability of fossil resources, primary energy has been and still is an important indicator for assessing the efficiency of an energy system.
    • In particular, primary energy factors have been used in energy policy making to illustrate the limited availability of fossil resources.
    • With the deployment of renewable energies and the need to define their primary energy factors, primary energy factors are becoming less important than other metrics, such as the shares of renewable energies in final energy supply or in final energy consumption as well as the greenhouse gas emissions.
    • Primary energy is very context-dependent.
    • For many energy carriers, there is no single, correct primary energy factor, but only one that is more or less appropriate for the objective in question.
    • Clarity of objectives and transparency of system boundaries and conventions are essential for a meaningful interpretation of primary energy factors.


    Primary energy factors (EN) or 

    Prim√§renergiefaktoren (DE)

  • Coming soon