ABSTRACT
When a lamp is turned on, the fuel input into a power plant somewhere has to be increased. In general when energy is used somewhere (direct energy use), it induces energy use somewhere else (indirect energy use). The total demand for primary energy can therefore be much higher than the direct energy use, because several prior processes are involved that have less than 100 per cent conversion efficiency. To calculate primary energy use, we need to analyse the energy chain that contributes to a certain final energy use. This chapter deals with the problems we may encounter when trying to determine the primary energy use.
