Utility transformers (or power transformers, TRAFO) transform an incoming alternating current (AC) power system into an outgoing AC power system, often converting from higher voltage to lower voltage or vice versa.
As TRAFOs essentially pass the upstream electricity (input) on to the downstream users (output), only the losses (input minus output) are accounted as electricity consumption.
TRAFOs are used in the transmission and distribution of electricity, between the point of generation and the point of use. The associated losses are already considered in the EIA as part of the efficiency assumed for electricity generation and distribution (PEF). This PEF is used when determining the primary energy (fuel) necessary to supply a given amount of electricity to the end-user.
Source: estimations from the Ecodesign Impact Accounting Overview Report 2023