Transmission and distribution losses
Electricity lost as heat and through non-technical causes between power plants and end users, usually expressed as a share of energy supplied.
Transmission and distribution (T&D) losses are the difference between electricity fed into the network and electricity billed to consumers. Technical losses arise mainly from resistive heating in conductors and transformers; non-technical losses come from theft, metering errors and unbilled consumption.
Because losses scale with the square of current, raising voltage cuts losses sharply: doubling voltage for the same power reduces resistive losses by about 75%. This is why bulk transmission runs at 220 to 765 kV AC or as HVDC, while distribution operates at 0.4 to 110 kV.
Typical total losses (World Bank, IEA data):
- Germany, Netherlands, Japan, South Korea: about 3 to 5%.
- United States: about 5% (EIA).
- World average: roughly 8%.
- India: around 15 to 20% including non-technical losses, down from over 25% in the 2000s.
- Some sub-Saharan countries and Iraq: above 20 to 30%.
Transmission typically accounts for one-third or less of technical losses; most occur in distribution transformers and low-voltage lines. Mitigation measures include higher voltages, amorphous-core transformers, reconductoring with high-temperature low-sag conductors, reactive power compensation to improve power factor, smart metering and distributed generation close to load.
Related terms
All terms →- HVDC (High-Voltage Direct Current)
Transmission technology that carries bulk power as direct current, with lower losses over long distances and the ability to link asynchronous grids.
- Interconnector
A transmission link, AC or HVDC, that connects the grids of two countries, regions or market zones and allows electricity to be traded between them.
- Reactive power
The component of AC power that oscillates between source and load without doing net work, needed to sustain magnetic and electric fields and control voltage.
- Power factor
The ratio of active power to apparent power in an AC circuit, between 0 and 1, indicating how effectively current delivers useful work.
- Smart meter
An electronic meter that records consumption in short intervals and communicates the data remotely to suppliers and network operators.
- Final energy
Energy delivered to end users (households, industry, transport, services) in forms such as electricity, fuels and district heat, after conversion and transmission.