Transmission Losses

Transmission losses are the power losses in an electrical system and are typically around 5-7% of the total power put into the system. Transmission losses represent a loss in value and an increase in fuel burn and environmental impact, as every MWh of power that is generated but cannot be sold costs money.

Transmission losses are caused by:

• The electrical resistance of the conductor lines (accounts for 5% losses or 147 million MWh)
• Converting the power between high voltages used for long distance transmission and safe low voltages used in most industry and the home (accounts for 2% losses or 55 million MWh)

Learn more about how transmission losses occur.

In Europe, the resistive loss in transmission lines alone represents the waste of around 20 million tonnes of coal, 3.1 million tonnes of gas and 1.7 million tonnes of oil. The annual loss in value is around €12 billion. The annual increase in greenhouse gas emissions is around 60 million tonnes of CO2 per year.

In some countries, older transformer infrastructure and lines can yield losses as high as 21%. To learn more about these older systems, visit the website of the UNEP Risoe Centre on Energy, Climate and Sustainable Development (URC), which has a useful paper explaining issues associated with Indian power infrastructure.

The cost breakdown of a delivered MWh of CCGT power