AC transmission: Overview
The high-voltage highways carrying power from plants to cities
What this tile covers High-voltage overhead lines carrying bulk power over long distances, up to ultra-high voltage. Share of use 18% share of world energy carried (2024)Share of world total energy supply (592 EJ in 2024, Energy Institute Statistical Review 2025, physical energy content) carried at least once by this mode; overlaps allowed, so shares do not add to 100 (calculated) World electricity demand passed 30,000 TWh in 2024 (Ember), about 108 EJ of the 592 EJ total. Nearly all grid power crosses AC transmission, so this is an upper bound (rooftop and captive generation skip it). Overlaps fully with distribution and partly with HVDC and cables. Source: Global Electricity Review 2025: 2024 in review, Ember.
Key facts
| Form | Electricity |
| Chain | Electrical → step-up transformer → high-voltage → step-down transformer → low-voltage |
Included from the reference tables
- High-voltage AC transmission
- Ultra-high-voltage lines (800 kV and above)
Linked to the material world
Al AluminiumCu CopperSt SteelAlso in Electricity
HVDC HVDC linksDist Distribution grids, mini-grids and interconnectorsCab Underground, submarine and superconducting cablesRW Railway electrification and wireless powerExplore paths from here
More on this tile in the tabs above: how it works, efficiency and losses, technology advances, value chain, geopolitics and regulation, unit economics, impact on the biosphere.