Power transmission

Transmission is the long-haul highway of electricity: the high-voltage lines that carry bulk power from distant power plants, dams, and wind farms toward the cities that consume it. Because resistive loss in a wire is I²R — proportional to the square of the current — engineers slash the current by cranking the voltage sky-high (typically 110 kV to 765 kV). Halve the current and you quarter the loss; that single trick is why a transmission tower's worth of wire can move the output of a whole power plant a thousand kilometres while wasting only a few percent.

Transmission is deliberately separated from distribution. Transmission ships power far at extreme voltage; distribution is the lower-voltage neighbourhood network that fans it out to streets and homes. The transmission grid is also a giant shared pool — plants and consumers across a whole region or country connect to it, so a cheap night-time wind farm in one province can quietly power an air conditioner in another.