[gnode]

The geography of power generation is important. The losses for a 345kV 1GW transmission line are about 4% over 100Mi. As I understand it, they also increase in a compound manner, so over ten times that distance would be 48%. Higher voltage / superconducting lines would reduce this, but they're expensive. The difficulty of transmission losses, combined with geographically specific power sources (hydro, geothermal, wind, solar, etc.) means that power costs legitimately vary throughout the world, and within countries the size of the United States.