Three Gorges Dam and China Southern Power Grid paid a flat rate of ¥250 per MWh (US$35.7) until July 2, 2008. Since then, the price has varied by province, from ¥228.7–401.8 per MWh. Higher-paying customers, such as Shanghai, receive priority. Nine provinces and two cities consume power from the dam. Power distribution and transmission infrastructure cost about 34.387 billion Yuan. Construction was completed in December 2007, one year ahead of schedule. Power is distributed over multiple 500 kilovolt (kV) transmission lines. Three direct current (DC) lines to the East China Grid carry 7,200 MW: Three Gorges – Shanghai (3,000 MW), HVDC Three Gorges
Three Gorges the river along vertical fractures, forming precipitous cliffs. When the river flows through areas of softer sandstone and shale, which have less resistance to erosion, the erosive effect is increased, carving wide valleys. There are different theories on how the Three Gorges were formed, but geographers and geologists have generally reached a consensus, believing mountain folding in the east of Sichuan Province and the west of Hubei Province, including the Wu Mountains (), were the outcome of the Yanshanian movement () around 70 million years ago. The gorges run from southwest to northeast, then turn, and from west to east,