China finishes half of controversial electricity grid network

Critics claim ultra-high voltage technology is immature.

China has built over half of a network of ultra-high voltage or UHV power lines to connect remote energy producing regions in the interior to the east coast.

The State Grid Corporation of China, the world's largest utility, will spend some US$100 billion by 2017 on 20 UHV lines covering 20,000 km.

SGCC said 4,633 km of the UHV lines has been completed and another 6,400 km is now being built. UHV lines are designed to minimize energy loss during transmission.

The project has been controversial with critics claiming SGCC is relying too much on costly and untested UHV technology that could expose the system to blackouts.

The National Development and Reform Commission earlier said that a dispute over UHV had not yet been settled.

"People say it is immature, and three years ago maybe they were right, but now it isn't really true. Our pilot project has been running for over four years without a single hitch, claimed Zhang Zhengling, SGCC deputy director of development and planning.

By 2017, SGCC aims to connect 210 GW of capacity in the west to markets in the east, triple the current rate and involving the transmission of 1.2 trillion kilowatt-hours of power a year across huge distances, Zhang said.