BEIJING -- Construction of two ultra-high voltage (UHV) power transmission projects in China began on Thursday as part of efforts to ensure clean electricity supply, according to the State Grid Corporation.

With a total investment of 10.9 billion yuan (about $1.71 billion) and a total length of 525 km, the two 1,000-KV projects will respectively link the eastern cities of Fuzhou and Xiamen, and the central cities of Zhumadian and Wuhan.

Both projects are expected to be put into operation next year, helping to promote the consumption of clean energy generated by offshore wind farms and photovoltaic power stations, the State Grid said.

So far, the State Grid has completed the construction of 29 UHV projects, transmitting more than 2.5 trillion kilowatt-hours of power, it said. It expects its trans-provincial and trans-regional power transmission capacity to rise from 240 million kilowatts at present to over 370 million kilowatts by 2030.

The State Grid, the world's largest utility company, supplies power to a population of over 1.1 billion people, with its service area covering 88 percent of China's territory.