The No.4 pipeline of China's west-to-east gas transmission project is under construction. (Photo: Screenshot of the official website of Pipe China)

China's west-to-east gas transmission project on Wednesday started the construction of the No.4 pipeline, which will lift the annual transmission capacity of the project to over 100 billion cubic meters after cooperating with the completed No.3 and No.2 pipelines, state-owned Pipe China, the constructor of the project, said on its official website on Wednesday.

The No.4 gas pipeline has a total length of 3,340 kilometers, starting from Wuqia county in Northwest China's Xinjiang Uygur Autonomous Region to Zhongwei in Northwest China's Ningxia Hui Autonomous Region, further secures the nation's natural gas supply and safety of energy.

According to the construction outline, the core phase of the No. 4 pipeline from Turpan city in Xinjiang to Zhongwei, crossing two autonomous regions and one province and with a total length of 1,745 kilometers, will be built as a priority.

The Turpan-Zhongwei phase has been designed to have annual transmission volume of 15 billion cubic meters which will be doubled after extension, which will largely ease the peak transmission load in winter by connecting domestic gas field in Tarim Basin in Xinjiang, said Pipe China.

Multiple advanced techniques will be applied in the construction keeping the working day for one-kilometer-pipeline to within four days. The new pipeline and related equipment will be deployed following in-service pipeline to reduce cost and damage to environment.

China's west-to-east gas transmission project started construction at the beginning of 21th century. The current annual capacity hits 77 billion cubic meters, and the accumulative transmitted volume has reached 750 billion cubic meters, according to Pipe China.