China’s energy demands have soared, driven by annual economic growth that has exceeded 10 percent the past four years. Energy companies have signed a flurry of deals to explore for and develop oil and gas in former Soviet republics, Africa and elsewhere.

The publicly listed PetroChina and China National Oil and Gas Exploration and Development Corp., both subsidiaries of CNPC, will each provide 8 billion yuan (US$1.1 billion, €750 million) in cash for the planned 1,818-kilometer (1,130-mile) pipeline, Xinhua News Agency said late Friday, citing an announcement from PetroChina.

The project was estimated to cost US$7.3 billion (€5 billion) in total, Xinhua said, but its report did not mention where the remaining funds would come from.

The pipeline will run through Uzbekistan and Kazakhstan before reaching northwest China, Xinhua said. The pipeline will be connected with China’s second West-to-East gas pipeline, which was expected to be operational by 2010 and reach eastern and southern China, including Shanghai and Guangdong province.

In July, CNPC signed a 30-year contract to buy gas from Turkmenistan, importing 30 billion cubic meters of natural gas annually.

CNPC Exploration and Development Co. will build the pipeline in cooperation with two state-owned development companies in Kazakhstan and Uzbekistan, Xinhua said.

Turkmenistan has some of the world’s biggest gas reserves and is the second-largest gas producer in the former Soviet Union after Russia. All its exports go through pipes controlled by Russia’s state-linked gas giant OAO Gazprom, but President Gurbanguli Berdymukhamedov has appeared eager to develop alternate export routes.