Shenzhen residents can expect to use natural gas imported from central Asia in three years' time following the completion of the second west-to-east natural gas pipeline project in 2011, Saturday's Daily Sunshine reported.

China began work on the natural gas transmission pipeline, the country's second cross-country gas pipeline, Friday. It will mainly carry natural gas from Turkmenistan and China's Xinjiang Uygur Autonomous Region to the Yangtze and Pearl River deltas, the country's two most developed regions.

It marked the first time China had initiated a project to pipe natural gas from a foreign country.

Construction of the 9,102 kilometer pipeline, which consists of a main line and eight sublines, will cost 142.2 billion yuan (US$20 billion).

One of the pipelines will pipe natural gas from Guangdong's Wengyuan to Shenzhen before diverting it to Hong Kong.

In a congratulatory letter, President Hu Jintao said the pipeline was of "strategic significance" and would help "optimize the country's energy structure and maintain energy security."

He hoped that people involved in the construction of the pipeline would strive to make the project "first class."

With a designed gas transmission capacity of 30 billion cubic meters annually, the pipeline would traverse 12 provinces and autonomous regions before reaching Shanghai and Guangdong.

Premier Wen Jiabao called on workers to ensure the quality of the project and make technical innovations to save land and other resources with a view to protecting the environment.

Vice Premier Zeng Peiyan said the country needed to continue integrating domestic pipeline construction with international cooperation in the oil and gas industry.

The main line extending 4,843 kilometers would start from Khorgos in northwestern Xinjiang to Guangzhou, capital of Guangdong Province.

The western segment of the main line would go into operation by 2009, said Jiang Jiemin, general manager of China National Petroleum Corporation (CNPC), leader of pipeline construction.

By the time the line goes into full operation in 2011, it will pipe gas,mainly from two contracted fields in Turkmenistan, to serve civilians, public facilities and producers who combine heat and power generation. Two domestic gas regions -- Tarim and Changqing -- would be the emergency sources.

Amid rising global oil prices and growing environmental concerns, China is looking for cheaper and cleaner energy sources.The country plans to raise the ratio of natural gas in its energy consumption by 2.5 percentage points to 5.3 percent by 2010, a figure still far below the international average of 25 percent.

The country is endeavoring to build a natural gas transmission network covering its whole territory. The first massive project topipe natural gas from west to east was put into commercial operation in late 2004, starting from Xinjiang's Tarim Basin and going to Shanghai.

The pipeline extending 4,000 kilometers traverses 10 province-level regions with a designed annual gas transmission capacity of 12 billion cubic meters. This can ensure stable gas supply for 30 years.(SD News)