China is considering moving the last four coal-fired power and heating plants out of Beijing's municipal area, replacing them with gas-fired stations, state media reported on Monday, in an effort to improve air quality in the capital.

"The existence of a number of coal-fired power plants in urban Beijing does not conform with the city's positioning as a metropolis," Zhang Guobao, head of the China's National Energy Administration (NEA), was quoted as saying in the China Energy News.

"While the heat supply to Beijing residents must be ensured, coal-fired stations that need to be relocated must be relocated, and building gas-fired plants with advanced environmental protection technologies is a first choice."

No timeframe was mentioned for the possible move, and it was not clear where the plants would be moved to if such a decision were approved.

The four plants, owned by Huaneng Power International, Datang International Power Generation Co Ltd, China Shenhua Energy and Beijing Jingneng Thermal Power Co Ltd, have a total power generating capacity of about 2.7 gigawatts.

Beijing's gas consumption by power plants alone would reach 13 cu m by 2020 if all coal-fired plants switch to gas turbines, far above earlier plans, Vice Mayor Huang Wei was quoted as saying in the report.

As a result, construction of gas pipelines, liquefied natural gas facilities and underground storage tanks need to be accelerated, Huang said.

PetroChina, the dominant gas supplier for Beijing, has two pipelines sending gas from Shaanxi province that combined have shipping capacity of 20 cu m a year.

PetroChina has the ability to meet Beijing's future gas demand from residents, heating and power generators, Zhao Zhongxun, vice general manager of PetroChina, was quoted as saying.

The top Chinese oil and gas firm has started early-stage work for a third pipeline, linking Shaanxi to Beijing, while a fourth line is also being planned, according to Zhao.

The third Shaanxi-Beijing gas pipeline, at 822 km, is designed to have transportation capacity of 12 cu m a year.