Oct 22 (Reuters) - U.S. liquefied natural gas company Venture Global LNG asked federal regulators on Friday for permission to start commissioning liquefaction systems at the company's Calcasieu Pass LNG export plant in Louisiana.

In a filing with the U.S. Federal Energy Regulatory Commission (FERC), Venture Global said it has fulfilled the environmental conditions needed to start commissioning and requested FERC give permission to proceed no later than Oct. 29.

Venture Global filed for permission to build the project in September 2015 and received FERC approval to start construction in February 2019.

The plant is expected to start producing LNG in test mode later this year before entering commercial service in early 2022.

Venture Global is installing 18 modular liquefaction trains at Calcasieu to produce about 10 million tonnes per annum (MTPA) of LNG, equivalent to about 1.5 billion cubic feet per day of natural gas. Analysts estimate the plant cost about $4.5 billion.

In addition to Calcasieu, Venture Global has about 60 MTPA of LNG export capacity under development in Louisiana, including the 20-MTPA Plaquemines, which could start construction later this year, the 20-MTPA Delta and the 20-MTPA CP2.

Several firms have entered long-term deals to buy LNG from Calcasieu, including units of Royal Dutch Shell PLC, BP PLC, Edison SpA, Galp Energia SGPS SA , Repsol SA and Polish Oil and Gas Co (PGNiG).

Units of China Petroleum and Chemical Corp, or Sinopec, have also agreed to buy LNG from Venture Global as China, the world's second-biggest economy, looks to secure long-term energy supplies amid soaring gas prices and domestic power shortages.

Some of the LNG that Sinopec will buy could come from Calcasieu and some from Plaquemines. Venture Global has not officially announced the Sinopec deal yet, but did talk about it in a Plaquemines filing with the U.S. Department of Energy.

(Reporting by Scott DiSavino Editing by Chizu Nomiyama)