Dec 8 (Reuters) - Top U.S. liquefied natural gas (LNG) exporter Cheniere Energy Inc (LNG.A) asked federal regulators to extend the amount of time it has to build the proposed Stage 3 expansion at its Corpus Christi LNG export plant in Texas due to pandemic delays. When the U.S. Federal Energy Regulatory Commission (FERC) approved construction of Stage 3 in November 2019, the regulator gave Cheniere five years, or until around November 2024, to complete the project. Cheniere asked FERC in a filing late Tuesday to extend the amount of time it has to put Stage 3 into service until June 2027. The company said it needed the extra time because the coronavirus pandemic "resulted in adverse economic and logistical conditions that slowed commercial progress and precluded" the company from making a timely final investment decision (FID). While the coronavirus caused significant energy demand destruction in 2020, Cheniere said its "long-term contracting activity (has) experienced significant growth in 2021" as LNG buyers seek to lock in prices and supplies now that global energy shortages have boosted prices to record highs. During the last 12 months, Cheniere said it signed about 6 million tonnes per annum (MTPA) of long-term contracts, which, along with previously signed contracts, means that commercialization for Stage 3 is "close to completion." read more Cheniere said it plans to make a positive FID to build Stage 3 in 2022, noting a June 2022 FID and a 60-month construction duration would put the plant in service by June 2027. Cheniere said it requests FERC approval of its extension request by March 30, 2022. Stage 3 would add up to seven mid-scale liquefaction trains that would produce around 10 MTPA of LNG. Cheniere is already the biggest buyer of gas in the United States and the biggest U.S. exporter of LNG with the capacity to produce about 45 MTPA of LNG.