(Adds details of reclassification and sale of gas to customers)
Sept 1 (Reuters) - Natural gas pipeline operator TransCanada Corp said on Tuesday the U.S. Federal Energy Regulatory Commission (FERC) has allowed it to reclassify some 1.1 billion cubic feet (bcf) of gas in storage as "working gas" which can be burned at any time for heating or electrical generation.
Previously, the gas was classified as "base gas" supply, which must be left underground to maintain a certain level of operational pressure in a gas cavern.
The reclassified gas was part of a 9 bcf supply that TransCanada wanted to sell from its underground storage on the ANR Pipeline at Winfield and Loreed to realign its storage capacity.
Transcanada said FERC approved the realignment plan last November. At that time, 1.1 bcf of that was deemed base gas and the balance 7.9 bcf working gas.
FERC has since "approved reclassification of all the gas to working gas", TransCanada said in an email to Reuters on Tuesday.
TransCanada said it reached agreement last week with customers to sell all of the gas, the last of which will be sold in January. (Reporting By Barani Krishnan; Editing by David Gregorio)