By William Opalka

TransCanada told regulators last week that it intends to mothball three of its Ravenswood gas peakers in New York City due to the units’ age and condition.

In a letter Tuesday to the New York Public Service Commission, the company wrote that gas turbine units 4, 5 and 6, which began operating in 1970 and total 64.2 MW, could be taken out of service on April 30, 2016. “Over the past 24 months, several operational and maintenance issues have occurred, including evaluation and repairs resulting from Hurricane Sandy. These units are reaching end of life unless substantial investment is made to numerous components.”

Unit 7, of similar size and vintage, was taken out of service in March 2014 after “it experienced an over speed condition, high vibrations, a rotor ground and discovery of failed bolts in the turbine rotor first stage section.”

The units are part of a 2,480-MW complex of gas-fired generators, including baseload plants, in Astoria, Queens. At its full capacity, the complex could serve about one-fifth of New York City’s peak demand.

“Over the next six months, they will continue to operate as we have obligations to make the units available to the New York market,” company attorney Jim D’Andrea told RTO Insider.

The company said it has not made a final decision on the plants’ fate. D’Andrea said that the company would make a decision on whether the units should be refurbished “based on the economics.”

According to the latest NYISO Gold Book, the three plants produced a combined 500 MWh of net energy in 2014.

The PSC will request a study by NYISO to determine if the units are needed to maintain reliability.