For the past couple of years, a large natural gas fired generation plant (named "Cricket Ridge") has been under construction adjacent to Route 22 south of Dover Plains (NY). I believe I read somewhere that it can take up about 50% or so of the output of Indian Point (once that's closed), but of course that's "only half".
There's another gas-fired plant that I believe is now complete next to interstate 84 in Middletown, but not sure if that was built to supply power to NYC, or instead is intended for the Orange County area.