A comment from the NYT's Dot Earth blog (or "Asked and answered, counselor"):
I’m pleased to report that the information on CARMA about the CO2 emissions and power-generating capacity of Con Ed’s East River plant appears to be accurate. According to the information below from Con Ed’s website, the utility upgraded its equipment at the East River plant two years ago, to wit:
“Con Edison declared full commercial operation of its East River Repowering Project on April 5, 2005, when the second of two state-of-the-art, natural-gas-fired steam generators began providing power to New York’s electricity grid. The first unit became operational on April 1. When the new equipment is in full operation, it produces 288 megawatts of electricity, in addition to the 309 megawatts of power already being generated by existing equipment.
“The repowering of Con Edison’s East River generating station was undertaken to enhance an already environmentally beneficial steam system, and is capable of producing 5.4 million pounds of steam per hour. Steam is used for heating, hot water, and in some buildings, to power air conditioning chillers. The use of steam-powered chillers reduces the load on the electric system during times of peak summer demand.
“The two steam-electric generators have up-to-date emission-control technology and burn natural gas 100 percent of the time, making East River one of the cleanest power generating facilities in New York.”
— Posted by John Hunka