Repowering cuts air pollution, improves station`s efficiency

This article reports that after rehab plans for 30-yr-old boilers proved untenable, gas-fired combined cycle, with the existing steam turbines retained, was the choice. Large reductions in NO{sub x}, SO{sub 2}, and CO{sub 2} will be benefits. A unique closed-loop cooling system reduces impact on environment in several ways. When the boilers of existing steam Units 1 and 2 at Bergen generating station were in need of major overhaul, Public Service Electric and Gas Co (PSE and G) began analysis of alternatives to the rehab work. Combined-cycle repowering offered several advantages, including improvement in efficiency -- from 28 to 44% -- and important reduction in air-pollutant and thermal emissions. Continued use of a large portion of the existing plant and infrastructure meant added economic advantages for repowering over construction of a new plant. The project which will come on line in 1995, increases station output from 570MW to 650MW. The station operates as a load-following unit, with expected capacity factor of 65% compared with 30% for the old station. For minimum load, one gas turbine (GT) runs at 100% load, with the steam turbine operational. The GTs operate independently, and the ramp up to 100% load is done immediately, whichmore » gives best efficiency and reduces air emissions.« less