System-wide emissions implications of increased wind power penetration
by Lauren Valentino, Viviana Valenzuela, Audun Botterud, Zhi Zhou, and Guenter Conzelmann
A new study from Argonne National Laboratory, part of the US Department of Energy, has found that increasing wind power many not lower grid emissions as much as previously thought.
The crux of the problem is wind's intermittency -- turbines generate power only when the wind is blowing. This requires that grid maintain backup systems to provide baseload power during periods of calm. The full report can be accessed by clicking on the link at the bottom of this page.
This paper discusses the environmental effects of incorporating wind energy into the electric power system. We present a detailed emissions analysis based on comprehensive modeling of power system operations with unit commitment and economic dispatch for different wind penetration levels. First, by minimizing cost, the unit commitment model decides which thermal power plants will be utilized based on a wind power forecast, and then, the economic dispatch model dictates the level of production for each unit as a function of the realized wind power generation. Finally, knowing the power production from each power plant, the emissions are calculated. The emissions model incorporates the effects of both cycling and start-ups of thermal power plants in analyzing emissions from an electric power system with increasing levels of wind power. Our results for the power system in the state of Illinois show significant emissions effects from increased cycling and particularly startups of thermal power plants. However, we conclude that as the wind power penetration increases, pollutant emissions decrease overall due to the replacement of fossil fuels.