Wind power is being added to the grid at a rapid pace, offsetting fossil fuel generation and reducing emissions. To accommodate the variability of wind, dispatchable generation must provide more load following capabilities, higher system-wide ramp rates are needed, and more frequent shut downs will occur. Coal plants were historically not designed to provide this flexibility and operating them in such a manner may increase emissions and reduce the environmental benefits of wind power. Using a comprehensive unit commitment and dispatch model, this study quantifies the impact on emissions from coal unit cycling caused by wind variability, including the impacts from partial load operation, number of unit starts, ancillary service requirements, increased forced outage rates, and heat rate degradation. The results inform a consequential life cycle assessment of wind power and help identify the environmentally optimal deployment of wind.