This map shows the area that would be significantly impacted by pollution emitted from the proposed power plant. The red dot in the center indicates the location the proposed fossil fuel burning power plant and the surrounding circle indicates a 20 km radius around the proposed plant. According to NTE the Significant Impact Area will actually include a radius of 20.2 km. from the plant.
Table L-10 on page L-17 on the following link lists the Significant Impact Area while running on natural gas however as you can see they do not quantify the Significant Impact Area while operating on diesel which they would be able to do for up to 30 days per year.