Big Stone II Power Plant and Transmission Project
In May 2006, Western Area Power Administration (Western), Rural Utilities Service (RUS), and U.S. Army Corps of Engineers (USACE) issued the Big Stone II Power Plant and Transmission Project Draft Environmental Impact Statement (Draft EIS, DOE/EIS-0377). The Draft EIS described the details of constructing and operating a nominal 600-megawatt (MW), coal-fired, baseload electric generating facility and associated transmission line and substation upgrades, known as the Big Stone II Project (proposed Project). Western determined that the use of groundwater as the back-up water supply would significantly change the environmental impacts of the proposed Project as presented in the Draft EIS and requires the preparation of a Supplemental Draft EIS. The change in the net capacity from 600 MW to 630 MW would not significantly change the environmental impacts of the proposed Big Stone II plant as presented in the Draft EIS. The purpose of this Supplemental Draft EIS is to present and analyze the environmental impacts of revisions to the proposed action presented in the Draft EIS. The Supplemental Draft EIS also analyzes alternative cooling system technologies for the proposed Project that use groundwater instead of surface water for the proposed Big Stone II power plant’s back-up water supply.