This study team’s objective is to evaluate the impact and mitigation of potential long-term Alcoa shutdown.
In 2015, Alcoa curtailed production at its Alcoa Wenatchee Works plant due to unfavorable market conditions for some of Alcoa’s aluminum products. At that time and presently, Alcoa has forecast its Wenatchee Works to return to operation in spring 2017. The loss of the Alcoa load has impacted electrical transmission and generation operations in the immediate area, including operations at Chelan PUD’s Rock Island hydroelectric project and McKenzie switchyard and BPA’s Valhalla substation, which includes a tie to the Douglas PUD system. To mitigate the impact from Alcoa plant shutdown, temporary procedures have been developed to separate Chelan PUD’s McKenzie switchyard from BPA’s Valhalla substation during these impacting conditions. Chelan PUD has also developed emergency ratings for its outgoing facilities from McKenzie.
Concurrent to implementing the above temporary mitigation procedure, a long term plan should be developed to address potential issues from both system operations and planning point of views in case the Alcoa plant does not resume operations in 2017 as predicted. Such a long term plan is discussed and evaluated with joint study efforts from neighboring system. ColumbiaGrid created a The study team includes representatives from Chelan PUD, BPA, Douglas PUD, Grant PUD. The purpose of this study team is to evaluate potential long-term alternatives to these temporary mitigation procedures. These alternatives could potentially include additional emergency ratings, reconductoring existing facilities, construction of new facilities, or the use of special protection schemes.