The Bonneville Power Administration (BPA) recently released a draft environmental assessment on a power line project that it said will help ease seasonal constraints on its hydroelectric dams due to grid congestion issues.
BPA is proposing to participate in the construction of a new 230-kV transmission line and associated facilities in the northern mid-Columbia area of Washington State. The overall project is referred to as the Northern Mid-Columbia Joint Project, while the proposed transmission line is referred to as the Rapids-Columbia 230-kV transmission line. This proposed transmission line would extend from Douglas County Public Utility District No. 1’s Rapids Switchyard, located outside the city limits of Rock Island, to BPA’s Columbia Substation.
The electrical systems of the mid-Columbia PUDs deliver electric power to and from BPA over a federal transmission system. There are currently periods of transmission congestion that occur on the mid-Columbia area transmission system. Transmission line congestion occurs when too much power enters transmission lines without sufficient capacity, causing them to overload. Overloading of transmission lines causes these lines to operate at over 100% of their present temperature rating. Overloads can result in thermal heating on transmission lines that can lead to power outages. Chelan County PUD, Grant County PUD, and Douglas County PUD (collectively called the mid-Columbia PUDs) own and operate electrical systems in the northern mid-Columbia area that are interconnected to this system. This project will ease those overloads, adding new capacity to the system, capacity that is also needed due to regional load growth.
“The implementation of operational procedures to prevent overloads in the northern mid-Columbia transmission area can result in the need to redispatch or reduce generation at the Chelan PUD Rocky Reach and Douglas PUD Wells hydroelectric generation facilities, decreasing the ability to serve hourly demands and reducing the ability of the PUDs to generate revenue,” the EA noted. “The congested system adds another undesirable variable that constrains the operation of the Columbia River hydroelectric generation facilities.”
Interested parties should send comments on the draft EA to BPA by Jan. 14, 2015. BPA and Douglas PUD have also scheduled two informal, open-house meetings in December, in Rock Island and Malaga, to answer questions and accept comments on the draft EA.