To deliver the power generated by the proposed plant at Big Stone, transmission facilities will need to be upgraded or added. While studies continue, two corridor alternatives appear the most beneficial. Although these alternatives appear to be the most likely, the final upgrades necessary could involve whichever of these alternatives will most effectively serve the region. Upgrades could be a combination of improvements within each of these alternative corridors.
Transmission studies are being conducted through the Midwest Independent System Operator (MISO). Otter Tail Power Company is doing the work as a contractor to MISO. Meetings are being held with interested stakeholders as study results become available.
While studies indicate that 230 kV lines would be sufficient for future needs, the participants plan to build a larger 345 kV line through the center of the corridor, to deliver additional power from other sources, possibly wind and other renewable forms of energy.
When the commissioners have conclusively determined the preferred route and upgrades, the public will be informed through a formal process with appropriate notification.
Environmental review
The entire project is subject to state and federal environmental review. Both Environmental Impact Statements (EIS) are underway.
Project cost and schedule
Federal and site permitting processes are underway and should be completed spring 2008. If permits are granted, construction could begin in 2008. Construction should be complete by early 2012 at a cost in the range of $225 million to $275 million.
CapX 2020 coordination
The transmission owners in the state, including the Big Stone transmission project participants, are committed to coordinated expansion of transmission. This will insure reliable and economic upgrades to the regional system.
Two corridor alternatives now appear most beneficial
The final decision will include the alternatives that will serve the region most effectively. Upgrades could be a combination of improvements within each of these corridors.
When the commission has determined the preferred route and upgrades, a formal notification process will begin.
The Big Stone transmission project includes 140 miles of transmission line—50 miles of which will be new construction—and six new or upgraded substations. Approximately 38 miles of transmission line will be located in South Dakota with the remainder in Minnesota.
The Big Stone transmission project fits into the regional transmission plan by supporting regional electric reliability. The new construction and upgrades, along with other regional facilities, will help ease transmission congestion and facilitate the development of 800 to 1,000 megawatts of additional generation including wind and other renewables. In addition, the decision to secure two transmission routes will lessen the likelihood of extended outages due to storm damage.
Many landowners with transmission structures on their property will not notice a difference caused by transmission upgrades. Existing structures will be replaced and new conductors will be added. The Big Stone participants are taking great care to balance landowner and environmental impact with electric reliability.
