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Columbia Water & Light is continuing to study ways to serve electric loads and improve reliability for the southwestern part of the city. This project involves adding transmission lines to connect the new Millcreek substation on Peach Tree Drive with some of the existing substations. The initial routes that were studied are referred to as Option A. In November 2010, the City Council directed Columbia Water & Light staff to seek alternative transmission line options for the project. Columbia Water & Light is now conducting a transmission line route study for Option B.
Tabulation of feedback will lead to preferred Option B transmission line routes
After holding an interested parties meeting last fall Columbia Water & Light collected feedback for several months on the second route study (Option B) for the proposed southwestern transmission line project. In December the feedback was put into a database and submitted to the engineering firm assisting with the project. An important part of determining the preferred routes for Option B is to make sure the selection matrix reflected the public opinion that was submitted. The selection matrix phase is complete and Columbia Water & Light staff is reviewing the results and preparing a report for the City Council. If the City Council agrees, the next step in the project would be to hold another interested parties meeting. Click here to download the adjusted time line for this project.
The intent of the alternatives in the Option B alignment study is to connect the Mill Creek substation with 69 kilovolt lines along the existing 69 kilovolt line route from the Grindstone substation to the Hinkson Creek substation. Option B will place the Mill Creek substation in series with the 69 kilovolt circuit from Grindstone to Hinkson Creek substations. In addition, Option B connects the McBaine substation to the Perche Creek substation via a 161 kilovolt line routed along the southwestern periphery of the city limits as Council suggested. The feedback that was collected will be tabulated and used in the evaluation matrix so another report can be made to the City Council. See the time line for more information about the process of selecting the transmission line routes.
September 28 Interested Parties meeting presentation
Report to Council on Option B August 1, 2011
McBaine to Perche Creek 161 kV Line Route Options (Figure 1)
Grindstone to Mill Creek to Hinkson Creek Options (Figure 2)
The initial route study from the fall of 2010 is now being referred to as Option A. The intent of the Option A alignment study was to connect 161 kV circuits to the Mill Creek substation from the Grindstone, Perche Creek, and McBaine substations. This option had various routes for each section of the project. All of the public comment that was received at the open house, through letters, e-mails and phone calls about the various routes was tabulated by Columbia Water & Light staff. There is a memo about Option A that went to Council on April 18, 2011.
Sega Engineering took the public feedback along with other evaluation criteria and conducted the analysis of the various routes for Option A. There were many decision factors that were considered and two evaluations were run. One evaluation used public input and costs as decision factors and the other evaluation removed cost as a decision factor. In both evaluations the same routes were identified as shown in this map of Option A. The Millcreek to Perche route runs along Nifong/Vawter and Scott Boulevard the Millcreek to McBaine route runs along Providence/ Route K. The Mill Creek to Grindstone route runs along Grindstone/Nifong.
Download a pdf file of the time line. The feedback from the September meeting that was submitted to Columbia Water & Light is being used to establish the evaluation matrix for Option B so the most desirable routes can be established. This is the same procedure that was used for the Option A analysis. The next step in the process is to send the results of the Option B analysis to the City Council.
Open House Meeting: September 28
presentation from the open house
Report to City Council: April 18, 2011
Council memo about Option A (other files from this meeting are listed above)
Change order to the contract with the Sega Engineering
Columbia Pre-City Council meeting: February 21, 2011
Download the power point presentation
Columbia City Council work session, November 22, 2010
Download the work session presentation
Watch the video of the work session
Questions and answers from the work session
Public Comment Overview for Option A
Download a .pdf with an overview of the top 5 the public concerns with the Perche, McBaine and Grindstone routes that were initially proposed under Option A. (Note: these are also included in the 2-21-11 power point presentation listed above)
Electricity is generated at a power station or power plant from fossil fuels or renewable resources. Approximately 90% of Columbia's energy comes from sources outside the city. Once the power is generated, it has to be moved to where it is going to be used. Large amounts of power are transferred with electric transmission lines. An interconnected network of transmission lines are commonly referred to as the power grid.
Transmission lines feed into substations where transformers step down the power to lower voltages. From there, power is delivered to individual electric customers by distribution lines. New distribution lines in Columbia must be placed underground according to city ordinances. In the older sections of town, distribution lines are mounted on wooden poles.
Electrical power delivery systems are built with an interconnected network of transmission and distribution lines. That way if there is a problem with one section of an electric line, operators can switch the flow and provide electricity to customers with another line. An interconnected electric grid helps the reliability of the system and can greatly reduce the length of an outage
To handle electric load growth in southern Columbia and for reliability purposes. There is a growing need for more electricity on the southern side of Columbia. Substations in the area are approaching their maximum capacity both electrically and physically. This makes them vulnerable to being overloaded which could cause power outages and damage to other equipment in the system.
Transmission systems need to be built so one outage will not cause overloading of another transmission line. If there are two outages, the system must be built so there are not cascading outages. A new substation and transmission lines in Columbia will reduce the loading on the existing substations, ensure greater electric reliability and will improve regional stability for the power grid.
Sega, Inc. was hired by the city to evaluate different transmission line routes to start the public discussion. The consultants divided the project into three different sections and proposed three to four different routes for each section. The initial routes were chosen using these criteria:
After the initial routes are selected, they are presented to the public and the City Council. Written public comment is tabulated to formulate a selection matrix. This matrix helps develop the routes that are most favorable to the community. Once both Option A and Option B routes are identified, the City Council will direct Columbia Water & Light if it is time for the final route selection process to begin. This could include another Open House and a public hearing before the City Council. The City Council will have the final decision on the route paths. Click here for a time line of the project.
A single arm transmission line could be used when there is only one transmission line
A double arm transmission line could be used when there are multiple electric lines
It is possible to bury electric transmission lines but it costs more than burying distribution lines. Placing transmission lines underground costs approximately five times more than placing the lines overhead. Due to the high voltage of these lines, different underground conduits are required than what is used for distribution lines. Placing lines underground also involves more disruption to the right-of-way during installation and repair, which is generally near private property.
Electric and Magnetic Fields (EMF) are generated by the flow of electrons. Electric fields are established between points of different voltages. Magnetic fields are generated by electrons flowing in a conductor. EMF are generated by electric lines as well as many common household items.
According to the Environmental Protection Agency, “Much of the research about power lines and potential health effects is inconclusive. Despite more than two decades of research to determine whether elevated EMF exposure, principally to magnetic fields, is related to an increased risk of childhood leukemia, there is still no definitive answer. The general scientific consensus is that, thus far, the evidence available is weak and is not sufficient to establish a definitive cause-effect relationship.”
Please see these web sites for more information about EMF and any possible health issues:
Environmental Protection Agency - (1 page overview with links)
Electric Power Research Institute – general overview and list of resources on EMF (5 pages)
Electric Power Research Institute - answers to frequently asked questions about EMF (2 pages)
National Institute of Environmental Health Sciences & National Institute of Health – detailed overview of EMF studies (65 pages)
Western Area Power Association – provides a basic overview of EMF and levels of EMF found in power lines (16 pages)
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