This project involves adding transmission lines to connect the new Mill creek substation on Peach Tree Drive with some of the existing substations. After a special, second public hearing on the route for the transmission lines, the Columbia City Council decided on January 19, 2016 not to build transmission lines according to the Option A route. This project is on hold until further direction is given by the City Council.
QUESTIONS? Call the Electric Transmission Project information line (844)244-7870 (toll free)
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Why do we need a new substation and transmission lines in Columbia?
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.
What is a power grid?
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
Can transmission lines be buried?
The Columbia City Council decided to build the new transmission lines overhead. Due to the high voltage of the electricity the lines carry, it is much more involved to bury them than it is distribution lines. Transmission lines are not frequently buried in the United States due to the cost. Placing transmission lines underground in Columbia is estimated to cost $7.6 million per mile versus $1.1 million per mile for overhead construction. The estimated rate impact per customer to build the lines underground would be $8.26 per month for 20 years versus $1.18 for overhead. (NOTE: This information has not been updated since 2013. Since that time, the Columbia City Council has not requested any additional information on the costs of burying transmission lines.
What process was used to come up with the proposed routes?
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:
- Streets preferred over backyards and cross country
- Main roads preferred over side streets
- Commercial corridors preferred over residential
- Most direct route preferred (fewest angles in the route)
After the initial routes were selected, they were presented to the public and the City Council. Written public comment was tabulated to formulate a selection matrix for each route. Columbia Water & Light collected feedback during late 2012/early 2013 to determine the public’s most favorable route and the preference for building overhead or underground electric transmission lines.
City Council work session Presentation May 16, 2016
Council information regarding the transmission project on January 19, 2016
Council information regarding the transmission project on November 16, 2015
- Report to City Council Nov 2015
- November 2015 City Council presentation
- Transmission Project Fact Sheet
City Council Public Hearing to Determine Route
Download the presentation file: July 15, 2013 City Council meeting
Option A Route
Option A was selected by the City Council as the route for the new transmission lines in 2013 and then the City Council decided against Option A in January 2016. The intent of the Option A alignment study is to connect 161 kilovolt circuits to the Mill Creek substation from the Grindstone, Perche Creek, and McBaine substations. The route will run along Providence, Grindstone/Nifong/Vawter School Road and Scott Boulevard.
Columbia Water & Light staff members support Option A for the following reasons:
- Meets the need for both the transmission and distribution capacity for the longest term with a single cost-effective solution.
- Transfers load to the 161 kV system and preserves current 69 kV capacity
161 kV option more than doubles the power transmission capacity
- Does not require rebuilding of existing 69kV system
- Provides connections between 3 different import substations which is a more reliable & longer term solution
- Route Option B has four times the number of second contingency issues than Option A
Uses more existing easements than route Option B
- Water & Light Advisory Board endorsed Option A without undergrounding options
Memo about Option A that went to Council on April 18, 2011
Option A Selection Matrix Results from 2011
- NOTE: The work on the pole structure type and locations was stopped after the City Council decided to hold a special, second public hearing on the transmission line route. The pole structure type and locations shown in the video are at the 30% design phase so there might still be changes to pole types and locations.
Option B & B-2 Routes
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. Public feedback was used for the evaluation matrix to determine the preferred routes for Option B.
After the publicly preferred route for Option B was identified, Columbia Water & Light staff looked into the possibility of moving a section of the line to city owned property near the Wastewater Treatment Plant, the city’s wetland cells and the Water Treatment Plant. These properties also contain a section of the MKT trail. Option B-2 was presented to the City Council in August 2012 and at a public meeting in November.
Option B map – publicly preferred route
Option B-2 map – publicly preferred route
Report to the City Council on 8-20-12: Mill Creek Substation Transmission Study – Option B
Determining Pole Placement
Determining pole placement along Option A has been stopped due to the City Council reversing its decision on building lines along the Option A route. opens in a new windowProposed pole placement along the route has been determined and comments regarding these locations are being collected. There are a number of factors taken into consideration before a decision can be made, including:
- working around underground utilities
- location of street intersections
- soil stability
- easement rights and space/lengths between each pole
Are there health concerns associated with EMF?
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. EMFs decrease in strength with distance from the source.
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 reports and web sites for more information about EMF and any possible health issues
Additional Reports and Presentations to City Council
- November 22, 2010: Presentation for the City Council work session
- Questions and answers from the work session
- February 21, 2011: Presentation for Pre-City Council meeting
- April 5, 2011: Amendment to change order to the contract with the Sega Engineering
- August 1, 2011: Report to Council on Option B
- September 28, 2011: Open House Presentation
- November 13, 2012: Open House Presentation
- May 20, 2013: Report to City Council on the public’s feedback
- June 13, 2013: Presentation for the City Council work session (6.87 MB)