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 GTC-EPRI Siting Model

We were surprised to find out when doing opinion research recently that most civic leaders in the state had no idea that we spend months, sometimes years, evaluating alternative routes for power lines before selecting a preferred location. Nothing illustrates our commitment to balancing environmental, community, engineering and cost concerns as much as the GTC-EPRI Siting Model, an approach we developed with the Electric Power Research Institute (EPRI), a leading industry research group. In an effort to improve siting – the industry’s name for evaluating future power line locations – and encourage an industry standard, we jointly funded research that produced an award-winning siting model which has been adopted by other utilities.

The methodology

A group of respected scientists and statisticians led the research, and Photo Science, Lexington, Ky., provided geographic information systems (GIS) expertise and built the software model called Corridor Analyst. More than 200 participants from government agencies, utilities, environmental groups and civic organizations helped select, rank and weight geographic factors to be considered. They also critiqued the overall siting process. The methodology developed during the research was detailed in a 200-page report, called the EPRI-GTC Electric Transmission Line Siting Methodology, which was released in 2006 by EPRI. GTC reengaged stakeholders in 2011 and 2013 to update and enhance the criteria for the methodology.

How it works​

The process begins by working with external groups to establish values for geographic features. Satellite imagery and geographic databases for the study area are collected. The Corridor Analyst GIS software analyzes and maps all geographic features in a study area, according to numerical suitability values assigned to all features and engineering constraints. Using statistically sound algorithms, the system generates alternative corridors for community, environmental and engineering conditions. Planning engineers can then adjust study assumptions or provide additional detail, such as aerial photography, to further evaluate the corridors and eventually define power line routes in the corridors. Reports for alternative corridors and criteria used and values assigned are automatically created. Our fact sheet explains the major steps taken when we evaluate line locations.

The benefits

  • Produces siting decisions that are more quantifiable, consistent and defensible.

  • Improves productivity and analytical capabilities.

  • Reduces risks by addressing regulatory scrutiny and stakeholder issues.

Cited by industry

Since its inception, the siting model has been adopted by E.ON US, East Kentucky Power Cooperative, Big Rivers Electric Cooperative, Vectren, Georgia Power, Exelon, Bluegrass Water Supply Commission, Pepco Holdings Inc., Oglethorpe Power Corp., The MillionMile Greenway and the Korean Power Engineering Company. It earned the Cooperative Research Network’s 2006 Cooperative Innovators Award from the National Rural Electric Cooperative Association (NRECA). It has been featured at utility conferences and in major trade publications, including Transmission & Distribution World, GeoWorld and Electric Transmission Week.

The team

Research was conducted by Dr. Joseph K. Berry, Colorado State University; Dr. Steven P. French, Georgia Institute of Technology; Dr. Elizabeth A. Kramer, University of Georgia; Steven Richardson, attorney; and Dr. Paul D. Zwick, University of Florida. Georgia Transmission’s project managers were Christy Johnson and the late Gayle Houston. EPRI's project manager was John Goodrich-Mahoney. Photo Science’s Jesse Glasgow and Chris Smith provided technical expertise and developed the Corridor Analyst software. Georgia Transmission acquired the copyright and intellectual property rights to the methodology.

More information

Please e-mail Chris Smith or call us at (770) 270-7919.​

Connecting the dots

Fact sheet explains the major steps of the GTC-EPRI siting methodology

fact sheet >>​​​


Links to industry magazine stories on GTC-EPRI siting

coverage >>​​


“We are pleased GTC and EPRI have taken the lead in developing a standardized siting methodology that is open and transparent, helps utility professionals make more informed decisions based on more comprehensive data and addresses public and regulatory concerns in measurable and meaningful ways.”

Mary Jane Warner, P.E., Manager, Power Delivery Expansion, East Kentucky Power Cooperative


“We applaud East Kentucky's efforts to employ a more objective method of siting than it has employed in the past.”

Kentucky Public Service Commission (after East Kentucky adopted the siting model)