There is a shortage of high-voltage transmission lines in the United States, and demand is expected to grow at least 20 percent in the next decade. Yet selection of transmission line routes is a growing source of public controversy and regulatory scrutiny throughout the world.
To keep pace with demand in a state where the population this decade is expected to grow by 19 percent and the energy demand is expected to grow by 39 percent, Georgia Transmission Corporation (GTC) builds about 70 miles of new transmission lines each year. GTC is an electric transmission cooperative owned by and serving 39 electric distribution cooperatives in Georgia. These member systems serve some of the fastest growing communities in the nation.
From our experience with highly organized opposition to new power lines, we concluded that there had to be a better way. The industry needed a better process for making routing decisions more consistent and defensible. So we helped produce it.
The siting methodology we use today was developed through a $500,000 tailored collaboration project we co-funded with the Electric Power Research Institute (EPRI) and Photo Science, a Kentucky-based geospatial solutions company. GTC assigned two project managers with environmental and routing expertise, Christy Johnson and Gayle Houston, to spearhead this three-year effort. We formed a team of national experts in global information systems, environmental compliance and other disciplines to head up the research. We also involved more than 200 participants from government agencies, utilities, environmental groups and neighborhood organizations.
The resulting EPRI-GTC Overhead Transmission Line Siting Methodology represents the most advanced, scientifically rigorous siting approach available today. EPRI published the methodology in February 2006 as a national model for siting transmission lines. In May 2006, the methodology earned GTC the National Rural Electric Cooperative Association’s 2006 Cooperative Innovators Award. It has been real-world tested on more than 200 miles of transmission line projects.
Why is a national model desirable?
While it is not a political panacea, it does produce more consistent, defensible and transparent siting decisions. It provides a unique mechanism for utilities to receive informed, proactive and constructive input from stakeholders, rather than just the “not-in-my-backyard” reaction that frustrates the public and utilities alike.
Equally important, an objective, consistent national model gives utilities and regulatory agencies something to hang their hat on. The Kentucky Public Service Commission (PSC) recently praised the metholology. After turning down previous requests, the Kentucky PSC approved an East Kentucky transmission line project using the EPRI-GTC Methodology.
The methodology has three main benefits. It produces siting decisions that are consistent, objective and defensible; it improves productivity and analytical capabilities; and it lowers data acquisition costs.
An analysis of eight GTC siting projects found an average data-collection cost savings of more than 60 percent. Cost savings on individual projects ranged from $12,000 for a smaller project to more than $130,000 for larger projects. These savings are in addition to improvements in site selection and project scheduling.
Having siting decisions backed by a more consistent rationale is by far the greatest benefit, particularly when we consider potential public, legal and legislative consequences. The EPRI-GTC Siting Methodology allows external groups to participate in the process and makes decisions by utility professionals more transparent and credible.
It uses GIS software called Corridor Analyst©. This software maps all geographic features, assigns numerical suitability values to features, assigns engineering constraints, generatescorridor alternatives, automatically generates alterative corridor reports and creates reports of criteria used and values assigned.
The GIS siting model, the software tool, does not replace judgment. I’ve heard misperceptions that we have developed a computer system that will tell you where to build a transmission line if you give it starting and end points and push a button. While the system rapidly processes huge amounts of data and defines corridors and routes, professional judgment and consensus are still needed to establish the relative importance of study criteria.
Most important, final routes are still selected by staff members who have to weigh visual impacts, community concerns and construction requirements and other issues. Instead of thinking “automated decision-making,” think “data-assisted decision-making.”
What sets the EPRI-GTC Siting Methodology apart from other GIS-based routing processes?
The utility team and external stakeholders work in collaboration to assess and rank criteria for siting. External stakeholder calibration can be done on a regional, statewide or local basis. The EPRI-GTC process standardizes alternative corridors. Unique to our approach, algorithms create different alternative corridors on suitability maps for manmade, natural and engineering features. A forth-alternative corridor is made from a composite average.
It is a well-defined four-step process that incorporates external stakeholder input, uses GIS technology to synthesize and quantify extensive amounts of data, and ultimately relies on the expert judgment of utility professionals to select a preferred route.
The steps are straightforward.
Step One: Identify Macro Corridors
First, the planning staff identifies beginning and end points where a new power line is needed. Satellite imagery and data on roads, terrain and existing transmission lines are merged to form one digital map of the study area. This map is comprised of a grid of 100-square-foot cells.
Each cell on the map is ranked. Features such as residential land use, agriculture and wetlands are ranked from 1 (most suitable) to 9 (least suitable). Using the cell values, a computer algorithm calculates optimal paths for three types of suitability surfaces:
• locating with existing transmission lines
• locating with existing road rights of way
• crossing less developed areas
The optimal paths are identified as macro corridors. Combined, the outer boundaries of the macro corridors define the study area.
Step Two: Identify Alternative Corridors
More detailed data (including aerial photography, detailed land use/land cover, buildings, etc.) are collected to identify alternative corridors within the macro corridors. Using suitability maps comprised of 15 square-foot cells, four types of alternative corridors are defined:
• Built environment - protecting human and cultural resource areas
• Natural environment - protecting plants, animals and aquatic resources
• Engineering requirements - maximizing co-location and minimizing cost and schedule challenges
• Simple Average - a composite of the other three
Collaborative rankings
The utility team and external stakeholders set evaluation criteria and rank factors, such as housing density, wetlands and land cover. Stakeholders from government and industry and from civic, homeowner, environmental and other interest groups are invited to participate in ranking these factors.
Step Three: Identify Alternative Routes
Within the alternative corridors, property lines are identified and buildings, which are digitized earlier in the process, are classified by type, such as occupied house, commercial building or industrial building. Collecting detailed data after alternative corridors are identified significantly reduces data acquisition costs. In this phase, utility professionals use their expert judgment to identify alternative routes within the corridors defined by stakeholders.
Step Four: Select A Preferred Route
GIS tools automatically calculate a standardized list of metrics for the alternative routes. Data evaluated include cost, number of houses close to the route, acres of forest in rights of way and so forth. The alternative route evaluation tool uses data to filter out the top few routes to forward to the expert judgment phase.
Using an expert judgment tool, the utility siting team assigns relative weights to community concerns, visual concerns, special permit issues, scheduling risks and construction and maintenance accessibility. Then the top route alternatives are ranked using expert analysis to identify a preferred route.
Throughout the process, GIS is a productivity tool to aid experts in the decision-making. It enables siting team members from engineering, land acquisition, environmental and other areas to use map overlays, spreadsheets, reports and graphic illustrations to make more informed, objective and defensible decisions.
Today utilities across the United States and around the world are embarking on large Ètransmission constructions to keep pace with demand. We continue to face strong, organized constituencies who demand more accountability and transparency in the route-selection process. We feel that the EPRI-GTC model is part of the answer.
By adopting the siting methodology, Georgia Transmission has demonstrated its willingness to improve the way we site lines. I encourage utility managers to get a copy of the report from EPRI. It’s available for free. And we hope our efforts will spur others in the industry to adopt, expand and improve the way we all determine where to locate lines. n
For more information, please contact GTC at (770) 270-7050, or e-mail GTC at EPRI-GTCsiting@gatrans.com. Information is also available at www.epri-gtc-siting.com.
About the Author
Jerry DonovanSenior Vice President, Project Services
Georgia Transmission Corporation
Jerry Donovan is Senior Vice President, Project Services for Georgia Transmission Corporation. His career in the electric utility industry spans more than 20 years. His experience encompasses all phases of facility planning, design and construction of electric power facilities. Additionally, he has extensive experience in project management and in corporate strategic planning and management.
Early in his career he served as a Project Engineer for both substation and transmission line projects. Additional duties have provided valuable experience in customer service, facilities planning, real estate and environmental issues.
Since the formation of Georgia Transmission Corporation in April 1997, he has served as Manager, Construction and Project Management Program and in early 1999 assumed the role of Vice President, Project Services. He was promoted to Senior Vice President, Projects Services in May 2006. This position is directly responsible for a capital construction program that includes land acquisition, environmental compliance, design, construction and project management for the corporation’s annual capital budget of more than $100 Million in 2003.
Donovan earned BS degree in Electrical Engineering from Mississippi State University. He is actively involved in the Institute for Electrical and Electronics Engineers (IEEE).
To keep pace with demand in a state where the population this decade is expected to grow by 19 percent and the energy demand is expected to grow by 39 percent, Georgia Transmission Corporation (GTC) builds about 70 miles of new transmission lines each year. GTC is an electric transmission cooperative owned by and serving 39 electric distribution cooperatives in Georgia. These member systems serve some of the fastest growing communities in the nation.
From our experience with highly organized opposition to new power lines, we concluded that there had to be a better way. The industry needed a better process for making routing decisions more consistent and defensible. So we helped produce it.
The siting methodology we use today was developed through a $500,000 tailored collaboration project we co-funded with the Electric Power Research Institute (EPRI) and Photo Science, a Kentucky-based geospatial solutions company. GTC assigned two project managers with environmental and routing expertise, Christy Johnson and Gayle Houston, to spearhead this three-year effort. We formed a team of national experts in global information systems, environmental compliance and other disciplines to head up the research. We also involved more than 200 participants from government agencies, utilities, environmental groups and neighborhood organizations.
The resulting EPRI-GTC Overhead Transmission Line Siting Methodology represents the most advanced, scientifically rigorous siting approach available today. EPRI published the methodology in February 2006 as a national model for siting transmission lines. In May 2006, the methodology earned GTC the National Rural Electric Cooperative Association’s 2006 Cooperative Innovators Award. It has been real-world tested on more than 200 miles of transmission line projects.
Why is a national model desirable?
While it is not a political panacea, it does produce more consistent, defensible and transparent siting decisions. It provides a unique mechanism for utilities to receive informed, proactive and constructive input from stakeholders, rather than just the “not-in-my-backyard” reaction that frustrates the public and utilities alike.
Equally important, an objective, consistent national model gives utilities and regulatory agencies something to hang their hat on. The Kentucky Public Service Commission (PSC) recently praised the metholology. After turning down previous requests, the Kentucky PSC approved an East Kentucky transmission line project using the EPRI-GTC Methodology.
The methodology has three main benefits. It produces siting decisions that are consistent, objective and defensible; it improves productivity and analytical capabilities; and it lowers data acquisition costs.
An analysis of eight GTC siting projects found an average data-collection cost savings of more than 60 percent. Cost savings on individual projects ranged from $12,000 for a smaller project to more than $130,000 for larger projects. These savings are in addition to improvements in site selection and project scheduling.
Having siting decisions backed by a more consistent rationale is by far the greatest benefit, particularly when we consider potential public, legal and legislative consequences. The EPRI-GTC Siting Methodology allows external groups to participate in the process and makes decisions by utility professionals more transparent and credible.
It uses GIS software called Corridor Analyst©. This software maps all geographic features, assigns numerical suitability values to features, assigns engineering constraints, generatescorridor alternatives, automatically generates alterative corridor reports and creates reports of criteria used and values assigned.
The GIS siting model, the software tool, does not replace judgment. I’ve heard misperceptions that we have developed a computer system that will tell you where to build a transmission line if you give it starting and end points and push a button. While the system rapidly processes huge amounts of data and defines corridors and routes, professional judgment and consensus are still needed to establish the relative importance of study criteria.
Most important, final routes are still selected by staff members who have to weigh visual impacts, community concerns and construction requirements and other issues. Instead of thinking “automated decision-making,” think “data-assisted decision-making.”
What sets the EPRI-GTC Siting Methodology apart from other GIS-based routing processes?
The utility team and external stakeholders work in collaboration to assess and rank criteria for siting. External stakeholder calibration can be done on a regional, statewide or local basis. The EPRI-GTC process standardizes alternative corridors. Unique to our approach, algorithms create different alternative corridors on suitability maps for manmade, natural and engineering features. A forth-alternative corridor is made from a composite average.
It is a well-defined four-step process that incorporates external stakeholder input, uses GIS technology to synthesize and quantify extensive amounts of data, and ultimately relies on the expert judgment of utility professionals to select a preferred route.
The steps are straightforward.
Step One: Identify Macro Corridors
First, the planning staff identifies beginning and end points where a new power line is needed. Satellite imagery and data on roads, terrain and existing transmission lines are merged to form one digital map of the study area. This map is comprised of a grid of 100-square-foot cells.
Each cell on the map is ranked. Features such as residential land use, agriculture and wetlands are ranked from 1 (most suitable) to 9 (least suitable). Using the cell values, a computer algorithm calculates optimal paths for three types of suitability surfaces:
• locating with existing transmission lines
• locating with existing road rights of way
• crossing less developed areas
The optimal paths are identified as macro corridors. Combined, the outer boundaries of the macro corridors define the study area.
Step Two: Identify Alternative Corridors
More detailed data (including aerial photography, detailed land use/land cover, buildings, etc.) are collected to identify alternative corridors within the macro corridors. Using suitability maps comprised of 15 square-foot cells, four types of alternative corridors are defined:
• Built environment - protecting human and cultural resource areas
• Natural environment - protecting plants, animals and aquatic resources
• Engineering requirements - maximizing co-location and minimizing cost and schedule challenges
• Simple Average - a composite of the other three
Collaborative rankings
The utility team and external stakeholders set evaluation criteria and rank factors, such as housing density, wetlands and land cover. Stakeholders from government and industry and from civic, homeowner, environmental and other interest groups are invited to participate in ranking these factors.
Step Three: Identify Alternative Routes
Within the alternative corridors, property lines are identified and buildings, which are digitized earlier in the process, are classified by type, such as occupied house, commercial building or industrial building. Collecting detailed data after alternative corridors are identified significantly reduces data acquisition costs. In this phase, utility professionals use their expert judgment to identify alternative routes within the corridors defined by stakeholders.
Step Four: Select A Preferred Route
GIS tools automatically calculate a standardized list of metrics for the alternative routes. Data evaluated include cost, number of houses close to the route, acres of forest in rights of way and so forth. The alternative route evaluation tool uses data to filter out the top few routes to forward to the expert judgment phase.
Using an expert judgment tool, the utility siting team assigns relative weights to community concerns, visual concerns, special permit issues, scheduling risks and construction and maintenance accessibility. Then the top route alternatives are ranked using expert analysis to identify a preferred route.
Throughout the process, GIS is a productivity tool to aid experts in the decision-making. It enables siting team members from engineering, land acquisition, environmental and other areas to use map overlays, spreadsheets, reports and graphic illustrations to make more informed, objective and defensible decisions.
Today utilities across the United States and around the world are embarking on large Ètransmission constructions to keep pace with demand. We continue to face strong, organized constituencies who demand more accountability and transparency in the route-selection process. We feel that the EPRI-GTC model is part of the answer.
By adopting the siting methodology, Georgia Transmission has demonstrated its willingness to improve the way we site lines. I encourage utility managers to get a copy of the report from EPRI. It’s available for free. And we hope our efforts will spur others in the industry to adopt, expand and improve the way we all determine where to locate lines. n
For more information, please contact GTC at (770) 270-7050, or e-mail GTC at EPRI-GTCsiting@gatrans.com. Information is also available at www.epri-gtc-siting.com.
About the Author
Jerry DonovanSenior Vice President, Project Services
Georgia Transmission Corporation
Jerry Donovan is Senior Vice President, Project Services for Georgia Transmission Corporation. His career in the electric utility industry spans more than 20 years. His experience encompasses all phases of facility planning, design and construction of electric power facilities. Additionally, he has extensive experience in project management and in corporate strategic planning and management.
Early in his career he served as a Project Engineer for both substation and transmission line projects. Additional duties have provided valuable experience in customer service, facilities planning, real estate and environmental issues.
Since the formation of Georgia Transmission Corporation in April 1997, he has served as Manager, Construction and Project Management Program and in early 1999 assumed the role of Vice President, Project Services. He was promoted to Senior Vice President, Projects Services in May 2006. This position is directly responsible for a capital construction program that includes land acquisition, environmental compliance, design, construction and project management for the corporation’s annual capital budget of more than $100 Million in 2003.
Donovan earned BS degree in Electrical Engineering from Mississippi State University. He is actively involved in the Institute for Electrical and Electronics Engineers (IEEE).
