Grid Resiliency, Environmental Consciousness are Key
A 67-year-old Dallas woman made national news in March when she climbed a tree and refused to come down, protesting electric delivery company Oncor’s plan to remove it. It wasn’t her first climb. (She carried a pellet gun the first time).
While stories like this are not the norm, they’re not uncommon. Most people find them humorous and, therefore, they’re often picked up by news outlets. Utility managers and property owners who don’t see eye-to-eye when it comes to vegetation management in right of ways (ROWs), however, find nothing funny about such situations.
Northern California-based Pacific Gas & Electric (PG&E) received even worse publicity last month, when the California Public Utility Commission fined it $8.3 million for failing to maintain a gray pine tree that connected with a power line and ignited a fire. The September 2015 fire burned 110 square miles, destroyed 549 homes, killed two people and caused about $300 million in insured losses.
Tree contact with power lines is a leading cause of power outages and has caused several past regional blackouts, including the August 2003 blackout that affected 50 million people in the northeast U.S. and parts of Canada. This and the PG&E incident show that inadequate vegetation management can cause worse devastation than a local power outage.
|ITC uses helicopters to conduct semi-annual aerial patrols of its high-voltage transmission towers and lines. Courtesy ITC.|
Utilities and transmission system owners/operators are under mounting pressure from politicians, regulators and customers to mitigate power disruptions, prompting many to step up their game when it comes to vegetation management practices. They are taking advantage of new technologies and software that allow them to better monitor their ROWs and track their management programs.
This increased focus on vegetation management has not, however, led utilities to be less cognizant of their customers’ and property owners’ concerns. In fact, most are more sensitive than ever to social and environmental impacts associated with tree trimming and removal. No utility wants to end up on the national news or find itself trending on social media because a customer or property owner is so unhappy that he or she resorted to headline-making stunts like climbing a tree and refusing to come down.
In the case of high voltage transmission lines, the laws and vegetation management requirements are clear. Following the 2003 blackout, federal legislation was enacted to address vegetation management along transmission corridors. The North American Electric Reliability Corp. (NERC) was designated as the “Electric Reliability Organization” and assigned the responsibility of developing and enforcing standards to ensure bulk power system reliability. This included development of reliability standard FAC-003-2, which addresses vegetation management on ROWs.
FAC-003-2 requires that trees and other vegetation growing in or adjacent to a power line ROW be trimmed to prevent power outages caused by tree contact with a transmission line. Each utility can develop and implements its own vegetation management plan, but that plan must conform to FAC-003-2, as well as all state and local requirements and any applicable ROW or easement agreements with property owners.
Lower voltage distribution lines-usually those lines below 100 kV-are not regulated by FAC-003-2, but are regulated by each state’s utility commission. These lines typically run in residential neighborhoods.
|Tree contact with power lines is a leading cause of electric power outages.
POWERGRID International interviewed executives from two companies that work extensively in vegetation management in several states. Joe Bennett is vice president of engineering for ITC Holdings Corp., which is the largest independent electricity transmission company in the U.S. It operates in Michigan’s Lower Peninsula and portions of Iowa, Minnesota, Illinois, Missouri, Kansas and Oklahoma. The company’s vegetation management program favors removal of incompatible trees over trimming because trees that are trimmed can produce aggressive new growth.
Joe Marshall is business development manager for ACRT, an independent utility vegetation management consulting company that operates vegetation management programs for utilities and grid owners nationwide. The company works with large and small utilities and with transmission and distribution systems.
Bennett and Marshall shared their knowledge and insight about working with property owners, their companies’ vegetation management programs, and some of the latest tools and techniques each company employs.
“Environmental considerations figure into all stages of a transmission line’s life cycle-from planning and siting to construction, maintenance and adaptive management through time,” said Bennett. “ITC is committed to the safe and reliable delivery of power in an environmentally responsible way to help protect land, water and species. Our vegetation management team of resource specialists, and community outreach and environmental project leaders are front and center in this effort.
“Knowing that tree removal can be a sensitive issue for landowners, we work closely with residents where vegetation issues need to be addressed,” he said. “Our foresters are available to discuss individual questions or concerns with residents, and we offer help to residents in selecting vegetation that can be safely established near transmission lines.”
ITC places community relations teams in the communities it serves. They serve as liaisons between its operating companies and local governments, community leaders, regulatory agencies and community groups.
“By the time we enter a neighborhood to perform vegetation work, there’s a good chance the community knows us and understands the need,” Bennett added.
ACRT’s Marshall said his company’s approach to communicating with stakeholders who own property in or adjacent to the ROW varies significantly. “FAC-003 standards are applicable on designated NERC critical infrastructure regardless of whether the right of way is in an urban area or a rural area,” he said.
While communication is important in both rural and urban areas, Marshall said it is generally easier to get the necessary work done in a rural area.
“Typically, in a more rural area, farmers and ranchers are accustomed to the methods used to control vegetation on the rights of ways, such as herbicides, because they are likely using these same methods themselves,” he said. “Therefore, it’s typically much easier to explain the process of utilization of herbicide or even mechanical methods to reclaim rights of ways in a more rural area.”
In a more populated area where the ROWs may be adjacent to occupied dwellings, a more structured communication and implementation strategy must be used, Marshall explained.
“Selective removal of incompatible species in urban, suburban and rural transmission corridors is the cornerstone of our vegetation management program,” said ITC’s Bennett. “When this work is completed in rural areas, we lay tree logs in a parallel windrow along both sides of the transmission corridor, which help define the corridor and benefits the natural habitat. In urban areas, we work with landowners on the disposal of the cut wood.”
“In many cases, vegetation along the right of way is used as a visual barrier between the right of way and someone’s house. Obviously, any activity that would alter this barrier will cause some grief to the homeowner,” said ACRT’s Marshall. “Therefore, we take a targeted approach with each property owner and discuss what work is necessary well in advance of the work actually taking place. It’s recommended that a professional utility arborist conduct these meetings and, if possible and within the constraints of FAC-003 compliance, offer some replacement tree or shrub options to the homeowner. It’s important to maintain the same standard for each property owner so each person understands they were treated fairly and no special deals were made with any one property owner.”
Tools and Technologies
Both ITC and ACRT understand that tools and technologies are important to their vegetation management programs. The companies use off-the-shelf software along with some customized software to run their programs.
“ITC employs a variety of proprietary and contractor software to support its vegetation management program,” Bennett said. “Our custom geographic information system and asset management software is supplemented by digital tools and work planning software used by our contractor. We also use collaborative spreadsheet software to track crew size, locations and frequency of vegetation work. The Utility Arborist Association (UAA) advocates for this process and trains ITC arborists to execute it.”
“I can speak only from the consultant perspective,” Marshall said. “But we use a wide variety of technologies in the field.”
ACRT has developed its own software systems that it uses to track things like budget, implementation of cycle and work planning data, which includes property information, work type, equipment needed and more, Marshall explained. These systems are built on a platform that uses existing utility GIS infrastructure or is integrated into Google Earth/Maps.
From a hardware perspective, Marshall said ACRT uses the most common field-based tablets but its software systems are designed to also be run as an app on iOS or Android devices.
|ACRT uses the most common field based tablets but its software systems also are designed to be run as an app on an iOS or Android devices.
“One powerful piece of technology we use is our Arborcision tool,” Marshall said.
Arborcision is a proactive vegetation management tool specifically designed for cooperatives. It was developed through a collaboration between ACRT and Arbor Intelligence, a global think tank company that provides consultancy, research and development for the utility vegetation management field.
“One of the biggest challenges utility managers face is understanding the quantity and characteristics of vegetation on their systems and then designing the appropriate response to those conditions.
Arborcision takes field data collected from across the system and then uses algorithms to analyze that data and provide a road map for how to manage the program, Marshall explained. It optimizes the system into the most efficient and cost-effective cycle length and prioritize circuits within each year of the cycle. In addition, it projects budget requirements and allows managers to run ‘what if’ scenarios to evaluate how a change in cycle length might affect budget.
Unmanned aerial vehicles, commonly called drones, are being touted as a tool for managing ROWs and inspecting power lines, but neither ITC nor ACRT use them now.
“ITC uses helicopters to conduct semi-annual aerial patrols of its high-voltage transmission towers and lines,” Bennett said. “Our patrols include steel towers, wood poles, conductors, insulators and other equipment. Crews check for damaged or worn equipment and vegetation hazards.
“As we do with any new technology, we are exploring the appropriate use of drones for these inspections,” he added.
Secrets to Success
Grid reliability and resiliency are under the microscopes of regulators, politicians and customers. Likewise, environment is top of mind to the same individuals.
“We (ITC) view our vegetation management program in the context of overall environmental stewardship and our overriding principle of operational excellence, because these areas are interrelated,” Bennett said. “Beyond our core mission of delivering bulk power efficiently and reliably to local distribution systems of utilities in the communities we serve, our transmission infrastructure needs to work in harmony with the environment.”
ACRT’s goal, per its website, is to ensure “utilities gain objective, comprehensive insights into how to enhance their electric transmission and distribution, identify and remove liabilities associated with vegetation and improve relations with their customers.”
Marshall has worked with hundreds of utilities across North America.
“I can safely say that the most successful managers I see are the ones who can evaluate, quantify and then prescribe their vegetation management process based on data,” he said. “Those who struggle are often doing so because they have an incomplete picture of what is happening on their system or they’re trying to force a management plan on the system that isn’t suited to the characteristics of vegetation on the right of way.”