Public Power - January/February 2009 - (Page 40)

Reliability The Tree Trimming Balance by William Atkinson The newCommissionEnergy Federal Regulatory regulations outlining tree-trimming requirements are designed to help reduce the number and severity of storm-related outages. The North American Electric Reliability Corp. (NERC) estimates that 90 percent of weather-related outages are caused by trees hitting power lines. However, the new requirements are causing many utilities to feel like they are between a tree and a hard place. On the one hand, they are required to keep trees properly trimmed or risk some hefty fines. On the other hand, they are faced with adamant and angry customers who resent having their trees trimmed in ways they consider aggressive and unsightly. Seattle City Light has experienced this conundrum firsthand. The utility sustained much criticism from customers following a devastating storm that passed through the area in December 2006. Customers claimed the utility had done a poor job of trimming trees, resulting in extensive tree-related outages. It seemed the utility could do nothing right, though, because a year and a half later, residents began complaining about the utility’s “aggressive” tree-trimming practices. Prior to the storm, the utility did not have a systematic program for trimming trees. It now does. Chris Heimgartner, customer service and energy delivery officer for Seattle City Light, noted that an effective tree-trimming program has two parts. One re40 January-February 2009 lates to trimming out the highvoltage bulk electric system. “This is what NERC really cares about,” he said. The other part is good utility practice on distribution, which involves keeping separation between trees and lines. “This is as much of a public safety issue as it is an outage issue,” he said. City Light’s Power Line Clearance Program involves trimming out all trees on roughly a four-year cycle. “Since we have gone on that cycle, we have seen a dramatic improvement in reliability,” said Heimgartner. “It has also improved the health of the tree canopy because we aren’t removing trees but rather park representatives, and the community. Together, they created a plan involving the “newest and best science.” “There is a lot of new science related to laminated root rot,” said Best. “We were much more conservative with our trimming in Bridle Trails than we would have been in other places.” The utility looked at what it really had to do in terms of laminated root rot. While some utilities would routinely cut 40 feet around an infected tree, City Light used scientific calculations to find it could limit that to 16 feet. “The community meeting over trimming in the park started out with a lot of tension,” said Best. “However, we ended up developing a plan that everyone felt good about because we took their concerns into consid- the late 1990s. “We realized that we needed to talk with property owners about their trees because it’s common courtesy,” said Ray Henning, utility-line clearance superintendent. Work planners go out ahead of the trimming crews, visiting every property where trimming is scheduled, identifying the work that needs to be done, documenting it on a form, and then try to talk with each property owner face to face. If an owner is not home, the crew leaves information on the door. The materials include a phone number so the owner can call the work planner. If the owner does not call, the work planner calls the owner to arrange a face-to-face meeting. “If we can’t reach the owner, we send them a registered letter along The North American Electric Reliability Corp. (NERC) estimates that 90 percent of weather-related outages are caused by trees hitting power lines. trimming out parts of trees.” In terms of transmission-related trimming, there is a transmission line running through a state park, Bridle Trails. “We hadn’t done a lot of trimming in that park for several years,” said Lynn Best, director of environmental affairs for Seattle City Light. The park is considered to be an important resource for the city as a recreational area. However, there were many trees near the line, some of which had laminated root rot, a problem that can afflict trees in the Pacific Northwest. The rot meant these trees could fall down easily in a storm with strong winds. The utility worked closely with the park ranger, the state eration.” In the end, Seattle City Light satisfied NERC while maintaining a very healthy forest that poses reduced risk to the transmission line. Austin Energy in Texas has also addressed the delicate balance between trimming trees to reduce outages and keeping customers happy. Recognizing that people are sensitive about tree trimming, the utility arranges to meet with every property owner prior to trimming. Austin Energy employs 13 arborists and foresters. Contracting crews led by arborists trim to best practices, which in part means trimming only during seasons when trees are less susceptible to certain diseases. These practices have been in place since with a copy of the work plan stating that, after a certain date, we are going to work on their property,” said Henning. Owners who object to having their trees trimmed are offered an opportunity to meet with the work planning supervisor to discuss possible alternatives. They are also invited to talk with field personnel. If there is still no agreement, the utility once again sends a registered letter with a copy of the work plan saying it is going to do the work, along with a copy of the city ordinance stating it has the right to do so. “If we show up and the property owner tries to chase us off, we call the police department,” said Henning. “When they arPublic Power

Table of Contents Feed for the Digital Edition of Public Power - January/February 2009

Public Power - December 2008 Contents Perspective 10 Questions Heat or Eat? Achieving Excellence in Nuclear Operations Training Grand Ambitions for Wind Power Visions of Green Carbon Trading Across The Pond Reliability Green Energy Customer Service DEED Hometown Connections Parting Shot

Public Power - January/February 2009

For optimal viewing of this digital publication, please enable JavaScript and then refresh the page. If you would like to try to load the digital publication without using Flash Player detection, please click here.