Resiliency/Hardening of Overhead Wood Pole Systems
Overhead systems that utilize wood poles must withstand a variety of environmental challenges, from potential deterioration due to decay and insects to destructive winds, ice storms or wildfire.
Often after these extreme events, wood poles may come under criticism for their performance, with calls to replace them with other “stronger” materials or to move the lines underground.
Such simplistic solutions ignore the economic benefits and inherent strengths of wood poles and the century-long record of solid performance in place. Advances in the smart grid and the coming wave of 5G will put more emphasis on overhead systems, and wood poles have the capabilities to meet these new challenges, both structurally and economically.
Negative perceptions about wood poles often stem from the lack of investment in overhead systems. A 2017 infrastructure report card by the American Society of Civil Engineers gave the U.S. energy system a D+, citing an aging inventory that dates back to the 1950s.
More demanding environment
Meanwhile, the conditions wood poles face are becoming more demanding. The Center for Climate and Energy Solutions notes an increase in Category 4 and 5 hurricanes is predicted as a result of climate change. Wildfires are also increasing as summer temperatures rise and drought conditions persist in the West.
Despite such challenges, wood poles offer unique capabilities that can improve their reliability in place. Proper remediation, with proven preservatives and techniques, can extend the life of a wood pole at a fraction of the cost of installing a new pole. Wood poles offer a unique overload capacity that is recognized in national design standards, allowing wood poles to withstand extreme loads beyond their design capacity without failing.
Performance
Efforts such as vegetation management around overhead lines, as well as new methods to protect poles against wildfires, are improving reliability. And a variety of studies note that while moving lines underground marginally improves reliability, the costs are as much as 10-20 times more expensive compared to wood pole overhead line systems.
Wood Pole Resiliency
Technical Bulletin – Estimated Service Life of Wood Poles
Overview of the actual service life of wood poles in use, which is often much longer than what is assumed by utilities and others.
8 pages, 12/21
Technical Bulletin – Sustainable Wood Pole Design for Overhead Systems
Review alternatives to sustainably improve overhead system resiliency without increasing pole sizes to classes that are more difficult and expensive to source. Includes examples for shortening spans between poles to utilize more sustainable and readily available wood pole sizes.
12 pages, 02/20
Technical Bulletin – Unique Overload Capacity of Wood Poles
Reviews how natural variations and recognition of such variations in the National Electric Safety Code allow wood poles to have a much greater overload capacity in extreme weather events compared to poles made from alternative materials.
8 pages, 10/19
Technical Bulletin – Wood Utility Pole Design Values in the NESC
Provides the fiber strength and Modulus of Elasticity (MOE) design values for all species used for wood poles in the U.S. The values are listed in the 2022 edition of ANSI O5.1 Wood Pole, Specifications and Dimensions.
4 pages, 08/24
Pole Principles – Myths and Truths: Wood vs. Alternatives
Review of common myths offered by promoters about the supposed advantages of alternative pole materials such as composite fiberglass, steel and concrete compared to wood poles. Includes reference notes.
4 pages, 01/25
Weather-Related Power Outages and System Resiliency
Congressional Research Service report on weather-related outages, the economic cost of such outages and recommendations on minimizing power disruptions.
18 pages, 08/12
Technical Bulletin – Wildfire Mitigation: Materials Science & Wood Pole Protection
Overview of wildfire impacts on pole materials, including wood, composite fiberglass, steel and concrete, and new technologies available to protect wood poles from fire.
8 pages, 09/24
Technical Bulletin – Performance of Utility Poles in Wildland Fires
Review of research on the performance of wood and steel utility poles in wildland fire hazard areas.
12 pages, 05/14