As humanity strives to transition towards more environmentally sustainable practices to combat climate change, our electrical power grid is grappling with significant challenges. The U.S. power grid, which received its last major upgrade over seven decades ago, is now burdened by aging infrastructure consisting of poles and lines that are ill-equipped to meet the demands of an increasingly electrified society. The proliferation of electric vehicles and the rapid expansion of 5G infrastructure are placing unprecedented strain on our power distribution systems and utility poles, exacerbating the situation. This strain is compounded by the escalating frequency and intensity of severe weather events that further stress the already fragile grid.
In addition to the perennial issues of insufficient funding and a shortage of skilled labor, the modernization of the grid faces a unique supply chain challenge posed by nature itself: the sourcing of high-strength poles from trees. To address this issue, it is crucial to first examine the state of our wood resources. Subsequently, it becomes imperative for power industry professionals to broaden their toolkit by incorporating composite materials into the grid infrastructure.
So, How Do The FRP Utility Poles Compare?
FRP, or Fiber-Reinforced Polymer, is an engineered material composed of reinforcement fibers, polymer resin, and additives, known for its exceptional strength and durability. FRP utility poles are manufactured using a pultrusion process, ensuring a consistent cross-sectional shape, fiber tension, and orientation. To put their lightweight advantage into perspective, consider that a typical 40-foot Class 1 wood pole weighs approximately 1,100 pounds, while a similar steel pole weighs about 692 pounds. In contrast, an equivalent FRP pole weighs only 412 pounds. This reduced weight makes FRP poles an excellent choice for applications in limited-access areas or helicopter setups, as they can be transported in larger quantities with fewer loads without compromising on strength.
When assessing the strength-to-weight ratio, FRP outperforms traditional materials. Although the stiffness-to-weight ratio of glass FRP is slightly lower than that of steel, this can be compensated for by optimizing the cross-section geometry. Moreover, FRP utility poles offer several other advantages that make them suitable for both transmission and distribution purposes, including their safety features, resilience, and extended service life.
- Safety is a paramount consideration, and FRP poles excel in this aspect. Demonstrations by line crews have shown that composite poles are light enough for a single person to move on the ground, and they can be field-drilled, a capability lacking in concrete and steel poles. Additionally, FRP poles are free from pesticides or harmful chemicals and do not release any hazardous substances into the ground. FRP poles address a significant drawback of steel poles: conductivity and low dielectric strength. Steel poles require proper insulation to prevent electrical hazards, interruptions, or breakdowns when exposed to high voltages due to their metallic nature. In contrast, FRP exhibits low thermal conductivity and impressive dielectric strength, enhancing safety in electrical applications.
- In terms of resiliency, the pultrusion process used to create composite poles ensures a coefficient of variation of less than 5%. These pultruded profiles boast higher tensile strength than conventional steel and are designed with some flexibility to withstand substantial loads during extreme conditions while returning to their original state. This resilience distinguishes them from steel, which remains deformed if stressed beyond its yield strength, as well as wood and concrete, which can fracture. Moreover, FRP’s ability to absorb impact energy is notably superior to competing materials. FRP poles can absorb twice as much impact energy as wood and, significantly, ten times more than steel. Additionally, FRP poles possess a commendable modulus of elasticity and flexural strength, making them a top choice for transmission design engineers seeking reliability and safety.
- FRP poles boast impressive longevity. Their inherent corrosion resistance stems from the composite’s inability to undergo oxidation. This inherent property renders FRP poles inert to a broad range of bases and acids. Unlike wood and concrete alternatives, FRP exhibits minimal moisture absorption, remaining impervious to degradation caused by moisture exposure, in stark contrast to steel. Additionally, composite poles lack appeal to termites, woodpeckers, squirrels, beavers, and other wildlife known for causing damage to wooden poles. To further enhance their durability, FRP poles receive a non-toxic coating for ultraviolet (UV) protection. Additionally, for aesthetic or architectural considerations, composite utility poles can be custom-tinted to meet customer color specifications, allowing them to seamlessly blend into their surroundings.
(Find more information on Fiber-Reinforced Polymer from the sourced blog post by Power Magazine written by Dustin Troutman, at this link: Click Here)
“Creative Composites Group (CCG) is just one manufacturer of pultruded FRP utility poles. The following link will open a large chart titled “StormStrong Round Pole Mechanical and Physical Properties,” which shares data for the four round FRP poles currently offered by CCG.
—Dustin Troutman is corporate director of Marketing and Product Development with Creative Pultrusions Inc., a CCG company.” -Power Magazine, Dustin Troutman