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Utility poles and their maintenance are one of the single largest costs for utility companies. In this article, we look at where these costs occur and how a Polesaver dual-barrier protection sleeve can significantly reduce pole maintenance and replacement costs.
While wooden poles are a proven and cost-effective means of supporting overhead lines, they are the only “non-engineered” component used in power distribution. They are made from natural materials and rely on preservatives for protection from decay (partial protection). Over time preservatives lose effectiveness due to leaching and oxidation, ultimately leading to a ground line decay and loss of strength. Combined with variations in ground conditions, timber durability, and climate, etc., it is easy to see why wooden pole life often varies. The variations in life cycles for wooden utility poles means that they require regular inspection, maintenance and more often than not, costly premature replacement.
To understand the financial case more clearly, let’s look at a cost breakdown example. Using annualised combined costing that includes installed cost and inspection and remediation costs spread over the poles expected life gives us a benchmark cost against which we can compare alternative options.
Pole life tends to vary significantly depending on location, as a general rule wooden pole life tends to be shorter around the equator and in the southern hemisphere where conditions tend to favour decay. Factor in the difficulty of treating certain timber types and the typical pole life in this region is often 20 years or less.
In the northern hemisphere, pole life tends to be longer. Having said this, there is ongoing pressure to introduce legislation limiting the use of effective but toxic wood preservatives, therefore, reducing pole life. And with pole replacement costs of up to $3000 and it is easy to see why many utilities are looking at alternative cost-saving options.
Looking at current costs, let’s take a 1000 miles North American of L.V. distribution network as an example, with an average pole life of around 35 to 40 years; industry feedback indicates the following cost build-up:
Assuming an average pole spacing of 250ft then 1000 miles of distribution network equates to 21,120 poles.
With an average installed cost per pole of $3000, the total installed cost is $63 million per 1000 miles.
Typically around 12% of these poles are inspected every ten years at an inspection cost of approximately $100 per pole using third-party inspectors. In addition to this, wooden poles are often subject to remediation work after around 20 years to extend the pole life. The remediation work typically involves more rigorous inspection and retreatment with preservative or reinforcing/strengthening as required. Feedback indicates this typically costs around $380 per pole, giving a total lifetime maintenance cost of $9 million over 40 years or $426 per pole.
So to summarise a typical wooden utility pole in North America with a service life of 40 years will have an installation cost of $3000 a lifetime inspection and maintenance cost of $426 giving a total lifetime cost of approximately $3426 or $72 million per 1000 miles. This equates to an annualised pole cost over 40 years of $85 per year per pole.
Whilst there are global variations in cost, the data nonetheless shows that the maintenance costs to Utilities are substantial.
Furthermore, wooden utility poles have the potential to incur various hidden costs that are not immediately apparent. Depending on market regulation, pole failure and a resulting power outage and fines can become costly. Pole collapse can also impose numerous safety hazards compromising both the safety of employees and the public as well as an increased fire risk in areas prone to wildfires.
While alternative pole materials such as steel, concrete and composites may offer increased lifespan, they are generally more costly and often difficult to handle and climb than wooden poles. The use of a Polesaver ground line barrier sleeve eliminates the traditional weakness of wooden utility poles. This potentially reduces the requirement for inspection and maintenance whilst significantly extending pole life to 50 years or more.
Calculation clearly shows that a wooden pole protected with a Polesaver dual layer barrier sleeve is the lowest cost pole option currently available.
Long term costs are reduced with Polesaver. By extending the life of a pole, it reduces the number of future replacements required. Additionally, there will also be a reduction in short term costs by eliminating early pole failures. With experience pole inspection intervals may be increased or the percentage of poles reduced at each inspection interval. Furthermore, the use of Polesaver sleeves also eliminates the requirement for costly ground line pole remediation.
Using the example above for North America, we can calculate the cost-benefit example of using Polesaver protected poles instead of a standard pole.
The cost-benefit of using Polesaver sleeves will come from an increase in the pole service life of at least ten years whilst also eliminating the requirement for costly remediation after 20 years. Assuming inspection intervals and the percentage of poles inspected remain unchanged, these changes lead to an annualised pole cost over 50 years of $51 per pole per year, a cost-saving of 40%. This equates to a lifetime cost saving of $35 million per 1000 mile of distribution network.
Looking at the additional applied sleeve cost, this gives a return on investment of over 5600%.
When looking at lifetime costs for alternative materials such as steel, concrete or composite, it is clear that a wooden pole fitted with a Polesaver offers the lowest cost pole option. To see how much you could save with Polesaver, try our free cost calculator.
The Polesaver dual-layer barrier sleeve is a proven and highly cost-effective means of extending the lifespan of wooden utility poles. Polesaver sleeves make ground line decay impossible and are backed by our 50-year guarantee. If you would like more information or a copy of the cost-benefit calculator spreadsheet, then please contact us.
In the next blog article, we will be looking in more detail at the environmental case for using wooden poles and the impact of using alternative materials such as steel or concrete.
Richard is the founder and CEO of Polesaver. With over 26 years of experience in developing and testing Polesaver products, Richard is an expert when it comes to wood preservation.
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Polesaver manufactures and supplies guaranteed products that are proven to extend the life of utility poles. With millions of sleeves supplied to date, our patented ground-line barrier sleeves have been proven in volume use since 1994.
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Unit 7, The Hawthorns, Staunton, Gloucestershire, GL19 3NY, UK
*Polesaver uses long term independent test data on the effectiveness of barrier sleeves and fire protection fabric to reach all the conclusions given on this website (test data available on request). Based on this data, Polesaver believes longer life, maintenance of strength over time, improved safety and reliability, extended inspection periods and reduced maintenance requirements are reasonable claims. This is subject to Polesaver products being correctly applied as per our instructions and used on correctly preservative treated (for long term in-ground use - use class 4 or higher) wooden utility poles that are free of decay at the time of sleeve application. The claims made, real or implied are not warranties. It is the responsibility of the user to evaluate and satisfy themselves that the performance of the product meets their specific safety, reliability, extended inspection, repair and any other performance or cost-benefit criteria before using Polesaver sleeves or fire protection fabric.