COLUMNS: Alternatives to wooden hydro poles

The use of concrete poles in our subdivision in the late 1970s seemed like a good idea.

The use of concrete poles in our subdivision in the late 1970s seemed like a good idea.

The concrete poles were neat and tidy and apparently much longer lasting (estimated to be 80 plus years compared to the 40 years for wood poles ).

The concrete poles are OK but the bolts used to attach the various components to the poles are failing.

Apparently the high voltages and grounding through the steel reinforcing rods are causing a breakdown of the hardware through electrolysis.

According to a recent BC Hydro report approximately 500 concrete poles will be replaced in the next few years.

Currently in BC  there are approximately 861,000 wood poles in the entire distribution system. The existing poles in the system are primarily manufactured from either the western red cedar or lodgepole pine species.

Approximately 67 per cent of the current poles are full length treated with either pentachlorophenol (PCP) or ammonia copper arsenate (ACA) or chromated copper arsenate (CCA). Less than seven per cent of the current poles are untreated during installation.

When concrete poles were first used there was some concern from the forest industry that wood poles would eventually be replaced with longer lasting alternatives but with the recent failure of concrete poles it looks like wood poles are still competitive.

According to a 2008 study in the U.S. some steel and concrete poles are in use but the vast majority of utility poles are wood.

Wooden poles are very robust, nonconductive, and allow for overhead wires to be attached in a variety of ways.

Another advantage is the low cost: approximately $250 for a standard 45-foot pole versus $260 and $350 for steel and concrete (respectively).

The report also describes  wooden poles with a seemingly small environmental impact based on energy consumption, greenhouse gas emissions and toxic releases.

There are significant environmental drawbacks, however,   around the poisonous chemical preservatives added to the wood to extend their lifespan and the options of dealing with the old poles.

There are plenty of studies comparing the various options of wood, steel, concrete, fibreglass and other composites. I can’t help but notice the outcome of the studies seems to depend on who is doing the research.

My conclusion is that there is a place for all of the options depending on the application, location and changing market demands.

There will no doubt  be ongoing research on creating the perfect hydro pole but as was the case with the concrete poles it may take a couple of decades to see if the new product lives up to the predictions for each new invention.

Even with the best pole available nothing seems to be immune to  the unpredictable weather events that can destroy many different kinds of  poles.

Extreme wind or ice storms can damage even the most expensive structures.

The bottom line is that wood  poles will likely be used to a large extent for some time to come and research should be ongoing to find preservatives that are more environmentally friendly.

Jim Hilton is a professional agrologist and forester who has lived and worked in the Cariboo Chilcotin for the past 40 years. Now retired, Hilton still volunteers his skills with local community forests organizations.