Wildfires have engulfed a major piece of electrical transmission infrastructure in northern Alberta, adding to the uncertainty over when pipelines and oilfields fed by the downed power lines will be able to resume service.
Roughly half of a 144-kilovolt transmission line that runs north of the fire-ravaged town of Slave Lake lies within active burn areas, said Bobbi Lambright, president of operations at Atco Electric, which runs the line.
The line is 200 kilometres long, and runs through "the centre of this 50,000-hectare fire," Ms. Lambright said. "It's a very unstable environment right now."
Power outages have been a primary source of trouble for the oil patch, since that line is used to power the Rainbow pipeline, a critical connection to a number of northern Alberta oilfields. With no power flowing, the pipe has not been able to operate, and the suspension of its operation has been responsible for much of the nearly 150,000 barrels that have been shut down.
The system is primarily used to power oilfield and pipeline operations, although it also brings electricity to several Alberta communities, including Gift Lake, Atikameg and the Peavine Metis Settlement.
But because fires continue to burn, the Atco Ltd. division has only been able to do a preliminary assessment of how well the line has survived the blaze.
"Based on those assessments, we know we have damage on the system. We just really can't say how extensive that damage is until the whole area is safe and we're able to do a full assessment of the line," Ms. Lambright said.
Electricity is carried along the line on wooden poles. Some of those have burned down.. Fire has damaged both the main transmission system and smaller distribution systems that are fed by it.
But Atco says its electrical substations, which are much more difficult and time-consuming to rebuild, have survived unscathed.
Still, Ms. Lambright declined to give any sense of how long it might take to fix the line. The company does plan to have electricity back on two 72-kilovolt feeder lines that run into Slave Lake by this week.
But with regard to the larger northern line that remains down, "we're very hesitant to estimate time frames," she said.