This Oregonian story has a lot of good background information on Portland General Electric and the challenges facing them (and us). Notable highlights:
The power outages experienced in the Willamette Valley over the past week are nothing like those experienced in Texas, where surging demand, power plant outages and lack of access to backup electricity supplies forced grid operators into rolling and extended blackouts that affected millions of customers across the state.
Closer to home, the problem was three waves of weather that began Thursday, Feb. 11, in the lower Willamette Valley and got worse with successive waves of icing that moved north over the weekend. More than a week later, the outage numbers had declined from a high of about 340,000 around Oregon to some 42,000 midday on Saturday.
Oregon’s outages have little to do with surging demand or available electricity, but repeated failures of transmission and distribution lines that aren’t designed to carry such heavy loads of ice, and problems with falling trees and branches that went well beyond the scope of state rules requiring utilities to keep vegetation around their infrastructure clear.
Our own power was out for just over a week. The city-owned diadora cedar dropped limbs all over the place, severing our neighbor’s power line and blowing out the transformer that served us and our neighbors on both sides.
The PUC issued a “warning” notice to PGE that based on its review of its system, its vegetation maintenance “appears to have deficiencies that are potentially systemwide.” In a review of “various” urban and rural areas, regulators found “719 locations where evidence existed of contact between vegetation and primary electrical conductors.” Based on historical reviews, they said the number of tree and energized conductor contacts were approaching all-time highs.
PGE says it typically trims trees on a three-year cycle, and has doubled its spending since 2017 to $26 million in 2020. The utility sees even higher spending moving forward — as high as $40 million with new construction and emergency trimming. It says it is actively using the audit results to improve its program.
I have no doubt that the tree trimming is insufficient—there’s just too many trees—but in our case, the tree in question is owned by the City of Salem and governed by their tree ordinance. That greatly constrains PGE’s ability to trim it back, and prevents us from doing anything with it at all, even though it drops crap all over our driveway and front yard. Along with our late neighbor Fred (who planted the tree and came to regret it), we wrote a letter to the city years ago asking to have it removed. Obviously no joy.
One common question after wildfires or ice storms is why utilities don’t simply run their lines underground.
In fact, it’s standard practice in new subdivisions or new buildings, and is often used in rural corridors with reliability issues, more unpaved rights of way, and high wildfire risks. The general limitation is cost, particularly in established urban neighborhoods where it involves digging a trench up streets and to each individual home. It also involves changing out customer-owned equipment – a significant and unwelcome cost for ratepayers, Berreth said.
California’s biggest electric utility, Pacific Gas & Electric, has estimated that it costs an average of $3 million per mile to convert overhead distribution lines to underground, compared to $800,000 a mile to build new overhead lines. Some industry studies put the disparity even higher.
I knew about the expense of putting power underground, but here’s what I did not know:
Data in the company’s 2019 annual reliability report shows equipment failures were responsible for about 15% of customer outage hours overall. In those cases, the largest contributor, responsible for almost 40% of the underlying outage hours, is problems with underground conductors.
“Underground cable is one of our biggest headaches in terms of failure rates,” he said. “When people say just ‘underground everything,’ (they don’t recognize) it fails more than other equipment and it takes you longer to repair it….”
I was under the impression that sticking things underground more or less solved the problems we saw in this weather event. This does not sound like it is the case, meaning I don’t see a viable grid-based solution for avoiding this same thing from happening again.