Trees vs. Poles

Moylan area, removing trees would clearly change the feel of the neighborhood.

As I noted in the last township board notes, PECO is looking to install new poles in the Moylan part of Nether Providence. Exactly which part is hard to tell, because when asked PECO provides shifting project details and rationales, giving little confidence in anything they’re telling residents. By some accounts, they’re going to soon start removing large numbers of trees (>50) from parts of Moylan and South Media, but by other accounts they’re just going to trim some trees. Which is correct seems up in the air. Maybe even PECO isn’t sure yet.

At the board meeting, residents asked, instead of new overhead lines, why not bury them like is done in new construction. The simplest answer is that burying lines in new construction is cheaper than burying existing overhead lines.

There are complicated tradeoffs involved in burying lines. And that’s before you consider secondary effects such as increased power usage due to the removal of shade trees and changes in property values.

This was the late 1800s, it’d probably be even crazier today. From this report.

Why bury power lines?

  • Aesthetics. Not having overhead lines gives the neighborhood a cleaner, more natural look.
  • Space. Dense, urban regions require so much cabling its not realistic to fit it all overhead without a mess (see image). In the denser region around Garden City and South Media, there’s so many overhead lines it crowds out most trees (and amateur radio antennas for that matter).
  • Reliability. Buried power lines are less likely to go out due to the most common problems – storms, wind and ice. Statistics show about 1/10 the outages compared to overhead lines. However, they are more prone to flooding.
  • Safety. Unless you’re digging, you’re less likely to come into contact with a buried power line compared to one overhead.

Why not bury power lines?

  • Cost. It is generally about 10 times as expensive to bury lines as to string overhead ones. Rural areas are cheaper than urban areas mostly due to less other infrastructure in the way. These increased costs are generally passed along to ratepayers (which can lead to inequalities where all ratepayers are paying to improve the areas that get the buried lines).
  • Maintenance. Overhead lines can be expected to last 50 years while buried ones generally last only 30. And they can be more expensive to service, but the data I’ve seen is vague on that differential and probably varies greatly.
  • Longer outages. When they do go out, buried lines take longer to repair than overhead ones as its less obvious what’s broken and requires digging to reach.
  • To completely remove poles you also have to shift cable and communications lines underground as well, further complicating work.
This study shows relative costs come in lower than a factor of 10. From this report.

Changes to power usage patterns are going to bring increasing challenges to the electric grid. In order for the township to meet its stated carbon goals, there must be massive electrification in coming decades. The primary drivers of residential electricity use – heating and transportation – will result in large shifts in electricity usage patterns and therefore require a reconfiguration of the grid. Expect this debate over where to run lines to intensify in coming years. But right now, PECO needs to have a clearer long term plan than the muddle they’re presenting to ratepayers in Moylan.

Categories: Ramblings