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Energy Currents
A Blog by Enerdynamics

Can Electric Utilities Coexist with Increasingly Severe Wildfires?

by Bob Shively, Enedynamics President and Lead Facilitator

Last week, PG&E Corporation and its utility subsidiary Pacific Gas and Electric Company declared voluntary bankruptcy. PG&E is one of the nation’s largest utilities providing electric and natural gas service to approximately 5.5 million customers in Northern California. The bankruptcy ranked as the sixth largest in history. PG&E will continue to operate throughout the bankruptcy process as consumers still need power and gas. The utility has lined up $5.5 billion in financing through various fire hardening, power line safetybanks.

So, what led to the bankruptcy? Potential liabilities associated with multiple wildfires in Northern California coupled with a California law that makes utilities liable for damage caused by their equipment even if no negligence occurs. 

It seems that PG&E is the first large corporate victim of global warming. PG&E’s service territory covers a 70,000-square-mile area in northern and central California. Much of the region comprises montane chaparral and woodlands that historically evolved with frequent wildfires. In recent years, an ongoing drought in California left a proliferation of dry grass, brush, and dying trees, and the region is subject to frequent strong winds. It’s a dangerous scenario for those tasked with power line safety for a utility company with 18,000 miles of transmission and 106,000 miles of distribution lines.

Hot weather causes lines to sag closer to the ground, wind causes lines to sway, and fires burn wooden power poles. All of these can result in live lines making contact with each other or with the ground, resulting in sparks that can quickly ignite dry vegetation. According to the California Department of Forestry and Fire Protection (CalFire), PG&E equipment was found to have caused 12 wildfires in 2017. And CalFire is still investigating the cause for the destructive Camp Fire in 2018.

Assuming the recent weather in California is the new normal, what can be done to protect electric systems against future incidents? 

Some fire hardening techniques include:

Vegetation management

The first key activity is to keep trees and brush trimmed and away from power lines. This is an ongoing activity that unfortunately can result in conflict with communities and landowners who live where they live because they like trees. More stringent requirements to completely clear rights-of-way may be necessary. 

Weather monitoring stations

Adding weather monitoring stations throughout the electric network can help utilities identify when dangerous weather conditions exist near a line, allowing the utilities to enhance power line safety measures during high-risk conditions.

Line monitoring

The conditions of lines themselves can be remotely monitored so that utilities know when lines are sagging and when lines have fallen and/or contact vegetation. This could be coupled with automatic breakers or fuses to allow utilities to immediately de-energize such lines.

De-energizing lines on high-risk days

Utilities that identify lines in high-risk areas can choose to de-energize these lines on high-risk days. Of course, this is highly unpopular to communities served by these power lines since they will be forced to experience long outages.

Changing recloser settings

Utilities typically utilize a power line safety device called a recloser. This device opens a breaker when a fault is sensed on a line. But rather than take the line out of service until a crew can be dispatched, the recloser twice attempts to put power back onto the line to see whether the source of the fault has been cleared (think of a squirrel that temporarily comes in contact with two wires).If the line remains in a fault condition, reclosing can result in sparking and a fire. Utilities can reset reclosers in high-fire regions or install “smart reclosers” that can be reset on high-risk days.  But this will result in more outages.

Replacing wood power poles

To further enhance power line safety, wooden poles can be replaced with more durable concrete or steel poles.

Insulating wires

Wires on distribution and transmission line are typically made of steel reinforced aluminum and are not insulated. Instead, insulators are used just on pole arms. Lines in high-risk areas can be reconductored with insulated wire, thus reducing the risk of sparking caused by lines slapping together or touching vegetation. 

Undergrounding

Power lines can be converted from overhead to underground. But this can cost between two to 10 times as much as running overhead lines.

Unfortunately, many of the fire hardening solutions go against at least one of two key principles of the utility business – high reliability and low costs. Shutting down lines on high-fire risk days means that communities are out of electric service for prolonged periods. And investing in fire hardening is expensive. In regions where wildfires are prevalent, utilities and regulators must work closely to decide what is the most efficient solution to reduce wildfire risk, protect customer interests, and allow utilities to maintain a viable business model. 

Learn more about power line safety and how the physical electric system operates with our online energy training courses.

Enerdynamics offers two online courses, Electric System Fundamentals and Electric System Fundamentals – Condensed, as well as a live seminar for groups called Electric System Fundamentals: From Generation to the Meter. For more details reach us at info@enerdynamics.com or 866-765-5432 ext. 700.


Fire hardening , Power line safety , Electric system ,