As vegetation contact can be a major driver of wildfire ignitions, the California Public Utilities Commission (CPUC) requires specific clearances around power lines. By making current advanced practices of onsite vegetation management more efficient, utilities can reduce risk on the many thousands of line-miles in High Fire-Threat Districts.
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Problem
As system hardening focuses on updating overhead lines and equipment, PG&E has to consider over 30,000 line-miles of transmission and distribution assets in High Fire Threat Districts in its operation. Industry-wide adoption of lighter, stronger, and/or more heat-resistant infrastructure has been limited by cost, availability and longevity.
Desired properties
- Conductor material or conductor sheathing with a higher strength-to-weight ratio and/or that is more heat resistant/tolerant than current state-of-the-art options
- Sheathing that is both heat-resistant and light enough to be applied to transmission lines
- Material that could prevent fire ignitions due to sparking during phase-to-ground faults
Specifications
Category 4: Innovative heat-resistant materials
Problem statement
PG&E is focused on hardening significant portions of the 5,500 line-miles of electric transmission and 25,500 line-miles of overhead distribution assets located in High Fire-Threat Districts. PG&E’s work to replace these lines with covered, stronger, more fire-resistant conductors supported by stronger, more fire-resistant poles or structures brings a new set of challenges that current state-of-the-art technology does not address. For instance, covered conductors are heavier, requiring sturdier poles or support structures due to the added strain especially during high wind events. Further, there are currently no viable covered conductor solutions for transmission. In addition, sheathing on covered distribution conductors is currently heat-resistant to several hundred degrees Fahrenheit —not always enough to prevent burning and additional failure in fire conditions. While PG&E has explored and tested various types of poles and covered conductors, today’s options are limited by cost, availability, survivability, and longevity issues. Innovations in lighter, stronger and more heat-resistant materials for poles, wires, and supporting equipment could materially improve the risk reduction provided by the current system hardening efforts.Possible approaches
Any technical solution or process innovation that makes grid infrastructure stronger, less likely to fault when contacted and more fire-resistant is welcome. These approaches could include innovations in pole infrastructure, particularly related to composite pole reliability, scalability, fabrication, and inputs. Also of interest is innovations in wiring and supporting equipment, especially lighter, stronger, and/or more heat resistant materials.| Industrywide Market Gap | Potential Solution Category |
|---|---|
| Current state-of-the-art covered conductor products are heavy, requiring larger/sturdier poles, due to the added strain especially during high winds events – and heat-resistant to several hundred degrees Fahrenheit. | Lighter and more heat-resistant alternatives to current covered conductor products |
| Wooden poles are more flammable and limited in stability, but composite poles have supply challenges. | Stronger, readily available composite poles with reliable and scalable manufacturing |
| Strong composite poles are difficult to find and expensive to produce, transport and install. | Onsite fabrication of new poles from cheap raw inputs, e.g., from woody biomass |
| There are no viable covered conductor solutions for transmission, due to weight and the fact that the wires can reach very high temperatures in the event of a fault. | Lightweight and heat-resistant covered transmission wires |
| Solutions that reduce fire risk underneath lines in places where there is high localized risk down to the level as if asphalt was underneath the lines. (Lowest fire risk corresponds with asphalt being underneath the lines.) | Laying non-flammable materials (e.g., gravel) underneath lines in forested area |
Known approaches not of interest
Software based and procedural/management solutions are not of interest.Key success criteria
Required:
- Easily and safely retrofitted in current infrastructure / rights of way
- At least 35% improvement in strength, weight, and/or heat resistance without sacrificing performance in the other categories nor increasing cost over current state-of-the-art options
- Demonstrated improvement over current state of the art technology
Desired:
- Commercially deployable available in 1 to 3 years
- Installation labor reduction of 20% or more compared to current materials/components