Undergrounding construction unavoidably disturbs soil at the site, generating excess spoils that must be properly disposed of. These spoils must be handled according to specific requirements and often must be hauled off-site for processing, remediation, or disposal. Moving soils back and forth for processing and disposal between off-site locations that are often far from dig sites requires time and resources that could be spent elsewhere. This process is particularly costly in cases where distrubed soil contains hazardous materials.
Sponsored by
Problem
In an effort to underground approximately 10,000 miles of power lines in high fire threat districts, PG&E is looking for ways to increase the efficiency and decrease the cost of undergrounding. In certain areas, however, soil conditions, geological formations or challenging topography may make tunneling efforts nearly impossible. Additionally, excavation in many of these challenging areas (e.g., water crossings, biologically sensitive sites) triggers lengthy permitting processes that further increases timelines and cost.
Desired properties
- Ability to traverse multiple terrain types at-surface without triggering typical permitting requirements for underground infrastructure
- Proven ability to provide resiliency and wildfire mitigation benefits commensurate with undergrounding infrastructure
Specifications
Category 3: At Surface Alternatives
Problem statement
Certain topographies, terrain types (e.g., granite), water crossings and culturally/biologically sensitive materials present at undergrounding sites tend to make proposed tunneling efforts difficult or impossible. When tunneling does proceed in these areas, the project typically requires a more stringent permitting process with longer lead times or more costly construction methods. While best efforts are made in the design phase to avoid these constraints, in some cases it is not feasible to sufficiently alter route design to avoid these areas and the associated additional costs or extended permitting period.
Possible approaches
To avoid disturbing sensitive landscapes (including water crossings) and to reduce the need to dig into dense rock types, we are looking for solutions that offer at-surface alternatives to underground wires at locations that fit this profile. Potential solutions could include surface mounted infrastructure that does not require digging (e.g., K-rails, surface troughs) or shallow dig alternatives to minimize disruption and to facilitate easy monitoring of the underground infrastructure.
| Industrywide Market Gap | Potential Solution Category |
|---|---|
| In certain conditions, underground construction costs remain exorbitantly high and / or permitting requirements for underground infrastructure can delay project progress for over a year | At-surface or level-grounded construction methods (e.g., K-rails) |
Known approaches not of interest
- Procedural / management solutions are not of interest.
- Software-based solutions are not of interest.
Key success criteria
Required:
- Demonstrated improvement over current state-of-the-art technology
- Same or better wildfire risk reduction relative to undergrounding at a 35% lower cost
- Deployable over water crossings or rocky terrain at grade
Desired
- Commercially deployable within 3 years