Public and private sector investment in transmission and distribution power systems is bolstered by substantial federal funding through the Inflation Reduction Act, which incentivizes the construction of critical infrastructure in challenging locations, including underground utility projects in populated areas.
As existing systems age, the need for new power systems that enhance reliability and improve worker and consumer safety will continue to be paramount. Technological advances and the increased emphasis on sustainability present an interesting set of considerations when designing, building and obtaining permits for underground power systems.
Knowledgeable and experienced specialists from architecture, engineering and construction firm Burns & McDonnell offer their opinions.
Permitting With Thomas Konopka
Beneath the bustling streets of congested cities lie the hidden veins of electric utilities, carefully buried underground for both practical and aesthetic reasons. Because of this, common underground utility permitting considerations include: stormwater management, flood plain/floodway, wetland/waterbody, cultural resources, NPDES, SWPPP, water discharges, site development, engineering, encroachment, utility construction, railroads and DOTs.
Establishing a permitting strategy early on will optimize alignments and positively impact schedules and budgets from design to construction. Best practices for navigating permitting processes involve developing a plan with a well-versed permitting team, engaging early with agencies and stakeholders, demonstrating familiarity with regulations, and leveraging innovation to streamline processes.
To inform design and construction decisions, a thorough understanding of local ordinances, zoning codes and technical guidance manuals is needed. When planning for and executing construction, it’s important to communicate permit requirements clearly to field teams and to provide training on best practices for compliance. Additionally, being aware of changes that don’t match authorizations and communicating the need for amendments is critical.
Designing to avoid construction-related disturbances and permanent impacts to areas of environmental concern can help avoid the need for mitigation within the footprint of in-place infrastructure. Other permitting considerations include factoring in the temporary impacts to softscape that will require restoration and maintenance periods that carry risks that could impact permit sign-off timelines.
Design With Anna Sleeter
A good underground electric design considers existing utilities and their associated clearance requirements, constructability, traffic impacts, future maintenance and electrical capacity needs. A proposed design must always meet current demand and take into account future expansion.
Thorough investigations are key to the design process. Topographic and subsurface utility engineering surveys can reveal utility congestion. Inspections — including scanning of utility holes or vaults — can help inform detailed design development by confirming existing conditions and helping determine how new electric systems can connect into existing infrastructure. Conducting pre-design studies pays dividends throughout the project life cycle by reducing project delays and costs, identifying potential conflicts and jumpstarting accurate planning for underground construction.
Another pre-design activity that is beneficial is coordination with other utilities. A critical part of this process includes obtaining detailed records, as well as understanding special considerations and future plans that may impact alignment.
While these general practices apply regardless of a project’s location, the value of these types of upfront field investigations is typically more pronounced and needed in congested subsurface environments.
Construction With Wally Petrovic
Safety comes first when constructing underground electric infrastructure. Safety plans must account for the safety of workers and the public around energized lines, confined spaces and traffic. A good plan involves coordinating with parties affected by a project, including utilities, municipalities, transportation organizations and community groups.
Before breaking ground, a maintenance of traffic plan must be developed to manage traffic interruptions. Changes to vehicular and pedestrian traffic patterns can be sensitive, so it’s important to communicate changes clearly and with enough time for workers, drivers and pedestrians to adjust.
The inherent risk of not being able to see what’s being built until after excavation has started can lead to surprises and design changes. Knowing this, it’s important to remember underground utility construction takes two things to be successful — a good plan and a good backup plan — when the original plan inevitably changes.
Of course, the way utility work is done today is different than in the past and different from how it will be done in the future. Innovations such as ground penetrating radar, which provides increased visibility below the ground’s surface, and remote equipment operation, which minimizes human exposure to hazardous work elements, help make underground construction safer. But, ultimately, no matter the era lived in or the technology used, deftly mastering intricate design, permitting and construction processes for complicated underground electric utility projects is crucial to success and takes an experienced team.
