Reliable power in large quantities is increasingly essential to modern life. Delivering sufficient quantities of electricity is constrained less by generation capacity than by the ability to get the power to the people who need it. Population density increases the localized demand while making the delivery to that area more complicated.

High-voltage direct current (HVDC) lines are one alternative for transmitting lots of power, but they can face the same challenges when it comes to destinations with limited airspace. Congestion and public concerns make routing overhead transmission trickier, especially when space within rights-of-way is at a premium.

A recent project for a confidential client involved exploring a more creative solution to these challenges. The client wanted to investigate the possibility of undergrounding an HVDC circuit over more than 75 miles. We were asked to perform a fatal flaw analysis of the concept.

Before sinking a lot of money into a project of that potential expense and complexity, it made good sense to conduct an initial desktop study and sweep for anything that would be likely to stop the project dead in its tracks.

We were able to draw on our deep experience with both transmission infrastructure and environmental permitting — as well as broad understanding of how to work with relevant regulatory bodies effectively — to investigate the proposal on behalf of the client. In addition to the sheer length of the proposed underground route, the fact that a significant portion of the route would pass under a major river was another unique aspect.

That initial assessment of an undergrounding approach was a prime example of how to help a client explore nontraditional rights-of-way and other corridors to deliver power. Working in close collaboration, we put together an initial report and then worked through an iterative process to fine-tune the client’s concept, segment by segment. While undergrounding can be an expensive proposition, the enhanced reliability and possibility of avoiding some of the restrictions associated with congested airspace could make this a cost-effective option for the client.

With the fatal flaw analysis completed, the client is now well-positioned to move forward with a technical feasibility analysis and other, more public steps. This was a relatively fast and inexpensive investment when compared to the scope of what a full project implementation would entail.

 

Utilities are investigating ways to tap into the power of HVDC for bulk energy transmission. Explore another solution: Converting existing AC systems to HVDC.

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Marianne Goldsborough is a project manager for Burns & McDonnell, overseeing the design, engineering and construction of substation and transmission line projects. With more than 30 years of experience in the electrical utility sector, Marianne specializes in HVDC and HVAC conversions, substations, transmission and distribution lines, and underground AC systems.