Will New Power Poles and Underground Lines Prevent Blackouts? A Case Study in the U.S. Virgin Islands - Energy Academic Group
Will New Power Poles and Underground Lines Prevent Blackouts? A Case Study in the U.S. Virgin Islands
By Dan Eisenberg, PhD,
Department of Operations Research,
Naval Postgraduate School
In September 2017, Hurricane Irma struck the islands of St. Thomas and St. John in the northern part of U.S. Virgin Islands (USVI), and Hurricane Maria struck St. Croix just two weeks later in the south. Together, these storms devastated local infrastructure and communities1. Since this catastrophic event, the Federal Emergency Management Agency (FEMA) has funded a Naval Postgraduate School (NPS) team led by Drs. David Alderson and Daniel Eisenberg of the NPS Center for Infrastructure Defense and Operations Research Department with colleagues in the NPS Energy Academic Group, USVI Territorial Government, U.S. Department of Energy, U.S. National Labs, University of the Virgin Islands (UVI), and Territorial infrastructure providers to ensure communities are resilient to the next big storm.
Recent work led by Maj. Dominik Wille of the German Army and his advisor Dr. Eisenberg measures the vulnerability of the USVI power system to future storms and identifies possible ways to keep the lights on after a hurricane2. Immediately after Irma and Maria, the USVI power system was rebuilt using wooden power poles known to be vulnerable to hurricane-force winds. Working with the University of the Virgin Islands, Sandia National Labs, and the Virgin Islands Water and Power Authority (VIWAPA), Wille was able to measure the benefit of installing composite poles and underground power lines that may survive future hurricanes. The analysis focused on St. Croix communities by using a computer model of the St. Croix power system provided by VIWAPA and Sandia National Labs, and subjecting it to simulated storm events to see what infrastructure might break and what communities might lose power.
Analysis shows how a hurricane may cause future blackouts on St. Croix. Specifically, communities should expect above ground, wooden power poles to fail in a Category 2 storm and that the majority of St. Croix will lose power. Analysis also shows that communities should expect a complete, island-wide blackout for a more extreme event (Category 3 and above). In contrast, even with debris strikes, storm surge, and flooding, replacing wooden poles with composite poles will ensure some communities still have power after a Category 3 storm.
Still, not all composite poles are expected to survive, and some communities will lose electricity even in the best-case scenarios. This is because composite poles are rated for high winds but are still vulnerable to flying debris that can strike and break them, which was experienced when Hurricane Dorian struck the USVI as a mere Category 1 storm last September, and some composite poles did not survive.
Underground power lines provide similar benefits as composite poles, but in different areas. This is because the buried part of the power grid is expected to survive the storms, but the secondary lines connecting the grid to your house may not.
If done right, a combined approach with composite poles and buried power lines is expected to prevent blackouts during Category 3 storms and above. This combined approach buries systems in areas surrounded by potential debris like forests and uses composite poles near customers to protect low-voltage household connections and above ground equipment.
Despite the possibility of a nearly stormproof power system, the federal government is paying to install the infrastructure, and system operators at VIWAPA who must maintain the system into the future need to consider whether these benefits are worth it for St. Croix communities.
No infrastructure is invulnerable, and we should expect at least a few composite poles or underground lines to require replacement after any hurricane season. These infrastructures are expensive—a composite power pole costs upwards of 50 times a wooden power pole to install in the Territory. Consideration of these future costs of system recovery and blackout need to be accounted for prior to deciding which part of the power system to harden. Cheaper power poles may be better in communities that are already used to living with blackouts. Critical services provided by hospitals and police stations may require hardened systems. Moreover, benefits to other utility services should also be accounted for, such as improving telephone and internet connectivity by hardening cables that hang alongside power lines on the same poles.
 Alderson, D. L., B. B. Bunn, D. A. Eisenberg, A. R. Howard, D. A. Nussbaum, and J. Templeton. "Interdependent Infrastructure Resilience in the US Virgin Islands: Preliminary Assessment." Naval Postgraduate School Technical Report NPS-OR-18-005 (2018).
 Wille, Dominik. "Simulation-Optimization for Operational Resilience of Interdependent Water-Power Systems in the US Virgin Islands." Master’s Thesis., Monterey, CA; Naval Postgraduate School, 2019.
Email Dan Eisenberg at firstname.lastname@example.org or call 831-656-2358