Our team was engaged by TECO to employ a resilience-based planning approach to identify hardening projects and prioritize investment in the transmission and distribution system. Utilizing a data-driven decision-making methodology through our Storm Resilience Model, we employed robust and sophisticated algorithms to calculate the resilience benefit of hardening projects in terms of reduced restoration costs and Customer Minutes Interrupted (CMI).

The model is designed to evaluate the impact on TECO’s system for nearly 100 storm scenarios against 20,000 potential hardening projects, each developed at the protection device level for laterals or circuit level for feeders and transmission circuits. This allows the model to associate assets with customers, and thus inform development of projects that are customer centric.

The model also leverages geospatial analytics to evaluate vegetation density, span by span, across the entire system as well right-of-way access. Additionally, we leveraged wood pole asset health algorithms and sophisticated storm surge modeling within the model to understand the likelihood of asset failure during a storm and the impact that failure will have on customers.

Monte Carlo analysis simulated storm events over the next 50 years, creating 1,000 storm futures. Each subsystem section was evaluated before and after hardening for each of these storm futures to generate a range in customer benefits from a restoration cost and CMI reduction perspective.

Finally, the model performed a budget optimization to identify the point of diminishing returns, where additional hardening investment offers minimal value to customers.

The results of the assessment and model produced a 10-year, $1.5 billion Storm Protection Plan across five different storm hardening programs, from undergrounding laterals to transmission pole replacements and more. The results show a decrease in storm restoration costs of approximately 32% to 37% and a 32% decrease in storm CMI over the next 50 years.

The budget optimization analysis showed that the overall $1.5 billion investment level was right before the point of diminishing returns. This provides confidence that the plan will not overinvest in hardening activities, providing customers with the most benefit from infrastructure improvements.

Fundamentally this allows TECO to provide the Florida Public Service Commission and their stakeholders with a robust and justifiable business case wholly focused on customer benefits rooted in how storms impact the system.

The plan was submitted to the commission on April 10, with a decision anticipated in October 2020. Our technical report is included in TECO’s filing to the commission and we are providing expert witness testimony throughout the regulatory process.

The model and supporting assessment provide TECO with the tools necessary to not only build impactful resilience into the grid but also justify those storm hardening investments to both internal and external stakeholders, making more effective use of large capital investments over the next 10 years.