Challenge

Faced with ongoing extreme weather events and related outages, Florida is looking to implement more grid resilience throughout the state. A recently passed statute requires each utility to develop a 10-year plan to mitigate the impact of major events on customers through infrastructure storm-hardening. The plan requires development of hardening projects, estimating restoration cost and outage time benefits, prioritizing projects, and justifying the overall investment level.

While the statute requirements are more than reasonable and seem straightforward, producing the results is a major challenge. First, the benefits of hardening investment are dependent on the frequency and impact to TECO’s system. Thus, the model needs to factor in the range of potential storm events over the life span of the infrastructure improvements — 50 years in most cases.

Second, the main driver of asset failures is vegetation blown into power lines, resulting in interruptions and pole failures. The model also needs to consider the vegetation around hundreds of thousands of assets, the condition of those assets and expected variance in wind speeds throughout a region.

Next, groups of assets serving customers require the model to consider the linkage between assets and customers. Further, the scope of the project needs to be comprehensive to avoid leaving a “weak link,” but not so encompassing as to harden parts of the system that provide minimal value to customers.