A Cost-Benefit Framework for Grid Modernization Based on Forecasted Reliability Outcomes

Duration Index (SAIDI) and the System Average Interruption Frequency Index (SAIFI). By offering a unified approach to benefit-cost evaluation, the framework supports consistent, datainformed decision-making that is defensible and aligned with stakeholder expectations.

A key strength of the LTM methodology is its accessibility and adaptability. Unlike many existing planning tools, the model does not rely on proprietary software, complex internal datasets, or detailed power-system simulations. Instead, it applies time-series forecasting techniques to establish a baseline of expected reliability performance under normal operational conditions, projecting future degradation trends in the absence of intervention. Reliability improvements for each proposed project are modelled by fitting a rational function to historical reliability data, reflecting the anticipated time-dependent improvement and its long-term asymptotic behaviour. By calculating the difference between the baseline and the postinvestment reliability improvement, a quantitative measure of impact is derived, creating a new post-investment baseline. Implementation of the LTM framework can be carried out with widely available platforms such as Microsoft Excel and Python, ensuring that utilities of all sizes and data maturities can adopt the methodology with minimal overhead. This paper presents the LTM process in its practical application to real-world planning scenarios.

By enabling transparent, repeatable, and stakeholder-friendly evaluations, the LTM methodology enhances accountability and strategic clarity in grid modernization efforts.

Furthermore, its scalable nature makes it suitable for both early-stage planning and portfoliolevel trade-off analysis, especially in environments where data availability or modelling resources are limited. The result is a practical, data-driven approach to directing reliability investments where they can deliver the greatest impact. By grounding decisions in standardized reliability metrics and benefit-cost analysis, the LTM framework contributes to more resilient, efficient, and customer-focused electric grid systems.