Linking bottom-up and top-down prognosis in integrated distribution grid expansion planning

(Netzentwicklungsplan, NEP). This paper proposes an enhanced forecasting methodology that integrates top-down scenarios with bottom-up projections derived from local technological trends and regional indicators. The approach evaluates temporal accuracy, geolocation, and technology-specific developments across multiple network levels using digital twins and planning tools. Results from a case study reveal substantial deviations between top-down forecasts and actual demand, with capacity increases in 2025 exceeding projections by over 50

MW. Technology-specific comparisons for 2045 show the integrated bottom-up estimates significantly surpassing top-down values for renewables and industrial electrification, leading to an 81% increase in required high-voltage line expansion. The findings underscore the limitations of centralized models and highlight the benefits of a dual forecast approach for improving investment decisions, infrastructure readiness, and adaptability to evolving energy landscapes. This integrated methodology provides DSOs with a more robust foundation for achieving climate neutrality and managing the energy transition.