Regional Reanalysis Applications for Extreme Weather and Energy Sector Resilience: A Case Study from Italy

The need for a reliable and up-to-date weather dataset with a history of at least 20 years has been repeatedly emphasized by transmission system operators and distribution companies. Reanalysis offers spatially distributed modelled data over extended periods with integrated observations, providing estimates of atmospheric variables applicable across various fields. Such datasets are crucial for protecting and managing infrastructure against extreme weather events, enhancing system resilience, and quantifying the availability of renewable resources (e.g., hydroelectric, wind, solar).

This study highlights the application of regional reanalysis in the electric and energy sector, utilizing a 4 km regional reanalysis product named MEteorological Reanalysis Italian DAtaset (MERIDA) High-RESolution (HRES), developed for Italy by Ricerca Sul Sistema Energetico (RSE) S.p.A. Examples of applications demonstrate the utility of regional reanalysis products in quantifying hazards and impacts of extreme precipitation, wet snow, strong winds, wildfires, and flooding at various scales (from climatology to single extreme events).

Analyses include calculating return periods and frequency of occurrence of extreme precipitation events over the Italian territory to highlight areas of the electro-energy infrastructure that are majorly exposed to impacts of extreme hydro-meteorological events and landslides. For winter events, return periods of snow sleeves on overhead power lines are calculated using the ice-accretion model of Makkonen, providing guidelines for stakeholders and TSO operators to identify areas prone to wet-snow events and develop solutions to increase infrastructure resilience. Additionally, Fire Weather Index maps were generated to identify typical fire danger distribution across Italy, aiding long-term planning of preventive fire-fighting measures and infrastructure design by stakeholders and decision-makers.

Specific case studies, such as the July 2016 convective storm near Bergamo and the Vaia storm in October 2018 over the Italian Alps, illustrate the dataset's capability in capturing both precipitation and wind extremes.

The findings affirm the potential applications of reanalyses and outline future challenges and next steps, including the need for higher resolution and improvements in some physical processes, along with the transition of these studies towards future scenarios. Although this study focuses on Italy, the methodologies and discussions presented are applicable to other regions globally and can be adapted using different reanalysis products. The ultimate aim of this presentation is not only to provide a successful example of applications in a specific region but also to stimulate dialogue among researchers, reanalysis developers, and stakeholders regarding common challenges, current strategies, and frontier questions in the use of regional atmospheric reanalysis products in the energy sector.