Task 51 – Forecasting for the Weather Driven Energy System

Objectives

A decade ago, the idea of "wind integration" discussed how to integrate 10% or more of wind energy into an otherwise unchanged power system. Today, the first countries and control areas surpassed the 50% mark, and they run their electric system with over 100% wind and solar at times. A decade from now, wind and solar will likely be the backbone of the energy system, at least in some areas of the world and most of the time.

Task 51 focuses on advancing forecasting methods for the weather-driven energy system across all relevant time scales, from minutes to seasons.

The Task emphasizes not only forecast accuracy, but also the value of forecasts for operational decision-making, market participation, and system resilience, through close interaction between meteorology, forecast providers, and end users.

Consequently, the work is organised across 3 work packages: Atmospheric Physics, Conversion to User Variables, and End Use spanning 11 work streams.

Task 51 identified the need to collaborate not only across work packages and hence stakeholders, but also across other IEA TCP tasks and other organisations such as the IEC, the WMO, etc.

Participation

There are 12 countries participating in Task 51 (Table 1) and the participants' list counts around 350 people, making Task 51 the largest global discussion group on forecasting of renewables.

The industry partners of Task 51 collaborate as end users by for example testing the software tools developed in the task, especially those: operating renewable generation facilities, trading renewable power or receiving forecasts for a control area as Transmission System Operators.

Progress, Results, and Impact in 2025

In 2025, significant emphasis was placed on dissemination, and cross-task collaboration, including growing activity on artificial intelligence (AI) methods for weather prediction and on forecasting of extreme power system events.

A major thematic event in 2025 was the public workshop on Forecasting Extremes in the Power System (Figure 1+2). Task 51 promoted activities addressing extreme weather conditions such as storms, heatwaves, cold snaps, icing, and prolonged low-renewable 'Dunkelflaute' events. Emphasis was placed on weather regime prediction, sub-seasonal forecasting, and uncertainty quantification for anticipating high-impact, low-frequency events affecting system reliability and markets.

The use of forecasting methods on all time scales in the energy industry requires continuous education and dissemination efforts in the form of guidelines, recommendations and standards to serve an industry in transformation, as the gap between academic knowledge and industry adaptation is still large. It also demonstrated that the work on testing the recommendations provided in the IEA Wind Recommended Practice [1] with real-data and use cases is a necessary step for the industry to be able to progress and adopt these recommendations on the book's companion page [1a]. Moreover, the Task has begun to create open software libraries for data exchange and forecast evaluation. Some of these error evaluation guidelines are now being incorporated into IEC standards.

Task 51 continues to work on a new Technical Specification in IEC SC8A WG2 on forecast error determination and data quality. The Task leverages the existing Liaison between IEA and IEC Technical Committee 8 (TC8, the parent of Sub-Committee 8A) to allow the experts from IEA Wind Task 51 to work on the standard. The primary objective of this standard is to establish a comprehensive framework for evaluating forecast results of renewable energy generation (such as wind and solar). This includes defining methods for data collection, processing, and deviation assessment, enabling cross-comparison of forecast deviations across different countries and forecast service providers. It also provides guidance for the scientifically grounded application of forecast results.

Task 51 further strengthened its role as a global discussion forum on AI in renewable energy forecasting. In collaboration with other IEA Wind Tasks, IEA PVPS Task 16, and experts from the meteorological and energy communities, Task 51 contributed to workshops and webinars focused on AI-based weather prediction and its integration into energy systems. Recordings of recent events are publicly available via the IEAWindForecasting YouTube channel.

A comprehensive stakeholder analysis was carried out after a workshop in 2024, leading to a publication [2] and providing input to the roadmap of the task for the next phase. In the analysis, forecasting challenges for weather-driven energy systems through mixed-methods engagement with 120 practitioners from 50+ organisations across universities, energy providers, and transmission system operators were addressed. Here, the implementation priorities and barriers in renewable energy forecasting were quantified and tested in a second workshop in 2025. Results reveal persistent implementation gaps between stakeholder recognition of forecasting needs and operational deployment.

Task 51 increased its dissemination efforts substantially, including one public workshop per year, and posters, talks and special sessions at several conferences such as WindEurope's Annual Event, EGU, ICEM, WESC, and the Wind & Solar Integration Workshop, among others. Photos & Graphics.

Lastly, members of Task 51 have published more than 10 articles in international journals and magazines.

Next Steps

In April 2026, Task 51 co-organises a workshop in Paris on AI in the Energy System, together with Task 63 Large-Scale Integration. Topics range from AI Weather Prediction and AI assisted downscaling of weather products to AI uses in power system management, privacy preserving data sharing through federated learning and opportunities for collaboration.

The Task's Information Portal on the website is kept up to date, and the work streams discuss their deliverables, working to update the Recommended Practices with additional tools and implementation guidelines and actively collaborating to the IEC SC8A WG2 new standard TS63531 on renewable energy forecast evaluation.

References

1. Corinna Möhrlen, John Zack, Gregor Giebel. IEA Wind Recommended Practice for the Implementation of Renewable Energy Forecasting Solutions. 370 pp. Elsevier Academic Press, November 11, 2022. ISBN: 9780443186813. DOI: 10.1016/C2021-0-03549-5.
2. Companion Page for Elsevier Book Recommended Practice for the Implementation of Renewable Energy Forecasting Solution. https://shop.elsevier.com/books/book-companion/9780443186813
3. Irene Schicker, Corinna Möhrlen, Anna-Maria Tilg, Lukas Strauss, Florian Mader, Advancing forecasting in mountainous terrain for weather-driven energy systems: Recommendations from a comprehensive stakeholder analysis, Energy Strategy Reviews, Volume 64, 2026, 102194, ISSN 2211-467X, DOI: 10.1016/j.esr.2026.102194.