Periodic Reporting for period 2 - S2S4E (Sub-seasonal to Seasonal climate forecasting for Energy) Reporting period: 2019-06-01 to 2020-12-31 Summary of the context and overall objectives of the project Large-scale deployment of renewable energy sources is key for the clean energy transition, which is needed to comply with the greenhouse gas (GHG) emissions reduction agreed upon in the Paris Agreement and achieve the European Green Deal ambition of reaching carbon neutrality by 2050. However, renewable energy generation and operational planning are strongly affected by weather and climate conditions, such as reduced wind speed, low solar radiation or persistent droughts. Together with the poor forecasting capacity beyond a few days for power output and demand , this dependence on climate conditions causes wide variations in the production and demand of electricity from renewable sources. Thus, matching the demand and supply constitutes a major challenge, hampering the integration of renewable energy sources in electricity networks despite being cost-competitive in many settings.To help solve this problem, S2S4E developed new research methods that explore the frontiers of climate conditions in the coming weeks and months. This research was contextualised in a new generation of climate services that are closely co-produced with users and markets in a user-centric approach. Hence, a tangible result of the project was the co-development of an operational Decision Support Tool (DST; s2s4e.eu/dst) with the support of key stakeholders in the renewable energy sector in the French, German, Spanish and Scandinavian markets. The DST integrated for the first time sub-seasonal to seasonal (S2S) climate predictions for renewable energy production and electricity demand.S2S4E has shown how to link climate information and decision-making to develop better-informed strategies that improve the integration of renewable energy into the electricity system. The long-term expected impact of the project is to make the European energy sector more resilient to climate variability and extreme events while contributing to a rapid energy transition to address the climate emergency.(watch the RESILIENCE documentary, a 3-minutes summary of S2S4E: https://youtu.be/f_j7rNmNonE) Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far S2S4E was a three-year project that finished in December 2020. A full overview of the project results can be found in the project website: www.s2s4e.eu. Some of the key achievements are listed below for five key aspects of the project:Climate science advances: The project has built methodologies and tools to analyse climate variability in the past and assess its impact on the energy sector. Initial efforts were focused on defining and analysing eight case studies for key periods in the past during which S2S predictions could have helped energy users to anticipate and react to extreme events. This knowledge helped prepare the methodologies and workflows to improve S2S climate predictions for energy and the integration of these predictions in an operational environment. A key exploitable result is the contribution to the R-package CSTools that provides process-based methods for forecast calibration, bias correction, statistical and stochastic downscaling, optimal forecast combination and multivariate verification, as well as basic and advanced tools to obtain tailored products.Operationalisation of climate services:S2S4E aimed to demonstrate and learn from the operationalisation of climate services. In June 2019, the project launched the S2S4E Decision Support Tool (www.s2s4e.eu/dst) a forecasting service that offered integrated S2S forecasts for electricity demand and power generation from solar panels, wind turbines and hydropower plants. The tool provided operational forecasts every week during 1.5 years. Currently, the tool and all the past forecasts released throughout the project (until December 2020) are open and available online, while there is an active strategy to commercialise the operational version of the tool.Knowledge transfer:The project had an active engagement and knowledge transfer strategy to ensure the impact and application of the project outcomes. This included the production of monthly forecast outlooks, a series of webinars (focusing on forecasts for each season and promoting climate services for energy), the release of weekly temperature extremes forecasts on social media during summer and winter 2020, and the punctual release of forecasts for the Euro-Atlantic teleconnections. S2S4E was present in diverse fairs and energy-relevant events to share key results, and closed the project with a research day bringing together the climate science and energy modelling communities.Policy advice: S2S4E aimed to inform policy makers on how S2S forecasts can support the clean energy transition by enhancing the renewable energy share in the energy mix. A comprehensive report analysing energy policies and interventions with an annex database was produced in D6.2. At the end of the project, a white report was released (https://www.bsc.es/Zd3) including six policy recommendations to increase the use of S2S forecasts and improve the quality of such forecasts. Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far) Co-production with energy users was at the core of the project, and close interaction was established with industry partners and other energy stakeholders. This approach supported the field of climate services for energy by determining the information needs of the renewable energy sector, drawing decision maps to help users understand how climate predictions can fit in their decision-making processes, and allowing the industry partners to define relevant case studies. S2S4E has also delved into the potential gains of using the DST for improving risk management activities of energy producers and the impact of having operational real-time forecasts. More importantly, the project demonstrated the value of a transdisciplinary approach to future initiatives aiming to develop climate services.The operationalisation of the DST was a major scientific and technical challenge and achievement of the project. Besides the reach and interest that operational forecasts had in the energy community, the operational tool was a unique testbed not only for energy stakeholders but also for scientists, allowing them to visually explore S2S forecasts, and providing a new perspective and approach to the data. The process also helped to understand the technical and infrastructure challenges of real-time forecasts with many useful lessons learned for the future activities and projects aiming to operationalise climate services.At policy level, the project has highlighted the links of S2S forecasts with the EU’s Risk Preparedness Regulation 2019/941 and the seasonal adequacy assessment methodology. Although this methodology currently only requires the use of weather forecasts, the dialogue between transmission system operators and climate service providers should be encouraged to ensure that the potential of S2S forecasts to fulfil the requirements of such regulations is assessed.The scientific advances in S2S4E are useful for the energy sector, but also for any other sector where climate-dependent decisions have to be taken at S2S time scales. The project has particularly focused on the replicability of the DST and the research approaches for the field of agriculture, food security and drought management, as well as tourism, insurance and public health. The developments of S2S4E and the operational tool developed have paved the way for the use of S2S forecasts by users in these fields. S2S4E User Tailored products S2S4E at EWORLD 2020 S2S4E Decision Support Tool (www.S2S4E.eu/dst)
