Managing the Seasonal Variability of Electricity Demand and Supply INTERNATIONAL ENERGY AGENCY The IEA examines the full spectrum of energy issues including oil, gas and coal supply and demand, renewable energy technologies, electricity markets, energy efficiency, access to energy, demand side management and much more. Through its work, the IEA advocates policies that will enhance the reliability, affordability and sustainability of energy in its 31 member countries, 13 association countries and beyond. This publication and any map included herein are without prejudice to the status of or sovereignty over any territory, to the delimitation of international frontiers and boundaries and to the name of any territory, city or area. Source: IEA. International Energy Agency Website: www.iea.org IEA member countries: Australia Austria Belgium Canada Czech Republic Denmark Estonia Finland France Germany Greece Hungary Ireland Italy Japan Korea Lithuania Luxembourg Mexico Netherlands New Zealand Norway Poland Portugal Slovak Republic Spain Sweden Switzerland Republic of Türkiye United Kingdom United States The European Commission also participates in the work of the IEA IEA association countries: Argentina Brazil China Egypt India Indonesia Kenya Morocco Senegal Singapore South Africa Thailand Ukraine Abstract Managing the Seasonal Variability of Electricity Demand and Supply Abstract Electrification of end-uses and the growth of solar and wind is changing how electricity systems operate on all time scales. This report analyses how seasonal variations in both demand and supply This work expands on the report Managing Seasonal and Interannual Variability, published in April 2023 which assesses the impact of weather-related variability on system operations across seasons and affect electricity system operations to 2050 – in Europe, India, Indonesia and Korea – and what sources will be used to manage them. Seasonal variations are put in context with the annual electricity mix and short-term (hourly) variability. Each of the analysed between years in different climatic zones. regions has a unique electricity mix today, available resources, geographies, and patterns of electricity demand. Each has charted a different course for their clean energy transitions and is located in different climatic zones. This study also recognises that weather conditions are uncertain and vary from year-to-year, exploring their impact on system operations and power system costs. The study finds that, in each system, both short-term and seasonal flexibility needs rise considerably to 2050. Flexibility, currently provided by thermal power plants and hydro, will increasingly come from new sources – demand response and batteries on shorter timescales and hydrogen across weeks to seasons – with low emissions thermal power plants and hydro remaining important providers of seasonal balancing. As the systems become more capital-intensive, consumers are increasingly insulated from the impact of weather variations on power plant operations and the volatility of fossil fuel prices. PAGE | 3 Table of contents Managing the Seasonal Variability of Electricity Demand and Supply Table of contents Executive summary ......................................................................................... 5 Introduction .................................................................................................... 11 Model set-up and methodology .................................................................... 13 Key findings ................................................................................................... 19 Regional insights ........................................................................................... 24 Europe .......................................................................................................... 25 India.............................................................................................................. 42 Indonesia ...................................................................................................... 58 Spotlight: Korea ............................................................................................ 71 Implications for power plant operations and costs ................................... 79 Annex .............................................................................................................. 88 PAGE | 4 Executive summary Managing the