Synopsis The dynamics of photovoltaics, wind power, and bioenergy shape the volatility of our energy supply, influenced by the time of day, season, weather, and developments in agriculture and forestry. BioFlex explores the fundamental commonalities in dealing with these fluctuations and the uncertainties in extrem events caused by climate change. The project targets modellers interested in a comprehensive and coherent analysis of the future resilience and flexibility needs in the energy system. Introduction Research on flexibilities in power systems is becoming increasingly important, but so far exceptional events due to (a lack of physical) resilience of infrastructures have been neglected in power market and power system models. In contrast, resilience research is predominantly concerned with disaster prevention, security considerations, and coping with sudden resource shortages. In the FFG BioFlex project, we combine resilience and flexibility concepts to provide a common basis for energy infrastructure planning. Research goals Sub-objective #1: Define a set of requirements for modelling resilience and flexibilisation concepts. Sub-objective #2: Test proprietary tools to identify their capabilities and limitations. Sub-objective #3: Formulate a guide for advancements in research, development, and innovation. Methodology In the FFG BioFlex project, we define flexibility as the ability to move resources through time, space, and between sectors. This option allows for balancing deficits with surpluses. The currently prevailing discussion of flexibilisation focuses on regular, well-known fluctuations, and thus on a limited risk space. We extend this space by including extreme events, considering resilience measures such as storage or redundancy as a special form of flexibilisation. Potential dangers of flexibilisation, such as the amplification of imbalances, are also considered. Examples of compound events which can stress power systems are e.g. cold related failure of power grid infrastructure during cold “dunkelflauten”, combined with increased charging of electric car fleets due to e.g. mobility demand induced during peak travelling times or storm related grid infrastructure failure with a concurrent drop in wind power production as turbines shut down in extreme winds, can be given here. To incorporate the expanded risk and uncertainty space into energy infrastructure planning, we are developing a detailed requirements profile for planning tools. To identify the capabilities and limitations of our own tools, we conduct tests. Here, we use the MEDEA electricity market model (Boku) and the BeWhere bioenergy supply chain model (IIASA). This choice of models allows us to investigate flexibility options on the interface between electricity and bioenergy supply. Considering multi- sector coupling, also called infrastructure coupling or system integration, allows us to better understand resource shifting between sectors as a flexibility option. The insights gained and results of the tests are used to create a research, development, and innovation (R&D&I) guide. The guide includes a SWOT analysis (Strengths-Weaknesses, Opportunities, and Threats), resource requirements, and an assessment of the likelihood of success for strategic, integrative planning and implementation of cross-sector resilience and flexibilisation approaches. Targeted communication in national and international networks as well as bilateral exchange with modeling experts in sister projects ensure the broader applicability of the project recommendations. In particular, the activities in the International Energy Agency (IEA) Bioenergy Technology Collaboration Program (TCP) Task44 on flexibilisation and system integration should be mentioned. The BioFlex project builds on the results of the first triennium of this Task [1]