Sector integrated renewable-based energy systems require new concepts for optimal operation and supply security assessment. Using an integrated optimization model of the German energy system, we identify two future peak loads: a harvesting peak load of ∼287 GW, where flexible sector coupling technologies and energy storage maximize renewable electricity use, and a resilience peak load of ∼139 GW, which occurs during dark lulls and must be met by flexible power plants. Our findings highlight that the flexibility of sector coupling technologies, alongside sufficient energy storage, is essential for balancing supply and demand in volatile renewable-based energy systems. A sensitivity analysis shows that limiting electrolyzer flexibility – by requiring at least 8000 full load hours – doubles renewable electricity curtailment and raises system costs by 10.5% compared to the reference scenario. Therefore, policymakers should incentivize flexible sector coupling and electricity demand while ensuring the expansion of long-term energy storage. • Novel concepts of harvesting peak load and resilience peak load introduced. • Variable renewable energy is harvested by flexible sector coupling options. • 139 GW of flexible power to bridge dark lull as critical situation for resilience. • Continuous operation of electrolyzers increases total system cost by 10.5%. • Resilient energy systems require flexibility and long-term storage.
Schöb et al. (Fri,) studied this question.