Book/Dissertation / PhD Thesis

FZJ-2026-02804

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Kostenoptimale Energieausfälle in erneuerbaren Energiesystemen

Franzmann, D. (Corresponding author)

2026
Forschungszentrum Jülich GmbH Zentralbibliothek, Verlag Jülich
ISBN: 978-3-95806-943-5

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Please use a persistent id in citations: doi:10.34734/FZJ-2026-02804

Abstract: Cost-Optimal Energy Deficits in Renewable Energy Systems. Fossil energies threaten human prosperity through environmental pollution, which is why renewable energies are needed as a sustainable alternative. However, due to their variability, renewable energies require flexibility options to compensate for fluctuations in generation. Recent studies suggest that power outages can be avoided with sufficient backup energy and capacity. However, these studies neither evaluate the economic viability of expanding a backup structure nor do they systematically analyze the influence of flexibility options.This study closes this gap by comparing the costs of expanding the energy system with the reliability of a renewable energy system and thus modeling global economically optimal power outages. It also systematically shows the influence of flexibility options on power outages and derives differences to stable renewable energy systems. To model economically optimal power outages, the “value of lost load” approach is used, which equates the costs of capacity expansion with the costs of power outages. The costs of energy outages are derived globally in a spatially and sectorally disaggregated manner. A global energy system model including all necessary flexibility options describes the costs of capacity expansion. For a detailed representation of the outages, the earth is divided into 1890 regions and calculated using hourly resolution. Global location-specific cost potentials are calculated for concentrated solar power (CSP), geothermal energy and hydrogen salt cavern storage. New approaches for CSP and geothermal energy are used for this purpose. It is shown that economically optimal energy outages occur between 2.5 and 70 times per year worldwide, with a median of 6 outages per year. 96% of power outages last less than 24 hours, while 4% occur as longer multi-day outages. The longest outages last 100 hours and occur with a probability of 2% per year. One-day lulls occur mainly in the evening and at night for up to seven consecutive days. The cause of power generation lulls are wind power generation lulls lasting up to seven days. In interconnected systems with seasonal PV feed-in, wind generation lulls occur during phases of low solar feed-in. Hydrogen storage and battery storage are used as flexibility options in the energy system to reduce the 7-day generation outages to individual daily lulls. The main causes of energy system lulls are limitations in battery storage capacities and the capacity of hydrogen reconversion. Restrictions on electricity transport are evident in individual interconnected systems. The selection of available technologies and the ‘’value of lost load” are the main influences for energy outages. The main feed-in from geothermal energy and CSP as well as the use of salt caverns have a positive effect on the outage level, while wind power has a negative effect. Outages occur more frequently when the ‘’Value of Lost Load” is below 1500 EUR/MWh, while energy systems above 3000 EUR/MWh are stable, as more stable energy systems are purchased here. The most important countermeasure is energy transportation, with electricity and hydrogen transportation being 99% substitutive. Sector coupling with hydrogen, in particularhydrogen storage, especially in salt caverns, is the second most important technology. Stable energy systems require above all the expansion of decentralized hydrogen storage and the expansion of hydrogen reconversion capacities, with additional costs of less than 2%. The results show that economic, lull-optimal renewable energy systems have a tenfold higher failure level globally than current energy systems. When expanding energy systems, wind power expansion should be taken into account at an early stage, as energy systems becomemore susceptible to outages with a greater expansion of wind power. On the other hand, the desired failure level can be adjusted at a later stage, primarily through the expansion of hydrogen infrastructure.

Note: Dissertation, RWTH Aachen University, 2026

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Contributing Institute(s):

1. Jülicher Systemanalyse (ICE-2)

Research Program(s):

1. 1111 - Effective System Transformation Pathways (POF4-111) (POF4-111)
2. 1112 - Societally Feasible Transformation Pathways (POF4-111) (POF4-111)

Appears in the scientific report 2026

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