Earth system modeling with endogenous and dynamic human societies: the copan:CORE open World-Earth modeling framework

Analysis of Earth system dynamics in the Anthropocene requires to explicitly take into account the increasing magnitude of processes operating in human societies, their cultures, economies and technosphere and their growing feedback entanglement with those in the physical, chemical and biological systems of the planet. However, current state-of-the-art Earth System Models do not represent dynamic human societies and their feedback interactions with the biogeophysical Earth system and macroeconomic Integrated Assessment Models typically do so only with limited scope. This paper (i) proposes design principles for constructing World-Earth Models (WEM) for Earth system analysis of the Anthropocene, i.e., models of social (World) - ecological (Earth) co-evolution on up to planetary scales, and (ii) presents the copan:CORE open simulation modeling framework for developing, composing and analyzing such WEMs based on the proposed principles. The framework provides a modular structure to flexibly construct and study WEMs. These can contain biophysical (e.g. carbon cycle dynamics), socio-metabolic/economic (e.g. economic growth) and socio-cultural processes (e.g. voting on climate policies or changing social norms) and their feedback interactions, and are based on elementary entity types, e.g., grid cells and social systems. Thereby, copan:CORE enables the epistemic flexibility needed for contributions towards Earth system analysis of the Anthropocene given the large diversity of competing theories and methodologies used for describing socio-metabolic/economic and socio-cultural processes in the Earth system by various fields and schools of thought. To illustrate the capabilities of the framework, we present an exemplary and highly stylized WEM implemented in copan:CORE that illustrates how endogenizing socio-cultural processes and feedbacks could fundamentally change macroscopic model outcomes

Reliable Flexibility Provision from Distribution Systems to Enable Higher Grid Utilization by Curative Operation

Operating power grids in the course of the ongoing decarbonization of energy systems is increasingly challenging. More and more decentral renewable energy sources are contributing to the supply of electricity and cause higher transport demands in the power grids. The necessary grid expansion is running behind schedule required to meet the targets of the Paris Climate Accords for reasons of social acceptance and high costs. Therefore, transmission system operators as well as regulatory authorities are investigating new approaches to enable higher network utilization. One way to alleviate the situation, is to shift from preventive n-1 safe grid operation to curative n-1 safe grid operation. To enable such a change, operational degrees of freedom are needed, which can stem from different sources. In this work, the focus is on flexibility provided by distribution grids and how it can be used as an operational degree of freedom for curative grid operation. Flexibility allocated by adapting the schedules of distributed energy sources is provided in such a way, that the resulting power-flow changes relieve congestion in the transmission system. These distributed energy sources can be generators, such as wind-power or photovoltaic power plants, as well as flexible loads, such as power-to-heat plants or heat pumps. Two key questions in the context of this concept are treated in this thesis: Firstly, is there enough flexibility in the German distribution grids to use those grids for curative transmission grid operation? And secondly, how can a distribution system operator calculate the flexibility of his grid that can safely be provided? To answer the first question, an energy system model of Germany in the year 2030 is set up and available flexibility for curative transmission system operation is calculated. Time-steps are selected, in which a loss of transmission capacity leads to critical states in the grid, and the available flexibility in the regions adjacent to the critical corridor is calculated. Results show, that especially power-to-heat can provide valuable flexibility in situations where transmission capacity losses lead to critical states and, together with flexibility from wind-power, in 40 % of these situations the power provided by these two technologies is sufficient to reduce power-line loadings back to safe values. In the remaining 60 % of situations other sources must complement the flexibility necessary for curative operation or the utilization of the grid has to be reduced accordingly. The second question is answered by the development of a fast and robust optimization approach to limit the allowed ranges in power injection changes from individual energy resources in order to guarantee a safe state in the flexibility-providing distribution grid. The derived analytical solution of the boundary conditions that ensure a secure state in the grid can be integrated as a subordinate problem of the optimization, so that a large part of the overall problem can be calculated before optimization. The robustness of the approach is not only shown by the guaranteed compliance with boundary conditions, but also by a stable convergence behavior. This method is successfully tested on both a conceptual test grid and a real distribution grid. This work shows both that flexibility from the distribution grids is available in orders of magnitude relevant for curative grid operation, and that it can be used for such operation. The approach developed in this thesis to calculate and provide flexibility can be applied to real grids and offers the necessary security and speed needed for curative grid operation due to the inherent robustness

Pathways toward a Decarbonized Future—Impact on Security of Supply and System Stability in a Sustainable German Energy System

Pathways leading to a carbon neutral future for the German energy system have to deal with the expected phase-out of coal-fired power generation, in addition to the shutdown of nuclear power plants and the rapid ramp-up of photovoltaics and wind power generation. An analysis of the expected impact on electricity market, security of supply, and system stability must consider the European context because of the strong coupling—both from an economic and a system operation point of view—through the cross-border power exchange of Germany with its neighbors. This analysis, complemented by options to improve the existing development plans, is the purpose of this paper. We propose a multilevel energy system modeling, including electricity market, network congestion management, and system stability, to identify challenges for the years 2023 and 2035. Out of the results, we would like to highlight the positive role of innovative combined heat and power (CHP) solutions securing power and heat supply, the importance of a network congestion management utilizing flexibility from sector coupling, and the essential network extension plans. Network congestion and reduced security margins will become the new normal. We conclude that future energy systems require expanded flexibilities in combination with forward planning of operation