Assessing the potential for immediate technical options for an optimized renewable energy supply – a case study for Germany

Zusammenfassung Um die ehrgeizigen politischen Ziele zur Reduzierung der Treibhausgasemissionen im Stromsektor zu erreichen, stimmen alle relevanten Energieszenarien überein, dass Deutschland kurz- bis mittelfristig bis 2035 seine Kapazitäten zur Erzeugung erneuerbarer Energien massiv ausbauen muss. Deutschland ist dabei wie viele andere Länder auch stark von fluktuierenden erneuerbaren Energiequellen (fEE) abhängig, insbesondere von der Wind- und Solarenergie. Die Spezifika der Stromerzeugung von fEE stellen neue und besondere Herausforderungen an ein zuverlässiges Stromversorgungssystem der Zukunft. Entsprechend hat die Erforschung der technischen Optionen bei der Integration großer Anteile von fEE in das Stromnetz in den letzten Jahren stark an Interesse gewonnen. Allerdings scheinen Energieszenarien die mit der schnellen technologischen Entwicklung einhergehenden Integrationsoptionen bisher nicht korrekt abzubilden. In der vorliegenden kumulativen Dissertation wurden ausgewählte technische Optionen für die Integration erneuerbarer Energiequellen in das Stromnetz im Rahmen einer Fallstudie für Deutschland sowie ausgewählter Übertragungsnetze in Deutschland untersucht. Zur Identifizierung und Bewertung der Integrationsmöglichkeiten, widmete sich die Arbeit den vielversprechendsten technischen Integrationsoptionen in Form von i.) systemfreundliche Auslegung von Wind- und Solaranalgen; ii.) optimale Kapazitätsanteile von Wind- und Solaranlagen, iii.) der räumlichen Allokation und Bewertung von Windenergieanlagen in herkömmlicher als auch systemfreundlicher Auslegung; iv.) und dem Beitrag welchen die flexible Stromerzeugung aus Bioenergie als Ergänzung zu steigenden Anteilen an fEE erbringen kann. Es wurde ein Methodenmix zur Beantwortung dieser Forschungsfragen genutzt, der von der numerischen Optimierung auf Basis von Zeitreihendaten über die räumliche Potenzialkartierung und Allokation bis hin zur multikriteriellen Entscheidungsanalyse reicht. Die Ergebnisse zeigen wie der Übergang zu einem von hohen Anteilen an vRES gekennzeichneten Stromversorgungssystem erleichtert werden kann. Darunter Möglichkeiten zur Beschleunigung des Umstiegs auf erneuerbare Energien mit deutlich reduzierten Erzeugungskapazitäten von Wind- und Solaranlagen, weniger negative Residuallasten und negativer residualer Energie, verbesserte Sektorenkopplung und die Potenziale der flexiblen Stromerzeugung aus Bioenergie als Ergänzung zu fEE.:Table of Contents Abstract Zusammenfassung Acknowledgements List of Publications List of Acronyms Table of Contents I. Introductory chapters 1. Introduction 1.1. Background 1.2. vRES in energy scenarios 1.3. Technical developments and options for the integration of vRES 2. Research questions 3. Methods applied in this PhD thesis 4. Discussion and conclusion 4.1. Summary of the main findings 4.2. Transferability of results and methods 4.3. Relevance and outreach 5. Appendix 6. Literature 7. Appended publications and the individual contribution to the publications 8. Curriculum Vitae (deleted) 9. SelbstständigkeitserklärungAbstract: For Germany to achieve its ambitious political targets for the reduction of greenhouse gas emissions in the electricity sector, major energy scenarios and reports project that the country will have to expand its renewable power generation capacities massively by 2035. As is the case for many countries, Germany will have to heavily rely on variable renewable energy sources (vRES), especially wind and solar photovoltaics. The characteristics of power production from vRES pose challenges for a stable and reliable future power supply system. Accordingly, the research into the technical challenges of integrating large shares of vRES into the power system has therefore attracted much interest in recent years; however, major energy scenarios seem to not cover integration options associated with the fast development of vRES correctly and lag behind the fast development in renewable energy technology. In this cumulative thesis, selected technical options for the integration of renewable energy sources into the power supply system have been investigated in a case study of Germany and a selected transmission system in Germany. To identify and assess these emerging integration options, the research in this PhD thesis covers the most promising technical options for the integration of vRES in the form of i) system-friendly layouts of wind and solar PV; ii) optimal capacity mixes of vRES; iii) the spatial allocation of wind turbines and the impact assessment of wind turbine allocation; and iv) the contribution of flexible power generation from biomass to complement vRES. Therefore, a mix of methods has been applied, ranging from numerical optimization based on time series data, GIS potential mapping and allocation including a multi-criterial decision analysis. The results show how the investigated options can facilitate the transition for a power supply system dominated by high shares of vRES in the near to medium term. A faster energy transition with significantly reduced overall vRES power generation capacities, less Excess Energy (EE) generation, improved cross-sectorial energy provision and flexible bioenergy as a complement to vRES are the major findings of the investigated options in this thesis.:Table of Contents Abstract Zusammenfassung Acknowledgements List of Publications List of Acronyms Table of Contents I. Introductory chapters 1. Introduction 1.1. Background 1.2. vRES in energy scenarios 1.3. Technical developments and options for the integration of vRES 2. Research questions 3. Methods applied in this PhD thesis 4. Discussion and conclusion 4.1. Summary of the main findings 4.2. Transferability of results and methods 4.3. Relevance and outreach 5. Appendix 6. Literature 7. Appended publications and the individual contribution to the publications 8. Curriculum Vitae (deleted) 9. Selbstständigkeitserklärun

Quantifying trade-offs for the spatial allocation of onshore wind generation capacity - a case study for Germany

The deployment of onshore wind power is an important means to mitigate climate change. However, wind turbines also have negative impacts at the local scale, like disamenities to residents living nearby, changes in landscape quality, or conflicts with nature conservation. Our paper analyses how these impacts affect the optimal siting of wind turbines, as compared to a spatial allocation focused solely on minimizing generation costs. To quantify the spatial trade-offs between these criteria, we propose a novel approach using Pareto frontiers and a Gini-like potential trade-off indicator. Our analysis builds on a spatial optimization model using geographical information system data for Germany. We show that spatial trade-offs between the criteria under consideration are significant. The size of the trade-off varies substantially with the criteria under consideration, depending on the spatial heterogeneity of each criterion as well as on the spatial correlation between the criteria. Spatial trade-offs are particularly pronounced between nature conservation (measured by impacts on wind power-sensitive birds) and other criteria

Optimal siting of onshore wind turbines: local disamenities matter

The deployment of onshore wind power is an important means to mitigate climate change. However, wind turbines also produce local disamenities to residents living next to them, mainly due to noise emissions and visual effects. Our paper analyzes how the presence of local disamenities affects the socially optimal siting of onshore wind power. The analysis builds on a spatial optimization model using geographical information system (GIS) data for Germany. Our results indicate a major spatial trade-off between the goals of minimizing electricity generation and disamenity costs. Considering disamenity costs substantially alters - and in fact dominates - the socially optimal spatial allocation of wind power deployment. This is because in Germany a) the spatial correlation between generation costs and disamenity costs is only moderately positive, and b) disamenity costs exhibit a larger spatial heterogeneity than the generation costs. These results are robust to variations in the level and slope of the disamenity cost function that we assume for the modeling. Our findings emphasize the importance of supplementing support schemes for wind power deployment with approaches that address local disamenties, e.g., compensation payments to local residents or minimum settlement distances

A model for cost- and greenhouse gas optimal material and energy allocation of biomass and hydrogen

BENOPT, an optimal material and energy allocation model is presented, which is used to assess cost-optimal and/or greenhouse gas abatement optimal allocation of renewable energy carriers across power, heat and transport sectors. A high level of detail on the processes from source to end service enables detailed life-cycle greenhouse gas and cost assessments. Pareto analyses can be performed, as well as thorough sensitivity analyses. The model is designed to analyse optimal biomass and hydrogen usage, as a complement to integrated assessment and power system models

Managing spatial sustainability trade-offs: The case of wind power

The deployment of onshore wind power involves spatial sustainability trade-offs, e.g., between the minimization of energy system costs, the mitigation of impacts on humans and biodiversity, and equity concerns. We analyze challenges arising for decision-making if wind power generation capacity has to be allocated spatially in the presence of such trade-offs. The analysis is based on a game developed for and played by stakeholders in Germany. The results of the game illustrate that there is no unanimously agreed ranking of sustainability criteria among the participating stakeholders. They disagreed not only on the weights of different criteria but also their definition and measurement. Group discussions further revealed that equity concerns mattered for spatial allocation. Yet, stakeholders used quite different concepts of equity. The results support the importance of transparent, multi-level and participatory approaches to take decisions on the spatial allocation of wind power generation capacity

Assessing the potential for immediate technical options for an optimized renewable energy supply – a case study for Germany

Zusammenfassung Um die ehrgeizigen politischen Ziele zur Reduzierung der Treibhausgasemissionen im Stromsektor zu erreichen, stimmen alle relevanten Energieszenarien überein, dass Deutschland kurz- bis mittelfristig bis 2035 seine Kapazitäten zur Erzeugung erneuerbarer Energien massiv ausbauen muss. Deutschland ist dabei wie viele andere Länder auch stark von fluktuierenden erneuerbaren Energiequellen (fEE) abhängig, insbesondere von der Wind- und Solarenergie. Die Spezifika der Stromerzeugung von fEE stellen neue und besondere Herausforderungen an ein zuverlässiges Stromversorgungssystem der Zukunft. Entsprechend hat die Erforschung der technischen Optionen bei der Integration großer Anteile von fEE in das Stromnetz in den letzten Jahren stark an Interesse gewonnen. Allerdings scheinen Energieszenarien die mit der schnellen technologischen Entwicklung einhergehenden Integrationsoptionen bisher nicht korrekt abzubilden. In der vorliegenden kumulativen Dissertation wurden ausgewählte technische Optionen für die Integration erneuerbarer Energiequellen in das Stromnetz im Rahmen einer Fallstudie für Deutschland sowie ausgewählter Übertragungsnetze in Deutschland untersucht. Zur Identifizierung und Bewertung der Integrationsmöglichkeiten, widmete sich die Arbeit den vielversprechendsten technischen Integrationsoptionen in Form von i.) systemfreundliche Auslegung von Wind- und Solaranalgen; ii.) optimale Kapazitätsanteile von Wind- und Solaranlagen, iii.) der räumlichen Allokation und Bewertung von Windenergieanlagen in herkömmlicher als auch systemfreundlicher Auslegung; iv.) und dem Beitrag welchen die flexible Stromerzeugung aus Bioenergie als Ergänzung zu steigenden Anteilen an fEE erbringen kann. Es wurde ein Methodenmix zur Beantwortung dieser Forschungsfragen genutzt, der von der numerischen Optimierung auf Basis von Zeitreihendaten über die räumliche Potenzialkartierung und Allokation bis hin zur multikriteriellen Entscheidungsanalyse reicht. Die Ergebnisse zeigen wie der Übergang zu einem von hohen Anteilen an vRES gekennzeichneten Stromversorgungssystem erleichtert werden kann. Darunter Möglichkeiten zur Beschleunigung des Umstiegs auf erneuerbare Energien mit deutlich reduzierten Erzeugungskapazitäten von Wind- und Solaranlagen, weniger negative Residuallasten und negativer residualer Energie, verbesserte Sektorenkopplung und die Potenziale der flexiblen Stromerzeugung aus Bioenergie als Ergänzung zu fEE.:Table of Contents Abstract Zusammenfassung Acknowledgements List of Publications List of Acronyms Table of Contents I. Introductory chapters 1. Introduction 1.1. Background 1.2. vRES in energy scenarios 1.3. Technical developments and options for the integration of vRES 2. Research questions 3. Methods applied in this PhD thesis 4. Discussion and conclusion 4.1. Summary of the main findings 4.2. Transferability of results and methods 4.3. Relevance and outreach 5. Appendix 6. Literature 7. Appended publications and the individual contribution to the publications 8. Curriculum Vitae (deleted) 9. SelbstständigkeitserklärungAbstract: For Germany to achieve its ambitious political targets for the reduction of greenhouse gas emissions in the electricity sector, major energy scenarios and reports project that the country will have to expand its renewable power generation capacities massively by 2035. As is the case for many countries, Germany will have to heavily rely on variable renewable energy sources (vRES), especially wind and solar photovoltaics. The characteristics of power production from vRES pose challenges for a stable and reliable future power supply system. Accordingly, the research into the technical challenges of integrating large shares of vRES into the power system has therefore attracted much interest in recent years; however, major energy scenarios seem to not cover integration options associated with the fast development of vRES correctly and lag behind the fast development in renewable energy technology. In this cumulative thesis, selected technical options for the integration of renewable energy sources into the power supply system have been investigated in a case study of Germany and a selected transmission system in Germany. To identify and assess these emerging integration options, the research in this PhD thesis covers the most promising technical options for the integration of vRES in the form of i) system-friendly layouts of wind and solar PV; ii) optimal capacity mixes of vRES; iii) the spatial allocation of wind turbines and the impact assessment of wind turbine allocation; and iv) the contribution of flexible power generation from biomass to complement vRES. Therefore, a mix of methods has been applied, ranging from numerical optimization based on time series data, GIS potential mapping and allocation including a multi-criterial decision analysis. The results show how the investigated options can facilitate the transition for a power supply system dominated by high shares of vRES in the near to medium term. A faster energy transition with significantly reduced overall vRES power generation capacities, less Excess Energy (EE) generation, improved cross-sectorial energy provision and flexible bioenergy as a complement to vRES are the major findings of the investigated options in this thesis.:Table of Contents Abstract Zusammenfassung Acknowledgements List of Publications List of Acronyms Table of Contents I. Introductory chapters 1. Introduction 1.1. Background 1.2. vRES in energy scenarios 1.3. Technical developments and options for the integration of vRES 2. Research questions 3. Methods applied in this PhD thesis 4. Discussion and conclusion 4.1. Summary of the main findings 4.2. Transferability of results and methods 4.3. Relevance and outreach 5. Appendix 6. Literature 7. Appended publications and the individual contribution to the publications 8. Curriculum Vitae (deleted) 9. Selbstständigkeitserklärun

The opportunity costs of environmental exclusion zones for renewable energy deployment

Exclusion zones, like protected areas or setback distances, are the most common policy instrument to mitigate environmental impacts of human land-use, including the deployment of renewable energy sources. While exclusion zones may provide environmental benefits, they may also bring about opportunity costs. This paper aims to understand and quantify the drivers determining the opportunity costs related to environmental exclusion zones. Using a simple analytical model, we propose that opportunity costs of exclusion zones can be decomposed into a substitution effect (because production is shifted to sites with higher or lower marginal production costs) and an output effect (because more sites may be needed to satisfy demand for produced goods). We provide a numerical illustration for the opportunity costs for two examples of environmental exclusion zones - setback distances to settlements and forest bans - which are implemented for wind power deployment in Germany. The numerical illustration builds on a spatially explicit optimization model using GIS data for more than 100,000 potential wind turbine sites in Germany. Our analysis reveals that opportunity costs may primarily arise in terms of higher local environmental impacts of wind power generation. Opportunity costs are mainly due to the output effect for setback distances, and the substitution effect for forest bans. We also show that the actual sign and size of opportunity costs depends a lot on the cost criteria under consideration as well as the type and stringency of the environmental exclusion zone. Our analysis emphasizes the importance to properly understand possible opportunity costs, and compare them carefully with possible benefits when implementing exclusion zones. Interestingly, our analysis also shows that very restrictive setback distances may not be recommendable at all: In our analysis they turn out to increase the total disamenity costs produced by wind power deployment - contrary to the policy objective pursued by this instrument. We believe that our analytical insights are also helpful when thinking about the impacts of environmental exclusion zones applied to other fields of environmental policy, such as urban development or agriculture

Land area targets for wind energy: How promising is the new onshore wind power legislation?

Die Ausbauziele für die Windenergie an Land sind von der Bundesregierung für die kommenden Jahre zuletzt mehr als verdreifacht worden. Gleichzeitig stockt aber seit einigen Jahren der tatsächliche Ausbau der Windenergie in Deutschland. Wesentlicher Hemmschuh für den Ausbau ist, dass zu wenige Flächen für Windenergieanlagen ausgewiesen werden. Um dieses Problem zu lösen, ist nun das Wind-an-Land-Gesetz verabschiedet worden. Dieses gibt den Bundesländern Flächenziele vor, damit bundesweit insgesamt 2 % der Landesfläche für Windenergie ausgewiesen werden. Ein Schritt in die richtige Richtung. Es bleibt aber zweifelhaft, ob das angelegte Zeit-Mengen-Gerüst konform mit den Windenergie-Ausbauzielen des Bundes ist.The expansion targets for onshore wind power have recently been more than tripled by the German government for the upcoming years. Meanwhile, the actual expansion of wind power in Germany has been stalled for several years. A major obstacle to expansion is that too few areas have been designated for wind turbines. To solve this problem, a new law has been passed, the "Windan-Land-Gesetz". It sets explicit land area targets for the federal states to ensure that a total of 2 % of the national territory will be designated for wind turbines. This is a step in the right direction. However, it remains questionable whether the time-quantity framework is in line with national expansion targets