Climate change is one of the pressing issues of our time. In order to limit global warming, the greenhouse gas emissions (GHG) need to be reduced drastically over the next decades in all sectors. A special role is played by the power sector, because it is the one responsible for most GHG emissions and because its costs for decarbonization are rather low. Consequently, national policies aim at reducing GHG emissions by supporting the expansion of renewable energy sources for electricity production (RES) and initiating a coal phase-out (CPO). European policymakers have implemented the EU Emissions Trading Scheme (EU ETS), a mechanism for pricing GHG emissions in the power and industry sector across Europe that incentives carbon mitigation. This dissertation investigates how national and European policies affect the power market and especially its GHG emissions and examines how these policies interact. This dissertation shows that RES, in addition to the short-term, well-studied, merit order effect, which reduces power wholesale prices, also have long-term effects on electricity markets. The long-term effect describes the impact that RES have on investment decisions into conventional technologies, which are reduced by over 8 GW in Germany. This indicates that the power market adapts to the expansion of RES. With regard to the GHG mitigation of RES, it is shown that currently RES contribute substantially to the mitigation of GHG emissions. Because wind power substitutes coal power, it has a significantly higher potential to avoid GHG emissions than solar power in Germany. Provided wind stays favorable in the future, this portends from a climate perspective that politics should focus on the expansion of wind. It further justifies higher support schemes for wind than solar energy. The impact of the CPO on the GHG emissions depends strongly on legal implementation. If no further actions are taken, the demand for emission decreases, because existing emitters leave the market and the price drops to 0 EUR/t. The EU ETS loses its incentive effect and the emissions are realized elsewhere since the cap remains the same and is fully exploited. Therefore, alongside the CPO, emission certificates have to be deleted in order to maintain the incentive effect of the EU ETS. Furthermore, the loss in valuation of the German coal power plants depends strongly on the time of the CPO. Given high expected emission prices and the expansion of RES, coal-fired power plants cannot be operated economically advantageously in the long-term. Therefore, no devaluation is expected if power plants are phased out in 2038 or shortly before and hence, those power plants should not receive any compensation. Additionally, this dissertation shows that the EU ETS is a strong European policy that provides sufficient incentives to meet the European climate targets in 2030 and to realize the necessary expansion of RES. However, if national RES development paths are implemented, this leads to higher overall costs but also very different profitability of RES in each country This is because countries with high ambitions regarding the expansion of RES face self-marginalization effects, which reduces the revenues for RES due to the merit order effect, and increases the level of support needed for them to expand. In contrast, countries with low RES ambitions have little or no need of support schemes but benefit from low prices in the EU ETS due to strong RES expansion in countries with high ambitions. Summarizing, this dissertation demonstrated that both national and European policy contribute to the decarbonization of the European power sector. However, the different policies interact. This can have negative impacts, which indicates that a greater harmonization of policies is necessary. Further research should develop comprehensive policy approaches and discuss possible challenges.

Reliable electricity supply remains a major problem in rural India nowadays. Renewable off-grid solutions have been applied in the last decades to increase power supply reliability but often failed to be feasible due to their high energy costs compared to the national grid. Grid Integrated Mini-grids with Storage (GIMS) can provide reliable power supply at an affordable price by combining mini-grids and national grid facilities. However, research on the techno-economic feasibility of these systems in the country is very limited and unavailable in the public sphere. This research project analysed three different aspects of the GIMS feasibility. First, the feasibility of the use of hybrid wind and solar Photovoltaic (PV) systems in GIMS was analysed by comparing the Levelised Cost of Electricity (LCOE) and Net Present Cost (NPC) of solar PV and hybrid PV/Wind GIMS systems. Second, the potential savings GIMS can offer due to the possibility of selling power to the grid were quantified by comparing the LCOE and NPC of the system with and without grid export. Lastly, the cost of reliability of the power supply was represented by the influence of the allowed percentage of capacity shortage on the total cost of the system. The analysis was carried out by means of the software HOMER and was based on three case studies in India. The results of this analysis showed that the use of hybrid systems could generate savings of up to 17% of the LCOE of the GIMS system in comparison to solar mini-grids. Moreover, power sales to the grid enabled LCOE savings up to 35% with respect to mini-grid without power sell-back possibility. In addition, the LCOE could be reduced in between 28% and 40% in all cases by enabling up to a 5% of capacity shortage in the system. / En tillförlitlig elförsörjning är ett stort problem på landsbygden i Indien. Elnätslösningar baserade på förnybara energikällor har undersökts under de senaste decennierna för att öka tillförlitligheten men har ofta misslyckats i genomförandefasen på grund av höga energikostnader jämfört med i det nationella nätet. Nätintegrerade mini-grids med energilagring (GIMS) kan ge tillförlitlig strömförsörjning till ett överkomligt pris genom att kombinera mini-grids och nationella elnätsanläggningar. Forskningen om den tekniskekonomiska genomförbarheten av dessa system i landet är emellertid mycket begränsad och otillgänglig inom den offentliga sfären. I den här studien analyseras tre olika aspekter av GIMS-genomförbarheten. För det första analyserades genomförbarheten av att använda hybrida vind- och solcellssystem i GIMS genom att jämföra ”Levelised Cost of Electricity” (LCOE) nivån och nuvärdeskostnaden (NPC) för solcellssystem (PV) och hybrid PV/Vind GIMS-system. För det andra kan de potentiella besparingar GIMS erbjuder, genom möjligheten att sälja elenergi till nätet, kvantifieras genom att jämföra LCOE och NPC i systemet med och utan ”nätexport”. Slutligen studeras kostnaden för tillförlitligheten hos strömförsörjningen i förhållande till accepterad kapacitetsbrist med avseende på systemets totala kostnad. Analysen har utförts med hjälp av mjukvaran HOMER och grundas på tre fallstudier i Indien. Resultaten av denna analys visar att användningen av hybridsystem skulle kunna generera besparingar på upp till 17% av LCOE i GIMS-systemet i jämförelse med enbart PV-baserade mini-grids. Försäljning av elenergi till nätet möjliggör LCOE-besparingar på upp till 35% med i förhållande till mini-grids utan möjlighet till export. Slutligen: LCOE kunde reduceras mellan 28% och 40% i samtliga fall genom att tillåta upp till 5% kapacitetsbrist i systemet.

Yes / The cost of electricity produced by thermal power plants in Republic of Djibouti is relatively high at about $0.32/ kWh. This is due to its dependence on imported oil coupled with fluctuating oil prices. Consequently, the customer pays a high electricity bill. However, Djibouti is endowed with indigenous renewable energy resources such as a good solar irradiance of 5.92 kWh/ m2 day, a potential geothermal energy estimated up to 1000 MW, and few sites with annual wind speed higher than 6 m/s. The goal of this paper is, therefore, to assess an economic evaluation of different grid connected hybrid renewable energy systems to a residential urban house located in Tadjourah city (11.7913◦ N, 42.8796◦ E) in the North-Eastern part of Djibouti to reduce the cost of electricity from the grid. To reach this objective, a powerful software tool called HOMER (Hybrid Optimization Model for Electric Renewables) has been used to find the optimum hybrid energy system using real wind and solar irradiation data. The results obtained from this study show that the best economical suited combination of hybrid renewable energy system is a PV-Wind grid connected system. This study shows also that potentially the indigenous renewable energy contribution, in Tadjourah, can be as much as 77 % with 47 % of solar and 30% of Wind energy. The Net Present Cost, the Levelized Cost of Energy, and the operating cost of the optimal HRES are $337, $0.002/kWh and $1,025/year, respectively. When compared with the average cost of grid-only connection of $0.32/kWh, the optimal hybrid renewable energy system is more economical and will save 51 % of the cost that the customer must pay when using only the electricity from the grid.

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. Selbstständigkeitserklärung / Abstract: 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. Selbstständigkeitserklärung

The energy used by building sector accounts for approximately 40% of the total energy usage. In residential buildings, 30-60% of this energy is used for space heating which is mainly wasted by transmission heat losses. A share of 20-30% is lost by the discarded residential wastewater and the rest is devoted to ventilation heat loss.   The main objective of this work was to evaluate the thermal potential of residential wastewater for improving the performance of mechanical ventilation with heat recovery (MVHR) systems during the coldest periods of year. The recovered heat from wastewater was used to preheat the incoming cold outdoor air to the MVHR in order to avoid frost formation on the heat exchanger surface.   Dynamic simulations using TRNSYS were used to evaluate the performance of the suggested air preheating systems as well as the impact of air preheating on the entire system. Temperature control systems were suggested based on the identified frost thresholds in order to optimally use the limited thermal capacity of wastewater and maintain high temperature efficiency of MVHR. Two configurations of air preheating systems with temperature stratified and unstratified tanks were designed and compared. A life cycle cost analysis further investigated the cost effectiveness of the studied systems.   The results obtained by this research work indicated that residential wastewater had the sufficient thermal potential to reduce the defrosting need of MVHR systems (equipped with a plate heat exchanger) in central Swedish cities to 25%. For colder regions in northern Sweden, the defrosting time was decreased by 50%. The temperature control systems could assure MVHR temperature efficiencies of more than 80% for most of the heating season while frosting period was minimized. LCC analysis revealed that wastewater air preheating systems equipped with temperature stratified and unstratified storage tanks could pay off their costs in 17 and 8 years, respectively. / <p>QC 20190830</p>

Climate change must deal with two market failures: global warming and learning by doing in renewable energy production. The first-best policy consists of an aggressive renewables subsidy in the near term and a gradually rising and falling carbon tax. Given that global carbon taxes remain elusive, policy makers might have to rely on a second-best subsidy only. With credible commitment the second-best subsidy is higher than the social benefit of learning to cut the transition time and peak warming close to first-best levels at the cost of higher fossil fuel use in the short run (weak Green Paradox). Without commitment the second-best subsidy is set to the social benefit of learning. It generates smaller weak Green Paradox effects, but the transition to the carbon-free takes longer and cumulative carbon emissions are higher. Under first best and second best with pre-commitment peak warming is 2.1-2.3 °C, under second best without commitment 3.5 °C, and without any policy 5.1 °C above pre-industrial levels. Not being able to commit yields a welfare loss of 95% of initial GDP compared to first best. Being able to commit brings this figure down to 7%.

We compare the effectiveness of different climate policies in terms of emissions abatement and costs in the British and German electricity markets. The two countries follow different climate policies, allowing us to compare the effectiveness of a relatively low EU ETS carbon price in Germany with a significantly higher carbon price due to a unilateral top-up tax (the Carbon Price Support) in the UK. We first estimate the emissions offsetting effects of carbon pricing and of subsidized wind and solar feed-in, and then derive the abatement costs of one tonne of CO2 for the different policies. We find that a reasonably high price for emissions is the most cost-effective climate policy, while subsidizing wind is preferable to subsidizing solar power. A carbon price of around EURO 35 is enough in the UK to induce vast short-run fuel switching between coal- and gas-fired power plants, leading to significant emissions abatement at low costs. / Series: Department of Economics Working Paper Series

Made available in DSpace on 2014-12-17T14:34:43Z (GMT). No. of bitstreams: 1 RaimundoPAN_DISSERT.pdf: 2435889 bytes, checksum: ed3710cb220189ae12e49e97f5125f78 (MD5) Previous issue date: 2012-06-01 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The object of this study involves the eolian energy and the scenario the training of wind pole in Rio Grande do Norte. The aim is to investigate how far the implementation of the potiguar eolian pole may represent a regional development policy with real change in the structure of the traditional local productive base. About the interaction between the public and private to development of the local eolian activity, the hypothesis is that there is no coordination between the sectors responsible for eolian activity in the state. The theoretical approach follows the developmental current and theory of growth poles, and methodology adopted is a search of exploratory and documentary, with analysis of relevant documents on the subject. As a result of the study it was found that owing to the fragility of the productive structure potiguar and imbalances produced by the concentration of capital in the Northeast, the eolian activity in the state, needs a greater state-owned intervention to ensure a basis of development based on the study and strengthening local productive chain / O objeto do presente estudo envolve a energia e?lica e o cen?rio da forma??o do p?lo e?lico no Rio Grande do Norte. O objetivo ? investigar at? onde a implanta??o do p?lo e?lico potiguar pode representar uma pol?tica de desenvolvimento regional com real mudan?a na estrutura da tradicional base produtiva local. Acerca da intera??o entre o p?blico e o privado para o desenvolvimento da atividade e?lica local, a hip?tese ? a de que n?o h? articula??o entre os setores respons?veis pela atividade e?lica do estado. O referencial te?rico adotado segue a ?gide desenvolvimentista e a teoria dos p?los de crescimento, e a metodologia adotada ? uma pesquisa bibliogr?fica de cunho explorat?rio e documental, com an?lise de documentos pertinentes sobre o tema. Como resultado do estudo verificou-se que em virtude da fragilidade da estrutura produtiva potiguar e dos desequil?brios apresentados pela concentra??o de capital no Nordeste, a atividade e?lica no estado carece de uma maior interven??o estatal no sentido de assegurar uma base de desenvolvimento pautada no estudo e fortalecimento da cadeia produtiva local

Les réseaux électriques subissent deux changements majeurs : le taux croissant de générateurs d’énergie distribuée (GED) intermittents et la dérégulation du système électrique. Les réseaux de distribution et leurs gestionnaires (GRD) sont plus particulièrement touchés. La planification, construction et exploitation des réseaux de la plupart des GRD doivent évoluer face à ces change- ments. Les réseaux actifs de distribution et la gestion intelligente de associée est une solution potentielle. Les GRD pourront ainsi adopter de nouveaux rôles, interagir avec de nouveaux acteurs et proposer de nouveaux services. Ils pourront aussi utiliser la flexibilité de manière optimale au travers, entre autres, d’outils intelligents pour la gestion prévisionnelle de leurs réseaux de moyenne tension (HTA). Développer ces outils est un défi, car les réseaux de distribution ont des spécificités techniques. Ces spécificités sont la présence d’éléments discrets comme les régleurs en charge et la reconfiguration, les flexibilités exogènes, la non-linéarité des calculs de répartition de charge, et l’incertitude liée aux prévisions des GED intermittents. Dans cette thèse, une analyse économique des flexibilités permet d’établir une référence commune pour une utilisation rentable et sans biais dans la gestion prévisionnelle. Des modèles linéaires des flexibilités sont développés en utilisant des reformulations mathématiques exactes. Le calcul de répartition de charge est “convexifié” à travers des reformulations. L’optimalité globale des solutions obtenues, avec ce modèle d’optimisation exact et convexe de gestion prévisionnelle, sont ainsi garanties. Les tests sur deux réseaux permettent d’en valider la performance. L’incertitude des prévisions de GED peut pourtant remettre en cause les solutions obtenues. Afin de résoudre ce problème, trois formulations différentes pour traiter cette incertitude sont développées. Leurs performances sont testées et comparées à travers des simulations. Une analyse permet d’identifier les formulations les plus adaptées pour la gestion prévisionnelle sous incertitude. / Power systems are faced by the rising shares of distributed renewable energy sources (DRES) and the deregulation of the electricity system. Distribution networks and their operators (DSO) are particularly at the front-line. The passive operational practives of many DSOs today have to evolve to overcome these challenges. Active Distribution Networks (ADN), and Active Network Management (ANM) have been touted as a potential solution. In this context, DSOs will streamline investment and operational decisions, creating a cost-effective framework of operations. They will evolve and take up new roles and optimally use flexibility to perform, for example, short-term op- erational planning of their networks. However, the development of such methods poses particular challenges. They are related to the presence of discrete elements (OLTCs and reconfiguration), the use of exogenous (external) flexibilities in these networks, the non-linear nature of optimal power flow (OPF) calculations, and uncertainties present in forecasts. The work leading to this thesis deals with and overcomes these challenges. First, a short-term economic analysis is done to ascertain the utilisation costs of flexibilities. This provides a common reference for different flexibilities. Then, exact linear flexibility models are developed using mathematical reformulation techniques. The OPF equations in operational planning are then convexified using reformulation techniques as well. The mixed-integer convex optimisation model thus developed, called the novel OP formulation, is exact and can guarantee globally optimal solutions. Simulations on two test networks allow us to evaluate the performance of this formulation. The uncertainty in DRES forecasts is then handled via three different formulations developed in this thesis. The best performing formulations under uncertainty are determined via comparison framework developed to test their performance.

Ireland is facing a great challenge in meeting renewable energy requirements, where due to past circumstances and decisions, the nation state is now heavily dependent on imported fossil fuels. Given the contribution of these imported fossil fuels to global climate change, price instability and supply insecurity, Ireland is under a pressing need to face up to the dilemma of an unsustainably fueled economy. This thesis explores how the EU policy process is helping Ireland to achieve the goals it has set with the EU and how these are being incorporated into the drivers of wind power development in Ireland. This research sought to uncover the dynamic of this relationship - the goodness of fit - through an assessment of three mechanisms of change, namely: Discourses, Directives and Finances, which were drawn on from the theoretical approach of Europeanisation. By doing a combined assessment of these three channels and their influence, this thesis provides a greater understanding of the ways in which the development of wind power in Ireland is influenced by the EU level. The thesis finishes with a concluding discussion on the importance of the national level in this process, as well as the importance of social and community engagement, which despite being previously seen as important, has to date largely manifested as a tokenistic gesture in Ireland. This thesis reasserts it as a common and crucial thread of the renewable energy transition that continuously arose as being pre-eminent during this study.