As part of the transition towards a fully sustainable energy system, green hydrogen shows great potential to decarbonise several hard-to-abate sectors. To provide the fossil-free electricity required for electrolysis, offshore wind power has emerged as a suggested option. In this report, four scenarios using different electrolyser placements and technologies are compared and applied in a 30-year case study considering a 1 GW offshore wind farm in the Baltic Sea. The scenarios are evaluated through the optimisation of electrolyser capacities, full system modelling and simulation, a techno-economic assessment, as well as a literature review of technological readiness, safety aspects and operational considerations. It is shown that a range of installed capacities offers only slight differences in levelised costs and that the optimal sizes to a large part depend on future electrolyser cost developments. A 1:1 sizing ratio between electrolyser capacity and maximum available power is not suggested for any of the studied configurations. Further, the simulations indicate that electrolyser inefficiencies constitute 63.2–68.5% of the total energylosses. Power transmission losses are relatively small due to the short transmission distance, while the power demands of several subsystems are nearly insignificant. Onshore H2 production using an alkaline electrolyser system is highlighted, offering the highest system efficiency and largest hydrogen production, at 55.93% and 2.23 Mton, respectively. This setup is further shown to be the most cost-efficient, offering a levelised cost of hydrogen at 3.15 €/kgH2. However, obstacles in the form of social and environmental concerns and regulations are seemingly larger compared to the scenarios using offshore electrolysis. Further, rapid future cost developments for electrolysers are likely to strengthen the case for offshore and PEM electrolyser configurations. A range of research opportunities are highlighted to fill the identified knowledge gaps and enable further insights. / Como parte de la transición hacia un sistema energético totalmente sostenible, el hidrógeno verde muestra un gran potencial para descarbonizar varios sectores en los que es difíciles de conseguir. La energía eólica marina ha surgido como una opción para suministrar la electricidad libre de fósiles necesaria para la electrólisis. En este informe se comparan y aplican cuatro escenarios que utilizan diferentes ubicaciones y tecnologías de electrolizadores en un estudio de caso a 30 años que considera un parque eólico marino de 1 GW en el Mar Báltico. Los escenarios se evalúan mediante una optimización de la capacidad de los electrolizadores, la modelización y simulación de todo el sistema, una revisión bibliográfica de la disponibilidad tecnológica, teniendo en cuenta los aspectos de seguridad y las consideraciones operativas. Se demuestra que una gama de capacidades instaladas ofrece sólo ligeras diferencias en los costes nivelados y que los tamaños óptimos dependen en gran medida de la evolución futura de los costes de los electrolizadores. No se recomienda una relación de tamaño de 1:1 entre entre la capacidad del electrolizador y la potencia máxima disponible. Además, las simulaciones indican que las ineficiencias del electrolizador constituyen entre el 63,2% y el 68,5% de las pérdidas totales de energía. Las pérdidas de transmisión de energía son relativamente pequeñas debido a la corta distancia de transmisión, mientras que las demandas de energía de varios subsistemas son casi insignificantes. Destaca la producción de H2 en tierra utilizando un sistema de electrolizador alcalino, que ofrece la mayor eficiencia del sistema y la mayor producción de hidrógeno, con un 55,93% y 2,23 Mton respectivamente. Además, este sistema es el más rentable, con un coste nivelado del hidrógeno de 3,15 €/kgH2. Sin embargo, los obstáculos sociales, medioambientales y normativos parecen ser mayores que en el caso de la electrólisis en alta mar. Además, es probable que la rápida evolución de los costes de los electrolizadores refuerce las configuraciones de electrolizadores marinos y PEM. Se destacan en el documento una serie de oportunidades de investigacin ócon el fin de completar el estado del arte identificado.

Die Dissertationsschrift untersucht die Interaktion zwischen Strom- und Wärmemarkt mit einem besonderen Fokus auf Wärmepumpen und Wärmenetzen. Vor dem Hintergrund des steigenden Ausbaus erneuerbarer Energien und der langfristigen Klimaziele stellt sich dabei die Frage der Wirkung, welche die Kopplung von Strom- und Wärmemarkt auf die Reduktion der CO2-Emissionen, die Energiesystemkosten und die Integration der erneuerbaren Energien hat. Zur Beantwortung der Forschungsfrage wird das lineare Optimierungsmodell Enertile um zwei Wärmemodule zur Berücksichtigung von Wärmepumpen und Wärmenetzen erweitert. Im Unterschied zu anderen Modellen wird in der Implementierung für diese Arbeit der Ausbau und der Einsatz der erneuerbaren Energien, der KWK und der weiteren fossilen Kraftwerkskapazitäten gleichzeitig optimiert, wodurch eine Analyse der Wechselwirkungen zwischen dem Ausbau erneuerbarer Energien und der Kopplung von Strom- und Wärmemarkt möglich ist. Die in dieser Arbeit vorgenommene modellgestützte Analyse zeigt die große Bedeutung der Interaktion zwischen Strom- und Wärmemarkt. Im Rahmen einer langfristigen Dekarbonisierung der Energieversorgung durch einen verstärkten Ausbau von erneuerbaren Energien ergeben sich sowohl Chancen als auch Herausforderungen für die Interaktion zwischen Strom- und Wärmemarkt. Die Modellierung der Wärmepumpen zeigt für den gesamten Zeitraum ab 2020 deutlich geringere spezifische CO2-Emissionen gegenüber der Wärmeerzeugung in modernen Gasbrennwertkesseln. Die Ergebnisse zeigen auch, dass bivalente Systeme – die kombinierte Nutzung verschiedener Wärmeerzeugungstechnologien wie beispielsweise KWK, Gasheizkessel und Elektroheizkessel – vor dem Hintergrund der Umstrukturierung des Stromsektors eine wichtige Rolle spielen. Langfristig stellt die flexible Wärmebereistellung durch elektrische Heizungstechnologien insbesondere bei hohen Anteilen erneuerbarer Energien eine kostengünstige und CO2-arme Alternative zur fossilen Wärmeerzeugung dar.:1 Einleitung 1 1.1 Ausgangslage 1 1.2 Problemstellung 3 1.3 Zielsetzung und Vorgehen 4 2 Rahmenbedingungen auf dem Strom- und Wärmemarkt in Deutschland 7 2.1 Rahmenbedingungen auf dem Strommarkt 7 2.2 Rahmenbedingungen auf dem Wärmemarkt 12 2.3 Schlussfolgerungen für diese Arbeit 16 3 Modellierung der Interaktionen von Strom- und Wärmemarkt 17 3.1 Stand der Forschung und Anforderungen an das Modell 17 3.2 Modelle zur Untersuchung von Strom- und Wärmemarkt 18 3.3 Stromsystemoptimierung Enertile 21 3.3.1 Eingangsdaten und Ergebnisse 23 3.3.2 Problemformulierung 24 3.4 Modellerweiterung zur Integration des Wärmemarktes 26 3.4.1 Wärmepumpen 26 3.4.2 Wärmenetze 32 4 Unsicherheiten in Energiesystemmodellen 42 4.1 Unsicherheiten im Rahmen dieser Arbeit 42 4.2 Methoden zum Umgang mit Unsicherheiten in Energiesystemmodellen 43 4.3 Szenarienentwicklung und Sensitivitäten 47 5 Definition von Szenarien zur Analyse der Wechselwirkungen zwischen Strom- und Wärmemarkt 50 5.1 Szenarienübersicht 50 5.2 Zentrale Annahmen 51 5.3 Strommarkt 56 5.3.1 Erneuerbare Energien 56 5.3.2 Konventionelle Kraftwerke 57 5.3.3 Stromnachfrage 59 5.4 Wärmenetze 59 5.5 Wärmepumpen 63 5.6 Sensitivitäten 65 5.7 Kritische Reflexion der Annahmen 66 6 Modellgestützte Analyse der Wechselwirkungen zwischen Strom- und Wärmemarkt 68 6.1 Einfluss auf die CO2-Emissionen 69 6.1.1 Strommarkt 69 6.1.2 Wärmepumpen 72 6.1.3 Wärmenetze 77 6.2 Entwicklung des Kraftwerksparks und des Erzeugungsmixes 82 6.2.1 Strommarkt 82 6.2.2 Wärmepumpen 95 6.2.3 Wärmenetze 106 6.2.4 Integration erneuerbarer Energien auf dem Strommarkt 128 6.3 Änderung der Systemkosten durch die Kopplung von Strom- und Wärmemarkt 131 6.3.1 Kosten der Stromerzeugung 132 6.3.2 Kosten der Wärmeerzeugung in Wärmepumpen 134 6.3.3 Kosten der Wärmeerzeugung in Wärmenetze 136 6.4 Zusammenfassung der Szenarienanalyse 140 6.4.1 Einfluss der Kopplung von Strom- und Wärmemarkt bei ambitionierten Klimaschutz 140 6.4.2 Einfluss der Kopplung von Strom- und Wärmemarkt bei mäßigem Klimaschutz 141 7 Sensitivitäten 142 7.1 Stabile Brennstoffpreise 142 7.2 Potentiale von erneuerbaren Energien 145 7.3 Isolierte Effekte von Elektroheizkesseln und KWK 148 7.3.1 Keine KWK 148 7.3.2 Keine Elektroheizkessel 150 7.4 Hohe Flexibilität der Wärmepumpen 151 7.5 Zusammenfassung Sensitivitäten 152 8 Zusammenfassung 154 8.1 Motivation und Forschungsfrage 154 8.2 Methodisches Vorgehen 154 8.3 Ergebnisse 155 8.4 Schlussfolgerungen und kritische Reflektion 156 8.4.1 Szenarienanalyse 156 8.4.2 Methodik 157 8.4.3 Ausblick 159

Made available in DSpace on 2016-07-27T13:52:21Z (GMT). No. of bitstreams: 1 Manoel Bezerra da Silva Junior.pdf: 641495 bytes, checksum: 14ce06e1e5ce174b30c3d508d5a39f5b (MD5) Previous issue date: 2011-09-29 / This research is linked to the research line Education Society and Culture Graduate Program in Education at the Catholic University of Goiás and has as its object of study Education in Prison. The formation of the Absolutist State from the clump of feudal societies and the transition state of this model to the so-called rule of law created in the eighteenth century, the importance of state structure that justified the creation of a prison sentence. The formation of the rule of law as an institution under a legal concept. State power and a confrontation with the notions of power in the design of Michel Foucault. The presence of the power to punish as a link between the two models of state, as well as relations of power with the construction of so-called disciplinary societies. The issue of education within the prison and implemented speech and the rule of law by educators around the return of the convicted individual to social life, the process of training to which this subject is in prison. Preparation of a study based on a methodology based on a literature search. The central question about the role of education within the prison environment. The research still needs further study. / Esta pesquisa se vincula à linha de pesquisa Educação Sociedade e Cultura do Programa de Pós-Graduação em Educação da Pontifícia Universidade Católica de Goiás e tem como objeto de estudo a Educação na Prisão. A formação do Estado Absolutista a partir do aglutinar das sociedades feudais e a transição deste modelo estatal para o denominado Estado de Direito criado no século XVIII, a relevância desta estrutura de Estado que fundamentou a criação da pena de prisão. A formação do Estado de Direito como instituição sob uma concepção jurídica. O poder estatal e um confronto com as noções de poder na concepção de Michel Foucault. A presença do poder de punir como um elo existente entre os dois modelos de Estado, bem como as relações desse poder com a construção das chamadas sociedades disciplinares. A problemática da educação dentro do cárcere e o discurso implementado pelo Estado de Direito e pelos educadores em torno do retorno do indivíduo condenado ao convívio social, o processo de adestramento a que este se sujeita dentro da prisão. Elaboração de um estudo baseado numa metodologia fundamentada em uma pesquisa bibliográfica. O questionamento central sobre qual o papel da educação dentro do ambiente prisional. A pesquisa ainda precisa de mais estudos.

nÃo hà / A investigaÃÃo aqui apresentada analisou como o trabalho repercute na saÃde dos profissionais com vÃnculo terceirizado que atuam na Universidade Federal do Cearà (UFC). A pesquisa fundamenta-se na ClÃnica da Atividade e situa-se no campo da SaÃde do Trabalhador; baseia-se na epistemologia qualitativa e desenvolveu-se como um estudo de caso derivado de intervenÃÃo efetivada no Almoxarifado Central da UFC. Todo o material produzido na intervenÃÃo foi utilizado para a construÃÃo do corpus pertinente ao caso analisado. Tal delineamento corrobora a perspectiva teÃrica mencionada para a qual, primeiro, realiza-se a intervenÃÃo para, em seguida, dar-se inÃcio à pesquisa. Assume-se que cada um desses momentos tem temporalidades e objetos diferentes, guardando uma relaÃÃo de mÃtua independÃncia. A intervenÃÃo compreendeu trÃs etapas: 1) formaÃÃo do grupo de anÃlise, no qual foram realizadas observaÃÃes, entrevistas, anÃlises documentais e filmagens; 2) autoconfrontaÃÃes simples e/ou cruzadas, durante as quais os trabalhadores foram confrontados com o registro audiovisual de suas atividades; e 3) retorno ao grupo inicial. A metodologia da pesquisa se deu a partir da videografia. Para anÃlise dos dados, utilizou-se a anÃlise de conteÃdo construtiva-interpretativa de GonzÃlez Rey. Adotou-se como unidade de anÃlise a atividade triplamente dirigida (para o objeto, pelo sujeito e para o outro). Considera-se a pertinÃncia do estudo, uma vez que nos encontramos num contexto marcado por retrocessos no mundo laboral, em que prÃticas arcaicas de gestÃo e controle da mÃo de obra e da produÃÃo coexistem com tendÃncias âinovadorasâ que vulnerabilizam a classe trabalhadora, representando uma ameaÃa ao trabalho em seu carÃter ontolÃgico e aos direitos dos trabalhadores. Objetiva-se que a pesquisa contribua para formulaÃÃo de aÃÃes voltadas à saÃde do trabalhador e ao desenvolvimento do seu poder de agir, bem como desnude as vulnerabilidades a que estÃo submetidos os trabalhadores que possuem vÃnculos laborais precÃrios. Desta forma, em relaÃÃo Ãs condiÃÃes de trabalho, percebeu-se que os trabalhadores com vÃnculo terceirizado estÃo mais sujeitos a situaÃÃes de vulnerabilidade, e seu universo de trabalho à permeado por situaÃÃes de risco à saÃde e à seguranÃa. Constatou-se ainda estarem eles mais suscetÃveis a situaÃÃes de assÃdio, ameaÃa, desrespeito, preconceito, autoritarismo devido à instabilidade do vÃnculo; estavam subordinados tambÃm a condiÃÃes inadequadas ao desenvolvimento de suas atividades, como ambiente empoeirado, mal iluminado e sem ventilaÃÃo, com estrutura precÃria e antiga, alÃm da carÃncia de materiais em boas condiÃÃes e/ou da utilizaÃÃo de equipamentos inapropriados para tal. Assim, pÃde-se perceber que na atividade dos sujeitos pesquisados vÃrios empecilhos sÃo impostos a sua aÃÃo, porÃm, atravÃs de um modelo de gestÃo participativo, eles encontraram as possibilidades de desenvolvimento do poder de agir e da construÃÃo da saÃde, fortalecendo o coletivo profissional, que passou a reconhecer-se enquanto grupo, ao discutir e debater as dificuldades e sugestÃes possÃveis para realizaÃÃo de um trabalho bem feito. Observou-se, ainda, atravÃs da participaÃÃo ativa dos trabalhadores nas mudanÃas empreendidas no setor investigado, melhorias tais como redefiniÃÃo das atribuiÃÃes e tarefas de cada trabalhador, dinamizaÃÃo e maior fluidez dos processos de trabalho, realizaÃÃo de reuniÃes sistemÃticas com a participaÃÃo e envolvimento de todos os profissionais do setor, ouvindo-se as sugestÃes e questionando-se coletivamente as problemÃticas em pauta. / The research presented here analyzed how the work affects the health of outsourced professionals working at the Federal University of Cearà (UFC). The research, based on the Clinic of Activity and located in the field of Workerâs Health, is based on qualitative epistemology and developed as a case study derived from intervention carried out in the UFC Central Warehouse. All the material produced in the intervention was used for the construction of the corpus pertaining to the case analyzed. Such a design corroborates the theoretical perspective mentioned for which the intervention is first performed, and then the research is started. It is acknowledged that each of these moments has different temporalities and objects, keeping a relation of mutual independence. The intervention comprised three stages: 1) formation of the analysis group, in which observations, interviews, documentary analyzes and filming were performed; 2) simple and/or cross self-confrontations, during which the workers were confronted with the audiovisual record of their activities; and 3) return to the initial group. The research methodology came from the videography method. To analyze the data, we used the constructive-interpretative content analysis of GonzÃlez Rey. The triple-directed activity (for the object, for the subject and for the other) was adopted as the unit of analysis. The relevance of the study is considered, since we are in a context marked by setbacks in the world of work, where archaic practices of management and control of labor and production coexist with âinnovativeâ tendencies that weaken the working class, representing a threat to work on its ontological character and to workersâ rights. It is intended that the research contributes to the formulation of actions aimed at workersâ health and development of their power to act, as well as undressing the vulnerabilities to which workers with precarious employment ties are subjected. Thus, regarding the working conditions, it was perceived that workers with outsourced links are more subject to situations of vulnerability, and their work surrounding is permeated by situations of risk to their health and safety. It was noted that these professionals were more susceptible to situations of harassment, threat, disrespect, prejudice, authoritarianism due to the instability of the work bond; moreover they underwent inadequate conditions for the development of their activities, such as dusty, poorly lit and unventilated environment, with a precarious and old structure, as well as the lack of materials in good conditions and/or the use of inappropriate ones. Thus, it was observed that in the activity of the subjects studied several obstacles are imposed on their action, but through a model of participatory management they found the possibilities of developing their power to act and build health, strengthening the professional group that could recognize themselves as a group when discussing and debating the difficulties and possible suggestions for doing a job well done. It was also observed through the active participation of workers in the changes undertaken in the researched sector improvements such as redefining the duties and tasks of each worker, improvements in work processes to become more fluid and dynamic, holding systematic meetings with the participation and involvement of all professionals in the sector, listening to the suggestions and collectively questioning the issues at hand.

Målet med uppsatsen är att visa hur Suzanne Collins’s The Hunger Games kan användas i ett språkklassrum för att introducera begreppet makt. Målet är även att, från ett makt-perspektiv, kunna påvisa att spektaklet Hungerspelen kan uppfattas som ett medel för systematiskt förtryck, förödmjukelse och avhumanisering av den styrande makten. Ett ytterligare mål är att yrka på att huvudkaraktären Katniss handlingar i Hungerspelen kan uppfattas som motstånd mot detta. Novellen analyseras med hjälp av teorierna ”power over” och ”power to” för att kunna identifiera olika kategorier av makt. ”Power over” är ett uttryck av makt som används för att påverka, tvinga eller utnyttja någon. I novellen kan detta bland annat identifieras när den styrande makten tvingar befolkningen att titta på, eller delta i Hungerspelen. ”Power to” hänvisar till en persons individuella förmågor och kan identifieras i Katniss intelligens, självständighet, överlevnadsfärdigheter och mod. ”The Theory of Consent” är en teori som berör medgivande i en dominant-underordnad relation. Teorin påvisar att utan de underordnas medgivande har den dominanta parten dåliga förutsättningar för att styra. Denna teori presenteras som grund till den styrande maktens motiv för att tvinga dess underordnade att medverka i de farliga spelen. Skolan kan vara en plats som ger ökad förståelse av makt och mänskligt värde, något som betonas i Skolverkets styrdokument.  Detta genom att koppla diskussioner om olika perspektiv om makt till läsningen. Teorierna kan bistå elever med djupare förståelse om begreppet och kunna identifiera och ifrågasätta maktmissbruk och maktutövanden som utnyttjar och förtrycker sina underordnade. Den didaktiska delen kommer ge förslag på ett lektionsupplägg där elever kommer, utöver utveckla sin kunskap om makt, även träna sina språkliga egenskaper genom att läsa, tala, lyssna och skriva. Detta är något som betonas i styrdokumenten.

No description available.

This master’s thesis deals with Power to Gas technology. In this concept electrical energy is used for hydrogen production via electrolysis. Hydrogen can be injected in limited amount into natural gas grid, used for power generation via fuel cells or as a reactant for methanation process. Characteristics of hydrogen and ways of hydrogen production, storage and transport are described. Fuel cells are described as a device which uses hydrogen for power production. Crucial part of this thesis consists of a description of Power to Gas concept and a design of Power to Gas unit with electrical power of 9,5 kW. Three different units were designed for three different times of day operation. Efficiency and economical assessment was carried out for these three Power to Gas units.

Europeiska Unionen presenterade den 8 juni 2020 sin vätgasstrategi i syfte för att minska koldioxidutsläppen. Det unionen vill uppnå med sin vätgasstrategi är att uttnytja konceptet Power-to-X där elektricitet omvandlas till energi. Om elektricitetkällan kommer från förnyelsebar energi kommer grön vätgas produceras. Problemet med vätgas idag är lagring, transport och hanteringstrukturen för ämnet men vätgas kan lagras i flertal applikationer. En av de mest lovande lagringsalternativen är ammoniak som bildas när vätgas med kvävgas reagerar med varandra via ammoniaksyntes. Eftersom vätgasproduktionen idag använder fossila bränslen kommer även dess applikation göra det, men med grön vätgas kommer dess applikation även att bli grön. Idag står ammoniakproduktion för 2 % av fossilbränsleanvändning globalt och frigör mer än 400 miljoner ton CO2 årligen. Dessa utsläpp skulle försvinna om produktionen av ammoniak gjordes med Power-to-X konceptet. Syftet med detta examensarbete är att undersöka förutsättningarna ur ett ekonomiskt, tekniskt och säkerhetsmässigt hållbart Power-to-X koncept i form av en Grön Ammoniakanläggning i Norra Sverige. Det innebär att processer för en ammoniakproduktion skall analyseras ur ett teknisk synvinkel där fokus på funktion mot grön ammoniak är i fokus. Den ekonomiska synvinkeln innebär vad kapitalkostnaden (CAPEX) blir för anläggningen samt driftkostnaden (OPEX) som processen får. Arbetet innehåller först en analys av de processer som krävs för att kunna producera ammoniak. Därefter en analys över möjliga tekniker för dessa processer, hur väl de fungerar mot grön ammoniak och vilka antaganden som är i detta arbete. Anläggningen skulle vara storskalig vilket innebär en produktion på 500 ton NH3 $/dag. Det är även antaget en kontinuerlig eltillförsel samt att elnät redan är tillgänglig. Detta gav att vätgasproduktionen gjordes med en PEM-elektrolys, där kvävgas fås från kryogen destillation och ammoniak produceras med HB-processen. Resultatet visades att anläggningens CAPEX och OPEX blev 2 820 MSEK respektive 1 272 MSEK/år. Den dominerande faktorn för kapitalkostnaden var för vätgasproduktion som utgjorde 60 % av CAPEX. Den höga kostnaden för PEM-elektrolys är dels för att utvecklingen av processen inte är fullbordad, där utvecklingen för tekniken skulle kunna ge en stor kostnadsreducering. Det elbehov som anläggningen kräver är 1,6 TWh och och utgör en påverkan på OPEX är 55,4 %. Den process som kräver mest energi är vätgasproduktionen vilket omfattar 94 % av hela anläggningens totala elbehov. En stor anledning till de dyra driftkostnaderna är elpriset. I detta arbete valdes elpriset till ett medelvärde för SE1 i Sverige under en 10 års period. I ett verkligt scenario hade vätgasproduktionen kunnat optimeras för uppnå billigare drift.

Globally, transport accounts for a significant part of the total energy utilization and is heavily dominated by fossil fuels. The main challenge is how the greenhouse gas emissions in road transport can be addressed. Moreover, the use of fossil fuels in road transport makes most countries or regions dependent on those with oil and/or gas assets. With that said, the question arises of what can be done to reduce the levels of greenhouse gas emissions and furthermore reduce dependency on oil? One angle is to study what source of energy is used. Biomass is considered to be an important energy contributor in future transport and has been a reliable energy source for a long time. However, it is commonly known that biomass alone cannot sustain the energy needs in the transport sector by far. This work presents an alternative where renewable electricity could play a significant role in road transport within a relatively short time period. Today the amount of electricity used in road transport is negligible but has a potential to contribute substantially. It is suggested that the electricity should be stored, or “packaged” in a chemical manner, as a way of conserving the electrical energy. One way of doing so is to chemically synthesize fuels. It has been investigated how a fossil free transport system could be designed, to reach high levels of self-sufficiency. According to the studies, renewable electricity could have the single most important role in such a system.    Among the synthetic fuels, synthetic methane (also called synthetic biogas) is the main focus of the thesis. Hydrogen is obtained through water electrolysis, driven by electricity (preferable renewable), and reacted with carbon dioxide to produce synthetic methane. The concept of the mentioned process goes under the name Power to Gas. The electricity to fuel efficiency of such a process reaches about 50 %, but if utilizing excess heat produced during the electrolysis and the reaction, the total process efficiency can reach much higher levels. The economics of the process is as important as the technology itself in terms of large scale implementation. The price of electricity and biogas are the most important influences on the economic viability. The minimum “spread” between purchase and selling price can be determined to obtain a general perception of the economic feasibility. In this case biogas must be sold about 2.6 times higher than purchased electricity per kWh. / <p>QC 20130111</p>

This project proposes a solar-driven hybrid system for electricity generation and hydrogen production, which includes concentrated solar power (CSP), photovoltaic (PV), solid oxide electrolyser (SOEC). Electricity from the CSP and PV provides a continuous 24/7 supply to meet demand-side power consumption. When demand-side power consumption is low, the excess power is used to electrolyse water in the SOEC system. In this study, an SOEC is modelled, operation strategy for the solar-driven hybrid system is developed, the techno-economic performance of the overall system is evaluated, and sensitivity analysis is performed. For the modelling part, first develop an SOEC component in Matlab and Trnsys by considering the electrochemical model, thermal model and electric model. Second, design the hybrid system layout and simulate the system under 8760 hours in Matlab and Trnsys. The hybrid system is divided into five blocks: Heat Energy Source Block, Thermal Energy Storage Block, Rankine Cycle Block, Photovoltaic Block, Power to Hydrogen (PtH) Block. The operation strategy is: the heat is collected using a tower solar receiver and stored in tanks by heat transfer fluid molten salt. These thermal energy heats the water in heat exchangers and the resulting high temperature water vapour is used in steam turbine to generate electricity; at the same time part of the heat transfer fluid heats the feedwater in the PtH block and the resulting high temperature water vapour is used in SOEC for hydrogen production, if the operation temperature of steam in SOEC is not reached after heat exchange, the electric heater will heat the steam to raise the temperature. The CSP and PV provide electricity to demand side and SOEC. The produced hydrogen will be transported by truck or ship after compressed. For results part, the minimum CSP configurations to provide a 24/7 demand-side electricity consumption is a solar multiple (SM) with 2 and thermal storage (TES) size of 14 hours. SOEC stack has the best techno-economic performance at a nominal power of 275 Watt. The hybrid system has a levelised cost of electricity (LCOE) at 0.219 USD/kWh and a levelised cost of hydrogen (LCOH) at 7.5 USD/Kg. There are several sensitivity parameters for increase the energy productivity and decrease levelised cost. The larger the SM, the better the ability to generate power. The larger the TES size, the more the hourly generation is similar, otherwise it will fluctuate more. Increasing the SM results in a higher LCOE and a significantly lower LCOH. Increasing TES size also increases the LCOE, whereas the TES size has a marginal impact on the decrease of LCOH. Increased installed capacity inevitably leads to increased power generation. The increasing total power capacity makes the surplus power at the same demand side increase, so the SOEC runs at higher input power and the total hydrogen production increases, resulting in a lower LCOH. The effect of SOEC capacity on LCOH depends on the relationship between input power and SOEC nominal power. Higher operation temperature of SOEC leads to the lower the reversible voltage and an increasing consumption for water vapour. However, when the water vapour concentration is too high, the electrolysis current will instead drop, meaning that the rate of hydrogen production will drop.