Dans le contexte de la transition énergétique, les grandes technologies de stockage d’énergie à grande échelle sont considérées comme l’une des options qui peut faciliter une pénétration élevée des sources d’énergie renouvelables. La thèse est concentrée sur l’évaluation de la mise en œuvre le Power-to-Gas sur le marché énergétique roumain, qui a enregistré une croissance significative des énergies renouvelables et les enjeux auxquels devra faire face. Après avoir établi l’approche générale, les deux voies techniques du Power-to-Gas, l’Hydrogène et SNG, sont techniquement dimensionnés et économiquement évalués du point de vue des investisseurs dans deux scénarios temporels (2015 et 2030), afin d’évaluer la situation économique actuelle et les prix appliqués pour atteindre une rentabilité positive. Les résultats indiquent que des facteurs de grande capacité sont nécessaires afin de compenser les coûts d’investissement élevés, mais même dans cette situation un prix élevé est nécessaire pour la faisabilité économique, 68,1 Euro / MWh pour la voie Hydrogène et 112 Euro/MWh pour Power-to Gas SNG. Le marché d’équilibrage est également étudié comme un marché à haute valeur ajoutée dans le contexte français, avec des résultats indiquant une amélioration de 4% de la NPV, mais soulignant également les limites dans le cadre de l’analyse. Un avantage significatif, en termes d’impact GWP et utilisation de l’énergie fossile, a été identifié dans l’évaluation du cycle de vie de base de plusieurs scénarios d’alimentation au gaz, qui a également révélé l’importance de la source d’électricité utilisée pour la compression d’hydrogène. / In the energy transition context, large scale energy storage technologies are considered as one of the options that can facilitate a high penetration of renewable energy sources. The Thesis focuses on evaluating the implementation of Power-to-Gas in the Romanian energy market that recorded a significant growth in the share of renewables and will potentially face the related issues. After establishing a general approach, the two technical pathways of Power-to-Gas, Hydrogen and SNG, are technically sized and economically evaluated from an investor’s point of view in two temporal scenarios (2015 and 2030), in order to assess the current economic feasibility and the required price premiums that have to be put in place in order to reach a positive business case. Results indicate that high capacity factors are needed to compensate for the high capital costs, but even in this situation price premiums are required for economic feasibility, 68.1 Euro/MWh for the Hydrogen pathway and 112 Euro/MWh for Power-to-Gas SNG. The balancing market is also investigated as a high-value market in the French context, with results indicating a 4% improvement in NPV, but also highlighting the limitations of the proposed analysis framework. A significant benefit in terms of GWP impact and fossil energy use has been identified in. the basic life cycle assessment of multiple Power-to-Gas scenarios that also revealed the importance of the source of electricity used for hydrogen compression.

Green hydrogen produced with renewable electricity has gotten more attention during the last years and its different usage areas has been identified as an important part of the transition to a fossil free society. In this project the potential of a stand-alone hydrogen system and a hydrogen system integrated with a CHP, are investigated regarding technical and economic feasibility. This is done through a case study at Jönköping Energi, a municipal energy company. The main interest for Jönköping Energi is to investigate Power to Mobility, PtM, where electricity is used to produce hydrogen that is sold as fuel for vehicles. Another usage case of interest for the company is Power to Power, PtP. In PtP, electricity is used to produce hydrogen when electricity prices are low, the hydrogen is then stored and later used to produce electricity again when the prices are higher. For a PtM-system an electrolyser, and a hydrogen storage are needed components. In addition to these components, a fuel cell is needed for a PtP-system. Feasible specific technology for Jönköping Energi is recommended based on a literature review and information regarding the CHP.   The combined PtM- and PtP-system is investigated in two contexts, integrated with Jönköping Energi’s CHP and stand-alone. Electricity prices affect the profitability of the studied systems and therefore scenarios with high and low prices are used. A script was created in MATLAB to do the calculations regarding economic and technical feasibility of the integrated and stand-alone system with high and low electricity prices. This resulted in a PtM-system with a Proton exchange membrane electrolyser of 1 MW and a pressurized hydrogen storage tank of 12 MWh, as the most profitable system with a hydrogen demand of 360 kg/day. The integrated system shows slightly higher Net Present Value than the stand-alone system. With low electricity prices, within both contexts, the system is profitable, but with high prices the system is not profitable, neither stand-alone nor integrated. A PtP-system with a Proton exchange membrane fuel cell is not economically viable to include in any system or scenario with current prerequisites. For it to be profitable, more volatile electricity prices than the previous years together with additional income from electricity grid balancing services are needed. Moreover, the investment cost needs to be almost completely subsidised and higher efficiencies of the components than available today are needed as well. The prerequisites needed in order for the PtP-system to be viable is not predicted to be plausible in the near future. However, with low electricity prices, a PtM-system is potentially profitable for Jönköping Energi, both integrated with the CHP and as a stand-alone system.

The production of methanol by use of water electrolysis and hydrogenation of carbon dioxide (Power-to-Methanol) is a promising pathway to reduce greenhouse gas emissions. The concept of process intensification and the associated utilization of an in-situ coupling of methanol synthesis with proton-conducting Solid Oxide Electrolysis Cells (H+-SOEC) is a possible way to increase the energy efficiency of this process. Based on an extensive literature research, a novel Power-to-Methanol reactor concept for a concentric in-situ-integration of a tubular H+-SOEC has been designed, manufactured and operated at the Chair of Hydrogen and Nuclear Energy at the Technische Universität Dresden. The conducted experiments served as reference points for the process simulations performed in the second part of this thesis. Here, the Power-to-Methanol process has been modelled and simulated by means of process systems engineering methods to evaluate the in-situ-process in comparison to an conventional uncoupled set-up based on planar H+-SOECs. For this task, a novel and firm H+-SOEC process model was developed and implemented. In addition, the heat integration potential and profitability of the two Power-to-Methanol concepts have been investigated by Pinch Point and Techno-Economic Analysis. On the experimental side, a proof-of-concept of the novel reactor design was demonstrated, but limitations regarding the optimal thermal profile and operational flexibility of each process were identified. Furthermore, the methanol production rate showed potential for further improvement. The simulation results have helped to understand the process characteristics and to locate optimal operation points regarding current density, temperature and pressure. In an optimised operation scenario, high energy efficiencies for both tubular in-situ and planar set-ups have been achieved, by means of harnessing the heat integration potential through exothermic H+-SOEC operation. Notwithstanding the above, planar set-ups have demonstrated to be substantially more profitable than tubular systems. This has been the first investigation on Power-to-Methanol processes based on H+-SOEC. The present work helps to identify remaining development objectives for the use of H+-SOEC and Power-to-Methanol processes in general. The results from experiments and simulations indicate the challenging utilization of tubular electrolysis cells, but also revealed new research priorities that should be addressed in the future.

Power to X, hereinafter PtX, is a conversion of electricity into some kind of energy carrier, such as gas or liquid. The purpose of the technique is often to store “excess” energy from renewable energy sources, usually wind power, in order to use it later. One aspect ofPtX is Power to Gas, hereinafter PtG, which involves the conversion of electricity often by the use of an electrolyser into a gaseous energy carrier, such as hydrogen or methane. The technology is a promising strategy for balancing the electricity supply in countries that striveto have near zero carbon dioxide emissions and have to rely on renewable energy sources. Another part of PtX that has received more attention lately and that may be important in the future, with more fluctuating electricity prices due to a larger share of renewableenergy in the energy systems, is the technique Power to gas to power, PtGtP. In PtGtP electrical energy, often with the help of anelectrolyser, is converted and stored in a gaseous energy carrier and later on when there is an electricity shortage it is converted backinto electrical energy through fuel cells. PtGtP can therefore be seenas a further development of PtG. The purpose of the study is therefore to investigate the potential forPtX, more specifically PtG and PtGtP in Sweden in terms ofprofitability. PtG was investigated considering production of hydrogenand methane where the hydrogen was sold as fuel for vehicles and the methane was injected into the gas distribution network in Stockholm.The methane production also results in surplus heat which was injected into the district heating network. To investigate this, a qualitativecase study was carried out on two hypothetical facilities. One fromthe Swedish company Euromekanik, that produces hydrogen and one from the German company Electrochaea that produces methane. Euromekanik’s facility was also used for the PtGtP application. The results weremainly based on the electricity prices of 2019. However, electricityprices for 2017, 2018 as well as more volatile electricity prices havebeen examined. Simulations of the input- and output flows in thefacilities have been performed in MATLAB and profitabilitycalculations have been performed using the net present value methodand the profitability index. A sensitivity analysis was conducted inwhich the values of the most important parameters were varied. The results regarding PtG in this study show that the idea ofproduction should take place when the electricity prices are low canbe rejected. The results also show that the conversion of hydrogeninto methane decreases the profitability. Running the PtG plant allhours of the year and producing hydrogen is therefore the mostprofitable design of the plant, even though this set-up still resultsin a negative net present value of approximately 24 MSEK after 20years. The result from the investigation of PtGtP shows that due tothe low system efficiency, the electricity sold back to the grid needsto have a price of 5000-6000 SEK/MWh for the plant to break-even when purchasing electricity a fourth of the hours of the year with thelowest electricity price. With the pattern and prices on the Swedish electricity market today this technique will not be profitable.However, both PtG and PtGtP will most likely have another value than solely the economic profitability in terms of energy storage andsystem balancing functions, though that has not been examined in this thesis.

Fossil fuels dominate the world energy supply today and the transport sector is no exception. Renewable alternatives must therefore be introduced to replace fossil fuels and their emissions, without sacrificing our standard of living. There is a good potential for biofuels but process improvements are essential, to ensure efficient use of a limited amount of biomass and better compete with fossil alternatives. The general aim of this research is therefore to investigate how to improve efficiency in biofuel production by process development and co-generation of heat and electricity. The work has been divided into three parts; power cycles in biofuel production, methane production via pyrolysis and biofuels from renewable electricity. The studies of bio-based methanol plants showed that steam power generation has a key role in the large-scale biofuel production process. However, a large portion of the steam from the recovered reaction heat is needed in the fuel production process. One measure to increase steam power generation, evaluated in this thesis, is to lower the steam demand by humidification of the gasification agent. Pinch analysis indicated synergies from gas turbine integration and our studies concluded that the electrical efficiency for natural gas fired gas turbines amounts to 56-58%, in the same range as for large combined cycle plants. The use of the off-gas from the biofuel production is also a potential integration option but difficult for modern high-efficient gas turbines. Furthermore, gasification with oxygen and extensive syngas cleaning might be too energy-consuming for efficient power generation. Methane production via pyrolysis showed improved efficiency compared with the competing route via gasification. The total biomass to methane efficiency, including additional biomass to fulfil the power demand, was calculated to 73-74%. The process benefits from lower thermal losses and less reaction heat when syngas is avoided as an intermediate step and can handle high-alkali fuels such as annual crops. Several synergies were discovered when integrating conventional biofuel production with addition of hydrogen. Introducing hydrogen would also greatly increase the biofuel production potential for regions with limited biomass resources. It was also concluded that methane produced from electrolysis of water could be economically feasible if the product was priced in parity with petrol. / <p>QC 20121127</p>

MELO, Pamella Beserra de. Precarização do trabalho e saúde dos trabalhadores terceirizados. 2016. 122f. – Dissertação (Mestrado) – Universidade Federal do Ceará, Programa de Pós-Graduação em Psicologia, Fortaleza (CE), 2016. / Submitted by Gustavo Daher (gdaherufc@hotmail.com) on 2017-05-31T15:09:12Z No. of bitstreams: 1 2016_dis_ pbmelo.pdf: 1093941 bytes, checksum: 6ab384ff90ea90983866611b091a4535 (MD5) / Approved for entry into archive by Márcia Araújo (marcia_m_bezerra@yahoo.com.br) on 2017-06-01T10:47:00Z (GMT) No. of bitstreams: 1 2016_dis_ pbmelo.pdf: 1093941 bytes, checksum: 6ab384ff90ea90983866611b091a4535 (MD5) / Made available in DSpace on 2017-06-01T10:47:00Z (GMT). No. of bitstreams: 1 2016_dis_ pbmelo.pdf: 1093941 bytes, checksum: 6ab384ff90ea90983866611b091a4535 (MD5) Previous issue date: 2016 / The research presented here analyzed how the work affects the health of outsourced professionals working at the Federal University of Ceará (UFC). The research, based on the Clinic of Activity and located in the field of Worker’s 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 González 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 “innovative” tendencies that weaken the working class, representing a threat to work on its ontological character and to workers’ rights. It is intended that the research contributes to the formulation of actions aimed at workers’ 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. / A investigação aqui apresentada analisou como o trabalho repercute na saúde dos profissionais com vínculo terceirizado que atuam na Universidade Federal do Ceará (UFC). A pesquisa fundamenta-se na Clínica da Atividade e situa-se no campo da Saúde do Trabalhador; baseia-se na epistemologia qualitativa e desenvolveu-se como um estudo de caso derivado de intervenção efetivada no Almoxarifado Central da UFC. Todo o material produzido na intervenção foi utilizado para a construção do corpus pertinente ao caso analisado. Tal delineamento corrobora a perspectiva teórica mencionada para a qual, primeiro, realiza-se a intervenção para, em seguida, dar-se início à pesquisa. Assume-se que cada um desses momentos tem temporalidades e objetos diferentes, guardando uma relação de mútua independência. A intervenção compreendeu três etapas: 1) formação do grupo de análise, no qual foram realizadas observações, entrevistas, análises documentais e filmagens; 2) autoconfrontações 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 análise dos dados, utilizou-se a análise de conteúdo construtiva-interpretativa de González Rey. Adotou-se como unidade de análise a atividade triplamente dirigida (para o objeto, pelo sujeito e para o outro). Considera-se a pertinência do estudo, uma vez que nos encontramos num contexto marcado por retrocessos no mundo laboral, em que práticas arcaicas de gestão e controle da mão de obra e da produção coexistem com tendências “inovadoras” que vulnerabilizam a classe trabalhadora, representando uma ameaça ao trabalho em seu caráter ontológico e aos direitos dos trabalhadores. Objetiva-se que a pesquisa contribua para formulação de ações voltadas à saúde do trabalhador e ao desenvolvimento do seu poder de agir, bem como desnude as vulnerabilidades a que estão submetidos os trabalhadores que possuem vínculos laborais precários. Desta forma, em relação às condições de trabalho, percebeu-se que os trabalhadores com vínculo terceirizado estão mais sujeitos a situações de vulnerabilidade, e seu universo de trabalho é permeado por situações de risco à saúde e à segurança. Constatou-se ainda estarem eles mais suscetíveis a situações de assédio, ameaça, desrespeito, preconceito, autoritarismo devido à instabilidade do vínculo; estavam subordinados também a condições inadequadas ao desenvolvimento de suas atividades, como ambiente empoeirado, mal iluminado e sem ventilação, com estrutura precária e antiga, além da carência de materiais em boas condições e/ou da utilização de equipamentos inapropriados para tal. Assim, pôde-se perceber que na atividade dos sujeitos pesquisados vários empecilhos são impostos a sua ação, porém, através de um modelo de gestão participativo, eles encontraram as possibilidades de desenvolvimento do poder de agir e da construção da saúde, fortalecendo o coletivo profissional, que passou a reconhecer-se enquanto grupo, ao discutir e debater as dificuldades e sugestões possíveis para realização de um trabalho bem feito. Observou-se, ainda, através da participação ativa dos trabalhadores nas mudanças empreendidas no setor investigado, melhorias tais como redefinição das atribuições e tarefas de cada trabalhador, dinamização e maior fluidez dos processos de trabalho, realização de reuniões sistemáticas com a participação e envolvimento de todos os profissionais do setor, ouvindo-se as sugestões e questionando-se coletivamente as problemáticas em pauta.

Energiomställningen är avgörande för att begränsa de globala koldioxidutsläppen. Det blir det allt viktigare att hitta sätt att ta tillvara på elöverskott och kunna lagra energi från förnybara energikällor som vind och sol. Vätgas är en energibärare och har stor potential för att ha en nyckelroll i ett hundraprocentigt förnybart energisystem. Syftet med studien var att undersöka förutsättningarna för ett ekonomiskt och tekniskt håll- bart logistiksystem för vätgastransport. Målet var att beräkna överföringskostnader och jämföra olika tekniker för transport av vätgas. Studien inleddes med en djupgående litte- raturstudie och omvärldsanalys. Därefter valdes två olika fall i norra Sverige och utifrån de förutsättningar som fanns på platserna jämfördes transport via pipeline, vägtransport och järnvägstransport. Resultaten för vägtransport via komprimerad form tyder på att det krävs ett stort antal transporter för att leverera den analyserade mängden i de olika fallen vilket resulterar i höga kostnader. Transport via järnväg tyder på relativt hög investeringskostnad och ingen större skillnad mellan fallen. Resultaten tyder på att transport via pipeline har relativt låga överföringskostnader för båda fallen och man kan se en skillnad i investeringskostnad mellan fallen. Överföringskostnader via pipeline tyder på lägre kostnader än att överföra el. Överföringskostnader kan bero på olika faktorer som förutsättningar på platsen, elkostnader, avstånd och volym. Det finns osäkerheter i resultaten för vägtransport och järnväg vilket gör det svårt att dra slutsaster utifrån den data som presenteras. Jämförelsen mellan vätgas och el ska ses som en grov uppskattning på grund av de osäkerheter som finns kopplat till elöverföringen. / The energy transition is crucial to limit the global carbon dioxide emissions. Renewable energy sources like wind and solar are intermittent and we need to find ways to use the electricity surplus and store energy. Hydrogen is an energy carrier and has the potential to be a key to achieve a renewable energy system. The aim of the study is to investigate the feasibility for an economic and technical sustainable system for hydrogen distribution. The goal was to calculate transmission cost for different types of hydrogen transport. A profound literature study and external analysis was made in the beginning. Then two cases were selected in the northern part of Sweden. Based on the conditions, transport through pipeline, road transport and transport by rail were choosen. The results for transport by road suggests that very frequent transports are required to deliver the quantity in the cases taken up, which results in high costs. Distribution cost by rail implies high investment costs and there are no significant difference between distribution cost for the cases. Furthermore the results implies that pipeline has low operating costs for both cases and it also implies a difference between investments cost for the cases. The result also indicates that transmission cost by pipelines is cheaper than transmission cost for electricity. Which one is the best option depends on many different factors such as conditions at the location, electricity price, distance and the volume. There are uncertainties in the results for transport by road and by rail, which makes it difficult to conclude based on the current findings. The comparision between hydrogen and electricity should be seen as a rough estimate due to the uncertanties.

För att Sverige ska uppnå de energimål som satts upp i enighet med Agenda 2030, är det av stor vikt att implementera mer förnybara resurser. Sektorkopplingsstrategier är en potentiell åtgärd vilket skulle optimera det svenska energisystemet. På sikt skulle det även kunna frigöra kapacitet, och därmed möjliggöra hantering av en större andel förnybara källor i elnätet. Syftet med den här studien är att bistå med en nulägesrapport av sektorkopplingsetablering i Sverige, med särskild fördjupning i region Gotland. Studien grundas i en omfattande litteraturstudie och kvalitativa intervjuer. Genom att studera tidigare litteratur inom området identifierades tekniker och metoder inom sektorkoppling, vars nuvarande utsträckning i Sverige kartlades. Den fördjupade datainsamlingen för studien var ostrukturerade kvalitativa intervjuer med projektledare och aktörer med relevans för Gotland. Resultatet från studien är en sammanställning av sektorkopplingtekniker samt hur dessa kan bidra till att öka flexibiliteten i energisystemet i allmänhet, och elnätet i synnerhet. Vidare kartlades projekt i Sverige som tillämpar dessa tekniker. Slutsatserna visar på att sektorkoppling redan är etablerat i Sverige, men befinner sig i ett tidigt stadium. Resultatet visade vidare att det krävs engagemang från kunder och aktörer, samt en viss standard i energisystemet för att möjliggöra en framgångsrik tillämpning av sektorkoppling i det svenska energisystemet. Resultaten belyser likväl att en fortsatt etablering av sektorkoppling kan komma att kräva ekonomiska incitament i form av bidrag och satsningar. / Including more renewable energy sources in the energy system is of great importance to enable Sweden to achieve its climate goals in unity of Agenda 2030. Sector coupling is a potential strategy for energy optimization, which in time could become a more established method to manage capacity issues, as well as permitting more renewable energy sources in the electricity grid. The purpose of this study is to compile a status report on current sector coupling in Sweden, with additional further investigation of region Gotland. The study is based on a comprehensive literature study as well as data collection through qualitative interviews with relevant stakeholders. Previous research and literature in the field enabled the identification of different technologies and methods relating to sector coupling. Qualitative data was gathered through unstructured interviews with represenatatives from companies and organizations having their focus set on energy planning in the Gotland region. The results consist of an assortment of various sector coupling technologies and their ability to increase the flexibility of the power grid and energy system in Sweden. In addition, several projects with diverse implementation of sector coupling strategies were also being mapped out. In conclusion, it became apparent that sector coupling is only at its earlier stages of implementation in Sweden. Further interest and commitment by customers and businesses is of great importance and needed to enable expansion of sector coupling technologies in Sweden. Moreover, the energy system requires standards, as well as financial incentives to promote further use of sector coupling in society.

The energy transition taking place in various parts of the world will have many effects on the current energy systems as an increasing amount of intermittent power supply gets installed every year. In Sweden, just as many other countries, this will cause both challenges and opportunities for today´s energy producers. Challenges that may arise along with an increasingly fluctuating electricity production include both power deficits at certain times and regions but also hours of over-production which can cause electricity prices to drop significantly. Such challenges will have to be met by both dispatchable power generation and dynamic consumption. Conversely, actors prepared to adapt to the new climate by implementing new technologies or innovative business models could benefit from the transition towards a fully renewable energy system.  This thesis evaluates the techno-economic potential of green hydrogen production at a combined heat and power plant with the objective to provide decision support to a district heat and electricity producer in Sweden. It was in the company’s interest to investigate how hydrogen production could help reduce the production cost of district heat as well as contribute to the reduction of greenhouse gases.  In the project, two separate business models: Power-to-gas and Power-to-power were evaluated on the basis of technical and economic performance and environmental impact. To do this, a mathematical model of the CHP plant and the hydrogen systems was developed in Python which optimizes the operation based on costs. The business models were then simulated for two different years with each year representing a distinctly different electricity market situation.  The main conclusions of the study show that Power-to-gas could already be profitable at a hydrogen retail price of 40 SEK per kg, which is the projected retail price for the transportation sector. The demand today is however limited but is expected to grow fast in the near future, especially within heavy transportation. Another limiting factor for hydrogen production showed to be the availability of storage space, as hydrogen gas even at pressures up to 200 bar require large volumes.  Power-to-power for frequency regulation was found to not be economically justifiable as the revenue for providing grid services could not outweigh the high investment costs for any of the simulated years. This resulted in a high levelized cost of energy at over 3000 SEK per MWh which was mostly due to the low capacity factor of the power-to-power system.  Finally, green hydrogen has the potential of replacing fossil fuels in sectors that is difficult to reach with electricity, for example long-haul road transport or the shipping industry. Therefore, green hydrogen production in large scale could help decarbonize many of society’s fossil-heavy segments. By also serving as a grid-balancer, hydrogen production in a power-to-gas process has the potential of becoming an important part of a renewable energy system. / Energiomställningen som äger rum i olika delar av världen kommer att ha många effekter på de nuvarande energisystemen eftersom en ökande mängd väderberoende kraftproduktion installeras varje år. I Sverige, precis som många andra länder, kommer detta att medföra både utmaningar och möjligheter för dagens energiproducenter. Utmaningar som kan uppstå tillsammans med en alltmer fluktuerande elproduktion inkluderar både kraftunderskott vid vissa tider och regioner men också timmar av överproduktion som kan få elpriserna att sjunka avsevärt. Sådana utmaningar måste mötas av både planerbar kraftproduktion och dynamisk konsumtion. Omvänt kan aktörer som är beredda att anpassa sig till det nya klimatet genom att implementera ny teknik eller innovativa affärsmodeller dra nytta av övergången till ett helt förnybart energisystem.  Denna rapport utvärderar den tekno-ekonomiska potentialen för produktion av grön vätgas vid ett kraftvärmeverk med målet att ge beslutsstöd till en fjärrvärme- och elproducent i Sverige. Det var i företagets intresse att undersöka hur vätgasproduktion kan bidra till att sänka produktionskostnaden för fjärrvärme samt bidra till att minska växthusgaser.  I projektet utvärderades två separata affärsmodeller: Power-to-gas och Power-to-power baserat på teknisk och ekonomisk prestanda samt miljöpåverkan. För att kunna göra detta utvecklades en matematisk modell i Python av kraftvärmeverket och vätgassystemen som optimerar driften baserat på kostnader. Affärsmodellerna simulerades sedan för två olika års elpriser för att undersöka modellens prestanda i olika typer av elmarknader.  De viktigaste slutsatserna i studien visar att Power-to-gas redan kan vara lönsamt till ett vätgaspris på 40 SEK per kg, vilket är det förväntade marknadspriset på grön vätgas for transportsektorn. Efterfrågan är idag begränsad men förväntas växa snabbt inom en snar framtid, särskilt inom tung transport. En annan begränsande faktor för vätgasproduktion visade sig vara tillgången på lagringsutrymme, eftersom vätgas även vid tryck upp till 200 bar kräver stora volymer.  Power-to-power för frekvensreglering visade sig inte vara ekonomiskt försvarbart, eftersom intäkterna för att tillhandahålla nättjänster inte kunde uppväga de höga investeringskostnaderna under några av de simulerade åren. Detta resulterade i en hög LCOE på över 3000 SEK per MWh, vilket främst berodde på Power-to-power-systemets låga utnyttjandegrad.  Slutligen kan det sägas att grön vätgas har stor potential att ersätta fossila bränslen i sektorer som är svåra att elektrifiera, exempelvis tunga vägtransporter eller sjöfart. Därför kan storskalig grön vätgasproduktion hjälpa till att dekarbonisera många av samhällets fossiltunga segment. Genom att dessutom fungera som balansering har väteproduktion i en Power-to-gas-process potential att bli en viktig del av ett system med stor andel förnybar energi.

L'objectif de cette thèse est de concevoir, d'évaluer les performances énergétiques et d'étudier le comportement en régime transitoire pendant les opérations de chauffage et de démarrage d'un procédé réversible Power To Gas qui est une solution pour l'intégration des énergies renouvelables dans le mix énergétique. L'évaluation des performances énergétiques montre que 66,7% de l'énergie électrique entrante est stockée sous forme de substitut du gaz naturel et que les pertes concernent principalement les étapes de conversion en particulier la conversion AC/DC, la co-électrolyse et la méthanation. Le déstockage de l'électricité (Gas To Power) est réalisé en inversant le RSOC en mode SOFC alimenté par le gaz de synthèse (H2 et CO) produit dans un tri-reformeur. Ce procédé est autonome énergétiquement et produit de la chaleur inexploitée qui est à l'origine de sa faible efficacité de 40%. Une étude de la réponse en régime transitoire est conduite en développant des modèles dynamiques du co-électrolyseur réversible, des réacteurs et des échangeurs par le biais de deux logiciels: Matlab et Dymola. Les résultats permettent de préciser la pénalité énergétique et de revoir l'architecture du procédé prédéfinie en régime stationnaire. Plusieurs stratégies ont été étudiées afin d'optimiser le temps de démarrage et l'énergie consommée. Il s'est avéré que le RSOC est le composant qui consomme le plus d'énergie (71% de l'énergie totale) et qui nécessite le plus de temps de démarrage (60% du temps total) à cause de la quantité du gaz utilisée pour le chauffage et du temps important qu'il faut respecter afin d'assurer une augmentation en température progressive qui évite la détérioration des cellules. / The objective of this thesis is to design, evaluate the energetic performance and study the transient behavior during heating and startup operations of a reversible process Power To Gas process which is a solution for the integration of renewable electricity in the energy mix. Steady state models are first established in Aspen plus. Assessment of energetic performance shows that 66.7% of the electrical energy is stored as a Synthetic Natural Gas and the losses are caused mainly by the converting steps: the AC/DC, co-electrolysis and methanation conversions. Electricity production (Gas to Power) is performed by reversing the RSOC in SOFC mode fueled by synthesis gas (CO and H2) produced in a tri-reformer. This process is energetically autonomous and produces untapped heat which causes its 40% low efficiency. A study of the transient response during heat-up and start-up operations is conducted through the development of dynamic models of reversible co- electrolyzer, reactors and heat exchangers by using Matlab and Dymola softwares. The results allow to specify the energetic penalty and to review the architecture of predefined process in steady state. Several strategies have been studied to optimize the time and the energy consumption. It turned out that the RSOC is the slowest component (60% of total time) with the most energetic consumption (71% of total energy) because of the amount of gas used in heat-up operation and the significant time that must be respected in order to ensure an increase in temperature that prevents the cells deterioration.