The transition to efficient, affordable, reliable, and clean sources of energy is one of the major challenges of this century. Despite advances in renewable energy technologies, fossil fuels remain the primary source of energy, and are expected to remain so for decades to come. Natural gas, a relatively cleaner fossil fuel vital to many industries such as power generation, is expected to play a more prominent role in the global energy mix. However, with the decline in conventional gas discoveries, it is crucial to improve recovery from mature reservoirs to satisfy the growing demand for energy. On the other hand, the combustion of fossil fuels significantly contributes to carbon dioxide (CO2) emissions and climate change, an issue of major concern. CO2-based enhanced gas recovery (EGR) is a useful method to improve gas recovery, and simultaneously store CO2 securely in depleted gas reservoirs, therefore reducing net CO2 emissions. However, CO2 injection for EGR has a drawback of excess mixing with the methane therefore reducing the quality of gas produced, and leading to early breakthrough. Although this issue has been identified as a major obstacle in CO2-based EGR, few strategies have been suggested to mitigate this problem. In this study, we propose a novel hybrid EGR method to reduce mixing and delay breakthrough. We propose the injection of a slug of carbonated water before beginning CO2 injection. Carbonated water hinders CO2-methane mixing, and reduces CO2 mobility therefore delaying breakthrough. We use reservoir simulation to assess the feasibility and benefit of the proposed method. Through a structured design of experiments (DoE) framework, we perform sensitivity analysis, uncertainty quantification, and optimization to identify the ideal operation and transition conditions. We show that the proposed method has an overall benefit for up to ~3% pore volumes of carbonated water injected. The proposed method is mainly influenced by the heterogeneity of the reservoir, slug volume injected, and production rates. Through Monte Carlo simulation we show that high recovery factors and storage ratios can be achieved while keeping recycled CO2 ratios low. These results are encouraging and highlight the overall benefit of the proposed hybrid EGR method.

Many countries strengthen their commitments to reduce greenhouse gas emissions to limit climate change and meet the Paris Agreement (Masson-Delmotte et al., 2019). Commitments include achieving net-zero emissions or in some cases even negative emissions (Government offices of Sweden, 2020a; United Nations, 2021a). To achieve these goals, carbon dioxide capture, utilization, and storage (CCUS) is considered as an essential strategy. Carbon capture storage and utilization are recognized methods of reducing or avoiding greenhouse gas emissions (IEA, 2019a, 2020). However, the uncertainty regarding costs, financial incentives, and pricing is impeding adoption. Further information is needed for CCUS concepts both in respect to cost estimates and required market prices for CCUS, this to provide guidance for decision makers and market actors. In this report a study has investigated the economic feasibility of three CCUS concepts for a biogas facility. One CCS concept where CO2 was captured and liquefied on-site to be transported to a terminal for shipping and end storage injection. The CCS concept annual capacity was ~16 500 ton net stored CO2. Two CCU concepts were considered, where synthetic natural gas (SNG) was produced via biologic methanation with on-site produced hydrogen, both with annual production of ~88 GWh SNG. A techno-economic assessment (TEA) was carried out where the key cost-drivers were identified, and the economic feasibility assessed. With performance and cost estimates for each process step in the different considered concepts a model was built where a cash flow was created and a net present value (NPV) could be calculated. The study found transportation to be the most prominent cost driver for CCS where shipping and storage represented 57 % of the total cost of CO2 removal. The cost driver for CCU concepts was found to be hydrogen production, where the electricity for the electrolyser constituted 65 % of the total cost of produced SNG. None of the concepts were found economic feasible when the Swedish market was considered. The break-even price for CO2 removal in the CCS concept was found to be 151 €/ton, just above the assumed base value used in this study. As the voluntary market is still undeveloped it is difficult to know what price that could be expected, however, in discussion with market experts a range between 150-200 €/ton would not be unthinkable for the concept studied. For the CCU concepts to be economically feasible, the estimated minimum price levels for SNG were 184 and 193 €/MWh respectively. Comparing to the benchmark price of diesel of 125 €/MWh, both CCU concepts were concluded to be unfeasible. The sensitivity analysis showed that the CCU concepts were very sensitive to variations in electricity price. When the German fuel market was considered, all studied concepts yielded a positive business case. CCS was the only concept showing economic feasibility, while the CCU concepts remained unfeasible. In the German market a GHG reduction quota credit was accounted for which was valued higher than the carbon removal credits in the voluntary market. / Många länder stärker sina åtaganden att minska utsläppen av växthusgaser för att begränsa klimatförändringen och uppfylla Parisavtalet (Masson-Delmotte et al., 2019). I åtagandena ingår att uppnå nettonollutsläpp eller i vissa fall till och med negativa utsläpp (Regeringskansliet, 2020a; FN, 2021a). För att uppnå dessa mål anses avskiljning, nyttjande och lagring av koldioxid (CCUS) vara en viktig strategi. Avskiljning, lagring och utnyttjande av koldioxid är erkända metoder för att minska eller undvika utsläpp av växthusgaser (IEA, 2019a, 2020). Osäkerheten kring kostnader, ekonomiska incitament och prissättning hindrar dock införandet. Ytterligare information behövs för CCUS-koncept både när det gäller kostnadsberäkningar och nödvändiga marknadspriser för CCUS, detta för att ge vägledning för beslutsfattare och marknadsaktörer. I den här rapporten undersöks den ekonomiska genomförbarheten av tre CCUS-koncept för en biogasanläggning. Ett CCS-koncept där koldioxid avskiljs och kondenseras på plats för att sedan transporteras till en terminal för slutlig sjöfrakt och injektion i geologiskt lager. Den årliga kapaciteten för CCS-konceptet var ~16 500 ton nettolagrad koldioxid. Två CCU-koncept övervägdes, där syntetisk natur gas (SNG) producerades genom biologisk metanisering med vätgas producerad på plats, där båda koncepten hade en årlig produktion av ~88 GWh SNG. En tekno-ekonomisk undersökning genomfördes där de viktigaste kostnadsdrivande faktorerna identifierades och den ekonomiska genomförbarheten bedömdes. Med hjälp av prestanda- och kostnadsberäkningar för varje processteg i de olika tänkta koncepten byggdes en modell där ett kassaflöde skapades och ett netto-nuvärde kunde beräknas. I studien konstaterades att transport var den mest framträdande kostnadsdrivande faktorn för CCS, där sjöfrakt och lagring stod för 57 % av den totala kostnaden för koldioxidavskiljning. Kostnadsdrivande för CCU-konceptet var vätgasproduktionen, där el till elektrolysen utgjorde 65 % av den totala kostnaden för producerad SNG. Inget av koncepten befanns vara ekonomiskt genomförbart när den svenska marknaden beaktades. Nollpunktspriset för koldioxidavskiljning i CCS-konceptet fanns vara 151 euro/ton, vilket är strax över det antagna basvärde som används i denna studie. Eftersom den frivilliga marknaden fortfarande är outvecklad är det svårt att veta vilket pris som kan förväntas, men i diskussioner med marknadsexperter skulle ett prisintervall på 150-200 €/ton inte vara otänkbart för det studerade konceptet. För att CCU-koncepten ska vara ekonomiskt genomförbara var de uppskattade minimipriserna för SNG 184 respektive 193 €/MWh. Jämfört med referenspriset för diesel på 125 €/MWh, ansågs båda CCU-koncepten vara ekonomiskt ogenomförbara. Känslighetsanalysen visade att CCU-koncepten var mycket känsliga för variationer i elpriset. När den tyska bränslemarknaden beaktades gav alla studerade koncept ett positivt netto-nuvärde. CCS konceptet var det enda konceptet som ansågs vara ekonomiskt genomförbart, medan CCU-koncepten förblev ogenomförbara. På den tyska marknaden räknades en kvot för minskning av växthusgasutsläpp in, som värderades högre än de krediter för avskiljning av koldioxid som fanns på den frivilliga marknaden.

The energy transition is one of the largest challenges our global society is facing. In 2015, the United Nations acknowledged the Paris Agreement, where the world’s nations were united to limit the global warming well below 2 °C in comparison with pre-historic levels. One of the measures to tackle this challenge that have been proposed by both the International Energy Agency and the European Union is carbon capture and storage or utilisation (CCUS). The concept of CCUS is relatively old but has in light of climate mitigation measures been identified as vital since carbon dioxide (CO2) either can be permanently stored or sequestered into products and materials. Previous research has shown a large potential in CCUS, and that it has a key role in enabling and achieving net-zero climate scenarios. However, large-scale and widely distributed CCUS facilities has not yet been deployed, and it is not fully clear which aspects that are the most important affecting the deployment and how this can be facilitated. This study aims to investigate the current and future market of captured CO2 in Europe during the next decade. The study aims to fill the knowledge gap on how policies affect the development of CCUS, the drivers and barriers that current actors have identified within the field, and lastly, possible pathways in which CO2 can be used. This study was performed using a literature scoping review and interviews with relevant CCUS actors in different parts of the value-chain. The results show CCUS is recognised as an important tool within the European Union to reach the climate goals set out by the European Commission. The development and further deployment of CCUS are however prevented due to economic and legislative barriers, of which low carbon pricing, such as the EU ETS, is identified as the main barrier against making CCUS commercially competitive. Additional legislative barriers are connected to the cross-national trade and export of CO2, as well as a lacking framework on verification and monitoring of captured CO2 and the trade with carbon removal credits. The results also show that CCUS initially will be developed at industrial clusters in the North-West Europe, where shared infrastructure is recognised as an enabler due to sharing risks of investments. The main focus within Europe is on offshore storage rather than CCU due to its large sequestering potential, although CCU can be relevant in regions lacking infrastructure for the transportation of CO2. Regarding the investigated utilisation options, synthetic fuels, building materials, and polymers have been identified to have high potential even if they are not believed to have a high influence as a climate mitigation measure in comparison with CCS. It is concluded that viable business models and cost-effective infrastructure solutions are essential for the European CCUS industry. Much of the deployment is however dependent on clear, beneficial frameworks and policies stating the rules and facilitating the economics of CCUS. Nevertheless, it is expected that especially the European CCS sector will grow in Europe in the upcoming decade, although the role of CCU should not be neglected.

No description available.

This research study explored the meanings former patients attributed to being on long-term mechanical ventilation in a critical care unit (CCU). An interpretive phenomenological-ontological perspective informed by the philosophical tenets of Heidegger (1927/1962) was used to examine the lived experience of a group of people who had previously been hospitalised in one of three critical care units in southeast Queensland, Australia, during which time they were on a mechanical ventilator for a period of seven days or more. Data were collected using 14 unstructured audio-taped interviews from participants, who had indicated that they were willing and able to recall aspects of their critical care experience. The data were analysed using the method developed by van Manen (1990). A total of nine people participated in the study, of which six were male and three female. Their ages ranged from 21 to 69 years. Thematic analysis of the data revealed four themes: Being thrown into an uneveryday world; Existing in an uneveryday world; Reclaiming the everyday world; and Reframing the experience. Throughout the description of these themes, excerpts from the interviews with the participants are provided to demonstrate, and bring to light the meaning and interpretations constructed. From this thematic analysis, a phenomenological description drawing on Heidegger's tenets of Being was constructed. Titled Being at its most elusive, this description showed that participants experienced momentary lapses of: situation, engagement, concern and care, temporality, and the ability to self-interpret. These findings highlight and affirm the relevance of Heidegger's ontological tenets to reveal Being. The findings of this study served as a basis for a number of recommendations relating to nursing practice, education and research. Recommendations relating to practice include: constructing a more patient-friendly critical care environment, increased involvement of patients and their families in decision making and patient care activities; ensuring adequate critical care nursing staff levels; ensuring and maintaining appropriate skill level of critical care nurses; enhancing methods of communication with patients; planning for effective patient discharge and adoption of a designated nurse position for discharge planning; providing opportunities for follow up contact of patients once they are discharged from CCU; and promoting the establishment of follow up services for former CCU patients, and their families. Recommendations relating to critical care education include: incorporating more in-depth information of the psychological and social aspects of patient and family care into care planning; incorporating communication and counselling education and training to assist nurses caring for mechanically ventilated patients, and their families; further education regarding the role and responsibilities of patient discharge planning from CCU; incorporating more advanced research skills training and utilisation of research findings into practice; and the provision of appropriate and ongoing training and education in areas such as manual handling and communication skills for all health care staff involved in the direct care of CCU patients. This study also recommended that further research be undertaken to: examine and compare different sedative and analgesic protocols and their effects on the incidence of nightmares and hallucinations reported by CCU patients; replicate this study in a group of patients from different cultural or ethnic backgrounds; evaluate the efficacy of current methods for communicating with intubated and mechanically ventilated patients in the CCU; develop, test and evaluate the efficacy of new methods for communicating with intubated and mechanically ventilated patients in the CCU; examine CCU patients' perceived level of control and power; explore the extent and type of involvement patients would like to have in their care whilst in the CCU; investigate the extent and type of problems experienced by CCU patients after discharge; explore the usefulness and appropriateness of personal diaries for individual patients as an aid to assist in understanding and resolving their CCU experience; and examine the value of follow up contacts by CCU staff to former patients and their families. In summary, the findings from this study add substantial knowledge to critical care nurses' understanding and knowledge about what it means to be on long-term mechanical ventilation in a critical care unit. Findings will help inform future critical care nursing practice and education, and the provision of holistic and evidenced-based care.

As the world pushes for ‘greener’ technologies and carbon neutrality, efforts have focused on creating novel ways to mitigate humankind’s carbon footprint. Carbon capture and storage (CCS) has become a prevalent technique that has proven to be an effective long-term method to safely relocate excess carbon dioxide (CO2) into subsurface formations. However, CCS is a newer technique which requires constant monitoring due to potential leakage pathways present in CO2 storage sites; therefore, a preventive approach to seal leakage pathways is recommended. This dissertation explores the potential of CO2-sensitive polyacrylamide (CO2-SPAM) as a novel sealing agent for enhanced oil recovery (EOR) and CCS applications. This manuscript explores the strength and weaknesses of various CO2-triggered chemicals and selects the appropriate fit for subsurface in-situ sealing. Relevant literature shows that CO2-SPAM can significantly reduce permeability in porous media. Additionally, organically cross-linked polyacrylamide-based gels, of which CO2-SPAM is one, are thermally stable, resistant to low pH levels, highly injectable, and widely used in various industrial processes. These characteristics make CO2-SPAM a suitable candidate for in-situ sealing. Further studies were performed to comprehend the chemical mechanism, rheological behavior, and injection effects of CO2-SPAM into subsurface formations. Firstly, past literature knowledge and organic chemistry principals were used to develop the complete chemical breakdown of CO2-SPAM gel’s synthesis. Secondly, the effect of salt and polyacrylamide (PAM) concentrations on gelation time, gel strength and viscosity were tested through qualitative (Sydansk gel strength coding system) and quantitative methods (rheometer measurement). The results showed that high salinities increase gelation time and decrease gel strength and viscosity, while high PAM concentrations do the opposite. Lastly, the effects on geomechanical stresses caused by CO2-SPAM injection into the subsurface are also addressed by using the image well method for pore pressure estimation, and frictional faulting theory. The final results determined that the injection of aqueous CO2-SPAM would induce seismicity in normal faulting zones dipping at a large array of angles in the plane of failure. These findings are significant as they determine the potential of induced seismicity in the area of CCS, which in this case was the Raton basin.

No description available.

Carbon dioxide from biogas production is currently considered to be without value and isbecause of this released into the atmosphere in the biogas upgrading process. The residualgas is a potential carbon source and can create value in the biogas manufacturing process.By finding a suitable value-creating process that utilizes carbon dioxide, it can be possibleto provide both economic and environmental incentives for companies to develop theiroperations. This project explored the possibility to create value from this CO2. Through anevaluation of the technical maturity of CCU technologies, a recommendation could be givenat the end of the project. An analysis of technical barriers, such as pollutants in the gas, aswell as barriers in the form of competence and corporate culture were examined in orderto provide a reasoned recommendation. The project mapped which value-creating systemswould be suitable for biogas producers in a Swedish context. This included established methaneand carbon dioxide upgrading techniques currently in use and suitable CCU techniquesthat can interact with the selected upgrading processes and serve as value creators. Based onthis survey, it was then possible to identify common, critical variables for these systems. Thereafter,a recommendation of an appropriate CCU technology could be given depending onthe CO2 composition produced. One conclusion from the study was that carbon dioxide concentrationsfrom the residual gas was often high (approx. 97-98 %) and did not contain anycorrosive or toxic components, and that this largely depends on how the digestion reactor ishandled in the production process. Thus, questions were raised about what the actual limitationsof the CCU are, as they did not seem to be technical. CCU techniques that proved to beof particular interest were pH regulation of sewage plants, CO2 as a nutrient substrate for thecultivation of microalgae, and manufacturing of dry-ice for refrigerated transports. All of thesetechnologies currently have a sufficiently high degree of technical maturity to be installedalready today. Other CCU techniques, such as "’Power to gas”, require a high CO2 concentrationand were discarded as the literature review did not suggest the economic potential forthem as they require additional CO2 upgrading steps. Instead, CCU techniques were chosenthat could be implemented directly with the existing CO2 quality. Furthermore, it was concludedthat one reason why CCU technologies have not been widely implemented is internalbarriers between distributors and manufacturers (or users) of CCU technologies. Thus, theuse of carbon dioxide from biogas production and implementation of CCU technologies canbe promoted by eliminating barriers in companies, such as a lack of both knowledge andfinancial incentives. / Koldioxid från biogasproduktion betraktas i dagsläget som utan värde och släpps ut i atmosfärenvid uppgradering av biogas. Restgasen är en potentiell kolkälla och kan vara värdeskapandeför biogasprocessen. Genom att finna en lämplig värdeskapande process som utnyttjarkoldioxid går det att ge både ekonomiska och miljömässiga incitament till företag att utvecklasin verksamhet. I detta projekt undersöktes möjligheten att skapa värde av denna CO2.Genom en utvärdering av den tekniska mognadsgraden hos CCU-tekniker kunde en rekommendationges vid projektets slut. En analys av tekniska hinder, såsom föroreningar i gassammansättningen,såväl som hinder i form av kompetens och företagskultur undersöktes för attkunna ge en motiverad rekommendation. I projektet kartlades vilka värdeskapande systemsom skulle passa för biogasproducenter i en svensk kontext. Detta inkluderade etableradeuppgraderingstekniker för metan- och koldioxid som används i dagsläget. I projektet undersöktesäven lämpliga CCU-tekniker som kan samverka med de valda uppgraderingsprocessernaoch och agera värdeskapande. Utifrån denna kartläggning kunde det sedan anges vilkagemensamma, kritiska variabler som finns för dessa system. Därefter kunde en rekommendationav lämplig CCU-teknik ges beroende på den producerade CO2 sammansättningen. Enslutsats i projektet var att koldioxid från restgasen ofta var av hög koncentration (ca. 97-98 %)och ej innehöll några korrosiva eller toxiska komponenter, och att detta till stor del beror påhur rötkammaren är hanterad i produktionsprocessen. Således väcktes frågor kring vilka defaktiska begränsningarna för CCU är, då de inte torde vara tekniska. CCU-tekniker som visadesig vara av särskilt intresse var pH-reglering av avloppsverk, CO2 som näringssubstratför odling av mikroalger, samt tillverkning av kolsyreis för kyltransporter. Samtliga dessatekniker har tillräckligt hög teknisk mognadsgrad för att kunna installeras i dagsläget. AndraCCU-tekniker, såsom ”Power to gas”, kräver en hög CO2-koncentration och avfärdades dålitteraturstudien inte talade för den ekonomiska potentialen i dessa eftersom de kräver ytterligareuppgraderingssteg för CO2. Således valdes istället CCU-tekniker som skulle gå attimplementera direkt med den befintliga CO2 kvalitén. Vidare drogs slutsatsen att en anledningtill att CCU-tekniker inte har blivit vida implementerade till stor del är interna hindermellan distributörer och tillverkare (eller utnyttjare) av CCU-tekniker. Således kan användandetav koldioxid från biogasproduktion och implementering av CCU-tekniker främjasgenom att eliminera hinder hos företag. I projektet yttrade sig detta som bristande ekonomiskaincitament och okunskap. Ett ökat användande av CCU-tekniker kan också uppnås genomatt införa lagar och regler som begränsar användandet av föråldrade tekniker som drivs avfossila bränslen, och som kan ersättas av klimatvänliga CCU-tekniker.