Over recent years, political, technological, environmental and economic factors have combined to increase interest in distributed energy resources (DER), and flexibility in the power system. As a resource which is both distributed and flexible, flexible demand (FD) can be considered to be particularly of interest. However, due to many facets of its nature, understanding the available flexibility, and potential value of that flexibility, is difficult. Further, understanding the effects of FD exploitation on other multi-energy system actors, given the complex nature of modern liberalised energy systems, complicates the picture further. These factors form material obstructions to the assessment of FD, for example, for the construction of business cases. To address these gaps this thesis first assesses the nature and value of various applicable current and potential markets and charging/incentive regimes, before detailing a novel multi-energy domestic demand simulation model, capable of modelling, in detail, domestic FD resources. Subsequently, a multi-commodity stochastic energy/reserve optimisation model, capable of modelling various DERs and taking into account price signals related to various energy-related commodities and services (including user utility) is specified. The separation of price components for application at different aggregation levels, which is applied in the optimisation model, also informs the described value mapping methodology, which illustrates the impacts of any, particularly demand-side, intervention on the wider multi-energy system. The power of the above detailed contributions are demonstrated through various studies, which show the physical and economic impact of various demand side interventions and of greater market participation by FD resources.

abstract: As the global community raises concerns regarding the ever-increasing urgency of climate change, efforts to explore innovative strategies in the fight against this anthropogenic threat is growing. Along with other greenhouse gas mitigation technologies, Direct Air Capture (DAC) or the technology of removing carbon dioxide directly from the air has received considerable attention. As an emerging technology, the cost of DAC has been the prime focus not only in scientific society but also between entrepreneurs and policymakers. While skeptics are concerned about the high cost and impact of DAC implementation at scales comparable to the magnitude of climate change, industrial practitioners have demonstrated a pragmatic path to cost reduction. Based on the latest advancements in the field, this dissertation investigates the economic feasibility of DAC and its role in future energy systems. With a focus on the economics of carbon capture, this work compares DAC with other carbon capture technologies from a systemic perspective. Moreover, DAC’s major expenses are investigated to highlight critical improvements necessary for commercialization. In this dissertation, DAC is treated as a backstop mitigation technology that can address carbon dioxide emissions regardless of the source of emission. DAC determines the price of carbon dioxide removal when other mitigation technologies fall short in meeting their goals. The results indicate that DAC, even at its current price, is a reliable backup and is competitive with more mature technologies such as post-combustion capture. To reduce the cost, the most crucial component of a DAC design, i.e., the sorbent material, must be the centerpiece of innovation. In conclusion, DAC demonstrates the potential for not only negative emissions (carbon dioxide removal with the purpose of addressing past emissions), but also for addressing today’s emissions. The results emphasize that by choosing an effective scale-up strategy, DAC can become sufficiently cheap to play a crucial role in decarbonizing the energy system in the near future. Compared to other large-scale decarbonization strategies, DAC can achieve this goal with the least impact on our existing energy infrastructure. / Dissertation/Thesis / Doctoral Dissertation Sustainable Engineering 2020

The aim of the thesis, which is divided into a theoretical and a practical part, is to describe and analyze the current tendency in a company’s cost management, and suggest a precaution leading to an improvement. The theoretical part compiles the classification of costs, calculations, and tools and processes of cost management. The practical part then describes cost management in the analyzed company. Both vertical and horizontal financial analysis are rendered – from the analyses, precautions are defined, as well as cost items, which are suggested to be paid attention to.

Social media has been idealised as a valuable tool for supporting democratic change, with digital advocates and international development organisations encouraging the mass adoption of internet-based technology to assist in giving voice to citizens, as a central constituent of the democratisation process. However, it is evident that many fragile states experience challenges posed by digital transitions. This thesis examines how digital transformation as a social process has affected the social cohesion and development of Myanmar. It further examines if the ‘Free Basics’ initiative played a role in the rapid digital transformation of Myanmar, and if there were ensuing effects on the social cohesion of the country. It also examines the role of social media in amplifying ‘voice’, and further analyses what voices are heard within the discourse. The comprehensive literature review, discourse analysis, and insight gained from interviewing a Rohingya community leader suggest that Myanmar underwent an extraordinarily rapid digital transformation which impacted the way information, socio-political events and national identity were mediated, created, and disseminated. This research demonstrates that social media did play a role in amplifying voice, which had been heralded by techno-optimists as a beacon of hope in democratisation. However, the platform amplified voices regardless of their veracity or potential to incite controversies, which led to a cataclysmic fuelling of existing ethnic tensions, and subsequently translated into an act of genocide being committed against the Rohingya population.

Solar Tower Power Plants with thermal energy storage are a promising technology for dispatchable renewable energy in the near future. Storage integration makes possible to shift the electricity production to more profitable peak hours. Usually two tanks are used to store cold and hot fluids, but this means both higher related investment costs and difficulties during the operation of the variable volume tanks. Another solution can be a single tank thermocline storage in a multi-layered configuration. In such tank both latent and sensible fillers are employed to decrease the related cost by up to 30% and maintain high efficiencies.  The Master thesis hereby presented describes the modelling and implementation of a thermocline-like multi-layered single tank storage in a STPP. The research work presents a comprehensive methodology to determine under which market structures such devices can outperform the more conventional two tank storage systems. As a first step the single tank is modelled by means of differential energy conservation equations. Secondly the tank geometrical design parameters and materials are taken accordingly with the applications taken into consideration. Both the steady state and dynamic models have been implemented in an existing techno-economic tool developed in KTH, in the CSP division (DYESOPT). The results show that under current cost estimates and technical limitations the multi-layered solid PCM storage concept is a better solution when peaking operating strategies are desired, as it is the case for the two-tier South African tariff scheme. In this case the IRR of an optimal designed power plant can be decreased by 2.1%. However, if a continuous operation is considered, the technology is not always preferred over the two tank solution, yet is a cheaper alternative with optimized power plants. As a result the obtained LCOE can be decreased by 2.4%.

On an architectural proposal of techno club is demonstrated a stenographic approach in designing based on a phenomenon of electronic subculture. The Klub visitor is participating a ritual under the influence of music and nightlife lead by an ephemeral architecture, tectonic and spatial dramaturgy.

Biomass to Liquids via Fischer-Tropsch synthesis (BTL-FT) is regarded as one of the most promising routes for providing alternative solution to growing demand for energy and environmental protection. In Chapter I, the development and key issues of BTL-FT process (especially Fischer-Tropsch synthesis) were reviewed and identified. In Chapter II, Mo/HZSM-5 catalyst was synthesized using Incipient Wetness Impregnation method and tested in nitrogen rich model bio-syngas. Different operation parameters (temperature, pressure, and GHSV) were tested to investigate their influence on the catalytic performance. Those parameters were found to affect the performance significantly. Liquid samples from conversion were mainly composed of C8 to C10 range hydrocarbons. The catalyst characterization revealed that molybdenum species were well distributed on the catalyst support, while dealumination, agglomeration and coke deposition were observed in spent catalyst. The top layer of the spent catalyst had the most coke deposition. A Three-Dimensionally Ordered Macro-porous (3DOM) Fe based Fischer-Tropsch catalyst was developed using a facile in-situ Nitrate Oxidation-PMMA templating technique in Chapter III. Several techniques (including SEM, BET, TPR, HRTEM, XRD, XPS, and DRIFTS) were combined to characterize the morphology, textural properties and microstructures of 3DOM Fe catalysts at different stages. The effects of bio-syngas composition on carbonaceous species formation, iron phase transformation and catalytic performance were investigated and correlated. A novel hybrid bio-refinery process co-converting biomass and natural gas into liquid fuels via FTS with a CO2 recycle loop was developed, modeled and simulated by using Aspen Plus in Chapter IV. The Aspen Plus model utilized experimental data from the 3DOM Fe catalyst. Economic analysis was performed on different scenarios based on the simulation results to determine profitability of the process. Results indicated that 102.65 t/h gasoline and 22.93 t/h diesel can be produced with the co-processing of 100.00 t/h biomass and 112.3 t/h natural gas using 307.78 t/h of recycled CO2 in the process simulation. The carbon conversion rate was estimated to be 81.23% for the hybrid process. Economic analysis revealed that the process can be profitable when using at least 10.00 t/h biomass and 11.23 t/h natural gas.

With increasing awareness of environmental issues and worldwide requirements for sustainable development, renewable energy technologies with lower environmental impact, especially those having abundant resources like wind and solar energy, attract more attention. Concentrating Solar Power (CSP) is one of the most promising solar energy technologies. Indeed, thermal energy storage (TES) units could be integrated into CSP plants, enhancing their flexibility and capacity factor. However, tower based CSP plants still remain cost intensive. This study evaluates the performance of a 55MWe combined-cycle CSP plant with rock-bed TES located in Sevilla, Spain. Sensitivity analysis has been performed to assess the influence of critical parameters. Furthermore, in order to decrease the costs with increasing efficiency, improved CSP plant schemes have been proposed. In the study, EES, SAM and TRNSYS are used to design and simulate the model from technological perspective, then the capital and operational costs are calculated in MATLAB. For one-year simulation of the designed case, the performance of the plant is determined by the trade-off among several conflicting factors. The study focuses on three key indicators to measure the performance- levelized costs of electricity (LCoE), capital expenditure (CAPEX) and efficiency factor (UF). As long as CAPEX is within the acceptable range, LCoE would be the most concerned one-as low as possible, then followed by UF. Compared to conventional CCGT plant, the proposed combined-cycle tower-based CSP plant, with efficiency of 0.49 and LCoE of 196USD/MWe, enables efficiency improvements, while both CAPEX and LCoE are higher. On the other hand, it has to be noticed that CCGT relies on fuel (natural gas) price, which means higher risks and operational expenditure (OPEX). A sensitivity study is involved varying gas turbine expansion ratio (to vary its outlet temperature and therefore supply power for the bottoming Rankine cycle), size of TES and solar multiple (SM). It can be found that same LCoE and UF could be achieved with lower CAPEX by setting appropriate parameters. The study also introduces two improved CSP plant schemes with sensitivity study. To some extent, the LCoE decreases due to increasing power output and the efficiency of the system simultaneously increases. / Med ökad medvetenhet om miljöfrågor och globala krav på hållbar utveckling lockar förnybar energi teknologi med lägre miljöpåverkan, särskilt de som har stora resurser som vind och solenergi, mer uppmärksamhet. Concentrating Solar Power (CSP) är en av de mest lovande solenergi teknologierna. Faktiskt kan värmeenergi lagringsenheter integreras i CSP-anläggningar, vilket förbättrar deras flexibilitet och kapacitetsfaktor. Träbaserade CSP-anläggningar är dock fortfarande kostnads intensiva. Denna studie utvärderar prestandan för en 55MWe CSP-anläggning med kombinerad cykel med TESsandbädd i Sevilla, Spanien. Känslighetsanalys har utförts för att bedöma påverkan av kritiska parametrar. För att minska kostnaderna med ökad effektivitet har dessutom förbättrade CSP-anläggningsprogram föreslagits. I studien används EES, SAM och TRNSYS för att designa och simulera modellen ur teknologiskt perspektiv, sedan beräknas kapital och driftskostnader i MATLAB. För ett års simulering av det planerade fallet bestäms anläggningens prestanda av bytet mellan flera motstridiga faktorer. Studien fokuserar på tre nyckelindikatorer för att mäta prestandanivå kostnaderna för el (LCoE), investeringar (CAPEX) och effektivitetsfaktor (UF). Så länge CAPEX ligger inom det acceptabla intervallet, skulle LCoE vara den mest bekymrade en så låg som möjligt, följt av UF. Jämfört med konventionell CCGT-anläggning möjliggör den föreslagna träbaserade CSP-anläggningen med kombinerad cykel med effektivitet 0,49 och LCoE på 196USD / MWe effektivitetsförbättringar, medan både CAPEX och LCoE är högre. Å andra sidan måste man notera att CCGT förlitar sig på bränslepriset (naturgas), vilket innebär högre risker och driftsutgifter (OPEX). En känslighetsstudie är involverad med varierande utvidgning förhållande för gasturbin (för att variera dess utloppstemperatur och därmed leverera ström för botten Rankine-cykeln), storlek på TES och sol multipel (SM). Det kan konstateras att samma LCoE och UF skulle kunna uppnås med lägre CAPEX genom att ställa in lämpliga parametrar. Studien introducerar också två förbättrade CSP-anläggningar med känslighetsstudie. I viss utsträckning minskar LCoE på grund av ökad effekt och systemets effektivitet ökar samtidigt.

Rapid growth of digitalization has urged Data Centres (DC) to be more energy efficient by recovering waste heat from server racks that would otherwise be wasted. This techno-economic study is focused on upgrading low temperature waste heat from typical Air-Cooled DC for District Heating Network (DHN) market in Stockholm region. The methodology is carried out by four system configurations that are experimented with different historical electricity data, impacts of climate change with simulated weather data, and variations in DHN temperature as the heat supply scenario development. The results show that DC configuration with combination of both free-cooling and waste heat recovery can foster techno-economic benefits by reducing cooling consumption by 55.6%, compared to DC configuration with free-cooling only; and further lowering Power Usage Effectiveness (PUE) from 1.95 to 1.52. Lifecycle Operational Expenditure (LCO) has also been used as the economic indicator to represent the maximum initial investment that data centre should accept when deciding to recover the waste heat to the DHN. Moreover, the new technical Key Performance Indicators (KPIs) were introduced to support the decision-making in the supply of recovered waste heat to DHN. The electricity price was further identified to have greater impact than the effect of climate change for the overall techno-economic performance. On one specific hand, heat supply with Price-Limit scenario concluded that 40.18% of available waste heat from DC is not profitable should it be injected to DHN in the case of low electricity price. In the case when the electricity price is high, the amount of waste heat not injected to DHN increases to 58.57%. / <p>The thesis defense presentation was held digitally on Zoom on June 19th 2023 at 09.00 CEST</p>

Exploring the use of currant pomace in foods is favourable due to its nutritional profile but also for economic and sustainability aspects. This by-product of fruit juice processing contains in addition to the dominating dietary fibre fraction considerable amounts of fat, protein, and polyphenols that are lost when the pomace is disposed of. Regardless of the intended use, the perishable material must be dried immediately or alternatively preserved. Three processing strategies (A, B, C) with different energy input and impact were outlined and related applications were implemented. The minimal (A) and intensive scenario (B) were examined comprehensively, whereas the complex processing (C) was considered only theoretically. For a prospective use in low-cost products (A), whole dry pomace was ground using various technologies. Ready-to-use powders were obtained by impact milling below 1 mm or simultaneous drying and grinding in a turbo rotor mill. A wide range of applications is possible, especially in baked products. The powder was used to partially replace flour in bread by considering its high water-binding capacity. In the example of wheat bread, 10% flour were simply replaced with pomace and dough handling properties (reduced stickiness) as well as bread quality parameters (lower baking loss, moister crumb) were improved by pre-hydration of the pomace in hot water. To expand the applicability of the pomace in the intensive scenario (B), the seeds were separated prior to milling and the remaining fibre fraction was treated thermomechanically either by planetary ball milling or extrusion cooking. This processing resulted in high fibre material with increased swelling capacity and water solubility. Based on the micronised seedless pomace, sweet creamy spreads were designed as an application example and the effects on rheology and physical stability were characterised. The pomace below 30 μm performed very well in spreads where it decreased oil separation. When it comes to zero-waste concepts, the seeds can be used for oil extraction whereas the stabilising effects of the fibre fraction may also be exploited to counteract sedimentation in aqueous suspensions and emulsions after pressure homogenisation.:1 Motivation 2 Literature review 2.1 Cultivation and processing of currants 2.2 Composition of currant pomace 2.2.1 Dietary fibre 2.2.2 Lipophilic components 2.2.3 Proteins, sugars, and minerals 2.2.4 Polyphenols and antioxidant capacity 2.3 Residues of toxicological importance 2.4 Preservation and comminution of food processing by-products 2.4.1 Drying 2.4.2 Particle size reduction 2.5 Extraction and fractionation of selected pomace components 2.5.1 Soluble and insoluble dietary fibre 2.5.2 Seed oil 2.5.3 Proteins 2.5.4 Anthocyanins 3 Objectives of the thesis 4 Materials and Methods 4.1 Origin of currant pomace 4.2 Processing of pomace 4.2.1 Minimal processing: Drying and milling 4.2.2 Intensive processing: Thermo-mechanical treatment of dried pomace 4.3 Pomace analysis 4.3.1 Proximate composition 4.3.2 Contamination analysis 4.3.3 Physical properties 4.3.4 Techno-functional properties 4.4 Food applications: Preparation and analysis 4.4.1 Preparation of wheat bread 4.4.2 Dough expansion, pH, and rheology 4.4.3 Bread appearance and texture 4.4.4 Preparation of sweet spreads 4.4.5 Spread analysis 4.5 Statistics 5 Results and discussion 5.1 Natural variation of currant pomace composition 5.2 Minimal processing scenario 5.2.1 Preservation of fresh pomace by convection drying 5.2.2 Milling techniques to obtain ready-to-use pomace powder 5.2.3 Hydration properties of pomace powders 5.3 Application of minimally processed pomace powder in wheat bread 5.3.1 Hydration properties and rheology during simulated baking 5.3.2 Changes in dough properties during proofing 5.3.3 Effects on bread characteristics 5.4 Intensive processing scenario 5.4.1 Composition of seedless currant pomace 5.4.2 Impact of HTST-extrusion 5.4.3 Influence of planetary ball milling on particle size 5.4.4 Modified functionality after thermo-mechanical treatments 5.5 Application of intensively processed pomace in fat-based spreads 5.5.1 Wet ball milling in oil-suspension 5.5.2 Rheological properties and physical stability of sweet spreads 5.5.3 Sensory attributes of pomace spreads 5.6 Concepts for the implementation of zero-waste strategies 6 Conclusions Bibliography List of figures List of tables Appendix List of publications / Die Verwertung von Johannisbeertrester in Lebensmitteln bietet sich nicht nur aufgrund seines Nährstoffprofils an, sondern ist auch im Sinne der Nachhaltigkeit und unter wirtschaftlichen Aspekten vorteilhaft. Das bei der Fruchtsaftherstellung anfallende Nebenprodukt besteht überwiegend aus Ballaststoffen sowie nennenswerten Mengen an Fett, Protein und Polyphenolen, welche im Falle einer Entsorgung für die menschliche Ernährung verloren gehen. Ganz unabhängig von der weiteren Nutzung muss der leicht verderbliche Trester zunächst getrocknet oder alternativ haltbar gemacht werden. Es wurden drei Aufarbeitungsstrategien (A, B, C) entworfen, welche sich in Energieaufwand und Intensität unterscheiden. Davon wurden das sogenannte minimale (A) und das intensive Szenario (B) inklusive entsprechender Anwendungen umfassend untersucht, während eine komplexe Verarbeitung (C) nur theoretisch betrachtet wurde. Für den Einsatz in niedrigpreisigen Lebensmitteln wurde getrockneter Trester im Gesamten (A) unter Anwendung verschiedener Technologien vermahlen. Direkt verwendbare Tresterpulver unter 1 mm wurden durch Vermahlung in einer Prallmühle oder mittels Mahltrocknung hergestellt. Es bieten sich eine ganze Reihe von Anwendungen, vor allem im Bereich der Backwaren, an. Unter Berücksichtigung der hohen Wasserbindekapazität erfolgte der Einsatz des Pulvers als Mehlsubstituent in Brot. Im Fall von Weizenbrot konnten 10% Mehl problemlos durch Trester ersetzt werden, wobei die Verarbeitungseigenschaften des Teigs (verminderte Klebrigkeit) und qualitätsbestimmende Broteigenschaften (geringerer Backverlust, feuchtere Krume) durch Vorquellen in heißem Wasser verbessert werden konnten. Um die Einsatzmöglichkeiten des Tresters zu erweitern, wurden im intensiven Verarbeitungsszenario (B) die Samen abgetrennt und die verbleibende Faserfraktion thermo-mechanisch behandelt, zum einen in einer Planetenkugelmühle, zum anderen durch Extrusion. Die intensive Aufarbeitung resultierte in einer ballaststoffreichen Faserfraktion mit erhöhtem Quellvermögen sowie höherer Wasserlöslichkeit. Als Einsatzbeispiel wurden ausgehend von der feinstvermahlenen Faserfraktion süße Streichcremes entwickelt, und die Auswirkungen des Tresters auf Rheologie und physikalische Stabilität charakterisiert. Der Trester unter 30 μm eignete sich hervorragend in der Herstellung von fettreichen Aufstrichen, da die Ölseparation vermindert wurde. Eine möglichst umfassende, reststofffreie Verwertung des Tresters (zero-waste) kann durch Nutzung der Samen zur Ölgewinnung erfolgen, wohingegen die stabilisierenden Eigenschaften der Faserfraktion nach Hochdruckhomogenisierung auch in wässrigen Suspensionen und Emulsionen ausgeschöpft werden könnten.:1 Motivation 2 Literature review 2.1 Cultivation and processing of currants 2.2 Composition of currant pomace 2.2.1 Dietary fibre 2.2.2 Lipophilic components 2.2.3 Proteins, sugars, and minerals 2.2.4 Polyphenols and antioxidant capacity 2.3 Residues of toxicological importance 2.4 Preservation and comminution of food processing by-products 2.4.1 Drying 2.4.2 Particle size reduction 2.5 Extraction and fractionation of selected pomace components 2.5.1 Soluble and insoluble dietary fibre 2.5.2 Seed oil 2.5.3 Proteins 2.5.4 Anthocyanins 3 Objectives of the thesis 4 Materials and Methods 4.1 Origin of currant pomace 4.2 Processing of pomace 4.2.1 Minimal processing: Drying and milling 4.2.2 Intensive processing: Thermo-mechanical treatment of dried pomace 4.3 Pomace analysis 4.3.1 Proximate composition 4.3.2 Contamination analysis 4.3.3 Physical properties 4.3.4 Techno-functional properties 4.4 Food applications: Preparation and analysis 4.4.1 Preparation of wheat bread 4.4.2 Dough expansion, pH, and rheology 4.4.3 Bread appearance and texture 4.4.4 Preparation of sweet spreads 4.4.5 Spread analysis 4.5 Statistics 5 Results and discussion 5.1 Natural variation of currant pomace composition 5.2 Minimal processing scenario 5.2.1 Preservation of fresh pomace by convection drying 5.2.2 Milling techniques to obtain ready-to-use pomace powder 5.2.3 Hydration properties of pomace powders 5.3 Application of minimally processed pomace powder in wheat bread 5.3.1 Hydration properties and rheology during simulated baking 5.3.2 Changes in dough properties during proofing 5.3.3 Effects on bread characteristics 5.4 Intensive processing scenario 5.4.1 Composition of seedless currant pomace 5.4.2 Impact of HTST-extrusion 5.4.3 Influence of planetary ball milling on particle size 5.4.4 Modified functionality after thermo-mechanical treatments 5.5 Application of intensively processed pomace in fat-based spreads 5.5.1 Wet ball milling in oil-suspension 5.5.2 Rheological properties and physical stability of sweet spreads 5.5.3 Sensory attributes of pomace spreads 5.6 Concepts for the implementation of zero-waste strategies 6 Conclusions Bibliography List of figures List of tables Appendix List of publications