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Funding Information: This research has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement (EnergyMatching project number 768766), and J. Gust. Richert foundation in Sweden (grant number: 2020-00586). Funding Information: This research has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement (EnergyMatching project number 768766 ), and J. Gust. Richert foundation in Sweden (grant number: 2020-00586 ). Publisher Copyright: © 2021 The Author(s) Peer-to-peer (P2P) energy sharing among neighboring households is a promising solution to mitigating the difficulties of renewable power (such as solar Photovoltaics (PV)) penetration on the power grid. Until now, there is still a lack of study on the impacts of future climate change on the P2P energy trading performances. The future climate change will cause variances in the renewable energy production and further lead to changes in the economic performances of households with various energy uses and affect the decision making in PV ownership and pricing strategies. Being unaware of these impacts could potentially hinder the P2P energy sharing application in practice. To bridge such knowledge gap, this paper conducts a systematic investigation of the climate change impacts on the energy sharing performance in solar PV power shared communities. The future weather data is generated using the Morphine method, and an agent-based modeling method is used for simulating the energy trading behaviors of households. Four comparative scenarios of different PV ownerships and pricing strategies are designed. The detailed energy trading performances (including the PV power self-sufficiency, cost saving, revenues, and compound annual growth rate) for the four comparative scenarios are analyzed under both the present and future climates and compared. The study results of a building community located in Sweden show that the future climate change is more beneficial to large energy use households while less beneficial to small households. High price of energy trading can improve the fairness of the economic performances in the community, especially when some of the households do not have any PV ownership. This study can help understand the future climate impacts on the energy sharing performances of building communities, which can in turn guide decision making in PV ownership and price setting for different households under the future climate change to facilitate real applications.

This study inspects the effect of tapered headers on pressure drop and flow distribution in a U-type polymeric absorber with novel tapered headers and lens-shaped absorber strings using a validated thermo-hydraulic model. The model results are compared with those obtained from the literature to attain credibility in the flow distribution trend for the U-configuration. A good agreement between the developed discrete model and comparison cases is found. Moreover, in order to examine the efficacy of tapered headers in more detail, different scenarios are treated in terms of header configuration by applying cylindrical geometry in one or both inlet/outlet headers. The outcomes exemplify that even a slight cone angle of 1.73 degrees in headers can significantly reduce non-uniformity (phi(max) < 8%) with negligible influence on the total pressured drop. Yet, further reduction in maldistribution (phi(max) < 5%) can be achieved in U-type absorbers if the tapered outlet header is combined with a cylindrical inlet header in the range of AR

The pulp and paper industry is the most energy intensive industry in Sweden. Most of the energy usedaims to supply the large amount of heat to the production processes that is required to produce pulp andpaper . By increasing the energy efficiency of paper mills, there is great potential to reduce productioncosts and reduce its environmental impact. This project involves mapping, analyzing and investigation ofmeasures that can contribute to increased thermal efficiency of an internal heating network at Holmen’spaper mill, Braviken. The heating network, called VVG, utilises excess heat from the pulp and paperproduction and supplies heat to production processes and premises at the factory. When the heat demandof the VVG-system exceeds the available recovered heat, heat from live steam is transferred. This projectaim at identifying measures with potential to reduce demand of live steam supply. The project started bymapping the entire VVG-system to identify which consumers are included and how it is connected. Thenthe consumers were studied and data was collected to determine their power and energy demands. Basedon the mapping and collected data, proposals for measures that have the potential to increase thermalenergy efficiency were noted which in turn can reduce the need for live steam supply. The measures havebeen focused on reducing the return temperature of the VVG-system and reducing the heat demand of thesystem. Reduced return temperatures are achieved by more efficient use of the existing heat flow. Thisleads to increased heat recovery potential which means that more excess heat can be utilised.The proposed measures that were identified as having potential to contribute to reduction of the returntemperatures of the VVG-system are as follow: • Utilising return flows with high flow rates and high temperatures to provide other consumers inVVG with heat. This allows the hot flow to be used instead of going directly into the return line. • Eliminate short circuits in the system where the supply line goes directly into the return line. Thesewere detected in the forms of three-way valves and flows through consumers that were not running. The proposed measures that have been identified as having the potential to contribute to reduction of theheating demand of the VVG are as follows: • Turning off flows passing through consumers that are not in use to reduce unnecessary temperaturedrops which will result in decreased power losses. • Preheating via residual flows at consumers where raw water tempered circuits is heated. As theraw water is cold during large parts of the year, a lot of heat can be saved by preheating it with aflow of lower energy quality than VVG. • Shut down the VVG flow through heat exchangers in the heat recovery system when the heatrecovery process not are running to avoid negative heat transfer. By implementing these measures, large improvements regarding the thermal efficiency of the VVG-system can be achieved at Holmen Paper Braviken. How much the return temperatures decrease and howmuch the heat recovery potential increases with the proposed measures has not been quantified during thisproject. However, the measures aimed at lowering the heat demand in the VVG-system can be quantifiedto contribute to an predicted energy saving of at least 2.8 GWh annually, but the investigations of themeasures indicates that significantly larger energy savings can be achieved. To ensure the potential of theproposed measures to contribute to the reduction of the demand for live steam supply, Holmen needs tocarry out further studies of the VVG system where this work is intended to form the basis for their furtherwork.

Cities are responsible for around 75% of global primary energy use and 70% of global greenhouse gas (GHG) emissions, with buildings and urban mobility being two key contributors. Actions to reduce GHG emissions have been promoted and implemented in many countries in the world. These include switching to electric vehicles (EVs) and renewable energy sources (RES), such as solar photovoltaics (PV). The transition has led to rapid increase in EV and PV adoption worldwide in the recent decades. However, large-scale integration of EVs and PV in urban energy systems poses new challenges such as increased peak loads, power mismatch, component overloading, and voltage violations. Improved synergy between EVs, PV and other loads can overcome these challenges. Coordinated charging of EVs, or so-called EV smart charging, is potentially a promising solution to improve the synergy. The synergy can be further enhanced with vehicle-to-grid (V2G) schemes, where an EV can not only charge, but also discharge power from its battery. This doctoral thesis investigates the synergy between EV charging and PV power generation with the application of EV smart charging and V2G schemes. The investigation was carried out through simulation studies on the system levels of residential buildings, workplaces, distribution grid, and city-scale. Smart charging and V2G optimization models with an objective to reduce the net-load (load minus generation) variability were developed and simulated. The results show that the PV-EV synergy can be improved with the proposed smart charging schemes. However, the levels of improvement depend highly on the user mobility behavior from and to the destined charging locations. PV-EV synergy is limited in residential buildings due to low EV occupancy during high solar power production, but has high potential at workplace charging stations due to high EV occupancy during the same time. In the case studies presented in this thesis, it was found that the implementation of smart charging can improve the synergy by up to around 9 percentage points in residential buildings and up to around 40 percentage points in workplaces. On a city-scale level, both optimal sizing and V2G play essential roles in improving city-scale generation-load synergy, as they can increase the load matching from 33% to 84%. The results also show that improved synergy leads to enhanced power grid performance and combined PV-EV grid hosting capacity. In conclusion, the thesis demonstrates that EV smart charging schemes can improve PV-EV synergy, leading to enhanced performance of urban energy systems.

Throughout history, major rivers and shared water bodies have allowed civilizations to flourish, and the effective management of shared water bodies has always been a priority for societies and nations. Today, about 40% of the world’s population lives in proximity to the 286 transboundary river and lake basins that supply 60% of the world’s freshwater flows and make up about half of the Earth’s land area. Moreover, around 2 billion people in the world depend on groundwater sources, which include over 460 transboundary aquifer systems. The mismanagement of water resources can result in catastrophic disasters that are often exacerbated by a domino effect so that the impacts of poor water management often extend beyond the water system. The interdependency of the water system with other systems such as energy and food, or with land-use, highlights the importance of ”systems thinking and planning” in resource management. Such a concept is not easily encapsulated into policy-making processes in many parts of the world because consideration of the resource systems in isolation as individual entities and ‘silo” thinking still dominate. Climate change adds another layer of complexity and exacerbates the issue of water management. Another important factor is geographical location because precipitation varies among and within continents. This results in some regions suffering from water shortages and some regions facing the risks of water redundancy and floods. The concept of the Water-Energy-Food (WEF) nexus was introduced in 2011 as a response to help address some of the issues mentioned above. Over the last decade, research on the WEF nexus has gained momentum in both the policy and academic areas and several methods have been introduced to operationalize the nexus in different contexts. One of the flagship methodologies is the Transboundary Basins Nexus Approach (TBNA) introduced by the United Nations Economic Commission of Europe (UNECE) in 2015 and designed to assess the nexus in shared (transboundary) water basins. The aim of this thesis is to support shared water management by using the WEF-nexus approach to quantify the benefits of coordinated management, motivate cooperation, and identify trade-offs in the optimal use of resources. To achieve this aim, four research questions are explored over the course of four academic publications. The first question explores the role of the energy sector in motivating shared water cooperation. The second question studies the risks and opportunities emerging from the interplay between climate and renewable energy in shared basins. The third question focuses on groundwater management and explores what benefits the consideration of the energy-water-agriculture nexus could bring to shared groundwater management in water-scarce areas. The fourth question examines how consideration of the energy-water-agriculture nexus could accelerate the low-carbon transition in the agricultural sector. These research questions are examined in two different, yet complementing, geographic locations. One is the Balkans in Southeastern Europe, which faces water redundancy and flood issues and the other is the Middle East and North Africa (MENA) region which suffers from water scarcity. In the first region, the Drina and the Drin River Basins represent the characteristics of Southeastern Europe while the North Western Sahara Aquifer System (NWSAS) and the Souss-Massa basin represent the characteristics of the MENA region. Three of the case applications are transboundary (Drina, Drin and NWSAS) while the last application (Souss-Massa Basin) is a subnational basin. Historiskt har stora floder och delade vattendrag gjort det möjligt för civilisationer att blomstra. Att effektivt hantera delade vattenresurser har alltid varit och är en prioritet för samhällen och nationer. Idag bor cirka 40 % av världens befolkning i nära anslutning till någon av de 286 internationella floder och sjöar som är just delade vattendrag. De försörjer 60 % av världens sötvatten och utgör ungefär hälften av jordens yta. Vidare är omkring 2 miljarder människor i världen beroende av grundvattenkällor, som inkluderar över 460 gränsöverskridande akvifera system. Dålig vattenförvaltning kan leda till katastrofala följder med efterföljande dominoeffekt där dålig vattenförvaltning inte bara påverkar vattensystemet, utan även andra relaterade system så som energi, mat och markanvändning. Vattensystemets ömsesidiga beroende av andra system understryker vikten av "systemtänkande och planering" i resurshantering. I många delar av världen domineras dock policyprocesserna av att se resurssystemen som isolerade individuella enheter, ett så kallat "silo"-tänkande. Klimatförändringarna lägger till ytterligare ett lager av komplexitet till frågan om vattenförvaltning. Det geografiska läget har också betydelse eftersom den globala nederbörden varierar mellan och inom kontinenter. Detta resulterar i att vissa regioner lider av vattenbrist och andra riskerar att få vattenöverflöd och bli översvämmade. Konceptet vatten-energi-mat (WEF)-nexus introducerades 2011 som en lösning för att hjälpa till att ta itu med några av de ovan nämnda problemen. Forskningen kring WEF-nexus tog fart under det efterföljande decenniet, både inom politiska och akademiska arenor, och flera metoder introducerades för att göra nexus användbart i olika sammanhang. En av flaggskeppsmetoderna är Transboundary Bassins Nexus Approach (TBNA) som introducerades av FN:s ekonomiska kommission för Europa (UNECE) 2015 och är utformad för att förstå och utvärdera delade (gränsöverskridande) vattenavrinningsområde. Denna avhandling syftar till att stödja delad (gränsöverskridande) vattenförvaltning genom att använda WEF-nexus-metoden till att kvantifiera fördelarna med samordnad förvaltning, motivera samarbete samt identifiera avvägningar i optimal användning av resurser. Detta undersöks genom fyra forskningsfrågor och redovisas i fyra publikationer. Den första frågan utforskar energisektorns roll i att motivera delad vattenförvaltning och vilka insikter som kan erhållas från modeller med öppen källkod. Den andra frågan studerar riskerna och möjligheterna av samspelet mellan klimat och förnybar energi i delade vattenavrinningsområden. Den tredje frågan fokuserar på grundvattenhantering och undersöker vilka fördelar systemtänkande kring energi-vatten-jordbruk kan ge till delad grundvattenhantering i områden med vattenbrist. Den fjärde frågan undersöker hur hänsynstagandet till sambandet energi-vatten-jordbruk kan påskynda omställningen med låga koldioxidutsläpp inom jordbrukssektorn. Dessa forskningsfrågor undersöks på två olika, men kompletterande, geografiska platser. Den ena är Balkanregionen i sydöstra Europa, som står inför översvämningsproblem, och den andra är Mellanöstern- och Nordafrika-regionen (MENA) som lider av vattenbrist. I den första regionen representerar floderna Drina och Drin några av särdragen för sydöstra Europa, medan North Western Sahara Aquifer System (NWSAS) och Souss-Massa-vattenavrinningsområde representerar särdrag i MENA-regionen. Tre av fallstudierna är gränsöverskridande (Drina, Drin och NWSAS) medan den sista studien (Souss-Massa Basin) är ett nationellt vattenavrinningsområde. لعبت الأنهار الرئيسية والمسطحات المائية المشتركة دورا محوريا في ازدهار الحضارات على مر التاريخ ، وشكلت الإدارة الفاعلة للمسطحات المائية المشتركة أولوية كبرى للأمم والمجتمعات، وفي الوقت الراهن يعيش حوالي 40٪ من سكان العالم بالقرب من أحواض الأنهار و البحيرات العابرة للحدود البالغ عددها 286 حوضا مشتركا، والتي تغطي حوالي نصف مساحة اليابسة وتشكل المصدر الرئيسي لـ 60٪ من تدفقات المياه العذبة في العالم. علاوة على ذلك، يعتمد حوالي 2 مليار نسمة في العالم على مصادر المياه الجوفية النابعة من 460 نظامًا لطبقات المياه الجوفية العابرة للحدود. إن سوء إدارة الموارد المائية يمكن أن يؤدي إلى كوارث متعددة الأبعاد غالبًا ما تتجاوز منظومة المياه، كما أن الترابط بين النظام المائي والأنظمة الأخرى مثل الطاقة والغذاء (أو استخدام الأراضي) يسلط الضوء على أهمية "التفكير والتخطيط النظمي" في إدارة الموارد، وهو مفهوم لا يمكن ترجمته بسهولة في عملية صنع السياسات في أجزاء كثيرة من العالم، حيث لا يزال التفكير والتخطيط الأحادي والمنعزل لأنظمة الموارد هو المسيطر. التغير المناخي يضيف بدوره مستوى آخر من التعقيد ويفاقم من أزمة إدارة المياه، والعامل الأخر المهم هو الموقع الجغرافي حيث تتباين مستويات هطول الأمطار بين القارات وفي داخلها، مما انعكس على تباين تحديات المياه حول العالم، ففي حين نجد بعض المناطق تعاني من شح الموارد المائية، نجد مناطق أخرى تعاني من مخاطر وفرة المياه والفيضانات. ظهر مفهوم "الترابط بين المياه والطاقة والغذاء (WEF-nexus)" في عام 2011م كمساهمة في معالجة بعض القضايا المذكورة أعلاه، وخلال العقد الماضي اكتسب البحث حول "الترابط بين الماء والطاقة والغذاء" زخمًا كبيرا في المجال الأكاديمي وكذلك في مجال صنع السياسات التنموية، وتم ابتكار العديد من النماذج التطبيقية لاسقاط مفهوم التفكير الترابطي بين الموارد على أرض الواقع وتطبيقه في سياقات مختلفة، إحدى المنهجيات الرئيسية هي منهجية الترابط في الأحواض العابرة للحدود (TBNA)، والتي ابتكرتها اللجنة الاقتصادية لأوروبا التابعة للأمم المتحدة (UNECE) في عام 2015 لتقييم الترابط بين الموارد في أحواض المياه المشتركة (العابرة للحدود). تهدف هذه الأطروحة إلى دعم إدارة المياه المشتركة باستخدام نهج "الترابط بين المياه والطاقة والغذاء WEF-nexus" وذلك من خلال الدراسة الكمية لفوائد الإدارة التكاملية للموارد، وتحفيز التعاون بين الشركاء، ودراسة التبعات أوالمقايضات في الاستخدام الأمثل للموارد، ولتحقيق هذا الهدف؛ تمت دراسة أربعة أسئلة بحثية عبر أربعة أبحاث علمية محكمة. يبحث السؤال الأول دور قطاع الطاقة في تحفيز التعاون في مجال المياه المشتركة، في حين يبحث السؤال الثاني المخاطر والفرص الناتجة من التفاعل بين المناخ ومصادر الطاقة المتجددة في الأحواض المشتركة، أما السؤال الثالث فيركز على إدارة المياه الجوفية ويستكشف الفوائد التي يمكن أن تجلبها دراسة "الترابط بين الطاقة والمياه والزراعة" في إدارة المياه الجوفية المشتركة وبالأخص في المناطق التي تعاني من شح الموارد المائية، أما السؤال الرابع فيدور حول كيف يمكن للتخطيط الترابطي بين موارد الطاقة والمياه والزراعة أن يساهم في تسريع التحول الى قطاع زراعي منخفض الكربون. يتم دراسة هذه الأسئلة البحثية في بيئتين جغرافيتين مختلفتين لكن متكاملتين؛ الأولى هي منطقة البلقان في جنوب شرق أوروبا، والتي تواجه مشكلات وفرة المياه والفيضانات، أما الثانية فهي منطقة الشرق الأوسط وشمال إفريقيا (MENA) والتي تعاني من ندرة المياه، وتمثل أحواض نهري "درينا" و "درين" خصائص المنطقة الأولى في جنوب شرق أوروبا، بينما يمثل نظام المياه الجوفية في شمال الصحراء الغربية (NWSAS) وحوض سوس-ماسة خصائص منطقة الشرق الأوسط وشمال إفريقيا، وللتنويه فإن ثلاثة من الأحواض المشتركة هي أحواض عابرة للحدود (درينا ودرين و NWSAS) بينما حوض سوس ماسة هو عبارة عن حوض محلي (يقع ضمن حدود المملكة المغربية).

The growing urgency of climate change has led to growth in the electrification technology field, where batteries have emerged as an essential role in the renewable energy transition, supporting the implementation of environmentally friendly technologies such as smart grids, energy storage systems, and electric vehicles. Battery cell degradation is a common occurrence indicating battery usage. Optimizing lithium-ion battery degradation during operation benefits the prediction of future degradation, minimizing the degradation mechanisms that result in power fade and capacity fade. This degree project aims to investigate battery degradation prediction based on capacity using deep learning methods. Through analysis of battery degradation and health prediction for lithium-ion cells using non-destructive techniques. Such as electrochemical impedance spectroscopy obtaining ECM and three different deep learning models using multi-channel data. Additionally, the AI models were designed and developed using multi-channel data and evaluated performance within MATLAB. The results reveal an increased resistance from EIS measurements as an indicator of ongoing battery aging processes such as loss o active materials, solid-electrolyte interphase thickening, and lithium plating. The AI models demonstrate accurate capacity estimation, with the LSTM model revealing exceptional performance based on the model evaluation with RMSE. These findings highlight the importance of carefully managing battery charging processes and considering factors contributing to degradation. Understanding degradation mechanisms enables the development of strategies to mitigate aging processes and extend battery lifespan, ultimately leading to improved performance.

Parabolic trough collectors (P.T.Cs) are efficient solar energy harvesting devices utilized in various industries, for instance, space heating, solar cooling, solar drying, pasteurization, sterilization, electricity generation, process heat, solar cooking, and many other applications. However, their usage is limited as the high capital and operating costs; according to the International Renewable Energy Agency's 2020 report, the global weighted average levelized cost of electricity (L.C.O.E) for P.T.Cs was 0.185 $/kWh in 2018. This work analyses the economic, technical, and environmental potential of sustainable energy to increase the use of P.T.Cs in different sectors. To study how self-weight, heat loss, and wind velocity affect P.T.C performance, prototype testing, and wind flow analysis were used. Although P.T.Cs outperform in capacity factor, gross-to-net conversion, and annual energy production, improving their overall efficiency is crucial in reducing total energy production costs. Wire coils, discs, and twisted tape-type inserts can enhance their performance by increasing turbulence and heat transfer area. Improving the system's overall efficiency by enhancing the functioning and operation of individual components will also help decrease total energy production costs. The aim is to minimize the L.C.O.E associated with a P.T.C in order to enhance its economic viability for an extended period. When the nanofluid-oriented P.T.C was included in the conventional P.T.C workings, there was a decrease in the L.C.O.E by 1%. Of all the technologies available, ocean, geothermal, and C.S.P parabolic trough plants generate lower amounts of waste and harmful gases, with average emissions of 2.39%, 2.23%, and 2.16%, respectively, throughout their lifespan. For solar-only and non-hybrid thermal energy storage plants, the range of greenhouse gas emissions is between 20 and 34 kgCO2 equivalents per megawatt-hour. Coal, natural gas steam turbines, nuclear power plants, bioenergy, solar PV, geothermal, concentrated solar power, hydropower reservoir, hydropower river, ocean, and wind power plants all release greenhouse gases at rates of 1022, 587.5, 110.5, 633, 111, 48, 41, 82.5, 7.5, 12.5, and 41.5 gCO2-e/kWh, respectively. This information is useful to compare the environmental effect of various energy sources and help us to choose cleaner, more sustainable options for the production of electricity. The ongoing advancements and future scope of P.T.Cs could potentially make them more economically viable for domestic, commercial, and industrial applications.

The construction sector is responsible for 20% of Greenhouse Gas (GHG) emissions, of whichdiesel-powered construction equipment are large contributors. Currently there are many ongoing Fuel Cell (FC) powered construction equipment projects as it is seen as an attractiveoption to power the futures zero-emission heavy-duty machines. Although an attractivealternative, hydrogen FC has drawbacks such as releasing liquid water and water vapor viathe exhaust as a byproduct which in their working environment can cause a suite of issues. Agap in the literature on the water exhausted is present and therefore this degree project seeksto investigate the amount, and ratio, of liquid water and water vapor released from threetypical construction equipment drive cycles which would allow further investigation onappropriate management. The method used for this degree project was to modify a pre-mademodel in Simulink built with Simscape blocks. The model was modified to represent a FCsystem used in a test-rig by implementing experimental and measured data for design andoperating parameters. Different pressures, temperatures, and cathode inlet RelativeHumidity (RH) were investigated to find their effect on the performance and water in theexhaust. A sensitivity analysis of different unknown parameters was also conducted tounderstand their influence on the results. For the reference case, the results showed that foran articulated hauler, the water in the exhaust was 26% liquid which translates to 8.6 kg for a1-hour drive cycle. The crawler excavator and wheel loader, both had 30-minute drive cyclesand had 1.1 kg liquid water with a liquid water ratio of 7% and 0.7 kg liquid water with aliquid water ratio of 5% in the exhaust respectively. For a full 8-hour workday with twoparallel FCs connected, the articulated hauler liquid water amount is 137.6 kg, the crawlerexcavator 35.2 kg, and the wheel loader 22.4 kg. Overall, it was found the liquid water ratiocould be changed to a large extent with different operating parameters, where thetemperature had the greatest influence. The system and stack efficiencies did not changeconsiderably with different operating parameters, meaning that the total water in the exhaustremained similar for the different respective drive cycles.

Energy storage solutions for grid applications are becoming more common among grid owners, system operators and end-users. Storage systems are enablers of several possibilities and may provide efficient solutions to e.g., energy balancing, ancillary services as well as deferral of infrastructure investments. To ensure that an energy storage investment is guaranteed a reasonable payback period and a good return of investment it is advantageous to consider the possibility of service stacking. By offering additional services in turns or in parallel with the main service it is possible to create important revenue streams. The aim of this review is to provide an up-to-date status of service stacking using grid connected energy storage systems by presenting current research and on-the-table ideas. Results from the review show that frequency regulation services are the most common services to offer together with energy arbitrage and integration of renewable energy sources. The results also show that it is strategically favorable to offer additional services for storage units which are used seasonally or with low frequency. It can be concluded that service stacking is a promising method to implement for storage operators to increase the degree of utilization of storage units. It may also be concluded that the increased need for ancillary services increases the opportunity for storage units to participate in markets for energy and ancillary services. Future studies could focus on the correlation between service stacking possibilities and actual placement of the storage, and how hybrid storage configurations would affect the potential of service stacking.

The overall performance of a hydrogen storage system can be affected by various parameters, such as operation and design parameters, but also by the state of the hydrogen contained inside the storage tanks. In this work, a methodology is developed to evaluate the state of the hydrogen during the filling process and its impact on the overall system performance under variable operation conditions and design parameters. To approach as close as possible hydrogen as real gas, the thermodynamic properties of it are obtained from experimental thermodynamic tables. Based on those thermodynamic tables, a discrete database for each thermodynamic property is constructed. To minimize the error and achieve acceptable execution time, a searching method based on curve fitting techniques is developed to derive the thermodynamic properties from the discretized data. The evaluation of the hydrogen state is done based on a developed method that derives the pressure and temperature based on calculated thermodynamic properties during the filling process. The interaction between the contained hydrogen and tank during the filling process is taken into account during the methodology development. Furthermore, energy requirements for the compression system of the hydrogen storage system, including the cooling demand, are also included in the methodology. Based on the developed methodology, a transient model that can evaluate the hydrogen state condition, storage tank wall temperature condition, and energy requirement of the storage system is developed. Validation against experimental and simulation results for an actual filling event of a hydrogen storage tank is done, showing good agreement in the results. The model was used to simulate the performance of a hydrogen storage system, inspired in terms of layout by a real-world HRS storage system. The results showed that the total amount of filled hydrogen and the filling duration of the charging process are greatly affected by the compression and heat transfer phenomena occurring inside the tank. The storage tanks with lower volumes and higher operation pressure tend to be more affected by compression and heat transfer phenomena. Operation parameters such as inlet mass flow and inlet temperature, can have an impact on the system, both in terms of energy consumption and filling performance. Furthermore, based on the investigation of compression stages, the results showed that the number of stages can affect the compression ratio of each stage, resulting in lower or higher efficiency, which directly affects the energy consumption of the compression system. A parametric investigation of the upper operation pressures of the hydrogen tanks showed that the total amount of stored hydrogen is affected when the respective upper pressures vary. Last, it was shown that there is an optimal upper pressure level for each bank that can result in lower specific compression energy, indicating that the model could be used for optimization purposes.

Efficient use of renewable energy is one of the critical measures to achieve carbon neutrality. Countries have introduced policies to put carbon neutrality on the agenda to achieve relatively zero emissions of greenhouse gases and to cope with the crisis brought about by global warming. This work analyzes the wave energy with high energy density and wide distribution based on understanding of various renewable energy sources. This study provides a wave energy prediction model for energy harvesting. At the same time, the Gated Recurrent Unit network (GRU), Bayesian optimization algorithm, and attention mechanism are introduced to improve the model's performance. Bayesian optimization methods are used to optimize hyperparameters throughout the model training, and attention mechanisms are used to assign different weights to features to increase the prediction accuracy. Finally, the 1-hour and 6-hour forecasts are made using the data from China's NJI and BSG observatories, and the system performance is analyzed. The results show that, compared with mainstream prediction algorithms, GRU based on Bayesian optimization and attention mechanism has the highest prediction accuracy, with the lowest MAE of 0.3686 and 0.8204, and the highest R2 of 0.9127 and 0.6436, respectively. Therefore, the prediction model proposed here can provide support and reference for the navigation of ships powered by wave energy. Export Date: 29 December 2022; Article; CODEN: APEND; 通讯地址: Lv, Z.; Extended Energy Big Data and Strategy Research Center, China; 电子邮件: lvzhihan@gmail.com; 基金资助详情: SKLMCPTS202103011; 基金资助详情: National Natural Science Foundation of China, NSFC, 61902203; 基金资助文本 1: Funding: This work was supported by the National Natural Science Foundation of China [grant number 61902203 ]; the open project of the Xinhua News Agency State Key Laboratory of Media Convergence Production Technology and System [grant number SKLMCPTS202103011 ].; 参考文献: Zhou, J., Zhang, Y., Zhang, Y., Parameters identification of photovoltaic models using a differential evolution algorithm based on elite and obsolete dynamic learning[J] (2022) Appl Energy, 314; Bi, H., Shang, W.L., Chen, Y., GIS aided sustainable urban road management with a unifying queueing and neural network model[J] (2021) Appl Energy, 291; Von Wald, G., Sundar, K., Sherwin, E., Optimal gas-electric energy system decarbonization planning[J] (2022) Adv Appl Energy, 6; 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The study explores the techno-economic feasibility and viability of a Photovoltaic-Diesel Hybrid system for rural electrification in sub-Sahara Africa with a case study of Chilubi island, a remote district without access to electricity in the Northern Province of Zambia. Using HOMER (Hybrid Optimization of Multiple Electric Renewables) Pro software, the best and most feasible technical solutions through different hybrid system configurations, combinations and the district's rate of access to electricity were considered based on the least Levelized Cost of Energy (LCoE) and life cycle costs of the project. The results show that operating diesel generators as stand-alone is not economically sustainable and has a high LCoE. Influencing factors include variability in diesel pump prices, high fuel transportation costs, high cost of operation and maintenance, among other factors of concern. 100% photovoltaic (PV) with a battery system gave the lowest LCoE. However, the initial capital cost of solar energy projects in Zambia is relatively high compared to the equivalent diesel-based plants, as shown herein. It explains why diesel power plants are favoured for off-grid settlements. On the hand, the low operational cost and LCoE of PV power plants favour rural districts as they offset the high initial capital costs. Additionally, the continued downward trend in the cost of PV installations per kWp has opened discussions among policymakers and energy planners in Zambia to favour rural electrification with renewable energy-based power generation. This study contributes to this discussion. Validerad;2023;Nivå 2;2023-01-01 (joosat);Licens full text: CC BY License

Large shares of variable renewable electricity (VRE) generation increase the demand for flexible power balancing capacities for handling power surpluses and deficits. Within district heating (DH) production systems, electricity can be produced in combined heat and power (CHP) plants but also consumed in heat pumps, and thus contribute with balancing capacity. However, this power balancing potential in DH production units is limited by heat load variations. To improve the potential, large-scale thermal energy storage (TES) can be used to increase heat-load flexibility. This study investigates the power balancing capacity of 85 existing Swedish DH systems, with hypothetical access to rock cavern oil depots assumed to have been converted into TES units. In the study, the Swedish power load is assumed to be covered by 60 % wind and 10 % solar power. The results show that Swedish DH systems, on a national scale, could reduce power deficits and surpluses by approximately 9 % respectively. There will be competition between heat pumps and CHP units for DH load supply while providing power balancing services. The use of heat pumps could also, on national level, yield a reduced fuel use in DH production by about 10 % when compared to conventional DH system operation. The study highlights the impact the temporal distribution and annual shares of VRE surpluses and deficits have on the fuel use.

The purpose of this work is to explore the role of the safe and optimal scheduling of thermal energy storage systems in intelligent buildings in promoting sustainable economic development under Digital Twins (DTs) technology. Phase Change Material (PCM) has high energy density, constant temperature storage, small footprint, and long service life. Here, PCM is first placed in the indoor building structure, and the DTs technology is introduced. In the development of intelligent buildings, the data generated by the energy storage system of intelligent buildings in the real space can be mapped to the virtual space in real time for simultaneous analysis. In addition, the PCM wall structure and thermal network DTs model are designed for the intelligent building. In addition, the PCW structure is used to build a thermal energy storage and dispatch model of the smart thermoelectric building based on DTs. Finally, the model is evaluated and analyzed experimentally. The analysis of system optimization power under different schemes indicates that the scheduling operation strategy of thermal energy storage of building walls can avoid overcharging or over-discharging batteries in the microgrid and reduce battery power consumption. Besides, the building wall energy storage capacity is always in the range of 0.2 ∼ 0.8 on the all-weather scale. Moreover, the model constructed here achieves significantly lower economic costs, environmental costs, and energy costs and a better energy-saving effect than the existing model. The model built here can serve as experimental reference for further digital energy storage in intelligent buildings and comprehensive energy utilization because of its superior safety performance and lower consumption.

Anaerobic digestion (AD) is an environmentally friendly process for recovering low-carbon energy from the breakdown of organic substrates. In recent years, AD has undergone a major paradigm shift, and now the technology is not only considered as a “waste treatment” method and is instead viewed as a key enabler of the future “circular economy” with its potential for resource recovery (low-carbon energy, safe water, and nutrients). Currently, waste-derived biogas from AD is the most affordable and scalable source of renewable energy. Biomethane (upgraded biogas) can serve as a significant renewable and dispatchable energy source for combating the problem of global warming. Acidogenesis, an intermediate step of AD, can produce molecular hydrogen (H2) along with green chemicals/platform chemicals. The use of low-carbon hydrogen as a clean energy source is on the rise throughout the world, and is currently considered a potential alternative energy source that can contribute to the transition to a carbon-neutral future. In order to determine the future trade routes for hydrogen, nations are developing hydrogen policies, and various agreements. Hydrogen produced by biological routes has been found to be suitable due to its potential as a green energy source that is carbon neutral for the developing “Hydrogen Economy”. Recently, hydrogen blended with methane to a specific proportion and known as biohythane/hydrogen-enriched compressed natural gas (HCNG) has emerged as a promising clean fuel that can substantially contribute to an integrated net-zero energy system. This review provides an overview of the current state of fermentative hydrogen and methane production from biogenic waste/wastewater in a biorefinery approach and its utilization in the context of energy transition. The limitations and economic viability of the process, which are crucial challenges associated with biohydrogen/biomethane production, are discussed, along with its utilization. Validerad;2023;Nivå 2;2023-05-10 (hanlid)

The integration of photovoltaic (PV) systems and electric vehicles (EVs) in the built environment, including at workplaces, has increased significantly in the recent decade and has posed new technical challenges for the power system, such as increased peak loads and component overloading. Several studies show that improved matching between PV generation and EV load through both optimal sizing and operation of PV-EV systems can minimize these challenges. This paper presents an optimal PV-EV sizing framework for workplace solar powered charging stations considering load matching performances. The proposed optimal sizing framework in this study uses a novel score, called self-consumption-sufficiency balance (SCSB), which conveys the balance between self-consumption (SC) and self-sufficiency (SS), based on a similar principle as the F1-score in machine learning. A high SCSB score implies that the system is close to being self-sufficient without exporting or curtailing a large share of local production. The results show that the SCSB performance tends to be higher with a larger combined PV-EV size. In addition to presenting PV-EV optimal sizing at the workplace charging station, this study also assesses a potential SC and SS enhancement with optimal operation through smart charging schemes. The results show that smart charging schemes can significantly improve the load matching performances by up to 42.6 and 40.8 percentage points for SC and SS, respectively. The smart charging scheme will also shift the combined optimal PV-EV sizes. Due to its simplicity and universality, the optimal sizing based on SCSB score proposed in this study can be a benchmark for future studies on optimal sizing of PV-EV system, or distributed generation-load in general. SweGRIDS FPS 26 - Smart charging strategies and optimal PV-EV sizing to increase the combined PV-EV hosting capacity in the distribution grid

Renewable energy sources, such as wind and solar power, are increasingly important today to reduce emissions from fossil-based energy sources. However, the electricity from wind and solar power varies over time and depends on weather conditions and the time of the day. Therefore, to include a large fraction of electricity from these energy sources in the electricity grid, large-scale and low-cost energy storage is needed. Herein, it is investigated how a combination of quantum dot based photovoltaic cells and perovskite-based photovoltaic cells can be used to increase the energy conversion efficiency and increase the working range of energy storage devices based on conversion between heat, light, and electricity. The results show that these new types of photovoltaic materials have very promising properties for efficient utilization in energy storage devices, which have the potential for large-scale and low-cost energy storage.

Sweden aims to achieve climate neutrality by 2045. The need to immediately reduce greenhouse gas emissions in order to achieve climate targets affects industry directly. The pulp and paper sector is responsible for more than 50% of industrial energy use in Sweden. Increased energy efficiency is expected to contribute significantly to the reduction of primary energy use. The recovery and utilisation of industrial excess heat (IEH) has been identified as an important potential contribution to energy efficiency in industry. Previous research based on top-down studies has estimated the availability of IEH for entire sectors, and bottom-up results for many case studies are available. While top-down studies lack detailed information on the profile of the excess heat available, bottom-up studies have limited coverage. Detailed information about excess heat amounts and temperature levels is required for the assessment of the potential of the various heat recovery technologies that are available. The aim of this thesis is to present, in a series of steps, methods to systematically analyse an industrial process to obtain a detailed profile of the excess heat available under various process conditions, to aggregate results that can be generalised to whole industrial sectors, and to obtain IEH recovery potentials using different technologies. The assessment of the utilisation options for IEH recovery is complemented with an analysis of system aspects that could affect profitability and global greenhouse gas (GHG) emissions. An energy-targeting procedure combined with optimisation has been applied to six case studies of kraft pulp and paper mills in Sweden. This method obtained IEH profiles that were used in a regression analysis to estimate the IEH availability and electricity generation potentials from low and medium temperature IEH using organic Rankine cycles (ORC). A comparison of profitability and global GHG emissions between ORC electricity generation using IEH and small-scale combined heat and electricity (CHP) production is presented for three energy markets. The results show that there is a potential to increase electricity generation from low and medium temperature IEH by 7–9% in the kraft mills in Sweden, depending on the level of process integration considered. The utilisation of low and medium temperature IEH for electricity generation has the potential to reduce global GHG emissions in all the energy-market scenarios considered, but if biomass is considered a limited resource, district heating (DH) deliveries can achieve higher global GHG reductions. ORC electricity generation from low and medium temperature IEH is economically viable and showed overall better profitability and GHG emissions reductions than small-scale CHP using ORCs. The economic feasibility of ORC electricity generation is less affected by external conditions and uncertainties than direct DH deliveries. Sverige siktar på att uppnå klimatneutralitet till 2045. Behovet av att omedelbart minska utsläppen av växthusgaser för att nå klimatmålen påverkar industrin direkt. Massa- och papperssektorn står för mer än 50% av den industriella energianvändningen i Sverige. Ökad energieffektivitet förväntas i hög grad bidra till att minska primärenergianvändningen. Återvinning och utnyttjande av industriell överskottsvärme (IÖV) har identifierats som ett betydande potentiellt bidrag till energieffektivitet i industrin. Tidigare forskning baserad på top-down studier har uppskattat tillgängligheten av IÖV för hela sektorer eller regioner, och bottom-up resultat för många fallstudier finns tillgängliga. Medan top-down studier saknar detaljerad information om profilen för tillgänglig överskottsvärme, har bottom-up studier begränsad täckning och precision. Detaljerad information om överskottsvärmemängder och temperaturnivåer krävs för att bedöma potentialen hos flera värmeåtervinningstekniker. Denna avhandling syftar till att i en serie steg presentera metoder för att systematiskt analysera en industriell process för att erhålla en detaljerad profil av tillgänglig överskottsvärme under olika processförhållanden, för att aggregera resultat som kan generaliseras för hela industrisektorer, och att erhålla återvinningspotentialer för industriell överskottsvärme med hjälp av olika teknologier. Bedömningen av olika möjligheter att använda industriell överskottsvärme kompletteras med en analys av systemaspekter som kan påverka lönsamhet och globala växthusgasutsläpp. Ett energimålsförfarande kombinerat med optimering har tillämpats på sex fallstudier av massa- och pappersbruk i Sverige, med produktion baserat på sulfatmassa. Med denna metod erhålls IÖV-profiler som används i en regressionsanalys för att uppskatta tillgängligheten av IÖV och potentialen för elproduktion från låg- och medeltempererad IÖV med organiska Rankine-cykler (ORC). En jämförelse av lönsamhet och globala växthusgasutsläpp mellan elproduktion med ORC, där IÖV utgör grunden, och småskalig kombinerad värme och el (KVV) produktion presenteras för tre energimarknader. Resultaten visar en potential att öka elproduktionen från låg- och medeltempererad IÖV med 7% till 9% i sulfatmassabruken i Sverige, beroende på graden av processintegration som beaktas. Användningen av låg- och medeltempererad IÖV för elproduktion kan potentiellt minska de globala växthusgasutsläppen i alla övervägda energimarknadsscenarier. Om biomassa betraktas som en begränsad resurs, kan emellertid direkta fjärrvärmeleveranser uppnå högre globala minskningar av växthusgaser. ORC-elproduktion från låg- och medeltempererad IÖV är ekonomiskt lönsam och visade överlag bättre lönsamhet och minskade växthusgasutsläpp än småskalig ORC-kraftvärme. Den ekonomiska genomförbarheten av ORC-elproduktion påverkas mindre av yttre förhållanden och osäkerheter än fjärrvärmeleveranser.

Hybrid heating systems with ground source heat pumps (GSHP) and district heating and cooling offer flexibility in operation to both building owners and energy providers. The flexibility can be used to make the heating system more economical and environmentally friendly. However, due to the lack of suitable models that can accurately predict the long-term performance of the GSHP, there is uncertainty in their performance and concerns about the long-term stability of the ground temperature, which has limited the utilization of such hybrid heating systems. This work presents a hybrid model of a GSHP system that uses analytical and artificial neural network models to accurately represent a GSHP system's long-term behavior. A method to improve the operation of a hybrid GSHP is also presented. The method was applied to hospital buildings in northern Sweden. It was shown that in the improved case, the cost of providing heating to the building can be reduced by 64 t€, and the CO2 emissions can be reduced by 92 tons while maintaining a stable ground temperature. Originally included in thesis in manuscript form.

Biomethane production from renewable residues with anaerobic digestion gains increasing attention as a crucial alternative to petroleum fuels. It has been vigorously developed, but the large amounts of subsidy from the government indicate that the process efficiency needs to be further improved. For biomethane production, on the one hand, a great amount of heat needs to be used for heating the feeding slurry, sanitation of slurry, and maintaining the temperature in the large-scale reactors. On the other hand, a large amount of thermophilic effluent slurries brings a huge amount of waste heat, which can be recovered. This makes it important to study how to increase production by improving the thermal efficiency of biogas plants with novel heat exchangers. The working fluids in the biogas plants are the non-Newtonian and high-viscous slurries, and the conventional heat exchangers in biogas plants always show much lower performance compared to those in other industries. Normally, the slurries in the biogas plant consist of different substrates, including straw, manure, food waste, municipal sludge, and their mixtures, and various factors such as the amount and type of solids, particle size, shear rate, and temperature impact the rheological properties of the slurries, which makes the complexity in the rheological properties and the difficulty in developing novel heat exchangers. The development of heat exchangers calls for the rheological properties of slurries. However, to the best of our knowledge, only the rheology of manure slurry was systematically determined and modeled considering the effect of temperature. The lack of the rheological properties of slurries further hinders the design and development of novel geometries to enhance the heat transfer of the slurries. Correspondingly, the quantitative contribution and potential of the waste-heat recovery from the slurries to production using the enhanced geometry remain unclear. In this thesis work, to design novel geometry with heat-transfer enhancement for different slurries and determine its potential in thermal cycles in the full-scale biogas plants, firstly, the temperature-dependent rheological properties of the slurries, including the corn straw, food waste, and mixed slurries, were tested and modeled. It was found that these slurries possess strong shear-thinning behavior, the temperature has a significant impact on their dynamic viscosity, and the power-law model combined with the Arrhenius equation can describe the rheology well. Subsequently, with the reliable models of the rheological properties as the key input, Computational Fluid Dynamics simulations were conducted to screen different twisted geometries, determine the heat-transfer performance, and reveal the mechanism of the heat-transfer enhancement. Lab- and pilot-scale experiments were also conducted to validate the numerical results. The twisted hexagonal tubes show a positive enhancement factor up to 2.6 compared to normal heat exchangers in a wide range of operating conditions. The continuous and strong near-wall shear effect is the intrinsic reason for achieving a significant heat-transfer enhancement in the twisted hexagonal tubes. Moreover, the generalized engineering equations for predicting the effective shear rate and heat-transfer performance with measurable parameters were established and verified with both numerical and experimental results. Finally, the twisted-hexagonal-tube heat exchange was integrated with complete thermal cycles, including waste-heat recovery and external heating processes in the biogas plant, and the potential of increased production and profits were modeled and analyzed combined with the practical operating conditions in a full-scale biogas plant. It was found that for the waste-heat recovery using the twisted hexagonal tubes, the net raw biogas production can increase by up to 17.0 %, and for the external heating process, the increased profit equivalent to 39 % of total production can be achieved owing to energy conservation in external heating using the twisted-hexagonal-tube heat exchangers for a full-scale biogas plant.

During the last years the number of installed PV-modules have increased significantly. As a result, the self-consumption of the solar electricity has become more important. One way to increase the self-consumption is to install an energy storage, for instance a battery. Another way is to introduce a physical energy community. An energy community is a way to share energy, in this case local produced renewable energy from the PV-panels, between buildings in a local electrical-grid. The aim of this project is to investigate how the self-consumption change when an energy community is introduced and explore differences depending on the heating system of the building. This energy community includes seven buildings, two buildings with district heating and five buildings with heat pumps. An economic analysis of the economic benefits of energy communities is also included. The project is conducted as a case study of a new block that is under construction in Örebro. A building simulation have been performed in IDA ICE 4.8 SP2. This includes simulations of energy consumption and energy production from PV-modules. The battery model is done in Matlab and used to simulate different battery sizes. The self-consumption increases when an energy community is established for all the individual buildings no matter of the heating method. For buildings with heat pump, the self-consumption was higher than it was for the buildings with distric-heating. The district heated building with the lowest self-consumption as an individual building increased its self-consumption from 66.7% to 72.5% when joining an energy community with only one other building. For building with heatpump the lowest self-consumption was 82.5% and in an energy community the self-consumption increased to 92.6% From an economic aspect it is a good idea to establish an energy community regardless of size and type of heating method that is used in the buildings. For all communities the repayment period for the PV-modules is shorter for the community than it is for the individual buildings. However, to install a battery for the community is not profitable if you only load the battery when there is an overproduction from the PV-modules compared to the need from the load.

Region Värmland har satt upp miljömålet att minska sina koldioxidutsläpp och sin energiförbrukning, samtidigt önskas att spara in så mycket pengar som möjligt. Eftersom värme- och kylsystemet på Centralsjukhuset i Karlstad (CSK) står för en stor del av hela regionens energiförbrukning kan det ge god effekt att driftoptimera systemet. Systemet består av fyra bergvärmepumpar, två kylvärmepumpar, frikyla från marklagren, fjärrvärme samt tre kylmaskiner. Studien syftar till att undersöka hur region Värmland kan komma närmre sina miljömål, minska sina driftskostnader, samt att förstå vilka begränsningar som deras värme- och kylsystem har. Målet var att ta fram driftstrategier utifrån systemets begränsningar för perioden april-september, samt att redovisa hur mycket köpt energi, koldioxidutsläpp samt pengar som kan sparas om systemet körs enligt dessa strategier. En modell av systemet har byggts i simuleringsprogrammet Simulink och kalibrerats mot mätdata från den studerade perioden. Eftersom ett av målen i studien varit att ta reda på mer om begränsningarna i marklagren har stor vikt lagts på att modellera borrhålen och frikylevärmeväxlaren. Studiens resultat visar att den begränsande faktorn för frikylan är marklagren och brinevätskans temperatur, det finns därmed inte mycket mer effekt att hämta genom att öka flödet genom värmeväxlaren. Att köra bergvärmepumparna och frikyla samtidigt ger därför bra förutsättningar att få ut mer frikyla och minska frysrisken i borrhålen. Ett alternativ till att köra bergvärme och frikyla samtidigt är att investera i nya kylvärmepumpar som har ett högre COP än de nuvarande, om det är lönsamt beror dock på hur stor investeringskostnaden är. Båda dessa alternativ har potential att minska driftens koldioxidutsläpp med ca 35 ton och mängden köpt energi med ca 1 GWh, vilket motsvara ca 1,1 % respektive 1,6 % av hela Region Värmlands utsläpp och köpta energi för hela 2021. Dessa två alternativ kommer även minska driftskostnaderna mest (ca 0,3–0,4 Mkr sparat) så länge elpriset inte stiger till ca 2 kr/kWh, då blir det billigast att bara använda fjärrvärme som värmekälla. Den driftstrategi som rekommenderas är att under hela perioden låta bergvärmepumparna gå maximalt och därmed även få ut maximalt med frikyla, då denna strategi har stor potential att spara driftskostnader och hjälpa Region Värmland att nå sina miljömål utan att behöva investera i nya komponenter. Hur koldioxidutsläpp och energi värderas i miljömålen bör dock utredas inför nya målsättningar, då det kan ge fördel åt att i stället köra fjärrvärme under sommarmånaderna.

The main objective of this paper is to develop a readiness index model that can serve as an analytical tool for exploring the achievements of electrification of transportation systems. We have applied this readiness index model to evaluate the readiness positioning of China, Norway, and Sweden towards transport electrification. We have chosen these three countries as they represent diversity among countries that are in the process of adopting electrified transport system solutions. Our developed readiness index model has four key dimensions, technological readiness, political readiness, societal readiness, and economic readiness. The embeddedness of all four dimensions in one model provides a multi-perspective way of analyzing and evaluating the readiness levels of countries moving towards transforming the transportation system. Therefore, we named the model a“multidimensional readiness index.” Our main conclusions are that the political processes and political decisiveness involved are the most important factors followed by the societal needs and economic ability, with the current technology available as the fourth. Without the participation of dedicated and determined political decision-makers being involved, the other three factors are challenging to obtain. Political decision-makers need to facilitate the use of economic means to support the transformation in the society and affected industries to balance the initial economic disadvantages of the electrically-powered systems until they pass the cost disadvantage turning point. The development of the relevant technology is no longer a great barrier as it was at the beginning of this transformation, about 20 years ago. The technology for electrically powered transportation systems and devices is widely available now, although it is continuously evolving and being improved. Associated industries cannot be expected to initiate, finance, take the risk, and take the lead in this global societal transformation without clear and strong political support. Based on our multidimensional readiness index analysis, China is being positioned as the leading country in the world in the electrification of its transportation systems. This is mainly so because of the strong technology advancements, control of the entire value chain of research, development (R&D), and manufacturing of EVs, strong government decisiveness, and execution power in developing and implementing favorable electric vehicle (EV) policies. The willingness of China’s public sector to take the lead and their citizen’s support to adopt clean technology are additional factors facilitating this advancement. Norway has rapidly become one of the newcomers in electrification with large numbers of registered electric vehicles, despite lacking manufacturing industries of electric vehicles. Sweden is a rapidly developing country in the electrification of transport, with three vehicle manufacturers introducing EVs in 2021. The government has been committed to building demonstration sites for electric roads systems for more than ten years. Sweden is also working on establishing battery manufacturing facilities dedicated to the needs of electrified transportation equipment and systems. Paper 4Project: Collaborative Academic Platform for the Electrification of Transportation Systems

De förhöjda halterna av växthusgaser i luften leder till ett varmare klimat och extremväder blir vanligare,vilket är två viktiga aspekter till att minska klimatavtrycket. Region Värmland skapade 2021 en miljöplan för att minimera klimatavtrycket, använda resurserna på ett klimatsmart sätt samt bidra till en hälsosammare miljö. Studien som genomförts har studerat Centralsjukhuset i Karlstads värme- och kylanläggning som består av fyra bergvärmepumpar, två kylvärmepumpar, tre kylmaskiner, en frikylevärmeväxlare och fjärrvärme. Bergvärmepumparna är kopplade till två geolager med sammanlagt 188 vertikala borrhål. Berget som borrhålen är borrade i förväntas vara antingen granit eller gnejs som båda har en hög kvartshalt. Kvartshalten är en viktig faktor för att bestämma bergets värmeledningsförmåga som i sin tur bestämmer bergets potential att överföra värme och kyla till brinen. Fjärrvärmen som köps in kommer från Heden i Karlstad och elen från en elmix skapad av olika energikällor både förnybara och fossila. Energiföretagen Sverige tillsammans med samarbetspartnersgenomför en miljöutvärdering utav fjärrvärmen årligen och det är fjärrvärmeutsläppen från 2019 som både Region Värmland och studien har använt för att beräkna koldioxidutsläppen fjärrvärmen ger upphov till. För beräkning av elmixens koldioxidutsläpp används Region Värmlands antagna värde som grundas i energimyndighetens siffror. Studien som genomförts undersöker olika driftstrategier från oktober till april. En modell byggdes upp i dataprogrammet Simulink som möjliggör en dynamisk simulering över tid. Syftet med studien är att öka Region Värmlands förståelse över hur effektuttaget från bergvärmepumparna och frikylevärmeväxlaren påverkar berget med målet att ta fram olika driftstrategier för att minska både driftkostnaderna och koldioxidutsläppen för anläggningen. Studien upptäckte att Region Värmland inte kör sitt system optimalt utan borde prioritera kylvärmepumparnas körning följt av bergvärmepumparna och fjärrvärmen. Denna prioriteringsordning skulle minska driftkostnaden från 4,6 miljoner kronor till 4,3 miljoner kronor samtidigt som det minskar koldioxidutsläppen från 218,9 ton till 179,7 ton. Om Carnotverkningsgraden skulle höjas från 0,30 till 0,35 skulle det ändra driftstrategin och det blir i stället gynnsamt att prioritera driften efter bergvärmepumparna, följt av kylvärmepumparna och sedan frikyla och fjärrvärme. Kylvärmepumparna som används på anläggningen är gamla och har därför ett lågt COP, nya kylvärmepumapar med ett COP på 5 skulle kunna minska driftkostnaden till 4,1 miljoner kronor och koldioxidutsläppen till 174,3 ton.Liknande studier som undersöker effektuttag från berg och hur bergets temperatur förändras tyder på att de finns mer att hämta från de etablerade geolagrerna. En installation av nya bergvärmepumpar med en maxeffekt på 4600 kW skulle minska driftkostnaderna till 4 miljoner kronor och koldioxidutsläppen till 162,6 ton. Elpriset varierar årligen och en höjning på endast 0,4 kr/kWh från 1 kr/kWh till 1,4 kr/kWh medför att det blir ekonomiskt mer gynnsamt att täcka hela värmebehovet med fjärrvärme och kylbehovet med frikyla. En ökning på endast 0,4 kr/kWh är ett rimligt antagande då elen för bostäder har höjts 0,73kr/kWh på två år. The elevated levels of greenhouse gases in the air lead to a warmer climate and extreme weather becomes more common, which are two important aspects in reducing the climate footprint. Region Värmlandcreated an environmental plan in 2021 to minimize the climate footprint, use resources in a climatesmart way and contribute to healthier environment. The study that has been carried out has studied the Central Hospital in Karlstad’s heating and cooling system consists of four geothermal heat pumps, two cooling heat pumps, three cooling machines, a free cooling heat exchanger and district heating. The geothermal heat pumps are connected to two ground sources with a total of 188 vertical boreholes. The rock on which the boreholes are drilled is expected to be either granite or gneiss, both of which have a high quartz content. Quartz content is an important factor in determining the rock’s potential to transfer heat and cold to the brine. The district heating that is purchased comes from Heden in Karlstad and the electricity from an electricity mix created by various energy sources, both renewable and fossil. The energy companies Sverige tillsammans with partners carry out an environmental evaluation of the district heating annually and it is the district heating emissions from 2019 that both Region Värmland and the study used to calculate the carbon dioxide emissions the district heating gives rise to. For the calculation of the electricity mix’s carbon dioxide emissions, is Region Värmland assumed value used, which is based on the energy authority’s figures. The study examines different operating strategies from October to April. A model was built in the computer program Simulink that enables a dynamic simulation over time. The purpose of the study is to increase Region Värmland’s understanding of how the power output from the geothermal heat pumpsand the free cooling heat exchanger affects the rock with the aim of developing different operating strategies to reduce both operating costs and carbon dioxide emissions for the plant. The study discovered that Region Värmland does not run its system optimally but should prioritize the cooling heat pumps followed by the geothermal heat pumps and district heating. This prioritization scheme would reduce operating costs from 4,6 million SEK to 4,3 million SEK while reducing carbon dioxide emissions from 218,9 tons to 179,7 tons. If the Carnot efficiency were to be raised from 0,30 to 0,35, it would change the operating strategy and it would instead be favorable to prioritize the geothermal heat pumps, followed by the cooling heat pumps and then free cooling and district heating. The Cooling heat pumps used at the facility are old and therefore have a low COP, new cooling heat pumps with a COP of 5 could reduce the operating cost to 4,1 million SEK and carbon dioxide emissions to 174,3 tones. Similar studies that examine power extractions from rock and how the rock’s temperature changes indicate that there is more to be gained from the established ground sources. An installation of new geothermal heat pumps with a maximum power of 4600 kW would reduce operation costs to 4 million SEK and carbon dioxide emissions to 162,6 tones. The price of electricity varies annually and an increase of only 0,4 SEK/kWh from 1 SEK/kWh to 1,4 SEK/kWh means that it becomes more economically favorable to cover the heating needed with district heating and the cooling with free cooling. An increase of only 0,4 SEK/kWh is a reasonable assumption as electricity for homes has been increased by 0,73 SEK in two years.

En studie har genomförts för att undersöka möjligheterna att torka gjutsand i en fluidiserad bädd. Sand är ett ändligt material och i gjutprocessen används tonvis gjutsand årligen. Volvo Powertrain Production har ett gjuteri i Skövde där de undersöker om de kan återanvända sin gjutsand. För att återanvända gjutsanden måste den först tvättas ren från föroreningar för att sedan torkas innan den kan användas i processen igen. Gjuteriet har stora mängder restvärme som skulle kunna utnyttjas till torkningen av gjuterisand. Studien genomförs för att öka kunskapen om torkning av gjutsand i en fluidiserad bädd vid olika gastemperaturer och flöden. Målet är att analysera gjutsandens fluidiseringsegenskaper och att beräkna vilken temperatur och vilket luftflöde som genererar lägst energibehov vid torkning. Gjutsanden ska torkas från en fukthalt på 12 % till en fukthalt på 0,1 %. Gjutsandens slitage mäts för att säkerställa att medelkornstorleken inte underskrider 150 µm och att finandelar under 63 µm inte överskrider 1 % av den totala massan. Målet är även att projektera en tork som kan torka 10 000 ton gjutsand/år samt att beräkna den miljömässiga förbättringen som genereras av att återvinna gjutsanden i CO2-ekv. Resultatet för studien visar att torr gjutsand fluidiserar vid en hastighet på 0,09 m/s. Studien visar också att fluidiseringen av gjutsand inte har ett betydande slitage på sangkornens storlek. Sandens slitagegrad är viktig eftersom sanden vill kunna återanvändas många gånger och resultatet tyder på att fluidisering är en skonsam process. Torkning av 10 000 ton gjutsand/år kräver en tork på 22,2 m3. Torkens storlek ses som rimlig och för att få en kontinuerlig torkning kan en fluidiserad bandtork användas. Resultatet visar att för att torka så energieffektivt som möjligt bör det ingående volymflödet på luften vara 0,028 m3/s. Ingående lufttemperatur bör vara 100 °C när sandbädden är fast och 45°C när gjutsanden är fluidiserad. Gjuteriet genererar stora mängder restvärme och procesströmmar upp till 100 °C kan ses som obegränsad. Det betyder att restvärme kan användas för att torka gjutsanden. Resultatet för de miljömässiga beräkningarna visar att 226 till 244 ton CO2-ekv kan reduceras genom att återvinna 10 000 ton gjutsand per år. Torkningseffekten är mycket låg och det kan vara ett problem om restvärmetillgången minskar. För att nyttja en större del av den tillförda energin kanett recirkulerande flöde användas. I dagens process ses dock inte det som nödvändigt eftersom energin är obegränsad och inte nyttjas till andra ändamål. A study has been made to investigate the possibilities of drying casting sand in a fluidized bed. Sand is a finite material and in the casting process tons of casting sand are used annually. Volvo Powertrain Production has a foundry in Skövde where they are investigating if it is possible to reuse their casting sand. To be able to reuse the casting sand, it must first be washed clean of contaminants and then dried before it can be used in the process again. Foundry has large amounts of residual heat that could be used for the drying of foundry sand. The study is carried out to increase knowledge about drying casting sand in a fluidized bed at different gas temperatures and flows. The goal is to analyze the fluidizing properties of the casting sand and to calculatewhich temperature and which air flow generate the lowest energy requirement duringdrying. The casting sand must be dried from a moisture content of 12 % to a moisture content of 0,1 %. The wear of the casting sand is measured to ensure that the average grain size does not exceed 150 µm and that fines below 63 µm do not exceed 1 % of the total mass. The goal is also to design a dryer that can dry 10 000 tonnes of casting sand/year and to calculate the environmental improvement generated by recycling the casting sand in CO2-eq. The results of the study show that dry casting sand fluidizes at a speed of 0,09 m/s. The study also shows that the fluidization of casting sand does not have a significant wear on the size of the grains. The degree of wear of the sand is important because the sand must be reused many times and the result indicates that fluidization is a gentle process. Drying of 10 000 tonnes of casting sand/year requires a dryer of 22,2 m3. The size of the dryer is considered reasonable and to obtain a continuous drying, a fluidized belt dryer can be used. The results show that to dry as energy-efficiently as possible, the input volume flow on the air should be 0,028 m3/s. The incoming air temperature should be 100 °C when the casting sand bed is solid and 45 °C when the casting sand is fluidized. The foundry generates large amounts of residual heat and process streams up to 100 ° C can be seen as unlimited. This means that residual heat can be used to dry the casting sand. The results of the environmental calculations show that 226 to 244 tonnes of CO2-eq can be reduced by recycling 10 000 tonnes of casting sand per year. The drying effect is very low and it can be a problem if the residual heat decreases. To utilize a larger part of the supplied energy, a recirculating flow can be used. In today's process, however, it is not seen as necessary because the energy is unlimited and is not used for other purposes.

In abstract, it can be emphasized that the concrete industry influences and is significant based on the sustainability dimensions. The concrete industry is also an industry where actors with different backgrounds interact to achieve the different climate goals. To achieve the climate goals, climate-neutral and energy-smart concrete production is a major step that actor in the concrete industry want to fulfill and take. One way to achieve or develop the concrete industry or operations is to raise and further develop the current competence that exists in the main areas of climate impact, concrete recycling, renewable energy, and sustainability. In the main areas, specific and concrete solutions and calculations have been identified and compiled to present guidelines and recommendations to achieve the purpose of the study. This study was carried out in collaboration with Skanska AB. By analytically quantifying and comparing the theoretical energy flow in concrete factories compared to the practical, concrete production is a resource- and energy intensive manufacturing process. In general, the manufacturing process of concrete is simple, as concrete is a mixture of product cement, water, aggregate (stone and gravel) and additives. The manufacturing process of concrete and the material flow is designed and carried out in a concrete factory where the materials are mixed and assembled to produce quantities of concrete. Cleaning and flushing of the concrete trucks take place at concrete factories and is also resource and energy intensive. Climate-improved concrete is a concrete concept that concrete actors have been further developed and commercialized to reduce the climate impact of standard concrete, where additives from residual products from industrial processes replace parts of the initial amount of cement. To analyze and compare the development of Skanska's Green Concrete and how significant the concrete types are based on the sustainability dimensions the assessment of environmental impact has been analyzed. The analysis is based on the environmental product declarations EPD, the environmental impact unit ELU and the EPS (Environment Priority Strategies) system. Based on the study's delimitations, the focus is mainly on the production and manufacturing phase, which based on LCA means that LCA phases A1-A3 are in focus, where LCA phase A3 stands for the manufacturing process. Although the manufacturing process of concrete is resource- and energy-intensive, the manufacturing process A3 stands for the smallest climate impact in comparison with LCA phases A1 and A2, where LCA phase A1, which is the raw material supply, stands for the largest climate impact. During the winter period when the temperature decreases less than 5 degrees Celsius, the manufacturing process of concrete becomes resource and energy demanding. The reason is because concrete is a temperature-sensitive material, whose properties vary and deteriorate at incorrect temperatures. In connection with concrete produced in concrete factories, a traditional heating system is used only during the winter period, which produces amounts of carbon dioxide through the combustion process of fuel oil. The purpose of the heating system and boiler is to heat an amount of water and aggregate, which is an energy-intensive process required only in the winter period because the outdoor temperature is not sufficient for concrete production. During the winter period, the manufactured concrete risks deteriorating the concrete characteristics, where the concrete can have a low formability and compressive strength. Purchased electricity from the electricity grid is also used or consumed in connection with heating processes, manufacturing processes or other sub-processes required for cleaning and flushing of concrete trucks. Based on this study’s result, the concrete factory in the Stockholm area consumes just over 16 kWh/m^3 during winter production. The results of this study consist of a compilation of results of Skanska's various environmental product declarations to emphasize how significant concrete production is based on the sustainability dimensions. Based on the result compilation of the ELU values, the manufacturing process (A3) - and the production of concrete (A1-A3) have the most significant impact on the ELU aspects YOLL and Cradle to gate GHG index. Based on Skanska's Green concrete types and the industry's reference concrete, the difference between the concrete types is 137 kg CO2 equivalent for Green Wall Concrete, 95 kg CO2 equivalent for Green Floor Concrete and 52 kg CO2 equivalent for Green Garage Concrete. The cost analysis and assessment of potential and identified recycling- and energy systems is another part of the result, where the Circulus system is an identified recycling system, while solar cells and batteries connected to the electricity grid are an identified energy system. The purpose of the recycling system is to carry out circular concrete production, and in connection with the observations and interviews carried out, the design of recycling processes will be achieved through the implementation of the innovative recycling system. The recycling system Circulus, which is a combination of two products from the company’s Mapei and Allu, is a present example of how the concrete industry's transition to circular concrete production is to be achieved. Based on the cost assessment of the Circulus system, the total cost, including investment and maintenance costs, has been calculated at just over 1 250 000 SEK. Based on the concrete factory in the Stockholm area's handling of recycled concrete and the C3C-blocks, a payback period of 9 years has been calculated. Regarding the energy system, the purpose is to present a new renewable energy source to the concrete plant and optimize the use of the energy system to minimize the costs of purchasing electricity from the electricity grid. Based on a sensitivity analysis of different optimization cases, an energy system of varying solar cell and battery sizes connected to the electricity grid is the most profitable structure of an energy system. The energy system with the solar cell power of 165 kW and the battery size of 330 kWh has a net cost of just over SEK 294 000, where the cost of buying electricity is just over SEK 373 000, and the income from selling electricity is just over SEK 72 000. Regardless of the energy system's structure or the construction of solar cells with or without a battery, the energy system's system operating costs will always be less than the cost of purchased electricity in 2021. In connection with electricity being the energy carrier in concrete factories, the use and implementation of solar cells is a long-term sustainable energy solution. Sammanfattningsvis kan det betonas att betongbranschen är en bransch som påverkas och är betydande utifrån hållbarhetsdimensionerna. Betongbranschen är en bransch där aktörer med olika bakgrunder samspelar för att uppnå de skilda klimatmålen. För att uppnå klimatmålen är klimatneutral- och energismartbetongtillverkning ett stort steg aktörer inom betongbranschen vill uppfylla och ta. Ett sätt att uppnå eller utveckla betongbranschen eller betongverksamheter är att lyfta upp och viderutveckla den nuvarande kompetensen som existerar inom huvudområdena klimatpåverkan, återvinning, förnybar energi och hållbarhet. Inom huvudområdena har specifika och konkreta lösningar och beräkningar identifierats samt sammanställts i syfte att framföra riktlinjer och rekommendationer för att uppnå studiens syfte. Denna studie är genomförd i samarbete med Skanska AB. Genom att analytisk kvantifiera och jämföra det teoretiska energiflödet i betongfabriker gentemot det praktiska är betongtillverkningen en resurs- och energikrävande tillverkningsprocess. Generellt sätt är tillverkningsprocessen av betong simpel, då betong är en sammanblandad produkt av cement, vatten, ballast (sten och grus) och tillsatsmedel. Tillverkningsprocessen av betong samt materialflödet är utformat och genomförs i en betongfabrik där man blandar materialen för att framställa betongmängder. Rengöring- och spolning av betonglastbilarna sker på betongfabriker och är resurs samt energikrävande. Klimatförbättrad betong är ett koncept som betongaktörer har viderutvecklats och kommersialiserat för att reducera klimatpåverkan standardbetong, där tillsatsmaterial av restprodukter från industriprocesser ersätter delar av den initiala cementmängden. För att analysera och jämföra utvecklingen av Skanskas Grön betong och hur betydande betongtyperna är utifrån hållbarhets dimensionerna har bedömandet av miljöpåverkan analyserat utifrån miljövarudeklarationerna EPD, miljöbelastningsenheten ELU samt EPS (Environment Priority Strategies) systemet. Baserat på studiens avgränsningar är fokuset främst på produktion- och tillverkningsfasen, vilket utifrån LCA innebär att LCA faserna A1-A3 är i fokus, där LCA fasen A3 står för tillverkningsprocessen. Även om tillverkningsprocessen av betong är resurs- och energikrävande står tillverkningsprocessen A3 för den minsta klimatpåverkan. I förhållande till resterande LCA faserna A1 och A2 står LCA fasen A1 för den största klimatpåverkan, vilket står för råvaruförsörjningen. Under vinterperioden då temperaturen minskar mindre än 5 grader Celsius blir tillverkningsprocessen av betong resurs- och energikrävande, eftersom betong är ett temperaturkänsligt material vars egenskaper varierar samt försämras vid felaktiga temperaturer. I samband med betong som tillverkas i betongfabriker används ett traditionellt uppvärmningssystem endast under vinterperioden. Det traditionella uppvärmningssystemet framställer mängder av koldioxid genom förbränningsprocessen av eldningsolja. Syftet med uppvärmningssystemet och värmepannan är att uppvärma vatten- och ballast mängder, eftersom under vinterperioden är utomhustemperaturen inte tillräcklig för betongtillverkning. Under vinterperioden riskerar den tillverkade betongen att betongegenskapernas försämras, då betongen kan få en låg formbarhet och tryckhållfasthet. Även köpt elektricitet från elnätet används eller förbrukas i samband med uppvärmningsprocesser, tillverkningsprocesser eller andra delprocesser som krävs för exempelvis rengöring- och spolning av betonglastbilar. Utifrån det beräknande resultatet förbrukar betongfabriken i Stockholmsområdet drygt 16 kWh/m^3 vid vintertillverkning. Resultatet i denna studie består av resultatsammanställning av Skanskas olika miljövarudeklarationerna för att betona hur betydande betongtillverkningen är utifrån hållbarhetsdimensionerna. Baserat på resultatsammanställningen av ELU värdena har verksamhetens tillverkning (A3) och produktionen av betong (A1-A3) den mest betydande påverkan på ELU aspekterna YOLL och Cradle to gate GHG index. Baserat på Skanskas Gröna betongtyper och branschens referensbetong är skillnaden mellan betongtyperna 137 kg CO2 -ekv för Grön Väggbetong, 95 kg CO2 -ekv för Grön Bjälklagsbetong och 52 kg CO2 -ekv för Grön Garagebetong. Kostnadsanalys och bedömning av potentiella samt identifierade återvinning- och energisystem är en annan del av resultatet, där Circulus systemet är ett identifierad återvinningssystemet, medan solceller och batteri sammankopplad med elnätet är ett identifierad energisystem. Syftet med återvinningssystemet är att framföra cirkulärbetongtillverkning. I samband med de genomförda observationerna och intervjun ska utformningen av återvinningsprocesser uppnås genom implementering av innovativa återvinningssystemet. Återvinningssystemet Circulus systemet som är en kombination av två produkter från Mapei samt Allu och är ett föreliggande exempel på hur betongbranschens omställning till cirkulärbetongtillverkning ska uppnå. Utifrån kostnadsbedömningen av Circulus systemet har den totala kostnaden inklusive investering- och underhåll kostnaden beräknats till drygt 1 250 000 kronor. Baserat på betongfabriken i Stockholmsområdets hantering av returbetong och C3C-blocken har en återbetalningstid på 9 år beräknats. Vad gäller energisystemet är syftet att framföra en ny förnybar energikälla till betongfabriken och optimera användandet av energisystemet för att minimera kostnaderna av att köpa elektricitet från elnätet. Baserat på en känslighetsanalys av olika optimeringsfall är ett energisystem av varierande solcell- och batteristorlekar sammankopplad med elnätet den lönsammaste uppbyggnaden av ett energisystem. Ett energisystem med solcellseffekten på 165 kW och batteristorleken på 330 kWh har en nettokostnad på drygt 294 000 kronor, där kostnaden av att köpa elektricitet är drygt 373 000 kronor, och intäkterna av att sälja elektricitet är drygt 72 000 kronor. Oavsett energisystemets struktur och uppbyggnad av solceller med eller utan batteri kommer energisystemets systemoperationskostnader alltid vara mindre än kostnaden för köpt elektricitet år 2021. I samband med att elektricitet är energibäraren i betongfabriker är användningen och implementering av solceller en långsiktig hållbar energilösning.

Different key performance indicators are used to assess various aspects of a wind turbine (performance, reliability, financial aspects…). Availability metrics mainly, time-based and energy-based availability are the main indicators used to monitor and evaluate turbine’s availability performance today. However, due to significant growth of the share of energy sold into the electricity market as well as different selling structures, a new indicator has been established in order to assess availability performance in terms of revenues rather than time or energy. This thesis compares energy and revenue-based availabilities of two turbines during 12 months of operational production. A methodology of calculation is suggested based on the International Electrotechnical Commission (IEC) information model for availability calculation. Time-based availability is calculated first, followed by energy-based, and finally revenue-based availability is derived from revenues as a result of combining energy production and electricity prices and revenue losses from energy losses and electricity prices. Availability metrics are calculated for three different scenarios, pure-market, mix of market and fixed price purchase agreement (PPA), and finally a PPA with a minimum monthly baseload to simulate the impact of volume risk. Results indicate a significant impact caused by the electricity price as well as the specifics of the selling agreement on revenue-based availability. Finding that in such cases, a significant divergence between energy and revenue-based indicators is possible. Limitations associated with the suggested methodology and case studies are presented and discussed.

The increasing share of wind and photovoltaic (PV) power in the electricity generation mix pose challenges in power system management due to their non-dispatchable and intermittent nature. Co-locating wind and PV parks, forming utility-scale hybrid power parks (HPPs), means that the sources can share grid connection, land, permitting procedures as well as operation and maintenance work. On top of this, the combined power output is generally smoothened due to the anti-correlated characteristics of the respective resources. This licentiate thesis contributes to the state-of-the-art and progress the knowledge of co-located wind and PV parks, where the total number of studies on HPPs are limited compared to the respective fields. According to the results, the power output of co-located wind and PV parks are generally anti-correlated for all studied time scales (seasonal, mid-term, synoptic, diurnal and hourly resolution). The useful anti-correlation is found on the seasonal and diurnal time scale where wind turbine sites are likely to be more anti-correlated than any randomly chosen site. On the synoptic time scale, the useful anti-correlation is consistent, although to a lesser extent. The smoothing effect as a result of co-location is also studied in terms of probabilistic forecasting, which corresponds to estimating the uncertainty of power production predictions by means of a probabilistic distribution. By forecasting aggregated time series of co-located wind and PV, the probabilistic forecasts can be improved which is explained by the aggregated time series being smoother and therefore more straightforward to predict. The value of improved forecasts could also be realized in the day-ahead market, where sharper and more reliable forecasts lower the regulation costs.

The increasing worldwide population is leading to a continuous increase in energy and food demand. These increasing demands have led to fierce land-use conflicts as we need agricultural land for food production while striving towards renewable energy systems such as large-scale solar photovoltaic (PV) systems, which also require in most of the cases agricultural flat land for implementation. It is therefore essential to identify the interrelationships between the food, and energy sectors and develop sustainable solutions to achieve global goals such as food and energy security. A technology that has shown promising potential in supporting food and energy security, as well as supporting water security, is agrivoltaic (AV) systems. This technology combines conventional farm activities with PV systems on the same land. Understanding the microclimatic conditions in an AV system is essential for an accurate assessment of crop yield potential as well as for the energy performance of the PV systems. Nevertheless, the complex mechanisms governing the microclimatic conditions under agrivoltaic systems represent an underdeveloped research area. In this study, a computational fluid dynamics (CFD) model for a vertical AV system is developed and validated. The CFD model showed PV module temperature estimation errors in the order of 0–2 °C and ground temperature errors in the order of 0–1 °C. The shading caused by the vertical PV system resulted in a reduction of solar irradiance by 38%. CFD modelling can be seen as a robust approach to analysing microclimatic parameters and assessing AV system performance.

Industrial heat production is responsible for around 20% of total greenhouse gas emissions in Europe. To achieve the climate change goals defined in the Paris Climate Agreement, the EU commission has shifted its focus on sustainable means to generate heating. Moreover, global dependencies are leading to a re-organization of natural gas supplies. Therefore, there is a need for less vulnerable and less price-volatile solutions for heating. This paper focuses on two decarbonization technologies for industrial process heat supply: a) electricity-driven steam-generating high-temperature heat pumps (HTHP), a technology that is more efficient than fossil fuel boilers in generating steam, and b) solar parabolic trough collector (PTC), which can produce heat economically and at a minimal carbon footprint compared to other technologies. The main aim of this paper is to evaluate the levelized cost of heat (LCOH) of these technologies to fulfill a comparative techno-economic analysis. A maximum PTC collector's solar fraction limit (SFlimit) is defined to indicate when the LCOH for these two technologies is equal. This allows for distinguishing between the economic stronghold of each technology. The evaluation is carried out through the annual energy simulations using TRNSYS and Excel spreadsheets for HTHPs, while TRNSED and OCTAVE are used for the solar thermal part. Boundary conditions for European geographical constraints have been applied to establish use cases for the analysis. The result shows that the design of a PTC system with optimal SF can reach cost parity with HTHP for most of the analyzed locations. The developed methodology serves as a valuable guide to quickly determine a preferred lower carbon heat solution, thus easing the decision-making for industries.

Biogas is one of the most crucial renewable energy and achieving high-efficient heat exchangers is the key to improve its production. In this study, the effect of pulsating flow on heat transfer in a twisted hexagonal tube with manure slurry was investigated for the first time by using computational fluid dynamics CFD. The performances of pulsating flows were simulated under different conditions, including the inlet velocity, frequency, and amplitude of pulsating flow in the twisted hexagonal tube with different torques. Pressure drops at different frequencies were further investigated. Moreover, the mechanism of heat-transfer enhancement was revealed with the evolution of the heat-transfer coefficient over time. It was found the pulsating flow achieves an 18.9% enhancement at low torque. Funder: National Natural Science Foundation of China (Grant Nos.21838004 and 91934302).

Hagelrums Gård/Biogas är ett lantbruk som producerar fordonsgas genom rötning.Till rötningen används främst gödsel i deras biogasanläggning med två rötkammare. Den här rapporten undersöker om installation av en värmepump som tar vara på den värmen från rötresten skulle vara ekonomisk och fördelaktig för uppvärmning av den första rötkammaren. Jämförelsen kommer att ske emot anläggningens nuvarande flispanna. I resultat presenteras den nuvarande anläggningens drift och tre olika scenarier med en värmepump med COP 4 och ett konstant flöde av rötrest. I resultatet presenterasäven jämförelser över hur installationen av den föreslagna värmepumpen skulle påverka driften av anläggningen. Slutsatsen av arbetet är att en värmepump inte är ekonomisk eller lämplig förnuvarande anläggning. Orsakerna är den extra kostnaden och driften av anläggningensom inte är optimal för en värmepump. Hagelrums Gård/Biogas is a farm that produces biomethane for transportation from anaerobic digestion. For the anaerobic digestion manure is mainly used in their facility with two digesters. This report investigates if installation of a heat pump that takes heat from the digestate would be economically and beneficial for heating of the first digester. The comparison will be done against the facility’s current chip boiler. The current facility’s operation and three different scenarios with a heat pump with COP 4 and continuous flow of digestate is presented in the result section. In the results section is also comparisons of how an installation of the proposed heat pump would affect the operation of the facility. The conclusion of the project is that a heat pump is not economical or suitable for the current facility. The extra costs and operation of the facility that is not optimal for a heat pump is the reasoning of the conclusion.

The report presents energy system performances for the property Forskningen consisting of three modern buildings designed as plus energy houses with 667 PV panels and a heated area of about10,590 m2. The property is located in central Stockholm, Sweden. Special features of the buildings and their shared energy system are: • 11 boreholes of variables lengths (225-350 m) organized in a “flower” configuration with Upipes • 1 research borehole (100 m) with coaxial borehole heat exchanger • heating through energy-recovery ventilation system • wastewater heat recovery • Domestic Hot Water (DHW) needs predominant (8 m3 DHW storage) • desuperheaters used for DHW production • vapor injection heat pump cycles • no auxiliary heating system • apartments well-equipped with sensors (more than 2000 sensors and alarms) • distributed temperature measurement in boreholes with fiber optics The monitoring period only extends from 2019-05-26 to 2020-02-03 (except for electricity consumption and production for which data is available for about two years). The energy needs for a full year could nevertheless be estimated and are: 257 MWh/yr (24.3 kWh/(m2 yr)) for heating and 442 MWh/yr (41.7kWh/(m2 yr)) for DHW. The ventilation heat recovery (no included in the heating needs) are estimated to cover a large part of the heating supplied to the buildings (about 70%). Performance factors (PFs) 1, 4, 4+, 5 and 5+ are presented (based on the definitions developed in the Annex 52, see part “Performance metrics” for more details). In addition, two extra PFs are introduced,5* and 5*’ which account for the whole fan energy and the ventilation heat recovery, respectively. For the whole monitored period, PF1 is about 3.6 while PF4 and PF5 are about 3.0 and 2.5, respectively. The electricity values available for about two years allows checking the claim of the buildings being plus energy. Unfortunately, there is a deficit of consumption varying between 50 to 90 MWh/yr. Besides performances, uncertainties are briefly discussed and the author performs verifications on the available data. It appears that data cannot be blindly trusted and requires a minimum level of interpretation. A short investigation about the relevance of cooling the ventilation incoming air to recharge the boreholes is conducted and it counter-intuitively appears that it can make sense to do so. Finally, a list of 10 improvement measures is provided, though some of them perhaps pertain to design considerations and improvements. This report is part of the work within IEA HPT Annex 52 - IEA HPT Annex 52 - Long-term performancemonitoring of GSHP systems for commercial, institutional and multi-family buildings, with project periodJanuary 1st 2018 to December 31 2021. Annex 52 Operating Agent is Sweden.Annex 52 aims to survey and create a library of quality long-term measurements of GSHP systemperformance for commercial, institutional and multi-family buildings. While previous work will besurveyed, the emphasis of the annex is on recent and current measurements. The annex also aims torefine and extend current methodology to better characterize GSHP system performance servingcommercial, institutional and multi-family buildings with the full range of features shown on the market,and to provide a set of benchmarks for comparisons of such GSHP systems around the world.The results from the annex will help building owners, designers and technicians evaluate, compare andoptimize GSHP systems. It will also provide useful guidance to manufacturers of instrumentation andGSHP system components, and developers of tools for monitoring, controlling and fault detection/diagnosis. This will lead to energy and cost savings.The work reported in this document was mainly performed by Willem Mazzotti Pallard at the RoyalInstitute of Technology (KTH) with support from his colleagues also involved in Annex 52: AlbertoLazzarotto, José Acuña and Mohammad Abuasbeh. Other KTH colleagues, Jonas Anund Vogel, in hisquality of director of the KTH Live-in Lab, Safira Figueiredo Monteiro and Davide Rolando, should bethanked for their indirect contributions to the project. In particular, Davide helped building the historicaldatabase, which has been useful for this project.In the text, you will find information and performance analysis of the original testbed of the KTH Live-inLab: three building on KTH main campus with about 305 student accommodations, 12 boreholes, 3ground source heat pumps, DHW dominated needs, heat recovery through ventilation and wastewater,667 PV panels and more. The results specific to these buildings are interesting per say, but there arealso more general things discussed, such as data quality and verification – can we blindly trust data?probably not – uncertainty analysis and some design considerations. In particular,The work that has led to this report has been funded by the Swedish Energy Agency(Energmyndigheten) through the project 45979-1. IEA HPT Annex 52

The negative impact of transport on climate has led to incentives to increase the amount of renewable fuels used in internal combustion engines (ICEs). Oxygenated, liquid biofuels are promising alternatives, as they exhibit similar combustion behaviour to gasoline. In this article, the effect of the different biofuels on engine efficiency, combustion propagation and emissions of a gasoline-optimised direct injected spark ignited (DISI) engine were evaluated through engine experiments. The experiments were performed without any engine hardware modifications. The investigated fuels are gasoline, four alcohols (methanol, ethanol, n-butanol and iso-butanol) and one ether (MTBE). All fuels were tested at two speed sweeps at low and mid load conditions, and a spark timing sweep at low load conditions. The oxygenated biofuels exhibit increased efficiencies, even at non-knock-limited conditions. At lower loads, the oxygenated fuels decrease CO, HC and NOx emissions. However, at mid load conditions, decreased volatility of the alcohols leads to increased emissions due to fuel impingement effects. Methanol exhibited the highest efficiencies and significantly increased burn rates compared to the other fuels. Gasoline exhibited the lowest level of PN and PM emissions. N-butanol and iso-butanol show significantly increased levels of particle emissions compared to the other fuels QC 20210917 Framtida alternativa transportbränslen

Photovoltaic thermal collectors (PVT) can generate electricity and heat from one module. In a typical aerothermal PVT system, the air flow behind the PV modules is created using air channels, and the heated air is ducted to the point of usage. The central aim of this paper is to simulate a system where the recovered heat from a PV installation is utilized in the energy system of a multifamily building cluster in Sweden. The paper tends to establish if the additional cost of “heat recovery system” components justify the savings obtained due to recovered heat from PV. To achieve this, a simulation model is built in TRNSYS for a multi-family building cluster in Sweden. Specifically, two energy system configurations are simulated.1) Recovered heat from PV collectors is used for pre-heating of domestic hot water.2) Heat from PV collectors is used at the evaporator of an air source heat pump to increase its performance. The heat pump is further used to generate domestic hot water.Results show that the advantage of PVT integration is more pronounced when recovered heat is used directly for pre-heating of DHW. The savings are lower when PVT is coupled with heat pump. EST

Renewable energy polygeneration systems are a viable alternative to fossil-fuel based systems, but storage solutions may be necessary when aiming for high sustainability and autonomy. As each storage technology has different strengths and weaknesses, combinations of various storage solutions may lead to better techno-economic performance than singular approaches. To this purpose, an optimization model including a novel dispatch control strategy for a hybrid energy storage system (HESS) is proposed, which uses biogas for long-term and batteries for short-term storage. The model optimizes for minimum lifetime costs while exploiting the biomass resources with maximum efficiency and quantifying the additional solar and battery capacities needed. It is applied in a case study with an innovative biomass-based polygeneration system in a rural locality of Bolivia to serve electricity, potable water, and bio-slurry as fertilizer. The results indicate that even with maximized efficiency of the biomass resource conversion, large PV and battery capacities are necessary to satisfy the electricity demand of the locality. Despite of the high investment costs, the biomass-based polygeneration system would cost 22% less over the project lifetime than the fossil-fuel based reference system while being less dependent on fuel price changes. It would also reduce CO2-emissions by over 98%. This research has been conducted in collaboration between UPC (Universitat Politècnica de Catalunya) and KTH Royal Institute of Technology, funded through Erasmus Mundus Joint Doctoral Programme SELECT+, the support of which is gratefully acknowledged. The project STandUP for Energy provided resources for supervision of this study. AI acknowledges support from Spanish project MOET_BIA2016-77675-R.

Predictive health monitoring of micro gas turbines can significantly increase the availability and reduce the operating and maintenance costs. Methods for predictive health monitoring are typically developed for large-scale gas turbines and have often focused on single systems. In an effort to enable fleet-level health monitoring of micro gas turbines, this work presents a novel data-driven approach for predicting system degradation over time. The approach utilises operational data from real installations and is not dependent on data from a reference system. The problem was solved in two steps by: 1) estimating the degradation from time-dependent variables and 2) forecasting into the future using only running hours. Linear regression technique is employed both for the estimation and forecasting of degradation. The method was evaluated on five different systems and it is shown that the result is consistent ( r > 0.8 ) with an existing method that computes corrected values based on data from a reference system, and the forecasting had a similar performance as the estimation model using only running hours as an input.

En stor andel av Sveriges bostäder och lokaler är beroende av fjärrvärmeleveransen. Energimyndigheten i Sverige påtalar att störningar och avbrott i fjärrvärmevärmeleveransen kan leda till allvarliga konsekvenser för individer och samhällsviktiga funktioner. Höga krav ställs på fjärrvärmesystemen som förväntas kunna leverera en trygg energiförsörjning till alla kunder, oavsett tid på dygnet. En viktig åtgärd för att öka leveranskvaliteten i fjärrvärmesystem är att säkerställa tillgängligheten på produktionsanläggningar. Energibolaget Sandviken Energi AB (SEAB) arbetar aktivt med frågeställningar som rör leveranssäkerhet i fjärrvärmesystem. SEAB har genom energikonsultbolaget FVB Sverige AB anlitat en praktiserande student för att undersöka hur leveranssäkerheten i Sandvikens fjärrvärmenät kan öka med hjälp av två externa samt en mobil panncentral. I studien riktades fokuset på prioriterade kunder, leveranskvalitet samt risker i fjärrvärmesystemet. Tillvägagångssättet i studien karaktäriseras av en simulering och optimeringsstrategi till vilket beräkningsverktyget NetSim använts. Simuleringarna baserades delvis på bedömda risker i fjärrvärmenätet, framtagna i intervjuer med nyckelpersoner inom SEAB. Utifrån riskbedömningen har sex olika driftscenarier konstruerats och simulerats i ett flertal olika temperaturfall. Scenarierna representerar driften av produktionsenheterna och innehåller bland annat ett basscenario då alla produktionsenheter i nätet fanns tillgängliga. I resterande scenarier simulerades konsekvenserna av driftstörningar i anläggningens olika produktionsenheter. Resultaten från studien visade på en fullgod värmeleverans i alla temperaturfall i fyra av sex driftscenarier. I två av driftscenarierna var den tillförda värmeeffekten för låg för att tillgodose kundernas behov fullt ut. En av slutsatserna som drogs var att när huvudproduktionen i nätet ej fanns tillgänglig, räckte inte värmeeffekten i nätet till för att försörja alla kunder vid alla temperaturfall. A large proportion of Sweden's homes and premises depend on district heating delivery. The Swedish Energy Agency points out that disruptions and interruptions in district heating supply can lead to serious consequences for individuals and socially important functions. An important measure to increase the delivery quality in district heating systems is to ensure the availability of production facilities. Through the energy consulting company FVB Sverige AB, Sandviken Energi AB (SEAB) has hired a practicing student to investigate how delivery security in Sandvikens district heating network can increase with the help of two external and a mobile boiler plant. The study focused on prioritized customers, delivery quality and risks in the district heating system. The approach in the study is characterized by a simulation and optimization strategy for which the calculation tool NetSim has been used. The simulations were partly based on assessed risks in the district heating network, developed in interviews with key people within SEAB. Based on the risk assessment, six different operating scenarios have been constructed and simulated in a number of different temperature cases. The scenarios represent the operation of the production units and contain, among other things, a base scenario when all production units in the network were available. In the remaining scenarios, the consequences of operational disruptions in the plant's various production units were simulated. The results from the study showed a satisfactory heat delivery in all temperature cases in four of six operating scenarios. In two of the operating scenarios, the added heat output was too low to fully meet customers' needs. One of the conclusions drawn was that when the main production in the network was not available, the heat output in the network was not sufficient to supply all customers in all temperature cases.

Transportation is embedded in the fabric of society and a key enabler of socio-economic development, but it is also a major source of carbon dioxide (CO2) and local air pollution (AP). Cities collectively account for around three quarters of total energy-related CO2 emissions, and the negative health impacts from local APs are most felt in dense urban environments. Thus, transitioning away from current fossil fuel regime in urban transportation is necessary to address both global and local challenges. Mathematical models as energy system optimisation models (ESOMs) are commonly applied to explore contrasting energy futures and to provide insights on how the energy system (or specific sub-sectors) may evolve under different conditions. However, ‘typical’ national level models are not fully adapted to capture the characteristics of local (city) transportation, and previous city-level ESOM based analyses have focused on decarbonisation of local energy systems, thus omitting other local policy considerations as e.g. air quality, and several studies excluded transportation altogether. In this thesis, a generic city-level ESOM framework (TIMES-City) was further adapted and used to provide policy-relevant insights on the anticipated energy transition of the local transport sector. The underlying work rests on a systems analysis approach, building on careful consideration of the overall system performance and boundaries, understanding of specific system characteristics, and challenges and opportunities facing local ‘system managers’; this has implications for model representation and for quantitative and qualitative modelling assumptions. Further, availability and quality of local transport, energy and emission data needed to calibrate models poses significant challenges, and considerable effort was also put on producing projections for future transport demand (a key model input), using lessons and input data from traditional transport demand models. These considerations were addressed in Paper I. The model was then applied to two different cases (in Sweden) to explore potential conflicts and co-benefits between ambitious climate targets and deep cuts in APs (Paper II), and to assess the roles of local and regional governments in CO2 mitigation when also considering ambitious national-scale policies (Paper III). The results of Paper II indicate that substituting fossil fuels for biofuels in conventional vehicles is the least-cost decarbonisation pathway, however this produces only minor or even negative benefits to air quality. While, zero-emission vehicles cut all local tail-pipe emissions, but their total impact on climate change mitigation is determined by upstream impacts from the conversion and distribution of energy carriers. Thus, ensuring low levels of total CO2 and APs from transportation calls for re-coupling of the local and global responsibilities and motivations into comprehensive mitigation strategies. The results of Paper III indicate that current Swedish national mitigation measures will drive down CO2 emissions in transportation considerably, but biofuel availability and BEV (battery electric vehicles) costs are critical for the rate and extent of the transition, while locally and regionally determined measures to enable shifts (from car) to active travelling, public transportation and home-based work have a much more limited direct impact. Nonetheless, these measures, along with city investments in BEVs and charging infrastructure which pave the way also for residents and local businesses, can help to reduce overall energy intensity of the transport sector, thus slowing down growth in fuel demand and contribute to reaching ambitious climate targets with limited renewable resources (as e.g. biofuels). The two studies (Papers II and III) illustrate the usefulness of applying comprehensive ESOMs also at sub-national levels, providing insights on both global and local sustainability implications as well as deeper understanding of the roles of local and regional decision-makers in enabling and supporting low-carbon transitions in transportation.

Sverige har höga ambitioner att ställa om till 100 procent förnybar energiproduktion och att tillmötesgå mål 7 i Agenda 2030, vilket är inom räckhåll. Med goda vindlägen, långa kuster och relativt grunda vatten har Sverige alla förutsättningar att lyckas om man enas politiskt, ser över riktlinjer och skapar ekonomiska förutsättningar för utbyggnad av vindkraft. Syftet med rapporten är dels att redovisa de vanligaste hindren för utbyggnad av vindkraft i Sverige, dels vad som har föreslagits för att främja vindkraftsutvecklingen. Rapporten ger en överblick över relevanta frågor kring vindkraftsutvecklingen och fokuserar på frågorna: Vilka är vanligaste hindren för vindkraftsprojekt? Vad har föreslagits för att underlätta för utbyggnad av vindkraft? Med hjälp av utförda myndighetsutredningar, rapporter från branschorganisationer, myndighetspressmeddelanden, debatter, intervjuer och EU-direktiv för förnybar energi och havsbaserad vindkraft utforskar den här rapporten den havsbaserade vindkraftens förutsättningar, samt betonar de vanligaste hindren för projektering och genomförande vid en framtida utbyggnad av vindkraft. Det finns stor potential för vindkraft genom direktiv från EU. De hinder som återkommande orsakar förseningar för utbyggnad av havsbaserad vindkraft är den kommunala vetorätten, Försvarsmakten intressen, anslutningskostnader som styr utbyggnadstakten, avvägning mellan riksintressen, tolkning och verkställande av artskyddsförordningen, politisk dragkamp och växande motstånd på lokalnivå. Trots befintliga hindren är uppsatsen slutsats att det finns stor potential för vindkraften. Sweden has high ambitions to adapt 100 percent renewable energy production and to meet goal 7 in Agenda 2030, which is within reach. With good wind conditions, long coasts and relatively shallow waters, Sweden has all the prerequisites to succeed if it agrees politically, reviews guidelines and creates economic conditions for wind power. The purpose of the thesis is partly to report common obstacles of wind power development in Sweden, and partly to report what has suggested for wind power development. The report provides an overview of relevant issues regarding wind power development and focuses on the issues: What are the most common obstacles to wind power projects?What has been proposed to facilitate the expansion of wind power? Through exploring government investigations, industry organization reports, government press releases, debates, interviews and EU directives for renewable energy and offshore wind power conditions for offshore wind power. Furthermore, highlighting what obstacles encounters for developers in the event of a future expansion of wind power. The obstacles that repeatedly cause delays in the development of offshore wind power are municipal endorsement that is being review now, the Armed Forces' interests, connection costs that control the pace of expansion, balancing national interests, interpretation and implementation of the species protection regulations, political disagreements and growing resistance at local level. Despite existing obstacles, the thesis concludes that there is great potential for wind power.

There are several alternatives for how to phase out diesel in heavy-duty transports, thereby reducing the sector’s climate change impact. This paper assesses the well-to-wheel (WTW) greenhouse gas (GHG) emissions of energy carriers for heavy-duty vehicles, analyzing the effect of the carbon intensity of the electricity used in production. The results show that energy carriers with high electricity dependence are not necessarily better than diesel from a WTW perspective. In particular, fuels produced through electrolysis are not well suited in carbon-intense electricity systems. Conversely, waste-based biofuels have low GHG emissions regardless of the electricity system. Battery-electric buses show a large reduction of GHG emissions compared to diesel buses and many other alternatives, while battery-electric trucks have higher GHG emissions than diesel in carbon intense electricity systems. Thus, electrifying transports or switching to renewable fuels will not suffice if the electricity system is not made renewable first. Funding: Swedish Biogas Research Center (BRC) - Swedish Energy Agency [35624-3] Biogas Research Center

Att koldioxidutsläppen neutraliseras är avgörande för att begränsa klimatförändringarna. Bioenergi i kombination med separation och lagring av koldioxid (BECCS) är en Teknik som kan generera negativa utsläpp. Det största hindret för dess storskaliga genomförande är de höga energikraven för processen. Detta projekt syftar till att kvantifiera energistraffen för lean solvent flash och modifikationer för multitrycksstrippning för att förbättra prestandan av koldioxidavskiljning (CC) i en kraftvärmeverksanläggning för förbränning av biomassa. En jämviktsmodell utvecklades och validerades för att simulera en fullskalig CC genom kemisk absorption i Aspen Plus med kaliumkarbonat som lösningsmedel. Båda layoutändringarna resulterar i energipåföljder på 18-21 % för en kraftvärmeverk, medan energistraffet för baslinjeprocessen är 5 %. För ett kraftverk går straffen från 32 till 62 %. Detta visar hur en förbättring av processen kan minska kostnaderna för CCS, särskilt om värme anses vara en värdefull produkt. CCS i kraftvärmeverk har en mycket lägre energipåverkan än i kraftverk där värme inte återvinns. Bio-energy with carbon capture and storage (BECCS) is a technology that can generate negative emissions. Hence it is recognized as a solution for becoming carbon neutral, which is essential for climate change mitigation. The main obstacle for its large scale implementation is the high energy requirements of the process. This thesis aims at quantifying the energy penalties for lean solvent flash and multi-pressure stripper layout modifications to improve the performance of carbon capture (CC) by means of absorption with a liquid solvent in a biomass-fired CHP plant. The work focuses on K2CO3 based solvents operated in a mixed temperature swing/pressure swing cycle witch is deemed advantageous for heat recovery. An equilibrium model was developed and validated to simulate a full-scale CC by chemical absorption in Aspen Plus using potassium carbonate as solvent. Both layout modifications result in energy penalties of 18-21 % for a CHP plant, while the energy penalty for the baseline process is 28 %. For a power plant, the penalties go from 32 % to 62 % for the lean solvent flash and the multi-pressure stripper respectively. This shows how improving the process can reduce the costs of CCS, especially if heat is considered a valuable product. CCS in CHP plants has a much lower energy impact than in power plants where heat is not recovered.

The global energy system is undergoing a transformative change towards renewable energies. The share of Renewable Energy Sources (RES) and bioenergy in the world’s primary energy use has increased in the recent years. Based on the EU Roadmap 2050 energy plan, the share of renewables in final energy use in Europe will reach at least 55%, a 45% increase from its share today. Due to the intermittent energy supply from renewables, their high penetration in energy systems can jeopardize the system flexibility, in terms of the balance between energy demand and supply. Lack of system flexibility could cause energy curtailments, increase system costs, or make renewables unreliable sources of energy. Moreover, the expansion of the renewable energy supply could influence the operational strategy of existing energy systems like Combined Heat and Power (CHP) plants. Therefore, the current study focuses on increasing system flexibility of a CHP-dominated regional energy system with increased renewable power supply. Two flexibility options, including a polygeneration strategy and large-scale energy storage using power-to-gas technology, were modelled. The system is then optimized using a Mixed Integer Linear Programming (MILP) method to investigate the production planning of CHP plants in a renewable-based energy system with higher level of flexibility. Different technical and market factors could influence the results of the optimization model, and thereby system flexibility. Thus, the study is carried out under various scenarios for better understanding of the future challenges regarding energy supply, market prices, and climate change. The investigation provides an increased knowledge of production planning for the existing CHP plants with increased interaction with renewables. Based on the overall observations of this thesis, the proposed power storage system contributes to the increased system flexibility. However, the study suggests polygeneration and integration strategy as the optimal pathway to increase RES penetration and to support system flexibility, considering future energy developments and changes in energy demand and supply.

The production of durable biomass pellets have always been challenged by several factors including the lack of understanding of the mechanism involved in how particles combine to form pellets under standard conditions of the pellet press. This is because contributing factors span several molecular, microscopic, and even nanoscopic levels as biomass undergoes pelleting. The characteristics of the bonds formed between the combining particles and their relevance to the quality of pellets remains vague, no matter how quality is defined. However, even though few researchers have attempted to explain the mechanism of bonding in densified biomass pellets using different theories, none of their hypotheses supports particle bonding from a structural chemistry perspective. There are still no clear explanations which consider the role of molecular structure and the interactions of substances as milled biomass undergo pelleting. In view of these arguments therefore, this review presents an in-depth analysis of a structural chemistry perspective of the mechanism of bonding and the use of additives in densified biomass pellets and helps identify research areas needed to facilitate better understanding of bonding in densified biomass pellets. The status of current research in biomass pelleting, types of materials suitable as additives and their structural characteristics, as well as the current technical specifications of using additives are also discussed.

Utility-scale solar photovoltaic (PV) parks have dominated the international market for the past few years. However, in some countries, like Sweden, utility-scale PV is on the verge to economic viability. Using existing infrastructure in a resource-efficient manner could be a crucial strategy for a successful implementation at scale. In this study, a new methodology for a utility-scale solar guide is developed by studying the hosting capacity in the local grid and identifying land appropriate for PV parks. The method is applied on a rural municipality in Sweden (512 km2) with a local distribution grid (5,000 customers). The impact on the grid, if connecting a PV park to a substation, was analyzed through power flow simulations and the geographical assessment was done using multi-criteria analysis with a Boolean approach. Three different sizes of PV parks, 1, 3, and 5 MWp, were analyzed. Results showed that 3.7% of the studied area is qualified for locating 1 MWp PV parks. However, if introducing a maximum distance threshold to the nearest substation that can host the PV generation from the park, the potential is further reduced (e.g., to 1% for a 750 m threshold). Furthermore, parts of the grid can host PV parks of 3 and 5 MWp, but only near urban areas, where qualified land is lacking. The results highlight that the proposed methodology can function as a tool in the dialog between utility companies, municipalities, PV companies, land-owners and other stakeholders in order to find resource- and system-efficient locations for PV parks.

To support the fulfillment of Sweden's targets in term of climate change and economic growth, we need to do a distinct study to show the Environmental Kuznets Curve (EKC) pattern in different sector of the economy, as the GDP allocation, energy intensities, GHG emission, and technological development are different between sectors. This kind of study helps to figure out how the different sectors contribute to climate change and could appoint more particular and effective environment-energy policies. For this aim, we analyzed the existence of the EKC by implementing the ARDL Bound test approach in the whole and individual sectors of Sweden's economy throughout 1990-2019. Our results indicated the contribution of a particular sector on total GHG emissions per capita. Results of the whole economy confirmed the EEKC hypothesis with a turning point in 1996, in which the AFF sector, unlike industry and service, had increased GHG emissions. Disaggregated sectoral analysis showed various results. The industry sector had efficient energy improvement. Policymakers should pay attention to AFF's GHG emissions, as different sources of energy consumption had not impressive impact in both the short and long term. Also, effective fossil-related policies are necessary for the service sector due to the main contribution to transportation.

I detta examensarbete i energiteknik har en litteraturstudie om de vanligaste energisystemen i Sverige och en webbundersökning gjorts där 550 husägare i Järfälla kommun erbjudits att delta. I undersökningen ställdes 11 frågor om deras nuvarande energisystem och ifall de var benägna att investera i solkraft. Av de 550 tillfrågade valde 78 att delta i undersökningen vilket motsvarar 14% svarsfrekvens. Det utreddes även om de vanligaste anledningarna varför fler husägare inte investerat i solkraft. De anledningarna var främst av ekonomiska skäl och att deras hus inte var lämpat för solkraft på grund av husets läge och takkonstruktion. Utvecklingen av solkraft går i rask takt och med en ny skattereduktion för grön teknik förutser författaren att takten ökar de kommande åren, speciellt då elbilsmarknaden förväntas växa enormt och intresset för laddstationer i samband med detta. Utvecklingen av förnybara energisystem går också i rask takt, värmepumpar som ses som förnybar har ökat från 754 000 år 2009 till 1 227 000 år 2016. Undersökningen bekräftade utvecklingen, från undersökningen hade 43 deltagare installerat en luftvärmepump och 30 deltagare installerat bergvärme. 13 deltagare hade installerat solel och den vanligaste anledningen varför var att öka självständigheten och minska behovet av att köpa el, även att minska klimatpåverkan. De statliga bidragen har spelat stor roll i deras villighet att installera solel. De vanligaste anledningar varför fler inte installerat solel var de långa återbetalningstiderna och den begränsade lagringsfunktionen. Deltagarna med en elpanna installerad i fastigheten var mest benägen till att investera i förnybar energi genom värmepump och solel.