Publikationer från KTH
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Användarbehov och visualisering i aggregatorsportaler för batterilagringssytem (BESS)
No full textAs battery energy storage systems (BESS) become increasingly central to maintaining grid stability in renewable-heavy energy markets, aggregator portals play a vital role in helping BESS owners monitor performance, understand costs, and build trust with third-party operators. This study investigates what information and metrics are most valuable to BESS owners using aggregator portals, how such data should be visualized, and how aggregator portals complement or overlap with integrator portals. Through seven semi-structured interviews with users of the aggregator Flower Portal, five key user needs were identified: cost and revenue tracking, evaluation of aggregator performance, algorithmic transparency, monitoring of battery degradation and warranties, and operational status of control systems. Three interactive prototypes were developed and evaluated in user testing sessions to explore how visualizations could address these needs. The findings highlight the importance of transparency, role-specific customization, and clearly defined system responsibilities in aggregator portal design. This work offers empirically grounded recommendations for improving aggregator portals and contributes new knowledge to a previously underexplored area in the energy technology domain.I takt med att batterienergilagringssystem (BESS) blir en allt viktigare del i att upprätthålla nätstabilitet i energimarknader med hög andel förnybar energi, spelar aggregatorportaler en central roll i att hjälpa BESS-ägare att övervaka prestanda, förstå kostnader och bygga förtroende. Denna studie undersöker vilken information och data som är mest värdefull för BESS-ägare i aggregatorportaler, hur sådan data bör visualiseras samt hur aggregatorportaler kompletterar eller överlappar med integratörsportaler. Genom sju semistrukturerade intervjuer med användare av aggregatorportalen Flower Portal identifierades fem centrala användarbehov: uppföljning av kostnader och intäkter, utvärdering av aggregatorns prestanda, algoritmisk transparens, övervakning av batteridegradering och garantier, samt operativ status för agreggatorns styrsystem. Tre interaktiva prototyper utvecklades och utvärderades i användartester för att undersöka hur visualiseringar kan möta dessa behov. Resultaten betonar vikten av transparens, rollanpassade gränssnitt och tydlig ansvarsfördelning i designen av aggregatorportaler. Studien bidrar med praktiska rekommendationer och ny kunskap inom ett tidigare outforskat område inom energiteknik
Timpriskontrollerat relä : För SG-Ready värmepumpar
No full textThis thesis explores how an embedded system can be used to improve the functionality of already present systems, more specifically, how a heat pump can be controlled with respect to the current price of electricity. Some modern heat pumps have this functionality present, but older models do not have it. Therefore, having sustainability in mind, improving heat pump installations without replacing them outright is of interest. The approach used to solve this problem was to use smart grid ready functionality that is present in heat pumps starting from 2013. This functionality is in use in Germany, Switzerland, and Austria for load balancing purposes in their electrical grids. This is accomplished by altering how hard heat pumps in the grid work by sending control signals. Therefore, instead of the electrical grid sending control signals, it should be possible to connect a device that sends the same kinds of signals, but the logic behind what signals to send will be based on the electricity price. The outcome of this thesis project is a device that can control a smart grid ready heat pump by sending control signals based on the current hourly rate for electricity.Detta examensarbete undersöker hur ett inbyggt system kan användas för att utöka funktionaliteten på redan installerade värmepumpar, mer specifikt hur en värmepump kan bli styrd med hjälp utav det nuvarande timpriset för elektricitet. Vissa moderna värmepumpar har redan denna funktionalitet, dock så saknar äldre värmepumpar detta. Med hållbarhet i åtanke så finns det ett intresse att förbättra äldre installationer utan att byta ut hela värmepumpen är därför av intresse. Tillvägagångssättet som valdes var att använda smart grid ready teknik som finns i värmepumpar från 2013 och framåt. detta används huvudsakligen i Tyskland, Schweiz och Österrike för att balansera elnätet i dessa länder. Detta genom att kontrollera hur hårt värmepumpar i elnätet arbetar genom att skicka kontrollsignaler. Genom att koppla in ett inbyggt system och skicka samma typ av signaler, men istället för elnäts balans, så bör det gå att kontrollera värmepumpen baserat på timpriset för elektricitet. Resultatet av detta är ett inbyggt system som kan kontrollera en smart grid ready värmepump baserat på nuvarande timpris för elektricitet
Objekttolkning i laserdata : En undersökning av möjligheten att ersätta eller komplettera ortofoton i topografisk kartering
No full textToday, the rate of topographic map production is limited by the acquisition rate of orthophotos. To increase the rate at which topographic maps can be supplied, the production rate of orthophotos needs to be improved. An alternative is to utilse other acquisition methods for topographic map production, such as LiDAR. To assess whether,and to what extent LiDAR can substitute, complement, and enhance orthophotos, various data layers are derived. The layers are LiDAR intensity, traditional monodirectional hillshade, multidirectional hillshade, slope and a composite layer. Five object types have been selected to examine the interpretability across the orthophoto and LiDAR-derived layers. The object types are minor road, tractor path, foot path, turnaround point and watercourse. For these object types, 3, 2, 2, 5 and 1 objects were selected, respectively. For the minor road, tractor path, foot path, and watercourse objects, line representations were created from the interpreted extent of the features. The interpretation of each object, across all layers, wasmeasured by two values: one statistical discrepancy value, CE90 and one evaluation grade assessing the visual interpretability of an object.The results indicate that orthophotos are superior in field terrain, however, intensity and composite are good alternatives for interpretation. In forest terrain, intensity is the most potent, but in dense forests, the two hillshades and slope layers provide better interpretability. In irregular terrain, the interpretability is mostly like other terrain types for thetwo hillshades and slope layers. The CE90 discrepancies are all within the positional accuracy specified for all objects that were interpreted. This study concludes that LiDARdata could substitute orthophotos, even though some limitations are present; that lidar can be an important complement to orthophotos, especially in forest and shaded areas; and that the combination of orthophoto and LiDAR tried in this project, is not the most efficient layersin any application. Alternating between layers may therefore be a more sensible approach
Trade with legal rights to electric power : Legal constraints and economic models for energy market independence and long-term real estate asset appreciation
No full textDenna uppsats undersöker möjligheterna för fastighetsägare att reducera sina energikostnader och samtidigt öka sina fastigheters värde genom investeringar i förnybar energi. Den klarlägger de juridiska och ekonomiska aspekterna för att genom så kallad rätt till elektrisk kraft enligt 15 Kap. JB att efter en engångsbetalning/delinvestering tillägna sig elkraft under överskådlig framtid från det externa kraftverk investeringen avser. Genom en kombinerad juridisk och ekonomisk analys utvärderas hur en sådan investering kan säkras för fastigheten, hur elöverföring kan ske på ett effektivt sätt samt vilka ekonomiska och juridiska risker som är förknippade med en sådan konstruktion. Den juridiska delen utgörs av studier av relevanta lagrum och förarbeten samt de ytterligt få rättsfall som finns på området. Den ekonomiska analysen utgår ifrån värdeanalysprincipen som genom Gordons formel och nettokapitaliseringsmetoden för värdebedömning vidareutvecklas och appliceras på problemet i fråga. Genom en kombination av juridisk analys och ekonomisk modellering identifierar uppsatsen begränsningar för investeringsmodellen samt strategier som möjliggör åtkomst till energimarknadsoberoende och ökad ekonomisk, såväl som ekologisk hållbarhet genom den modell som utvecklas.Slutsatserna visar att en investeringsmodell där rätt till elektrisk kraft genom direktförsörjning från externa energikällor kan skapa en stabilare och mer förutsägbar energiförsörjning för fastighetsägaren samt att investeringen måste betraktas ha stora möjligheter till lönsamhet givet dagens svenska energimarknad. Investeringen minskar inte bara fastighetsägarens beroende av energimarknadens volatila elpriser, utan bidrar också till att stärka fastighetens ekonomiska värde och attraktionskraft. Dock identifieras begränsningar, såsom krav på att fastigheten är bolagiserad.This thesis explores the potential for property owners to reduce their electricity costs while simultaneously increasing the value of their properties through investments in renewable energy. It examines the legal and economic aspects of utilizing so-called "right to electric power" under Chapter 15 of the Swedish Land Code (Jordabalken), enabling property owners to secure electricity from an external power plant, tied to the investment via a one-time payment or partial ownership investment, ensuring supply for the foreseeable future.Through a combined legal and economic analysis, the study evaluates how such an investment may be secured for the property, how electricity transmission may be carried out efficiently, as well as the economic and legal risks associated with the proposed arrangement. The legal section comprises an examination of relevant statutes, the legislative background, and the limited applied cases available in this area. The economic analysis applies the value assessment principle, utilizing Gordon's formula and the net capitalization method for real estate evaluation to further develop and address the specific problem.By combining legal analysis with economic modelling, the thesis identifies limitations of the investment model and outlines strategies to achieve energy market independence and enhanced economic and ecological sustainability through the proposed framework.The findings demonstrate that an investment model involving legal rights to electric power through direct supply from an external energy source could provide property owners with a more stable and predictable energy supply. Additionally, such investments show strong prospects for profitability given the current dynamics of the Swedish energy market. This approach not only reduces dependency on the currently volatile electricity prices of the Nordic energy market, but also enhances the economic value and attractiveness of the property. However, the study highlights certain limitations, such as the requirement for the property to be incorporated as a legal entity
Mobility knowledge graph : review and its application in public transport
No full textUnderstanding human mobility in urban areas is crucial for transportation planning, operations, and online control. The availability of large-scale and diverse mobility data (e.g., smart card data, GPS data), provides valuable insights into human mobility patterns. However, organizing and analyzing such data pose significant challenges. Knowledge graph (KG), a graph-based knowledge representation method, has been successfully applied in various domains but has limited applications in urban mobility. This paper aims to address this gap by reviewing existing KG studies, introducing the concept of a mobility knowledge graph (MKG), and proposing a general learning framework to construct MKG from smart card data. The MKG represents hidden travel activities between public transport stations, with stations as nodes and their relations as edges. Two decomposition approaches, rule-based and neural network-based models, are developed to extract MKG relations from smart card data, capturing latent spatiotemporal travel dependencies. The case study is conducted using smart card data from a heavily used urban railway system to validate the effectiveness of MKG in predicting individual trip destinations. The results demonstrate the significance of establishing an MKG database, as it assists in a typical problem of predicting individual trip destinations for public transport systems with only tap-in records. Additionally, the MKG framework offers potential for efficient data management and applications such as individual mobility prediction and personalized travel recommendations.QC 20231211</p
Homing in Husby
No full textHoming is used to describe the state in which people, after beginning life in a completely new environment, always attempt to create a sense of home. This design focuses on the local residents of Husby, studying how their process of homing influences the spatial dynamics of Husby. Key spaces associated with this process are abstracted into fundamental spatial typologies. Based on these new spatial typologies, the design integrates scaffolding structures to transform Husby’s parking garages, enabling local residents to experience a sense of home within these large-scale infrastructures
Bedömning av drivkrafterna för obalans i det franska elnätet för kontounderskott 2022
No full textThe global energy landscape has undergone dramatic changes in recent years, driven by a combination of factors including the push for the adoption of renewable energy, geopolitical tensions, and economic pressures. In Europe, these challenges converged in 2022, a year marked by an acute energy crisis due to a surge in global energy prices, supply chain disruptions, and a decrease in gas supplies from Russia following the invasion of Ukraine. The ripple effects of this crisis severely impacted energy security, costs, and the operational stability of electrical grids across the continent, including in France. France’s electrical grid, operated by the national Transmission System Operator (TSO) RTE (Réseau de Transport d’Électricité), experienced significant challenges as it sought to balance supply and demand in real-time while managing the impacts of these external pressures. Complicating matters was the continued integration of variable renewable energy sources (such as wind and solar), which, while crucial for France’s decarbonization goals, introduce complexity due to their intermittency. These conditions frequently led to imbalances in the grid—periods when supply and demand were misaligned, causing fluctuations in grid stability. To correct these imbalances and prevent potential disruptions, RTE activated its adjustment mechanism, a set of interventions aimed at stabilizing the grid by adjusting energy inputs and outputs. These interventions, however, come with significant costs, and in 2022, the Balancing-Imbalance Account (BIA), which tracks these corrective expenses and redistributes them to Balance Responsible Parties (BRPs), recorded a historic deficit of €170 million. This deficit not only highlights the operational difficulties faced by RTE and the BRPs but also underscores the financial strain imposed on the entire system in a year of unprecedented energy challenges.Det globala energilandskapet har genomgått dramatiska förändringar de senaste åren, drivet av en kombination av faktorer, bland annat ökad användning av förnybar energi, geopolitiska spänningar och ekonomiska påtryckningar. I Europa sammanföll dessa utmaningar 2022, ett år som präglades av en akut energikris till följd av en kraftig ökning av de globala energipriserna, störningar i leveranskedjan och minskade gasleveranser från Ryssland efter invasionen av Ukraina. Krisens följdeffekter påverkade allvarligt energisäkerheten, kostnaderna och driftstabiliteten i elnäten över hela kontinenten, inklusive i Frankrike. Frankrikes elnät, som drivs av den nationella systemoperatören RTE (Réseau de Transport d’Électricité), stod inför stora utmaningar när man försökte balansera utbud och efterfrågan i realtid och samtidigt hantera effekterna av dessa externa påfrestningar. En komplicerande faktor var den fortsatta integrationen av variabla förnybara energikällor (som vind och sol), som visserligen är avgörande för Frankrikes mål att minska koldioxidutsläppen, men som också skapar komplexitet på grund av sin intermittens. Dessa förhållanden ledde ofta till obalanser i elnätet – perioder då tillgång och efterfrågan inte var i linje med varandra, vilket orsakade fluktuationer i elnätets stabilitet. För att korrigera dessa obalanser och förhindra potentiella störningar aktiverade RTE sin justeringsmekanism, en uppsättning åtgärder som syftar till att stabilisera nätet genom att justera energitillförsel och -uttag. Dessa åtgärder medför dock betydande kostnader och 2022 uppvisade balanseringskontot (BIA), som spårar dessa korrigeringskostnader och omfördelar dem till balansansvariga parter (BRP), ett historiskt underskott på 170 miljoner euro. Detta underskott belyser inte bara de operativa svårigheter som RTE och de balansansvariga står inför, utan understryker också den finansiella påfrestning som hela systemet utsätts för under ett år med oöverträffade energiutmaningar
Direct digital synthesis of microwave continuous-variable cluster states
No full textContinuous-variable quantum computation has emerged as a promising paradigm for scalable, fault-tolerant, measurement-based quantum computing. Key resources for this approach are cluster states, which are multipartite entangled states characterized by a specific correlation structure. In this thesis we use microwave digital signal processing techniques and a superconducting parametric oscillator to generate, measure, and analyze continuous-variable cluster states in the frequency domain. We employ a Josephson parametric amplifier with a phase-controlled multifrequency pump waveform to engineer connections between modes in a microwave frequency comb multiplexed in a single transmission line. Mode-coupling theory and the scattering formalism are applied to model these connections, showing good agreement with experiments. The scattering framework provides an effective tool to explore parametric interactions, and we extend it to include non-reciprocal scattering between modes. Through programming the phase and amplitude of the multifrequency components of the pump waveform, we demonstrate the directionality of mode coupling, realizing two-mode isolation and a three-mode circulation. The scattering measurements and simulations provide a foundation to explore quantum correlations within the Gaussian quantum information framework. We characterize entanglement through measurement and analysis of the covariance matrix in our frequency-comb mode basis, demonstrating up to 1.4 dB of squeezing in a square-ladder cluster state containing 94 modes. Our work represents a scalable and hardware-efficient method for creating large-scale entanglement with possible applications in quantum computation, sensing, and communication.QC 2025-02-20</p
Contemplative Spaces: Sculptural architecture in an (un)natural landscape
No full textThis thesis projects explores the creation of contemplative spaces that integrate architecture, sculpture, art and nature. The aim is to design sculptural spaces that invite stillness and evoke emotions through the use of light, materiality, form and spatial transitions. This will result in a series of four pavilions engaging with the landscape of the former limestone quarry on Bungenäs, Gotland. The limestone quarry is an ideal context for this exploration. It has a strong sense of place with an intensity of emotions within the landscape itself. The contrast between nature and industrial remnants highlights the duality of the artificial and natural, as well as themes of permanence and ephemerality. Its bright limestone ground, raw jagged stone formations, water-filled pit, proximity to the sea, pine trees, and the wind make it a tranquil and otherworldly place. Inspiration is drawn from places such as Kivik Art Center, Wanås Konst, Ekebergsparken and the Hombroich Museum Insel which combine art, nature, and architecture. These projects show how sculptural structures can engage with a landscape to enhance its sensory and emotional presence. Similarly, this project aims to create pavilions that interact with the characteristics of the quarry at Bungenäs
En studie av solpanel för bostäder i tre svenska städer: Stockholm, Malmö och Umeå
No full textThis thesis examines the energy production and economic feasibility of a 5kW monocrystalline silicon solar panel system in three Swedish cities: Malmö, Stockholm, and Umeå. Sweden aims to rely entirely on renewable energy by 2040, which makes residential solar panels a practical and sustainable solution for future energy needs. However, differences in weather conditions, snow accumulation, and electricity prices across the country impact the energy output and payback period of solar panels. This creates uncertainty for homeowners, who often struggle to assess the panels' true potential and financial return, especially when faced with biased information from solar panel companies. To provide clear and unbiased insights, this study uses weather data from 2023, including solar irradiation, diffuse radiation, and temperature to calculate monthly energy production through MATLAB simulations. The calculations show potential annual energy production of 5937 kWh for Malmö, 5302 kWh for Stockholm, and 5186 kWh for Umeå. Using the production data, the study then conducts an economic analysis to estimate the payback period for each city. The findings show that Malmö has the shortest payback period at 8 years 15 days, followed by Stockholm about 11 years 4 months, while Umeå has the longest payback period at 12 years 10 months approximately.Denna rapport undersöker energiproduktionen och den ekonomiska genomförbarheten av ett 5kW monokristallint kiselsolpanelsystem i tre svenska städer: Malmö, Stockholm och Umeå. Sverige har som mål att helt förlita sig på förnybar energi år 2040, vilket gör solpaneler för bostäder till en praktisk och hållbar lösning för framtida energibehov. Skillnader i väderförhållanden, snöansamling och elpriser över landet påverkar dock energiproduktionen och återbetalningstiden för solpaneler. Detta skapar osäkerhet för husägare, som ofta har svårt att bedöma panelernas verkliga potential och ekonomiska avkastning, särskilt när de möts av partisk information från solpanelsföretag. För att ge tydliga och opartiska insikter använder denna studie väderdata från 2023, inklusive solinstrålning, diffus strålning och temperatur, för att beräkna månatlig energiproduktion genom MATLAB-simuleringar. Beräkningarna visar en potentiell årlig energiproduktion på 5 937 kWh för Malmö, 5 302 kWh för Stockholm och 5 186 kWh för Umeå. Med hjälp av produktionsdata genomför studien sedan en ekonomisk analys för att uppskatta återbetalningstiden för varje stad. Resultaten visar att Malmö har den kortaste återbetalningstiden på 8 år 15 dagar, följt av Stockholm på cirka 11 år 4 månader, medan Umeå har den längsta återbetalningstiden på cirka 12 år 10 månader.