The grid connected solar PV system with battery storage is one of the promising alternativeenergy solutions for electricity consumers. The Local System Operator (LSO) will be a newactor to operate its own energy system by integrating PV and battery system with other technicalsolutions. This thesis investigates the technical and economic viability of a grid connected PVsystem with battery storage in behind-the-meter approach for aggregated residential load toassess the LSO model for the present conditions in Sweden.The system model is developed using the System Advisory Model (SAM) – a simulationsoftware for renewable energy system analysis. The PV system model is designed using solarirradiation profile and fifty multi-dwelling aggregated residential load data from Sweden. Theappropriate design inputs of solar PV module, inverter and system loss are taken from previousstudies. The electricity price is analysed from the comparative study of Nord-pool wholesaleprice, market retail price and distribution grid tariffs. The financial metrics such as discountrate, inflation rate, system cost and currently available PV incentives are considered to make anaccurate model. To help with the assessment, three cases are formed; the first case representsonly the PV system and the other cases include storage - using a lithium-ion or lead-acid battery.This comparative study helps to determine the optimum PV and battery size at two differentlocations in Sweden.The optimum net present value (NPV) and profitability index (PI) is found at the 40 kW PVand 3 kWh battery system at Karlstad, Sweden. The optimum case is considered for furtherinvestigation to evaluate the system life time energy profile, electricity bill saving capabilityand battery performance. The system peak shaving potential is investigated by making twoother scenarios with higher battery capacity. Sensitivity analysis is also performed to assess thesystem’s technical and financial input parameters. The system capacity factor at the site locationis found as an influential parameter to the annual production and profitability. The optimumsize of PV system with a lithium-ion battery investment is found feasible for the LSO realimplementation only considering the current PV incentives and electricity price in Sweden. Thereport concludes with the assessment, the technical and economic feasibility of the studied PVand battery storage system profitability depends on the system site location, residential loadsize, consumer electricity cost and available PV incentives. / solcellsystem (PV) med batterilagring är en lovande alternativenergilösning förslutkonsumenten. Den 'local system operator', LSO, blir en ny aktör som driver egetenergisystem genom att integrera PV- och batterisystem med andra tekniska lösningar. Dennaavhandling undersöker det tekniska och ekonomiska genomförbarhetet i ett nätanslutet PVsystem med batterilagring i 'bakom mätaren' scenario för aggregerade bostäder i ettflerbostadshus, för att urvärdera LSO modellen.Systemmodellen är utvecklat med 'system advisory model' (rådgivande modell), SAM, ettsimuleringsprogram för förnybara energisystem. PV systemparametrarna beräknas med hänsyntill väderprofiler och lastdata från Sverige. Lämpliga parametrar för solcellsmoduler, omriktareoch systemförluster tas från tidigare studier. Slutkonsumenternas elpriser analyseras frånjämförande studie av NordPool grosshandelspris, konsumentpris och distributionnätstariffer.Finansiella mått såsom system kostnad, rabatt och inflationstakten och tillgängliga incitamentför PV investeringar används för att göra modellen noggrannare. Tre fall undersöks; det förstarepresenterar systemet med bara PV, och de övriga fallen lägger till lagring, genom antingenlitiumjon eller bly-syre batterier. Denna jämförande studie är ett underlag för att bestämma denoptimala PV och batteristorleken för anläggninar på två olika område i Sverige.Den optimala netto nuvarande värde (NPV) och lönsamhet index (PI) är på 40 kW PV systemetoch 3 kWh batteri på Karlstad, Sverige. Ytterligare undersökning av detta fall används för attutvärdera energiprofilen under systemets livstid, möjlighet till minskad elräkning, och batterietsprestanda. Potential för utjämning av systemets topplast utreds genom att skapa två andrascenarier med högre batterikapacitet. Känslighetsanalys utförs också för att bedöma de tekniskaoch ekonomiska parametrarna. Den optimuma storleken på PV system med ett litium-jonbatterifinns rimligt för LSO riktiga genomförande med tanke på incitamenten. Simuleringsresultatenoch systemkonsekvenserna av LSO modellen diskuteras. Rapporten visar att den tekniska ochekonomiska genomförbarheten av det studerade PV systemet med litium-jon batteri beror påslutkonsumentelpriset, PV incitament och globala trender i kostnaderna försystemkomponenter, samt på valet av lämplig plats med en effektiv analys av väder profil ochsystemetförluster.

As we are moving towards a future carbon-neutralsociety, development of residential microgrids attracts much attentionaround the world with its efficient utilization of renewableenergy. A residential microgrid is a small power system fora house, which consists of a solar photovoltaic (PV) source,a battery storage, residential loads, and an interface to thegrid. In this paper, a hybrid AC-DC microgrid is proposed,studied and simulated in Matlab/Simulink. A coordinated controlstrategy is developed so that the PV converter is controlledto maximize its power generation, the battery converter iscontrolled to stabilize the system with the battery state of chargeconstraints, and an interlinking converter is controlled to decidethe connection/disconnection and the power flow with the grid.The simulation results show the effectiveness of the proposedsolution under various operating conditions. / I det här pappret föreslås, studeras ochsimuleras ett hybrid-anpassat lokalt självförsörjande elnät iSimulink och Matlab. Solpaneler utgör den distribueradeförnyelsebara energikällan i nätet. Panelerna styrs med enMPPT-algoritm för att maximera kraftgenereringen. Batterietsladdningstillstånd används i det designade batterilagringssystemetför att garantera lång livstid och för att fatta beslut omladdning och urladdning. Kraftöverföring mellan ACoch DCnätverk sker via en dubbelriktad omvandlare. Det konstrueradehybridnätet fungerar självständigt samt vid sammankopplingtill huvudnätet. Ett koordinerat kontrollsystem implementerasför att möjliggöra kommunikationen mellan lokalnätets olikadelar. Resultaten från simuleringstestet visar att det föreslagnanätet uppfyller stabilitetskrav och god funktion under varierandedriftstillstånd. / Kandidatexjobb i elektroteknik 2021, KTH, Stockholm

Förnybar energi sägs vara en stor bidragande faktor till att lösa klimatproblem med global uppvärmning och den svenska regeringen har som mål att Sverige ska vara 100% fossilfritt år 2045. Ett förslag från Energimyndigheten är att cirka 5-10% av den svenska elkonsumtionen ska komma från solceller. Utvecklingen med solceller går framåt och allt fler privatpersoner och företag väljer att investera i det. Denna rapport ämnar att undersöka hur solceller kan dimensioneras för större kommersiella företag, samt även att kartlägga hur nyckelpersoner i koppling till företaget Dahl Sverige AB resonerar om hållbarhet och solceller. Dahl har valt att utvärdera möjligheten med solceller och används därför som ett studieobjekt i denna rapport. Efter insamling av av data kunde programmet System Advisor Model användas för att dimensionera solcellssystemet. Utifrån resultaten av simuleringarna togs tre olika storleksalternativ på solcellssystemet fram för att kunna fungera som beslutsunderlag vid beslutsfattande från Dahl; ett alternativ för att undvika energiskatten och främja det ekonomiska, ett för att undvika överproduktion och slutligen ett för maximal miljönytta. Dock kan en avvägning göras utifrån vad företaget själva accepterar för tröskelränta, eftersom att solcellssystemet blev mer miljövänligt men krävde en större investering allt eftersom storleken ökade. För att undersöka resonemang beträffande solceller och hållbarhet har intervjuer genomförts med fem nyckelpersoner i logistikprojektet där Dahl bygger ett nytt centrallager. Intervjuerna kategoriserades i sex olika teman. Dessa jämfördes sedan utifrån ett teoretiskt ramverk om olika paradigm: ett transformativt ekocentriskt paradigm samt ett dominant kulturellt paradigm. Resultatet synliggjorde att informanterna resonerade på olika sätt. Det fanns inslag av båda paradigmen men informanterna resonerade främst utifrån det dominanta kulturella paradigmet som motsvarar dagens marknadsdrivna konkurrensbaserade samhälle. Ett alternativ för att utveckla företaget i en mer hållbar riktning blir således att införa mer internutbildning för att främja en transformativ ekocentrisk världssyn. Denna slutsats uppskattas vara applicerbar även inom andra företag utanför Dahl. / Renewable energy is said to be a contributing factor in solving the environmental problems with global warming, which is why the Swedish Government has decided that Sweden will be 100% fossil free by 2045. A proposition from the Swedish Energy Agency is that around 5-10% of the Swedish consumption should come from solar energy. The development of solar PVs are going forward, and the number of private households and organisations that are choosing to invest are growing. This report aims to investigate how a solar PV system can be dimensioned for bigger commercial companies. It also seeks to map how stakeholders at Dahl Sverige AB, a large trading company in the plumbing industry, reason about solar cells and sustainability. Dahl is evaluating the possibilities with solar PVs, and will be used as a case in this report. After collecting data, the System Advisor Model program could be used to dimension the solar cell system. Based on the results of the simulations, three different size alternatives on the solar cell system were developed in order to be able to function as a basis for a decision for the study object; one option to avoid the energy tax and promote the economy, one to avoid overproduction and one for maximum environmental benefit. However, a trade-off could be made depending on what hurdle rate the company deems acceptable, as the solarsystem becomes more environmentally friendly but requires a larger investment as the size increases.To investigate reasoning regarding solar cells and sustainability, five interviews were conducted with five stakeholders with a connection to the logistics project to build a new central warehouse. The interviews went through a thematic analysis and the answers were characterized as six different themes. These were analysed on the basis of a theoretical framework that distinguishes between a dominant cultural paradigm and a transformative ecocentric paradigm. The result showed that the informants reasoned differently. There were elements from both paradigms, but the informants largely expressed opinions that could be characterized as the dominant cultural paradigm. An alternative for Dahl to become more sustainable was thus to introduce more internal training to promote a transformative ecocentric worldview. This conclusion is assessed to be applicable for other companies outside the Dahl case as well.

The Republic of Kosovo, and its 1.8 million inhabitants, is heavily reliant on two highly pollutive lignite coal-fired power plants, Kosova A and Kosova B for energy generation. The coal-fired power plants, that cover 91% of the energy generation, are reaching the end of their operational life and are in need of either restoration or discontinuation. This implies that Kosovo is in need of energy alternatives for a more flexible energy system which could open opportunities for renewable energy. Solar power in Kosovo is still at a low percentage of less than 1%, and its future penetration is being held back by lack of investments and underdeveloped regulatory framework. Affordable and reliable energy, from solar power, could reduce poverty, lower unemployment, boost economic growth and improve people's health in Kosovo. This coincides with the sustainability goals set by the UN Agenda 2030 and specifically goal 7, ‘Ensure access to affordable, reliable, sustainable and modern energy for all’. The aim of the project was to design a techno-economically optimal PV-system at The University of Prishtina and to investigate the potential technical, social and economic impacts of implementing PV-systems in Kosovo to help achieve the UN 2030 Agenda, specifically SDG 7. The project consists of a quantitative part where simulations were done with the System Advisor Model (SAM) in order to calculate the energy generation and profitability of installing photovoltaic modules at The University of Prishtina with different policy-schemes. In addition, a qualitative study was done by compiling information on the policy structures in Kosovo and other european countries in order to identify obstacles and future trends in the development of renewables. The results showed that it is profitable for the University of Prishtina to install a PV-system in which the inspected financial indicators such as NPV, LCOE and payback time showed profitability for all policy-scenarios. In the base scenario with 200 kWp, which follows the current policy and capacity restrictions on the maximum allowed capacity of 100 kWp per metering point, 60% of the yearly electricity bills were covered. Two additional models were made with alternative policy-scenarios, one with a net-billing model in which sell-rates were altered and another with a higher capacity of 298.49 kWp utilizing the whole roof area. The system of 298.49 kWp gave the highest energy production and could cover 80% of the early electricity bills. The net-billing simulations indicated that profitability is also feasible for small-scale PV in a net-billing scheme with low sell-rates of electricity. LCOE ranged from $6.98 to 8.24 ¢/kWh, for all policy-scenarios, which was lower than the buy-rate of electricity for The University of Prishtina. The results from the simulations along with the qualitative study conclude that the cost- and technical potential for solar power is profitable and feasible. In addition to socio-economic factors such as job-opportunities and health benefits, solar power could be a competitive energy alternative in comparison to current forms of energy generation in Kosovo. However, due to restrictive RES-policy and potentially costly FiT’s in Kosovo a proposition, collected through qualitative studies, is to switch to auctioning schemes with possible usage of FiP’s, if needed, for large- scale PV with regulators putting an emphasis on an open, fair and competitive market. Solar power is competitive and would fare well in such schemes and its implementation should be encouraged by stakeholders and regulators in Kosovo. / Republiken Kosovo och dess 1.8 miljoner invånare är starkt beroende av de två kraftigt förorenade kolkraftverken Kosova A och B för sin energiproduktion. Kolkraftverken, som är i slutskedet av sin livslängd, utgör närmare 91% av landets energiproduktion och är i behov av antingen restaurering eller avveckling. Detta medför ett stort behov av nya, flexibla energikällor i Kosovo vilket luckrar upp möjligheter för förnybar energi, särskilt solkraft. Andelen solkraft i Kosovo utgör idag mindre än 1 % av landets energimix och hämmas avsevärt av underutvecklade regelverk och brist på investering. Ekonomiskt överkomlig och tillförlitlig energi från solkraft skulle kunna bidra till minskad fattigdom, sänkt arbetslöshet, ökad ekonomisk tillväxt samt förbättrad hälsotillstånd hos Kosovos invånare. Detta sammanfaller i sin tur med FN:s globala hållbarhetsmål stipulerade i Agenda 2030, särskilt mål 7, ”Säkerställa tillgång till ekonomiskt överkomlig, tillförlitlig, hållbar och modern energi för alla”. Syftet med arbetet var att utforma ett tekno-ekonomiskt optimalt solcellssystem vid Universitetet i Pristina, samt undersöka de potentiella tekniska, sociala och ekonomiska effekterna av att implementera solcellssystem i Kosovo. Detta i mån om FN:s hållbarhetsmål och Agenda 2030, inriktat på mål 7. Projektet består av en kvantitativ analys där energiproduktionen och lönsamheten av att installera solcellsmoduler vid Universitetet i Pristina simuleras i anknytning till olika policy regelverk med hjälp av System Advisor Model (SAM). Vidare utfördes en kvalitativ studie där information om rådande politiska strukturer och regelverk i Kosovo och andra europeiska länder sammanställdes för att identifiera aktuella hinder och framtida trender i utvecklingen av förnybar energi. Resultaten visade att det är lönsamt för Pristinas universitet att installera ett solcellssystem. De granskade finansiella indikatorerna som NPV, LCOE och payback påvisade lönsamhet för alla simulerade policy scenarion. I bas-scenariot med 200 kWp med nuvarande kapacitets och policy restriktioner på maximalt 100 kWp per mätningspunkt, täcks 60% av de årliga elräkningarna. Därutöver simuleras ytterligare två modeller med alternativa policy-scenarion. En net-billing modell med varierande el-försäljningspriser samt en modell med högre kapacitet på 298,49 kWp. I systemet med 298,49 kWp erhölls den högsta energiproduktionen som täckte närmare 80% av de årliga elräkningarna. Net-billing simuleringarna gemensamt med låga el-försäljningspriser indikerade även lönsamhet i net-billing systemet. Denna typ av elförsäljning kan därmed vara realiserbart och tillämpas för småskaliga solkraftsanläggningar i Kosovo. För alla policy scenarion varierade LCOE från $ 6,98 till 8,24 ¢/kWh, vilket var lägre än elpriserna för Universitetet i Pristina. Resultaten från simuleringarna och den kvalitativa studien antyder att den tekniska och ekonomiska potentialen för solenergi är hög. Utöver socioekonomiska faktorer som jobbmöjligheter och hälsofördelar kan solenergi vara ett konkurrenskraftigt energialternativ jämfört med nuvarande former av energiproduktion i Kosovo tack vare dess billiga kostnader. Med avseende på restriktiva regelverk gällande förnybar energi och den potentiellt dyra feed-in tariff-policyn i Kosovo är det till fördel, baserat på den kvalitativa och kvantitativa analysen, att utveckla ett auktionssystem med kompletterande feed-in premium för storskaliga solkraftsanläggningar. Detta med betoning på en öppen, rättvis och konkurrenskraftig marknad. Solkraft är billigt, konkurrenskraftig och är gynnsam för de socioekonomiska aspekterna i Kosovo. Dess implementering bör uppmuntras av intressenter och lagstiftare i Kosovo. / Në Republiken e Kosovës me 1.8 milion banorë, qytetarët e saj varen shumë nga dy termocentrale të ndotura, Kosova A dhe Kosova B. Termocentralet me linjit, që mbulojnë 91% të gjenerimit të energjisë, po arrijnë fundin e jetës së tyre operacionale dhe kanë nevojë për restaurim ose ndërprerje. Kjo nënkupton që Kosova ka nevojë për energji alternative dhe për një sistem më fleksibël, i cili mund të hapë mundësi për energji të rinovueshme. Energjia diellore në Kosovë është akoma në një përqindje të ulët të perdorimit prej më pak se 1%. Energjia diellore po frenohet nga mungesa e përpilimit të ligjeve dhe mungesa e investimeve. Nga energjia diellore Kosova mund të ketë perfitime në rritjen ekonomike dhe përmirësim të shëndetit për popullatën e Kosovës. Kjo ç ështje eshtë në perputhshmëri me qëllimet të vendosura nga agjenda e OKB-së 2030, në veqanti pika 7 në të cilën thuhet: ‘ të sigurohet aksesi në energji të përballueshme, të besueshme, të qëndrueshme dhe moderne për të gjithë ’. Qëllimi ynë me këtë studim është të hulumtojmë mundësitë për një sistem optimal fotvoltaike (PV) në Universitetin e Prishtinës ‘Hasan Prishtina’. Gjithashtu qellimi me ketë studim është të hulumtojmë ndikimet e mundshme teknike, sociale dhe ekonomike në zbatimin e sistemeve PV në Kosovë për të arritur agjendën e OKB-së 2030, posaçërisht pika 7. Projekti përbëhet nga një pjesë sasiore ku janë bërë simulime me System Advisor Model (SAM) në mënyrë që të llogaritet gjenerimi i energjisë dhe përfitimi i instalimit të moduleve PV në Universitetin e Prishtinës me skema të ndryshme rregullative. Për më tepër, është bërë një studim cilësor duke përpiluar informacione mbi strukturat rregullative në Kosovë dhe vendet e tjera evropiane në mënyrë që të identifikohen pengesat dhe tendencat e ardhshme në zhvillimin e burimeve të ripërtëritshme (BRE). Rezultatet e këtijë studimi tregojnë se, për Universitetin e Prishtinës, është veprim fitimprurëse të instalohet një sistem PV. Përmes këtijë sistemi, treguesit financiarë si NPV, LCOE dhe payback rezultojnë në përfitime ekonomike ne të gjitha skemat e provuara rregullative. Në modelin e parë bazë me 200 kWp, i cili ndjek politikat (policy) aktuale me kufizime të kapaciteteve të lejuar prej 100 kWp për një pikë matëse, mbulohen 60% e faturave vjetore të energjisë elektrike. Ndërsa në dy modelet tjera shtesë, bëmë percaktime të skemave alternative. Një nga modelet ishte net-billing në të cilin ndryshuam normat e shitjes. Tjetri model ishte një sistem PV me kapacitet më të lartë prej 298.49 kWp duke përfshirë gjithë siperfaqën e kulmit. Sistemi prej 298.49 kWp dha prodhimin më të lartë të energjisë dhe mund të mbulojë 80% të faturave të energjisë elektrike. Rezultatët e skemës së net-billing treguan se përfitimi është i mundshëm gjithashtu, me norma të ulëta të shitjes së energjisë elektrike. Kjo skemë mund të zbatohet për instalime të vogla me PV në Kosovë. Vlerat e LCOE varion nga $6.98 ¢/kWh- 8.24 ¢/kWh dollar, në të gjitha modelet. Kjo tregon se kostoja është më e ulët se norma e blerjes së energjisë elektrike për Universitetin e Prishtinës. Rezultatet nga simulimet e të gjitha modeleve së bashku me studimin cilësor arrijnë në përfundim se kostoja dhe potenciali teknik për energjinë diellore është fitimprurëse dhe i realizueshëm. Ky studim tregon se përveç faktorëve socio-ekonomikë siç janë mundësitë e punësimit dhe beneficioneve shëndetësore, energjia diellore mund të jetë një alternativë konkurruese e energjisë në krahasim me format aktuale të gjenerimit të energjisë në Kosovë. Sidoqoftë, për shkak të politikave përkufizuese të BRE-ve dhe feed-in tariff ose FiT-ve, qe janë potencialisht të kushtueshme, një rekomandim për instalime të mëdha të PV-së është kalimi në skema tender, potencialisht me përdorimin të feed-in premium ose FiP-ve. Ne ketë skeme, politikbërësitë duhet të krejojnë mundesit për një treg të hapur, të barabartë dhe konkurrues. Energjia diellore do të jetë me kosto më të ulëta në të ardhmen dhe implementimi i saj duhet të inkurajohet nga palët e interesit dhe politikbërësitë në Kosovë.

<p>Solar energy is a clean and abundant renewable energy source which is currently used in many types of photovoltaic (PV) designs. In practical PV systems, solar panels are used to harvest solar energy and convert it into a usable form of electricity. Due to the intermittent nature of solar energy input however, battery storage, in combination with solar panels, must be used to provide an uninterrupted source of power.</p> <p>The process of assigning solar panel and battery configurations for a PV system is referred to as energy resource provisioning. Unfortunately, energy provisioning costs are still relatively high, and this is one of the main obstacles that inhibits the adoption of solar power for many applications. These costs however, can be substantially reduced through cost-efficient resource provisioning methods. The focus of this thesis is on the development of efficient algorithms and energy management methods that will reduce energy provisioning costs in solar powered systems.</p> <p>First, we consider resource provisioning in solar powered wireless mesh networks. In practical solar powered systems, there are usually restrictions in the way that the mesh nodes can be positioned, and this results in a time-varying and node-dependent attenuation of the available solar energy. Unfortunately, conventional resource provisioning methods cannot take this into account and therefore the deployed system may be unnecessarily expensive. In this part of the thesis, the resource provisioning problem is considered from this point of view. We first review conventional resource provisioning mechanisms and give an example which shows the value of introducing positional solar insolation awareness. A Position Aware Provisioning (PAP) algorithm is then introduced that takes known positional variations into consideration when performing the energy provisioning. Simulation results show that reductions in total network provisioning cost can be obtained using the proposed methodology compared to conventional algorithms.</p> <p>In the second part of the thesis, we consider communication infrastructure that is operated from the power grid with a solar powered addition. Resource provisioning and energy management algorithms are introduced to minimize the capital expenditure (CAPEX) and operating expenditure (OPEX) costs. We first derive lower bounds on the costs using a linear programming (LP) formulation where solar components are sized using solar insolation and projected loading data. A variety of different node configurations are considered. Three energy scheduling algorithms are then introduced to optimize online OPEX costs, namely, Grid Purchase Last (GPL), Solar Load Optimization (SLO) and Solar Load Simulation (SLS) algorithms. Simulation results show the extent to which a solar powered add-on can reduce total cost.</p> <p>Finally, we consider solar powered systems where part of their energy demands are deferrable, up to some maximum tolerable delay. The objective is to exploit the flexibility of deferrable energy demands in a way that decreases the total provisioning cost. A mixed integer linear optimization program is derived which gives a lower bound on the provisioning cost. A Delay Aware Provisioning (DAP) algorithm is then proposed to determine practical cost-efficient energy provisioning. The performance of DAP is compared to the provisioning bound and the conventional Stand-alone Node Provisioning (SNP) algorithm. Results are presented which show the significant provisioning cost savings that can be obtained.</p> / Doctor of Philosophy (PhD)

Due to the growing population and climate change, the world will see an increase in demand for food, freshwater and renewable energy supply. Agrivoltaics has the possibility to address all these problems, by producing food and renewable energy but also by reducing water usage in agriculture. This thesis aims to study if agrivoltaics including storage has the potential to enable sustainable greenhouses in Stockholm, Sweden by trying to create a near net zero energy consumption for greenhouses with Agrivoltaics (AV) implemented. Furthermore a techno-economic assessment will be made for the AV-systems where Key Performance Indicator (KPI)’s are compared to economic parameters. The selected KPI’s were a near net zero energy consumption and irradiance underneath the Photovoltaics (PV) technology. The selected PV-technology was standard PV-modules, Semi-Transparent Module (STM) and Organic Solar Cell (OSC) PV. These technologies were paired with li-ion batteries between 0-100 kWh and simulated in the software System Advisor Model (SAM) over a 25 year period. The AV system was applied to two load profiles, one for indoor plants and one for tomatoes. The economic parameters calculated was Net Present Value (NPV), Net Capital Cost (NCC), and Levelised Cost of Electricity (LCOE).  The results showed that the system is efficient in summertime where the PV reached maximum capacity in summer and the battery works as a complement. In wintertime, the AV-system is not very efficient and most of the electricity comes from the grid. It was not possible to create a near net zero energy consumption including storage in Stockholm Sweden. The irradiance beneath the panels were at a maximum for OSC, it was slightly reduced for the STM, and below 50% for the standard PV-module, depending on the size of the AV-system. Depending on the shade tolerance of the plant, the PV-technology should be selected.

With the growing installation of home photovoltaics, traditional energy trading is evolving from a unidirectional utility-to-consumer model into a more distributed peer-to-peer paradigm. Besides, with the development of building energy management platforms and demand response-enabled smart devices, energy consumption saved, known as negawatt-hours, has also emerged as another commodity that can be exchanged. Users may tune their heating, ventilation, and air conditioning (HVAC) system setpoints to adjust building hourly energy consumption to generate negawatt-hours. Both photovoltaic (PV) energy and negawatt-hours are two major resources of peer-to-peer electricity trading. Blockchain has been touted as an enabler for trustworthy and reliable peer-to-peer trading to facilitate the deployment of such distributed electricity trading through encrypted processes and records. Unfortunately, blockchain cannot fully detect anomalous participant behaviors or malicious inputs to the network. Consequentially, end-user anomaly detection is imperative in enhancing trust in peer-to-peer electricity trading. This dissertation introduces machine learning-based anomaly detection techniques in peer-to-peer PV energy and negawatt-hour trading. This can help predict the next hour's PV energy and negawatt-hours available and flag potential anomalies when submitted bids. As the traditional energy trading market is agnostic to tangible real-world resources, developing, evaluating, and integrating machine learning forecasting-based anomaly detection methods can give users knowledge of reasonable bid offer quantity. Suppose a user intentionally or unintentionally submits extremely high/low bids that do not match their solar panel capability or are not backed by substantial negawatt-hours and PV energy resources. Some anomalies occur because the participant's sensor is suffering from integrity errors. At the same time, some other abnormal offers are maliciously submitted intentionally to benefit attackers themselves from market disruption. In both cases, anomalies should be detected by the algorithm and rejected by the market. Artificial Neural Networks (ANN), Recurrent Neural Network (RNN) with Long Short-Term Memory (LSTM) and Gated Recurrent Units (GRU), and Convolutional Neural Network (CNN) are compared and studied in PV energy and negawatt-hour forecasting. The semi-supervised anomaly detection framework is explained, and its performance is demonstrated. The threshold values of anomaly detection are determined based on the model trained on historical data. Besides ambient weather information, HVAC setpoint and building occupancy are input parameters to predict building hourly energy consumption in negawatt-hour trading. The building model is trained and managed by negawatt-hour aggregators. CO2 monitoring devices are integrated into the cloud-based smart building platform BEMOSS™ to demonstrate occupancy levels, further improving building load forecasting accuracy in negawatt-hour trading. The relationship between building occupancy and CO2 measurement is analyzed. Finally, experiments based on the Hyperledger platform demonstrate blockchain-based peer-to-peer energy trading and how the platform detects anomalies. / Doctor of Philosophy / The modern power grid is transforming from unidirectional to transactive power systems. Distributed peer-to-peer (P2P) energy trading is becoming more and more popular. Rooftop PV energy and negawatt-hours as two main sources of electricity assets are playing important roles in peer-to-peer energy trading. It enables the building owner to join the electricity market as both energy consumer and producer, also named prosumer. While P2P energy trading participants are usually un-informed and do not know how much energy they can generate during the next hour. Thus, a system is needed to guide the participant to submit a reasonable amount of PV energy or negawatt-hours to be supplied. This dissertation develops a machine learning-based anomaly detection model for an energy trading platform to detect the reasonable PV energy and negawatt-hours available for the next hour's electricity trading market. The anomaly detection performance of this framework is analyzed. The building load forecasting model used in negawatt-hour trading also considers the effect of building occupancy level and HVAC setpoint adjustment. Moreover, the implication of CO2 measurement devices to monitor building occupancy levels is demonstrated. Finally, a simple Hyperledger-based electricity trading platform that enables participants to sell photovoltaic solar energy/ negawatt-hours to other participants is simulated to demonstrate the potential benefits of blockchain.

The neural circuitry responsible for memory consists of complex components with dynamic interactions. In hippocampal area CA1, interactions between excitatory pyramidal cells and inhibitory interneurons shape ensemble activity which encodes sequential experience. An extremely diverse set of inhibitory interneurons, with variation in gene expression, synaptic targeting, state-dependent activity, and connectivity, contribute substantially to circuit activity, such as theta and sharp wave-ripple oscillations. The precise roles of each interneuron group is not well understood, though characterization of their activity reveals mechanisms underlying hippocampal circuit computation. In this dissertation, I aim to identify and disrupt interactions between pyramidal cells and local interneurons to clarify their role in shaping cell assembly activity. We characterized axo-axonic cell activity in sharp wave-ripples, and compared their control of pyramidal cell activity and ripple events to parvalbumin expressing neurons. We identified pyramidal cell-interneuron interactions during ripples, suggesting they serve as lateral inhibitors between cell assemblies. We additionally developed and implemented a novel neural device to explore the role of cannabinoid disruption of hippocampal oscillations and organization of assemblies in vivo in awake animals. We demonstrate that cannabinoid receptor type 1 within CA1 is responsible for suppression of theta and SPW-Rs. We also found that cannabinoid activation within CA1 circuitry, regardless of muted input from CA3, was sufficient to disrupt sharp wave-ripples, likely through interference of pyramidal cell-interneuron interactions. The work in this dissertation provides insight suggesting that interneuron activity must be studied at the spiking timescale to characterize their control over cell assembly activity. / Doctor of Philosophy / Understanding how the brain creates memory remains one of the greatest questions in the field of neuroscience. Coordinated brain activity serves to build communication on large and small scales, across brain regions and within circuits consisting of small groups of neurons. Precise coordination of activity and communication across neurons and regions is thought to build salient experience, which is achieved through the timing of neuron action potentials, or spikes. Neurons receive thousands of inputs that control their spiking activity. "Go and stop" signals from excitatory and inhibitory interneurons act to conduct synchronized activity, which is required for proper circuit function. Importantly, coordinated spiking across large groups of neurons is responsible for observed "brain waves", or oscillations, which reflect organized activity. In CA1 of the hippocampus, there are >20 subtypes of interneurons that all make distinct contributions to memory function, and the roles of these interneurons have not been fully studied within behaving animals. As engineers develop new tools, new methods become available to study and classify how unique groups of interneurons play a part in circuit activity. Thus, we sought to characterize the role of axo-axonic cells, a specialized interneuron with strong control over spiking activity, in hippocampal oscillations that are responsible for memory encoding and consolidation. We identified a new role for axo-axonic cells in the regulation of pyramidal cell spiking in sharp wave-ripple oscillations. Additionally, we developed a novel neural device that allowed us to investigate the mechanisms that underlie cannabinoids, molecules found in Cannabis sativa, and memory dysfunction. We leveraged the multifunctionality of our T-DOpE probe to focally deliver synthetic cannabinoid into the hippocampus in combination with optical control of circuits, with simultaneous recording of activity. We found that cannabinoids acting within CA1 sufficiently disrupt hippocampal oscillations, likely through hindering pyramidal cell-interneuron interactions. Together, these findings suggest that the spatial and temporal resolution required to study diverse roles of interneurons is high, and experiments designed to explore interneuron activity should especially emphasize fine time-scales.

Uppsala Municipality is planning to build the southeast city district (SÖS), aiming to achieve climate neutrality by 2030 and climate positivity by 2050. In this thesis, the integration of electric vehicles (EVs) and charging infrastructure was investigated. It also examined the power demand, and the potential of photovoltaic (PV) production in combination with a battery storage system in SÖS, and its ability to reduce power peaks. The study was delimited to only incorporating charging demand in mobility houses, not from the private parking spots, as well as excluding alternative fossil-free vehicle options. Utilizing a stochastic model and data from Copenhagen and Stockholm, using trends for car pools and EV ratio, two scenarios were designed to forecast the spread of EVs and their impact on the power grid in SÖS by 2050. Since SÖS consists of both residential housing and workplaces, three different simulations were created to take their differences in mobility pattern into account. The two scenarios generated a different number of EVs, which resulted in a varied amount of charging points. Furthermore, the difference in EVs and mobility patterns showed different values of power demands and power peaks. PV panels combined with a battery storage system were able to both reduce the daily power demand, as well as the power peaks. For the sensitivity analysis, different sizes of the battery storage were examined. Finally, this report presents guidance for how to manage the challenges with an increased power demand from the more extensive use of EVs.

Die praepositio als einseitiger Rechtsakt, mit dem ein Unternehmer eine Person zum selbständigen Abschluss von Verträgen und zur Durchführung von Rechtsgeschäften einsetzte, den Geschäftskreis des Angestellten absteckte und sich verpflichtete, in diesem Rahmen für dessen Verpflichtungen wie für eigene einzustehen, war ein wichtiger Bestandteil im Wirtschaftslebens des antiken Rom. Sie überbrückte die Lücke, die sich aus der wirtschaftlichen Notwendigkeit ergeben hatte, bei zunehmend arbeitsteiliger Wirtschaft denjenigen direkt verpflichten zu können, dessen Geschäfte geführt wurden, und der noch fehlenden direkten Stellvertretung. Sie bot dem jeweiligen Handelspartner die für Geschäftsabschlüsse notwendige Sicherheit, berechtigte Forderungen auch durchsetzen zu können, dem Unternehmer die Möglichkeit, durch Beschreibung des Geschäftskreises seines Angestellten Unternehmensziele zu definieren aber auch die eigene Haftung zu begrenzen, und dem Angestellten die Gewissheit, dass der Unternehmer für Verpflichtungen aus den von ihm im Rahmen seiner Befugnisse abgeschlossenen Rechtsgeschäften mit einstehen würde. Die praepositio hat damit wesentlich zur Fortbildung des Rechts beigetragen, indem sie die stark obligationenrechtliche Bindung der Vertragsparteien langsam aufgelöst und damit den Weg zur direkten Stellvertretung geebnet hat. / Praepositio was the unilateral act by a businessman granting authority to an employee. This act gave authority to the latter to conclude and execute contracts with third parties. It described the area of accountability of the employee’s activity and engaged the businessman to answer for the obligations concluded by his employee. Praepositio thus bridged the gap between the necessity to act on behalf of another person and the rules of agency which did not yet exist in the modern understanding. Thus, it played an important role in the economic life of Ancient Rome. Praepositio provided a third party the assurance that, in the end, his contractual claims will be honoured. At the same time, the businessman was enabled to define the goals of his enterprise and to limit his own responsibility. Finally, the employee had the necessary assurance that the businessman will honour the obligations which were concluded within the limits described by the praepositio. Hence, the praepositio was an important step towards the suspension of the strict person-to-person relationship of the Roman law and towards agency in the modern understanding.