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Vomsentrert sammenstilling av storfeholobionten
Get PDFThe holobiont perspective takes into account the complete system of an animal including its microbiomes and to some extent the factors that form its external environment. This view has a scientific motivation: In the case that the microbiome affects the host, studying the host in isolation severely limits access to the complete information needed to understand the biology of the host. As a model for such a “holobiont” system, a starting point was taken in cattle and focused on the rumen and the interface that connects its inherent microbiome to the metabolism of the host. As the rumen microbiome produces a vital component of metabolites that the host budgets for energy and nutrient assimilation, it has a wide potential to impact the host. The association between the host and its rumen microbiome has made it a focal point for modulation strategies to improve health, nutrition and sustainable production of ruminants. However, the complexity of the rumen microbiome and its interactions with the host represent major challenges that must be overcome before microbiome-based approaches can be used in practice. To improve reconstruction of the rumen microbiome, a high-resolution dataset was generated for deep analysis from 80 cattle subjected to a feedlot trial. Here, the rumen microbiome was sampled over time, and host tissue (rumen wall and liver) samples were collected upon sacrifice, after rigorous measurement of the cattle’s key performance traits (KPTs) and methane emissions.
To study the ruminant holobiont, molecular layers in both the host and its rumen microbiome were reconstructed. Multiple molecular layers (DNA, RNA, protein, metabolites, and glycans) as well as the host phenotype were analyzed, in order to track how potential interactions affected metabolism in 24 individual animals that exhibited the highest natural variation in measured methane yield. As most biological variation of an organism is encoded in the genome, DNA sequencing is central to forming a foundation upon which to assemble the holobiont. To further enhance our DNA analyses, long-read and high accuracy short-read shotgun metagenome sequencing was applied to reconstruct the microbial genomes of the rumen microbiome. To track which genes were expressed, transcriptomics was applied, and to analyze the presence of translated proteins and their derived metabolites, also proteomics and metabolomics. For complex eukaryotic populations that are unamenable to shotgun sequencing approaches, such as the protozoa and fungi, genomes were sourced from collaborative projects.
Analyzing a single molecular layer requires a specific set of technical tools. For this purpose, it is described how microbial genomes can be reconstructed, and how their relevant metabolic functions can be identified. Specifically in relation to the carbohydrate-active enzymes (CAZymes) that enable ruminants to assimilate carbon and energy from plant fibers, representing the basis for the energy budget of the host. As it was not possible to identify a suitable pipeline with the tools necessary to analyze and compare the metabolic function of the archaeal and bacterial genomes generated in our datasets, an easy to use platform for analyzing metagenome-assembled genomes (MAGs) was developed. This pipeline is now distributed on Bioconda as CompareM2.
To apply the wide tool set that was put together and attempt to improve resolution and general understanding of how the ruminant host and its microbiome function as an integrated unit, an experimental cattle holobiont dataset was analyzed. The sampled molecular layers were refined to become biologically relevant representations on which integrative holo-omic methods could be applied to identify and investigate possible host-microbiome interactions. In practice, simpler computational dimensionality reduction methods may offer greater interpretability and allow more direct biological interpretation than more complex computational methods. Applying these methods to our experimental data led to the discovery that the protozoal fraction of the rumen seemingly drives two exclusive community types across the individual animals that were sampled, which have previously been described from micrography and 18S studies. These are referred to as RCT-A and -B (rumen community type). RCT-B is dominated by protozoa affiliated to Epidinium spp. that were observed to employ a plethora of fiber-degrading enzymes, which most likely provide favorable conditions for saccharolytic bacteria such as Prevotella spp. Conversely RCT-A is dominated by Isotricha and Entodinium protozoal species and harbors a wider representation of fiber, protein and amino acid fermenters. While no clear host effect for these rumen community types is found, there are signs in the more complex network analysis based computational methods that certain microbial populations of Acutalibacteraceae prevalent in RCT-A affect methionine metabolism in the rumen wall. This calls for further refinement of the holo-omic analyses and biological characterization.
Finally, our work highlights the need for de facto standards to refine individual molecular layers, and to find common methods for data integration across these molecular layers that represent the host-microbiome axis.Holobiont-perspektivet tar hensyn til det komplette systemet til et dyr, inkludert dets mikrobiomer og, til en viss grad, faktorene som danner dets ytre miljø. Dette perspektivet har en vitenskapelig motivasjon: I tilfeller der mikrobiomene påvirker verten, begrenser det å studere verten i isolasjon tilgangen til den komplette informasjonen som er nødvendig for å forstå vertens biologi. Som en modell for et slikt holobiont-system har vi tatt utgangspunkt i storfe, med fokus på vomma og grensesnittet som forbinder dets iboende mikrobiom med vertens metabolisme, spesifikt vomveggen og leveren. Siden mikrobiomet i vomma produserer en viktig komponent av metabolitter som verten bruker til energibudsjettering og næringsopptak, har det et stort potensial til å påvirke verten. Sammenhengen mellom verten og dens iboende vommikrobiom er derfor et fokusområde for moduleringsstrategier for å forbedre helse, ernæring og bærekraftig storfeproduksjon. Vommikrobiomets kompleksitet og dets interaksjoner med verten representerer imidlertid store utfordringer som må takles før mikrobiom-baserte tilnærminger kan brukes i praksis. For å forbedre rekonstruksjonen av vommikrobiomet har vi generert et høyoppløselig datasett for dyp analyse fra 80 storfe som ble eksponert for en fôringsprøve. Her ble vommikrobiomet tatt prøver av over tid, og prøver fra vomveggen og leveren ble samlet ved avliving, kort tid etter grundige målinger av storfeets nøkkelprestasjonsegenskaper, inkludert metanutslipp.Novo Nordisk Foundation ; NORBISpublishedVersio
Quantifying sustainability and resilience in food systems: a systematic analysis for evaluating the convergence of current methodologies and metrics
No full textpublishedVersio
Correction of precipitation data from disdrometers with machine learning - Machine learning based approach to adjust rainfall data from disdrometers
No full textThe correction of rainfall data from a Thies laser precipitation monitor
has been investigated with data from a catching bucket gauge and
different machine learning approaches. 360 slightly different linear models
and 72 deep models have been trained and tested. It has been shown
possible to correct precipitation amounts with linear models, but only
to a certain degree. The addition of other meteorological variables has
shown some sign of improving some deep models, but the best model
does not utilize additional meteorological data
Multivariate Anomaly Detection in Ventilation Systems for Commercial Buildings
Get PDFAdvancements in technology have enabled large-scale data collection, increasing the demand for tools that can extract information and support fast, informed actions. Condition monitoring of technical systems has become a widely used approach to reduce operational costs by detecting anomalies before they escalate, i.e., unexpected patterns that may indicate emerging issues. Soundsensing AS, a start-up based in Oslo since 2019, provides monitoring solutions for technical systems in commercial buildings. They collect and process vibration data using commercially available sensors, offering early warnings of irregular system behavior. The company expressed interest in exploring additional data sources to improve their product and deliver better customer service.
This study investigated how combining multiple data sources (i.e., multivariate approaches) can improve the detection of ventilation system problems. Using real-world data from Soundsensing AS, it examined whether previously unrecognized (novel) anomaly types can be identified. The analysis further examined how vibration and temperature features affect the detection process and the practical relevance of the identified anomalies. Three modeling approaches with varying complexities were explored: one statistical model and two deep learning models. The models were trained using data from interconnected ventilation components: the supply fan, the exhaust fan, and the heat exchanger. A ventilation technician was consulted to interpret a selection of the results.
The results showed that increased model complexity did not improve performance compared to simpler and more transparent models. Most identified problems could be detected using single-signal (i.e., univariate) methods, although combining signals improved the detection of certain behaviors. Weather conditions were a major source of false alarms, suggesting that models carefully including weather data could greatly reduce them. Temperature measurements (from sensors), previously unused by Soundsensing AS, also showed promise for detecting economically important problems such as overheating.
Another key benefit of combining data sources was improved interpretability. Where univariate data lack context, combined visualizations help distinguish whether irregular behavior is a real problem or an expected variation. Although root cause analysis is not a primary focus for Soundsensing AS, leveraging this information can enhance detection accuracy. Additionally, visualizing interconnected equipment as a unified system could support more efficient troubleshooting
A Glass Half Full (or Empty): Assessing the EU’s Sanctions Regime on Belarus as a Foreign Policy Strategy
Get PDFThis thesis examines the EU’s sanctions regime on Belarus, focusing on the strategic role sanctions have played within Brussels’s broader foreign policy toward Minsk and how that role has evolved as Belarus became increasingly engulfed in Lukashenka’s authoritarian rule. While sanctions are typically evaluated as static instruments of coercion aimed at altering the target’s behaviour, this study draws on existing literature to challenge that narrow view, instead presenting their complex and dynamic nature. Adopting a mixed-methods approach - combining Giumelli’s structured framework with an interpretive analytical lens – the analysis reveals that sanctions have shifted from being a complementary policy tool to the Brussel’s primary, and ultimately sole, means of engagement with Belarus, particularly in the wake of country’s involvement in Russia’s 2022 full-scale invasion of Ukraine. Despite their expanding scope, the sanctions have completely failed to achieve declared objectives and, in some respects, may even be considered counterproductive. Nevertheless, the thesis contends that this is not merely a matter of sanctions failing to deliver results, but of the EU reconfiguring its strategic priorities in ways that sidelined their initial aim – Belarus’s democratization. Tracing this shift reveals that the EU’s approach to Belarus no longer reflects a coherent foreign policy, with sanctions effectively acting as a substitute for one - raising important questions about how Belarus fits within the EU’s foreign policy as the region faces escalating turmoil
Municipal management of trees in low-density residential areas
Get PDFTrær i områder med småhusbebyggelse forvaltes i all hovedsak av kommunene. Det er enkelte unntak hvor statlige lover og bestemmelser gjelder. Et eksempel på dette er Vannressursloven § 11 og Naturmangfoldloven § 52. Kommunene er pålagt etter Plan- og bygningsloven å utarbeide planer for arealene sine. Kommuneplanens arealdel er en langsiktig plan som inneholder bestemmelser for hvordan arealene i kommunen skal forvaltes i perioden planen gjelder. Kommuneplanens arealdel kan gjennom bestemmelsene legge føringer for reguleringsplanene som blir utarbeidet.
Nesten alle de utvalgte kommunene har utarbeidet definisjoner for trær som skal bevares, og de fleste har bestemmelser som sier at trær skal bevares. Definisjonen av trærne som skal bevares er relativt like mellom kommunene. Samtlige kommuner som har definert trær som skal bevares, har på en eller annen måte brukt «trær som er større enn 90 cm i stammeomkrets» i definisjonen. Selv om definisjonene av trær som skal bevares ser like ut i er forskjellene i realiteten store. Det er detaljer i både definisjonene og bestemmelsene som fører til at virkeområdet for bestemmelsene varierer mye.
For å sikre en god forvaltning av trær i områder med småhusbebyggelse i fremtiden er kommunene avhengige av å utarbeide gode bestemmelser. Kommuner i Norge kan bruke oversikten over bestemmelsene til de utvalgte kommunene til inspirasjon når de skal utarbeide nye bestemmelser til kommuneplanens arealdel. Det kan bidra til at kommunene kan bli inspirert til å utarbeide gode bestemmelser som i fremtiden forvalter trær i småhusområder tilpasset deres lokale forhold.Trees in areas characterized by low-density residential development are primarily managed by municipal authorities. However, there are certain exceptions where national legislation and regulations apply. Two examples are “Vannressursloven § 11” and “Naturmangfoldloven § 52”. According to the “Plan- og bygningsloven”, municipalities are required to develop land-use plans. The land-use plan is a long-term strategic document that outlines regulations for how land within the municipality is to be managed in the duration of the plan. The general land-use plan can influence the development of detailed land-use plans by its regulations.
Nearly all the selected municipalities have formulated definitions for trees that are to be preserved, and most of them have adopted regulations mandating tree preservation. The definitions of trees to be preserved are consistent across municipalities. All the municipalities that have defined trees to be preserved, have in some form used the criterion “trees with a circumference greater than 90 cm”. Although these definitions appear similar, the differences are big. Nuances in both the definition and the regulations make a huge variety in the outcome of the regulations.
To ensure effective management of trees low-density residential areas in the future, municipalities must develop robust regulatory frameworks. Municipalities in Norway may draw inspiration from the regulations adopted by the selected municipalities when drafting new plans for land-use. This may contribute to the development of well-adapted regulations that support the sustainable management of trees in residential areas.B-L
Challenges of carbon pricing : essays on evidence from real-world implementations
Get PDFLimiting climate change requires rapid action to reduce carbon and other greenhouse gas emissions. Pricing carbon creates an economic incentive to decarbonise economic activity. Even though carbon pricing has theoretical appeal, real world adoption of carbon pricing has thus far been insufficient to be able to deliver the climate targets the international community has agreed on.
The papers featured in this thesis are concerned with challenges around carbon pricing and the consequences of those carbon pricing policies that have been implemented to date. A particular focus lies on incomplete policy coverage as most policies have not been implemented uniformly across economies, but instead by sector. Based on a novel dataset that captures variation of carbon prices across countries, across sectors, and across time, we study environmental effectiveness and impacts on jobs econometrically, and we use ex-post simulations to identify the consequences of incomplete coverage on household expenditure burdens and on carbon leakage.
In line with expectation, we find that increasing carbon prices lead to reduced carbon emissions while we do not identify an impact on the number of jobs in the OECD. Contrary to expectations, we find that heterogenous carbon prices have made household expenditure burdens in Europe more regressive on average, and more prone to carbon leakage. Our findings add new evidence to the existing literature that advocates for more stringent and uniform carbon pricing.Begrensning av klimaendringer krever rask handling for å redusere utslipp av karbon og andre klimagasser. Å sette en pris på karbonutslipp skaper et økonomisk insentiv for å redusere karbonintensiteten av økonomisk aktivitet. Selv om karbonprising er teoretisk hensiktsmessig, har den faktiske bruken av karbonprising hittil vært utilstrekkelig for å kunne oppnå de klimamålene det internasjonale samfunnet har blitt enige om.
Artiklene i denne avhandlingen omhandler utfordringer rundt karbonprising og konsekvensene av de karbonprisene som hittil har blitt implementert. Vi legger vekt på det faktum at de fleste karbonprisene har blitt implementert ulikt i de forskjellige økonomiske sektorer i stedet for jevnt over hele økonomien. Basert på et nytt datasett som viser variasjon av karbonpriser mellom land, sektorer og tid, beregner vi miljøeffektivitet og virkninger på arbeidsplasser økonometrisk, og vi bruker eks-post simuleringer for å identifisere konsekvensene av heterogene priser på karbonutslipp for husholdningenes forbruksutgifter og for karbonlekkasje.
I tråd med forventningene finner vi at økende karbonpriser i OECD-land fører til reduserte karbonutslipp. Vi finner ikke at økende karbonpriser påvirker antall jobber. I motsetning til forventningene finner vi at sektorvis klimapolitikk har virket regressivt på europeiske husholdningenes forbruksutgifter, og bidratt til at europeiske virksomheter har blitt mer utsatt for karbonlekkasje, i gjennomsnitt. Våre funn gir ny innsikt til litteraturen om høyere og ens karbonpriser.updatedVersio
Effekt av behandling med plantehormonet metyljasmonat og gunstige bakterier på vekst og resistens mot Botrytis spp. hos gran (Picea abies)
Get PDFGran (Picea abies (L.) H. Karst.) er et av Norges viktigste treslag, både økonomisk og økologisk. Dagens produksjonssystem i skogplanteskoler, hvor granplanter dyrkes tett i tett, kombinert med økende forekomst av skadegjørere, strengere regulering av fungicider og økt fungicidresistens, forsterker behovet for å utvikle alternative beskyttelsesmetoder. I denne oppgaven ble frø og småplanter behandlet med ulike kombinasjoner av vann, plantehormonet metyljasmonat (MeJA), bakterier og en kombinasjon av MeJA og bakterier (totalt åtte behandlinger). Hensikten var å undersøke hvordan de ulike behandlingene påvirket granplantenes vekst og motstandsdyktighet mot plantepatogenet Botrytis cinerea. Studien ble gjennomført i to eksperimenter: Eksperiment 1 ble utført under forhold som etterlignet en skogplanteskole, mens eksperiment 2 ble gjennomført i kontrollerte laboratorieforhold. Behandlingseffektene ble vurdert gjennom fenotyping av plantehelse og høyde, samt analyser av rotvekt, pigmentinnhold (klorofyll a, klorofyll b og karotenoider), smitteforsøk med Botrytis cinerea, og genuttrykksanalyser (RT-qPCR) av genene PaCHI4, PaNRT og PaPSII.
Hovedfunnene viste at bakteriebehandling alene hadde best effekt, med høyest andel friske og lavest andel døde planter. Bakteriene viste også en tydelig vekstfremmende effekt og reduserte MeJAs negative påvirkning på plantehøyde. Dette peker på at bakterier har stort potensial som biostimulerende middel i skogplanteskoler, med mulig indirekte beskyttelse mot patogener. MeJA alene ga mer varierende resultater, men plantene som ble plantebehandlet med MeJA hadde de tyngste røttene blant de øvrige plantebehandlingene, noe som kan indikere at effekten er avhengig av tidspunkt for applikasjon. Kombinasjonsbehandlingen av MeJA og bakterier førte derimot til lav plantehelse og høy dødelighet, som tyder på negativ interaksjon. Studien illustrerer både muligheter og utfordringer ved bruk av MeJA og bakterier, og understreker viktigheten av videre studier for å forstå deres interaksjoner og mekanismer i planteforsvar.Norway spruce (Picea abies (L.) H. Karst.) is one of Norway’s most important tree species, both economically and ecologically. The current production system in forest nurseries, where seedlings are grown at high density, combined with increasing pest and disease pressure, stricter fungicide regulations, and rising fungicide resistance, highlights the growing need for alternative plant protection strategies. In this study, seeds and seedlings were treated with different combinations of water, the plant hormone methyl jasmonate (MeJA), beneficial bacteria, and a combination of MeJA and bacteria (a total of eight treatments). The aim was to investigate how these treatments affected plant growth and resistance to the fungal pathogen Botrytis cinerea. The study was carried out in two experiments: Experiment 1 was conducted under conditions simulating a forest nursery, while Experiment 2 was performed under controlled laboratory conditions. Treatment effects were assessed through phenotyping of plant health and height, and analyses of root biomass, pigment content (chlorophyll a, chlorophyll b, and carotenoids), infection experiment with B. cinerea, and gene expression analyses (RT-qPCR) of the genes PaCHI4, PaNRT, and PaPSII.
The main findings showed that bacterial treatment alone had the most beneficial effect, resulting in the highest proportion of healthy plants and the lowest mortality. The bacteria also had a clear growth-promoting effect and reduced MeJA’s negative impact on plant height. These results suggest that beneficial bacteria have strong potential as biostimulants in forest nurseries, with possible indirect protective effects against pathogens. MeJA alone gave more variable results, but plants treated with MeJA had the heaviest roots among the plant treatments, indicating that the effect may depend on the timing of application. In contrast, the combined treatment with MeJA and bacteria resulted in poor plant health and high mortality, suggesting a negative interaction. This study highlights both the opportunities and challenges associated with using MeJA and beneficial bacteria, and emphasizes the need for further research to better understand their interactions and underlying mechanisms in plant defense
Grønn aksjon for levende byer - En studie av byøkologiske prosjekter i Oslo
No full textKlima- og naturkrisen krever umiddelbar handling. Gjennom internasjonale avtaler er Norge forpliktet til å redusere effektene av klimaendringer, tap av natur og jobbe for en bærekraftig utvikling. Det er bred enighet om at en bærekraftig omstilling må skje gjennom en felles innsats på tvers av sektorer og nivåer. På det lokale nivået følger Oslo kommune opp dette med blant annet politiske mål om å skape en grønnere og mer klimarobust by. Viktige måter det arbeides med bærekraftsutfordringene i Oslo er gjennom byøkologiske prosjekter som Oslo kommunes treplantingsdugnad og frivillige initiativ som urbane dyrkingsprosjekter.
Gjennom kvalitative intervjuer undersøker vi fire slike byøkologiske prosjekter i Oslo og samarbeidet mellom dem: Bykuben, Oslotrær, Líf laga og Ungdyrk. Gjennom å undersøke disse prosjektene og deres arbeid, i tillegg til å se til relevant teori, diskuterer vi hvordan byøkologiske prosjekter kan bidra til en bærekraftig omstilling av byen. Teorigrunnlaget er hentet fra fagfelt som urban transformasjon, urban økologi, landskapsdemokrati og samstyring. Oppgaven undersøker betydningen av byøkologiske prosjekters arbeid med bynatur, lokalt engasjement og samarbeid i en bærekraftig omstilling av urbane områder. Funnene våre viser at de byøkologiske prosjektene i Oslo møter bærekraftsutfordringene med handling på et lokalt plan. Funnene viser også at innbyggernes aktive deltakelse i prosjektene bidrar til indre endringsprosesser, som økt kunnskap og tilhørighet. Videre viser funnene at det byøkologiske samarbeidet mellom kommunen og innbyggere er viktig i prosjektenes handlingsrettede innsats. Et viktig funn er den avgjørende rollen enkeltaktører har i å opprette samarbeid og skape engasjement rundt det byøkologiske arbeidet. Basert på dette, foreslår vi en urban bærekraftsstrategi som gir innspill til hvordan kommuner, innbyggere og andre aktører kan jobbe sammen og handlingsrettet for en grønn urban omstilling.The sustainability crisis calls for immediate action. International agreements commit Norway to enhance a sustainable development and reduce the loss of biodiversity and the consequences of climate change. There is a broad consensus to address the sustainability crisis through a collective effort across sectors and levels of governance. In line with this, the municipality of Oslo has defined political goals, aimed at greening the city to make it more resilient faced with the consequences of climate change. These goals have been translated into practice through urban ecology projects such as the municipality’s tree planting project and through voluntary initiatives, such as urban farming initiatives.
Using qualitative interviews, we study four urban ecology projects in Oslo and the collaboration between them: Bykuben, Oslotrær, Líf laga and UngDyrk. By examining these initiatives and their work, in addition to relevant theoretical knowledge, we discuss the potential role of urban ecology projects in a green urban transformation. Our theoretical framework draws on research fields such as urban transformation, urban ecology, landscape democracy and governance. The thesis studies the significance of urban ecology projects’ contributions for urban nature, local participation and collaboration for an urban sustainability transformation. Our findings show that urban ecology projects in Oslo work in an action-oriented manner related to the sustainability crisis, at a local level. The results indicate that the projects’ active involvement of citizens foster internal transformation, such as increased knowledge and sense of belonging. Furthermore, our study shows that the collaboration between the local government and the citizens, is important for the realization of these urban ecology projects. A key finding is the importance of individual actors to initiate cooperation and foster engagement. On this basis, we propose an urban sustainability strategy, aimed at guiding municipalities, citizens and other actors to act collectively and action-oriented for a green urban transformation
Large-Scale Optimization of the Nordic Power System in Connection with Statnett’s Grid Development Plans using PyPSA
Get PDFDet nordiske kraftsystemet gjennomgår en betydelig omstilling for å oppfylle den europeiske unionens krav om netto nullutslipp innen 2050. Denne masteroppgaven undersøker kostnadsoptimale løsninger for integrering av fornybar energi i Finland, Norge og Sverige, samtidig som systemets pålitelighet opprettholdes og kostnader for nettutbygging av transmisjonsnettet minimeres. Ved bruk av PyPSA-Eur, en åpen kildekode for modellering av energisystemet i Europa, simuleres flere scenarier, inkludert økt utbygging av havvind, utvidelse av solkraft, og fleksibel fornybar integrasjon. Scenarioene vurderer avveiningene mellom utvidelse av kraftproduksjon, nettinvesteringer og behov for energilagring.
Resultatene viser at nettutvidelse er nødvendig i alle scenarier, med krav til oppgraderinger som varierer mellom 3.66% og 4.97%. Off- shore Expansion scenariet, som inkluderer 71.24 GW havvind, krever de høyeste nettinvesteringene og totale systemkostnadene (37.3 milliarder euro). Flexible Expansion scenariet, som prioriterer landbasert vindkraft og solkraft, oppnår den laveste totale systemkostnaden (33.9 milliarder euro). Vannkraft fremstår som en nøkkelressurs for fleksibilitet, noe som reduserer behovet for batteri- og metanollagring. Funnene viser også avvik fra Statnetts systemutviklingsplan, spesielt når det gjelder utbygging av havvind. Modellen indikerer at kun 12.12GW havvind er kostnadsoptimalt i Norden, langt under Norges mål om 30 GW.
Denne studien viser at det er mulig å oppnå et karbon nøytralt nordisk kraftsystem innen 2050 ved hjelp av variert fornybar energi, oppgradering av transmisjonsnettet og optimaliserte løsninger for en- ergilagring. Imidlertid er det behov for videre forskning for å inkludere kraftutveksling med resten av Europa, høyoppløselige forbruksdata, og detaljert fyllingsgrad for vannkraft for mer presise vurderinger av den nordiske energiovergangen.The Nordic power system is undergoing a significant transformation to meet the European Union’s 2050 net-zero emission targets. This thesis explores the cost-optimal pathways for integrating renewable energy in Finland, Norway, and Sweden while ensuring system reliability and min- imizing transmission expansion costs. Using PyPSA-Eur, an open-source energy system modeling tool for Europe, the study simulates multiple scenarios, including increased offshore wind deployment, solar power expansion, and flexible renewable integration. The scenarios assess the trade-offs between generation expansion, grid investments, and storage requirements.
The results indicate that grid expansion is necessary in all scenar- ios, with required transmission upgrades ranging from 3.66% to 4.97%. The Offshore Expansion scenario, which includes 71.24GW of offshore wind, requires the highest grid investment and system cost (37.3 billion euros). In contrast, the Flexible Expansion scenario, which prioritizes onshore wind and solar, achieves the lowest total system cost (33.9 billion euros). Hydropower emerges as a key enabler of flexibility, reducing the reliance on battery and methanol storage. The findings also highlight deviations from Statnett’s Grid Development Plan, particularly regarding the scale of offshore wind deployment, as the model suggests only 12.12GW of offshore wind in the Nordics as cost-optimal—far below Norway’s 30 GW target.
This study demonstrates that achieving a carbon neutral Nordic power system by 2050 is feasible through a diversified renewable energy portfolio, grid reinforcements, and optimized energy storage solutions. However, further research is needed to incorporate cross-border electric- ity trade, high-resolution load data, and detailed hydropower modeling for a more precise assessment of the Nordic energy transition