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Generasjonsskifte i familielandbruket
Full text linkGod rådgivning og kunnskapsbaserte overdragelsesprosesser i landbruket er en nøkkelfaktor for å oppnå landbrukspolitiske mål for bærekraft, verdiskaping og levende bygder. Dette prosjektet har brukt SAFA-rammeverket for bærekraft som analytisk tilnærming og undersøkt hvordan utvikling av landbrukets rådgivningstjenester kan bidra til at generasjonsskifte fremmer bærekraftig utvikling, både for det enkelte gårdsbruk og landbruket som helhet. Undersøkelser viser at vi kan sikre en mer helhetlig og bærekraftig utvikling i landbruket ved å rette større oppmerksomhet mot den sosiale bærekraften og de menneskelige ressursene på gården.publishedVersio
Future electricity tariffs: designing electricity rates fit for the energy transition
Full text linkacceptedVersio
Towards quantitative partial discharge simulations
Full text linkThis paper computationally investigates partial discharges (PDs) in the form of self-sustained gas discharges. It presents two methods for predictive modeling: (1) a new low-fidelity algorithm for the PD inception voltage is introduced. The method is volume-resolved and describes both the strength of the self-sustained Townsend mechanism as well as the conventional streamer (or bulk) mechanism. It also intrinsically computes the inception region, i.e. the region where a first electron also leads to a discharge. (2) We apply a high-fidelity plasma model based on kinetic Monte Carlo, which self-consistently resolves the plasma dynamics during the PD process. The two models are complementary in the sense that the low-fidelity model provides the when and where the PD occurs, while the high-fidelity model resolves the PD process itself, starting from the first electron. Prediction and quantification of the PD processes is provided for four application cases: (1) protrusion-plane gaps, (2) spherical voids, (3) twisted wire pairs, and (4) triple junctions. Validation of the low-fidelity method is done through comparison with published experiments (where available), as well as virtual verification through comparison with the high-fidelity plasma model.publishedVersio
Supply chain choices for battery materials: Effects on carbon footprints and societal impacts of battery production
Full text linkThis study uses life cycle assessment (LCA) and multi-region input-output (MRIO) models to evaluate the impact of material sourcing routes on the carbon footprint and ESG risks for producing NMC 622 batteries. A baseline scenario, with battery production and material sourcing in China, is compared to alternative scenarios with battery production in Norway and material supply from European and Norwegian industries. Findings indicate that relocating battery manufacturing to Norway significantly reduces carbon emissions due to the country’s low-carbon electricity. Further emission reductions are possible by onshoring the production of key components like aluminium and copper foil. ESG analysis reveals that sourcing materials from Europe or Norway substantially lowers risks across most categories and increases the share of economic output in low-risk regions. However, some high-risk exposures, such as water stress and biodiversity impact, may increase depending on specific material sources.publishedVersio
Positive Backstrokes from a Propagating Negative Streamer in Transformer Oil in an 80-mm gap
Full text linkNegative streamers with an applied step voltage in an 80-mm point-to-plane gaps in transformer oil have been studied with a fast 16-frame camera. The negative streamers propagated for around 200 µs – 300 µs before breakdown occurred or the streamer channel disappeared. The streamer velocity was approx. 0.4 mm/µs. For some of the captured images, we have seen that faster positive streamers have propagated in the opposite direction from the propagating negative streamer head. This clearly shows there is little or no contact back to the electrode behind the head of the propagating negative streamer, and a positive field towards the electrode must exist, likely due to charge separation in the streamer head.Positive Backstrokes from a Propagating Negative Streamer in Transformer Oil in an 80-mm gapacceptedVersio
Experimental hypothermia by cold air: a randomized, double-blind, placebo-controlled crossover trial
Full text linkBackground: Accidental hypothermia is associated with high morbidity and mortality. Research on treatment strategies for accidental hypothermia is complicated by the low incidence and heterogeneous patient population. We have developed a new method for clinical trials of experimental hypothermia, to enable further studies of active rewarming. If cold ambient air is effective as a cooling method, this would mimic the most frequent clinical setting of hypothermic patients and provide a feasible cooling method for field studies. We aimed to induce mild hypothermia in healthy volunteers by exposure to cold ambient air, and tested the hypothesis that drug-induced suppression of endogenous thermoregulation would be required.
Methods: In a randomized, double-blind, crossover design, 15 healthy volunteers wearing wet clothes were put in a windy climate chamber set to 5 °C. Each participant completed the experimental procedure twice, once receiving active drugs (meperidine and buspirone) and once receiving placebo. The experiments were separated by a one-week wash-out period. Primary outcome was core temperature at termination, defined as 3 h of exposure or 35 °C. The between-groups difference was assessed using analysis of covariance (ANCOVA) with left censoring (Tobit model) and individual random intercept. Secondary outcomes were trajectory of core temperature and reduction of shivering.
Results: At termination, the active drug vs placebo group differed in temperature by 1.4 °C. With adjustment for the removal of participants reaching 35 °C, the estimated mean difference was 1.7 °C (1.4–2.0, p < 0.001). Shivering was effectively reduced, but not completely inhibited by the drug regimen, and core temperature declined at a rate of − 0.82 °C per hour.
Conclusion: The novel protocol utilizing cold air as a cooling method and drug-induced suppression of endogenous thermoregulation, is effective and enables future research projects. We have provided suggestions for minor alterations.publishedVersio
Comparing Machine Learning Architectures for Long-Term Icing Risk Forecasting in the Norwegian Arctic Sea
Full text linkWe compare modern machine learning architectures on the problem of long-term prediction of the air temperature at atmospheric pressure level 850hPa, denoted T850, for five locations of interest in the Norwegian Arctic sea. Our motivation comes from the utility of T850 for estimating long-term sea-spray icing risk, as developed in (Samuelsen et al. 2019, Section 5). Our comparison includes LSTM, N-HiTS, Temporal Fusion Transformer, and PatchTST. These architectures are compared against climatological normals and a (classical) statistical baseline consisting of MSTL and Prophet.
Our results show that some architectures which have shown promise for time-series weather forecasting fail to perform on the longer time horizons we consider. Other machine learning models are able to beat classical statistical methods, and we find it interesting that they appear to learn different features in the historical time-series in order to make their predictions. Our benchmark is carried out using both metrics from climatology and general statistics.acceptedVersio
Characterizing and structuring open datasets for assessment of residential building energy use on the neighborhood and urban scale
Full text linkThis study investigates the potential of utilizing and integrating open datasets to assess and visualize energy use in the residential building stock by employing models aligned with national calculation methods, statistics and aggregated data from smart metering platforms. A case study of a Norwegian municipality is employed to illustrate these concepts. The study also examines the possibilities and limitations of using open data to reconstruct building geometry and derive relevant information to generate a new enriched dataset consistent with statistics. Enabling the use of open data and interoperable modeling frameworks is crucial for developing tools that cater to various stakeholders and evolving use cases. The findings demonstrate that the implemented residential building energy model, validated against multiple years of hourly aggregated electricity consumption, performs well on daily and monthly timescales, consistently meeting validation thresholds specified for CV(RMSE) and NMBE. The model’s performance on an hourly basis, critical for assessing strategies to reduce peak electricity loads during the coldest hours, could be improved with more advanced approaches. Additionally, if authorities regularly release up-to-date building footprints, these can be effectively combined with other open datasets to create more accurate inputs for archetypes or georeferenced building simulations, but future releases should be versioned to ensure their applicability. Georeferencing enables the visualization of results in thematic maps, illustrating the impact of future developments at the neighborhood scale, while also facilitating comparisons between building-specific outcomes and area-wide averages or archetypes, potentially empowering individual building owners with actionable insights.publishedVersio
The Aggregation of Wind Time-Series in Capacity Expansion Models
Full text linkCapacity Expansion Models (CEMs) are widely used in the academic literature to understand the needs and dynamics of highly renewable energy systems. Due to computational constraints, it is common to aggregate time-series data such as hourly power output from Variable Renewable Energy Sources (VRES) using clustering algorithms. However, there is evidence that the presence of wind data leads to increased clustering errors and biased investment decisions. With the above motivation, we combine two approaches from the literature and compare them against the state-of-the-art approach. For a small number of clusters, the proposed approach recovers 95% of the original variance and correlation. This leads to more robust investment decisions. However, we stress the increased computational burden involved.publishedVersio
Anbefalt metode for beregning av utslipp fra strøm og fjernvarme. Oppsummering og anbefaling på tvers av studier i FME ZEN
Full text linkFME ZEN har som en sentral del av sitt mandat hatt i oppgave å utvikle kunnskap om hvordan man kan oppnå netto nullutslippsområder (ZEN), med tanke på klimagassutslipp fra utbyggingsprosjekter i våre byer og tettsteder. Direkte og indirekte utslipp knyttet til energibruk i slike prosjekter utgjør en hovedandel av samlede utslipp. Derfor er det essensielt at man kan samles om omforente prinsipper og metodikk for beregning av utslipp fra strøm og fjernvarme, både i dag og frem i tid for et område. Senteret har gjennom årene hatt flere delprosjekt som har omhandlet dette, noen med avansert modellering og metodeutvikling, andre med beregninger for hva som vil være utslippsnivået for ZENpiloter forutsatt at noen beregningsmetoder benyttes eller der alternative metoder sammenlignes. I tillegg forholder man seg til NS3720:2018 Klimagassberegninger for bygninger, som nå er under revisjon, og Senteret ser behov for å gi forskningsbaserte innspill til utformingen av ny standard. Denne vil også bli viktig i implementeringen av ny teknisk forskrift etter TEK17, og for den fremtidige implementeringen av EUs reviderte bygningsenergidirektiv EPBD:2023. Dette notatet gir et sammendrag og endelig anbefaling av metoder for å beregne utslipp fra bruk av strøm og fjernvarme i ZEN-prosjekter, på tvers av øvrige studier og rapporter i FME ZEN. Notatet er utarbeidet av Senterets arbeidsutvalg for ZEN-definisjonen, som en anbefaling til Senterets ledelse.
For utslipp fra strøm har Senteret frem til nå i hovedsak valgt å følge prinsippene i NS3720:2018, men her er det påpekt en inkonsistens i hvordan beregningene utføres som ved eksport av strøm, eksempelvis produsert av solkraft (PV) lokalt i området, gir dobbelt bokføring av klimagevinst. En justert metode (kalt ZEN-c) er derfor foreslått, og beskrevet i ZEN Memo 52, som bør benyttes for å beregne utslippskoeffisienter (gCO2e/kWh) for strøm. Denne er nå bearbeidet videre, til en metode som er anvendbar i praksis og oppsummert i dette notatet. I tillegg er det utviklet en alternativ metode (kalt «Metode 2») for allokering av utslipp uten kompensering som er i tråd med ISO Net Zero Guidelines.
For utslipp fra fjernvarme har mye av diskusjonene vært knyttet til hvordan man bør allokere (fordele) utslippene fra avfallsforbrenning når et forbrenningsanlegg leverer varme inn i et fjernvarmenett. Valget av allokeringsprinsipp og allokeringsfaktor vil kunne påvirke mye de samlede utslipp fra et ZENprosjekt der fjernvarme inngår, spesielt frem i tid når utslippene fra bruk av strøm vil måtte reduseres kraftig og det må forventes økt miljømessig konkurranse der utslippsintensiteter kan bli avgjørende for investeringsbeslutninger. Frem til nå har Senteret også her valgt å følge NS3720:2018, som baseres på at alle utslipp fra avfallsforbrenning i et fjernvarmenett skal allokeres til avfallssystemet og ikke til den eventuelle bruken av fjernvarme i et ZEN-prosjekt. Dette er også anbefalingen i ZEN Rapport 61, som med basis i forskningslitteraturen, LCA-metodikk og egne vurderinger gir en systematisk vurdering av alternative allokeringsmetoder. Anbefalingen om full allokering til avfallssystemet ble i denne rapporten likevel gitt med visse reservasjoner, slik at hensynet til ambisiøs energieffektivitet i et ZEN-prosjekt også skal kunne ivaretas når fjernvarme med lave utslipp benyttes. For å sikre seg en enda grundigere vitenskapelig og LCA-faglig tilnærming til hvordan balansere slike hensyn, under alternative forutsetninger for avfallshåndtering og for oppvarming av bygninger, er det etter initiativ fra Arbeidsutvalget for ZEN-definisjonen nylig utført en lovende studie for internasjonal publisering, basert på prinsippet ‘hevdbasert allokering’. Dette notatet oppsummerer denne metoden, og det er utvalgets anbefaling at dette prinsippet velges for allokering for fjernvarme fremover.publishedVersio