Incorporating power transmission bottlenecks into aggregated energy system models

Energy scenario analyses are able to provide insights into the future and possible strategies for coping with challenges such as the integration of renewable energy sources. The models used for analyzing and developing future energy systems must be simplified, e.g., due to computational constraints. Therefore, grid-related effects and regional differences are often ignored. We tackle this issue by presenting a new methodology for aggregating spatially highly resolved transmission grid information for energy system models. In particular, such approaches are required in studies that evaluate the demand for spatially balancing power generation and consumption in future energy systems. Electricity transmission between regions is crucial, especially for scenarios that rely on high shares of renewable energy sources. The presented methodology estimates transmission line congestions by evaluating the nodal price differences and then applies a spectral clustering on these particular link attributes. The objective of the proposed approach is to derive aggregated model instances that preserve information regarding electricity transmission bottlenecks. The resulting models are evaluated against observables such as the annual amount of redispatched power generation. For a selection of defined performance indicators, we find a significantly higher accuracy compared to the commonly used, spatially aggregated models applied in the field of energy scenario analysis

Incorporating Power Transmission Bottlenecks into Aggregated Energy System Models

Energy scenario analyses are able to provide insights into the future and possible strategies for coping with challenges such as the integration of renewable energy sources. The models used for analyzing and developing future energy systems must be simplified, e.g., due to computational constraints. Therefore, grid-related effects and regional differences are often ignored. We tackle this issue by presenting a new methodology for aggregating spatially highly resolved transmission grid information for energy system models. In particular, such approaches are required in studies that evaluate the demand for spatially balancing power generation and consumption in future energy systems. Electricity transmission between regions is crucial, especially for scenarios that rely on high shares of renewable energy sources. The presented methodology estimates transmission line congestions by evaluating the nodal price differences and then applies a spectral clustering on these particular link attributes. The objective of the proposed approach is to derive aggregated model instances that preserve information regarding electricity transmission bottlenecks. The resulting models are evaluated against observables such as the annual amount of redispatched power generation. For a selection of defined performance indicators, we find a significantly higher accuracy compared to the commonly used, spatially aggregated models applied in the field of energy scenario analysis

Modulation by steroid hormones of a "sexy" acoustic signal in an Oscine species, the Common Canary Serinus canaria

The respective influence of testosterone and estradiol on the structure of the Common Canary Serinus canaria song was studied by experimentally controlling blood levels of steroid hormones in males and analyzing the consequent effects on acoustic parameters. A detailed acoustic analysis of the songs produced before and after hormonal manipulation revealed that testosterone and estradiol seem to control distinct song parameters independently. The presence of receptors for testosterone and estradiol in the brain neural pathway controlling song production strongly suggests that the observed effects are mediated by a steroid action at the neuronal level.<br>A influência da testosterona e do estradiol, respectivamente, na estrutura do canto do Canário-do-reino Serinus canaria foi estudada analisando o efeito da manipulação dos níveis sanguíneos de hormônios esteróides em machos nos parâmetros acústicos do canto. Uma analise detalhada dos cantos produzidos antes e depois da manipulação hormonal revelou que testosterona e estradiol parecem controlar independentemente parâmetros acústicos distintos. A presença de receptores para esses hormônios no circuito neuronal para controle da produção do canto sugere fortemente que os efeitos observados são mediados pela ação de esteróides a nivel neuronal

Impact of Fractional Flow Reserve Derived from Coronary Computed Tomography Angiography on Heart Team Treatment Decision-Making in Patients with Multivessel Coronary Artery Disease: Insights from the SYNTAX III REVOLUTION Trial

Background: Fractional flow reserve (FFR) is a reliable tool for the functional assessment of coronary stenoses. FFR computed tomography (CT) derived (FFRCT) has shown to be accurate, but its clinical usefulness in patients with complex coronary artery disease remains to be investigated. The present study sought to determine the impact of FFRCT on heart team's treatment decision-making and selection of vessels for revascularization in patients with 3-vessel coronary artery disease. Methods: The trial was an international, multicenter study randomizing 2 heart teams to make a treatment decision between percutaneous coronary interventions and coronary artery bypass grafting using either coronary computed tomography angiography or conventional angiography. The heart teams received the FFRCT and had to make a treatment decision and planning integrating the functional component of the stenoses. Each heart team calculated the anatomic SYNTAX score, the noninvasive functional SYNTAX score and subsequently integrated the clinical information to compute the SYNTAX score III providing a treatment recommendation, that is, coronary artery bypass grafting, percutaneous coronary intervention, or equipoise coronary artery bypass grafting-percutaneous coronary intervention. The primary objective was to determine the proportion of patients in whom FFRCT changed the treatment decision and planning. Results: Overall, 223 patients were included. Coronary computed tomography angiography assessment was feasible in 99% of the patients and FFRCT analysis in 88%. FFRCT was available for 1030 lesions (mean FFRCT value 0.64\ub113). A treatment recommendation of coronary artery bypass grafting was made in 24% of the patients with coronary computed tomography angiography with FFRCT. The addition of FFRCT changed the treatment decision in 7% of the patients and modified selection of vessels for revascularization in 12%. With conventional angiography as reference, FFRCT assessment resulted in reclassification of 14% of patients from intermediate and high to low SYNTAX score tertile. Conclusions: In patients with 3-vessel coronary artery disease, a noninvasive physiology assessment using FFRCT changed heart team's treatment decision-making and procedural planning in one-fifth of the patients

Bi-Directional Sexual Dimorphisms of the Song Control Nucleus HVC in a Songbird with Unison Song

Sexually dimorphic anatomy of brain areas is thought to be causally linked to sex differences in behaviour and cognitive functions. The sex with the regional size advantage (male or female) differs between brain areas and species. Among adult songbirds, males have larger brain areas such as the HVC (proper name) and RA (robust nucleus of the arcopallium) that control the production of learned songs. Forest weavers (Ploceus bicolor) mated pairs sing a unison duet in which male and female mates learn to produce identical songs. We show with histological techniques that the volume and neuron numbers of HVC and RA were ≥1.5 times larger in males than in females despite their identical songs. In contrast, using in-situ hybridizations, females have much higher (30–70%) expression levels of mRNA of a number of synapse-related proteins in HVC and/or RA than their male counterparts. Male-typical and female-typical sexual differentiation appears to act on different aspects of the phenotypes within the same brain areas, leading females and males to produce the same behaviour using different cellular mechanisms

Interband-Faradayeffekt und -Kerreffekt in Halbleitern Eine Grundsatzanalyse anhand aequivalenter magnetooptischer Modulationsspektren von Germanium und Silizium

TIB: ZN 5905 (8A) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Interband-Faradayeffekt und -Kerreffekt in Halbleitern: Eine Grundsatzanalyse anhand aequivalenter magnetooptischer Modulationsspektren von Germanium und Silizium

SIGLECopy held by FIZ Karlsruhe; available from UB/TIB Hannover / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekDEGerman