Grid Integration Costs of Fluctuating Renewable Energy Sources

The grid integration of intermittent Renewable Energy Sources (RES) causes costs for grid operators due to forecast uncertainty and the resulting production schedule mismatches. These so-called profile service costs are marginal cost components and can be understood as an insurance fee against RES production schedule uncertainty that the system operator incurs due to the obligation to always provide sufficient control reserve capacity for power imbalance mitigation. This paper studies the situation for the German power system and the existing German RES support schemes. The profile service costs incurred by German Transmission System Operators (TSOs) are quantified and means for cost reduction are discussed. In general, profile service costs are dependent on the RES prediction error and the specific workings of the power markets via which the prediction error is balanced. This paper shows both how the prediction error can be reduced in daily operation as well as how profile service costs can be reduced via optimization against power markets and/or active curtailment of RES generation.Comment: Accepted for SUSTECH 2014, Portland, Oregon, USA, July 201

The dual use of an historical event: 'Rwanda 1994', the justification and critique of liberal interventionism

This essay places the 1994 genocide in Rwanda in the context of the academic and political rise of liberal interventionism since 1990. It argues that this historical event is important for the debate about 'humanitarian interventions' in two different ways: on the one hand, as a signifier, 'Rwanda 1994' has been used (or, for that matter, misused) in order to justify an almost unlimited international agenda of liberal interventionism and social engineering; on the other, the genocide that could arguably have been prevented represents the exceptional case where military intervention can indeed be justified - but precisely because it is not in need of a specifically liberal justification. What would have made a military-based prevention of genocide justifiable in this particular case is precisely the aim to prevent something that is universally agreed to be inacceptable (genocide). The liberal twist in the justification narrative, in contrast, tends to emphasize the difference between the (liberal) 'us' and the non-liberal 'them', consequently claiming the legitimate right for the ‘us’ to decide about the use of force exclusively, that is, without the 'them'. The continuation of the narrative into answering the post-intervention question 'what now?' then leads consequently into the necessity of imposing one's own system of rule as a general norm without due attention for the specifics of the situation 'on the ground'. The exceptional features of 'Rwanda 1994' (the empirical event), thus, point in a critical way to all those cases where 'Rwanda 1994' (the signifier) has been used to make the case for an ever expanding agenda of liberal ('just') war

Life is… great! : emotional attention during instructed and uninstructed ambiguity resolution in relation to depressive symptoms

Attention and interpretation biases are closely involved in depression-related processing of emotional material. However, it is unclear whether attention and interpretation biases reflect a processing tendency (i.e., driven by schemas or prior learning) or an ability-related process (i.e., dependent on attentional control). This study tested how depressive symptom severity, attention bias, and interpretation bias are related under tendency versus ability processing conditions. Fifty-two participants completed two versions of the scrambled sentences test (to measure interpretation bias) while eye movements were recorded (to measure attention bias) in separate experimental sessions. To assess tendency and ability processes, participants were instructed to unscramble the sentences by reporting the first sentence that comes to mind (tendency version; session 1) and to unscramble the sentences in a fixed, positive manner (ability version; session 2). Results showed that depressive symptom severity was correlated with attention bias under both tendency and ability conditions. Analyses showed that attention bias (i.e., the fixation time spent on positive versus negative words) acted as an intervening variable in the relation between depressive symptoms and interpretation bias only during ability processes. These findings suggest that depression-linked biases in attention reflect both processing tendencies and ability-related processes in attentional control, with attentional control as a relevant mechanism in the subsequent interpretation of emotional material. Implications for cognitive theories and cognitive training methods are discussed.Depto. de Personalidad, Evaluación y Psicología ClínicaFac. de PsicologíaTRUEpu

Investigation Of Suitable Solutions For A Digital Chain For Tactile On-Machine Measurement Based On Solutions For Coordinate Measurement Machines

The trend towards customer-specific products remains strong. The modern industry faces the challenge of meeting significantly higher quality requirements in the context of variant-rich production. The traditional process for machined workpieces consists of inspection on coordinate measuring machines after the machining is done. For machining processes that require quick response and early quality assurance, a tactile on-machine inspection is more suitable. This approach allows real-time control within the process, enabling high levels of automation on the shop floor and minimizing manual rework. The increased complexity of this system lies in the preparation of the measurement task, which involves selecting the measurement strategy, planning the inspection task and creating an inspection program. This paper explores existing computer-aided inspection planning approaches for coordinate measuring machines and assess their suitability for on-machine inspection. This enables a valuable component for enabling automated quality assurance of customer-specific products and highlights existing gaps in the process

Electroweak phase transition in non-minimal Higgs sectors

Higgs sector extensions beyond the Standard Model (BSM) provide additional sources of CP violation and further scalar states that help to trigger a strong first order electroweak phase transition (SFOEWPT) required to generate the observed baryon asymmetry of the Universe through electroweak baryogenesis. We investigate the CP-violating 2-Higgs-Doublet Model (C2HDM) and the Next-to-Minimal 2-Higgs-Doublet Model (N2HDM) with respect to their potential to generate an SFOEWPT while being compatible with all relevant and recent theoretical and experimental constraints. The implications of an SFOEWPT on the collider phenomenology of the two models are analysed in detail in particular with respect to Higgs pair production. We provide benchmark points for parameter points that are compatible with an SFOEWPT and provide distinct di-Higgs signatures

Utjecaj enoloških uvjeta na potrošnju kisika u vinskom talogu nakon fermentacije

Postfermentation wine yeast lees show antioxidant properties based on their ability to consume dissolved oxygen. The oxygen consumption capacity of suspended yeast lees obtained after fermentations with six commercial active dry yeast strains was investigated in model, white and red wines using fluorescence-based oxygen sensors operating in a nondestructive way. In model solution, the oxygen consumption rate of yeast lees was shown to depend on their amount, yeast strain, sulfur dioxide and temperature. It is slightly lower in red than in white wines. It is strongly decreased by current levels of free sulfur dioxide, thus excluding the complementary use of both as antioxidants in wine. However, in 25 randomly sampled white wines produced under commercial conditions, the rate and extent of oxygen consumption during the first six months of postfermentation had no significant correlation with any of these interacting factors, making it difficult to predict the actual antioxidant effect of yeast lees. In these wines, yeast lees consumed 0 to 47 % of the dissolved oxygen. Although total oxygen consumption capacity of yeast lees is not a limiting factor under commercial winemaking conditions, their oxygen consumption proceeds at a limited rate that reduces but cannot totally prevent concomitant chemical oxidation of the wine.Antioksidacijska svojstva kvasaca zaostalih u talogu nakon fermentacije ovise o njihovoj potrošnji otopljenog kisika. U radu je ispitan kapacitet potrošnje kisika suspendiranih stanica šest komercijalnih sojeva kvasca neinvazivnom metodom pomoću fluorescentnog senzora u vinskom talogu dobivenom nakon fermentacije modelne alkoholne otopine, bijelih i crnih vina. U modelnoj je otopini potrošnja kisika ovisila o soju i količini kvasaca, koncentraciji sumporovog dioksida i temperaturi. U crnim je vinima potrošnja kisika bila nešto manja nego u bijelim. Povećanjem koncentracije slobodnog sumporovog dioksida potrošnja se kisika smanjila, pa je zaključeno da se vinski talog i sumporov dioksid ne mogu istodobno koristiti kao antioksidansi u vinu. Međutim, utvrđeno je da potrošnja kisika u 25 slučajno odabranih uzoraka bijelog vina proizvedenih u komercijalnim uvjetima prvih šest mjeseci nakon fermentacije nije bitno ovisila o soju i količini kvasaca, koncentraciji sumporovog dioksida ili temperaturi, pa je u tim vinima bilo teško predvidjeti stvarni antioksidacijski učinak kvasaca. Kvasci iz taloga bijelih vina potrošili su od 0 do 47 % otopljenog kisika. Iako ukupan kapacitet potrošnje kisika nije ograničio uporabu kvasaca u komercijalnoj proizvodnji vina, s vremenom se potrošnja kisika smanjila i djelomično, ali ne u potpunosti, zaustavila kemijsku oksidaciju vina