Search

In order to reach the goals of the United Nations Framework Convention on Climate Change, a stepwise reduction of energy related greenhouse gas emissions as well as an increase in the share of renewable energies is necessary. For a successful realization of these changes in energy supply, an integrated view of multiple energy sectors is necessary. The coupling of different energy sectors is seen as an option to achieve the climate goals in a cost-effective way. In this paper, a methodical approach for multi-modal energy system planning and technology impact evaluation is presented. A key feature of the model is a coupled consideration of the sectors electricity, heat, fuel and mobility. The modeling framework enables system planners to optimally plan future investments in a detailed transition pathway of the energy system of a country, considering politically defined climate goals. Based on these calculations, in-depth analyses of energy markets as well as electrical transmission and distribution grids can be performed using the presented optimization models. Energy demands, conversion and storage technologies in households, the Commerce, Trade and Services (CTS) area and the industry are modeled employing a bottom-up modeling approach. The results for the optimal planning of the German energy system until 2050 show that the combination of an increased share of renewable energies and the direct electrification of heat and mobility sectors together with the use of synthetic fuels are the main drivers to achieve the climate goals in a cost-efficient way.

Innovative Solutions for Energy Transitions / Edited by Jinyue Yan, Hong-xing Yang, Hailong Li, Xi Chen 10th International Conference on Applied Energy, ICAE2018, Hong Kong, Hong Kong, 22 Aug 2018 - 25 Aug 2018; Amsterdam [u.a.] : Elsevier, Energy Procedia 158, 3482-3487 (2018). doi:10.1016/j.egypro.2019.01.923, Published by Elsevier, Amsterdam [u.a.]

Pathways leading to a carbon neutral future for the German energy system have to deal with the expected phase-out of coal-fired power generation, in addition to the shutdown of nuclear power plants and the rapid ramp-up of photovoltaics and wind power generation. An analysis of the expected impact on electricity market, security of supply, and system stability must consider the European context because of the strong coupling&mdash, both from an economic and a system operation point of view&mdash, through the cross-border power exchange of Germany with its neighbors. This analysis, complemented by options to improve the existing development plans, is the purpose of this paper. We propose a multilevel energy system modeling, including electricity market, network congestion management, and system stability, to identify challenges for the years 2023 and 2035. Out of the results, we would like to highlight the positive role of innovative combined heat and power (CHP) solutions securing power and heat supply, the importance of a network congestion management utilizing flexibility from sector coupling, and the essential network extension plans. Network congestion and reduced security margins will become the new normal. We conclude that future energy systems require expanded flexibilities in combination with forward planning of operation.

Regulated Electricity Price Components (REPCs) such as fees, taxes and levies dominate the cost structure for every consumed, stored, or even generated kWh of electricity in Germany and other European countries. This decreases financial incentives for flexible consumption, storage or generation which will be needed to handle increasing volatility in generation and demand.In this paper, we propose a linear optimization-based market matching mechanism for Local Energy Markets (LEMs) which considers REPCs. With this approach, the REPCs can be split and allocated to substations, feeders, and participants thereby incentivizing trades within close spatial proximity.We compare different schemes for spatially distributed REPCs for a demonstration scenario with 120 LEM participants with electric vehicles, battery storage and solar PV systems. Compared to a business as usual scenario, local self-sufficiency can be increased by about 14 percentage points. Additionally, peak loads during midday and evening can be decreased by 13-58 %.

The performance of electrode arrays insulated by low-temperature atomic layer deposited (ALD) titanium dioxide (TiO2) or hafnium dioxide (HfO2) for culture of electrogenic cells and for recording of extracellular action potentials is investigated. If successful, such insulation may be considered to increase the stability of future neural implants. Here, insulation of titanium nitride electrodes of microelectrode arrays (MEAs) was performed using ALD of nanometer-sized TiO2 or hafnium oxide at low temperatures (100-200°C). The electrode properties, impedance, and leakage current were measured and compared. Although electrode insulation using ALD oxides increased the electrode impedance, it did not prevent stable, physiological recordings of electrical activity from electrogenic cells (cardiomyocytes and neurons). The insulation quality, estimated from leakage current measurements, was less than 100 nA/cm2 in a range of 3 V. Cardiomyocytes were successfully cultured and recorded after 5 days on the insulated MEAs with signal shapes similar to the recordings obtained using uncoated electrodes. Light-induced electrical activity of retinal ganglion cells was recorded using a complementary metal-oxide semiconductor-based MEA insulated with HfO2 without driving the recording electrode into saturation. The presented results demonstrate that low-temperature ALD-deposited TiO2 and hafnium oxide are biocompatible and biostable and enable physiological recordings. Our results indicate that nanometer-sized ALD insulation can be used to protect electrodes for long-term biological applications.

Energies 13(16), 4076-4090 (2020). doi:10.3390/en13164076, Published by MDPI, Basel

The increasing share of distributed energy resources gives rise to new opportunities for deploying innovative business models and coordination schemes within sustainable energy systems. Different concepts entail different implications at socioeconomic, technical and institutional level. Hence, their thorough assessment is key to understanding their actual potential as enablers of the energy transition. Considering this background, we focus on local energy markets as an increasingly discussed approach for coordinating distributed energy systems and introduce a simulative framework for enabling a multi-regional assessment of this concept. Local energy markets bear the potential for increasing the active participation of end consumers, which could increase their acceptance for energy projects in general and their returns on investment, as well as for reducing the peak load on increasingly congested electrical grids by enhancing local energy balancing. We evaluate these hypotheses for twelve representative German regions, for which we formulate assumptions regarding the energy demand as well as the shares of distributed energy resources that are consistently aligned with an overall European energy scenario envisaging a rapid growth of electric vehicles in Germany. For this purpose, we enhance an existing framework for the assessment of local energy markets in order to be able to include the flexibility of the electric mobility sector in local trade activities. The simulation results show that local energy markets have a significant impact on energy systems: First, local trading increases the economic benefits over all participants, who would otherwise only be able to use their generation for self-consumption or direct marketing in central energy markets. Second, local energy balancing increases on average by 60 % over all regions. Third, infrastructural relief of the overlaying transmission grids can be accomplished by reducing the yearly peak load at the point of common coupling by 39 % on average and at the most by 97 % . Furthermore, we find that including electric vehicles in local market activities does not alter but rather reinforces these effects.

The current situation, which is driven by environmental concerns and increased air traffic, forces airport operators to examine their energy systems in an integrated approach. In order to optimize total expenditures, demands of energy in all forms must be considered. This paper introduces a novel method for the optimal design of multi-modal energy systems, which will be put to further use in the European Union Horizon 2020 MODER project. The optimization problem was formulated as mixed-integer linear programming based on a superstructure approach, including all feasible state-of-the-art technologies. Part-load efficiencies as well as the influence of ambient conditions on available output capacities were considered. The model took into account several types of energy storages, i.e., electrochemical, thermal and water storages. For fifteen locations, the optimal set of technologies, their capacity and operation was identified. Results showed that for this load range, combined heat and power plants were economically very attractive. Furthermore, photovoltaic energy was a viable option, even without designated feed-in tariff. Last but not least, compression chillers with chilled water storages offered an attractive option for enhanced flexibility. Combined total cost savings by using both the described method and on-site generation of up to 61% were achieved.

Global challenges as decarbonization, the integration of renewables or an increasing electrification are confronting countries worldwide. Based on an analysis of different energy system models, archetypes of country energy systems are identified as an approach to simplify modeling the global challenges for most countries around the world. Applying a modified K-means algorithm to a broad and transparent data basis of socio-economic, geographic/climatic and energy-related data leads to the definition of the archetypes. An exemplary clustering of 140 countries generating 15 archetypes underlines the existence of patterns in energy systems, which can e.g. be characterized by the climatic circumstances or the energy mix. Overall the archetypes represent a possibility to summarize countries on a global level, leading to a simplified modeling process of countries in energy system models, providing a common data basis for models and identifying common challenges of different countries.

The increasing decentralization of the power supply poses new challenges to the market integration of renewable energies. One concept for the market integration of distributed energy resources (DER) is the virtual power plant (VPP). A VPP aggregates a portfolio of smaller DERs and operates them as a unified and flexible resource on the energy and balancing power markets. The operation planning of the market participation is, however, characterized by uncertainties, mainly due to the forecasting errors of renewable energy resources. Thus, this paper presents a model for the multi-market operation planning plan of a VPP with regard to the forecasting errors of the associated DERs. The spot- and intraday markets and the balancing power markets are modeled individually to ensure a valid market participation of the VPP. The forecasting errors are integrated in the planning process through a two-stage stochastic optimization. Exemplary results show the impact of controllable DERs in the planning process of a VPP consisting of a storage system and several PV power plants.

Turbidity sensing is very common in the control of drinking water. Furthermore, turbidity measurements are applied in the chemical (e.g., process monitoring), pharmaceutical (e.g., drug discovery), and food industries (e.g., the filtration of wine and beer). The most common measurement technique is nephelometric turbidimetry. A nephelometer is a device for measuring the amount of scattered light of suspended particles in a liquid by using a light source and a light detector orientated in 90° to each other. Commercially available nephelometers cost usually-depending on the measurable range, reliability, and precision-thousands of euros. In contrast, our new developed GRIN-lens-based nephelometer, called GRINephy, combines low costs with excellent reproducibility and precision, even at very low turbidity levels, which is achieved by its ability to rotate the sample. Thereby, many cuvette positions can be measured, which results in a more precise average value for the turbidity calculated by an algorithm, which also eliminates errors caused by scratches and contaminations on the cuvettes. With our compact and cheap Arduino-based sensor, we are able to measure in the range of 0.1-1000 NTU and confirm the ISO 7027-1:2016 for low turbidity values.

In this study we examined the energy transfer dynamics of a FRET coupled pair of chromophores at the single molecule level embedded in a tunable sub-wavelength Fabry-Pérot resonator with two silver mirrors and separations in the λ/2 region. By varying the spectral mode density in the resonator via the mirror separation we altered the radiative relaxation properties of the single chromophores and thus the FRET efficiency. We were able to achieve wavelength dependent enhancement factors of up to three for the spontaneous emission rate of the chromophores while the quenching due to the metal surfaces was nearly constant. We could show by confocal spectroscopy, time correlated single photon counting and time domain rate equation modeling that the FRET rate constant is not altered by our resonator.

Voltage and angle stability of power systems with renewable power supply and the corresponding region of attraction are analyzed jointly. First, the power system model is derived that consists of algebraic power network equations and differential power generator equations. The renewable power generators like photovoltaic inverters or wind turbines are modeled with first order dynamics. Second, power system stability is analyzed for two kinds of power networks: high-voltage networks with purely inductive power lines and medium-/low-voltage networks with homogeneous resistive-inductive power lines. For both cases, decoupling droop controllers are presented and the stability of this power system including these controllers is analyzed. The analysis is based on contraction arguments that have been used before to prove consensus in multi-agent system. However, due to the particular structure of the power system model, conventional contraction arguments have to be adapted for this analysis.

Subject area A consulting team to an international food packaging company (SDYesBox) is attempting to decide which algorithm is the most useful for selecting two national markets in Central America and the Caribbean. SDYesBox wants to work closely with its immediate customers – manufacturers in the dairy and food industry and their customers (retailers) – to develop and market innovative products to low-income consumers in emerging markets; the “next big opportunity for the dairy industry” according to SDYesBox. Study level/applicability New product development and market selection in emerging markets in Latin America. Case overview Five algorithms are “on the table” for assessing 14 countries by 12 performance indicators: weighted-benchmarking each country by the country leader's indicator scores; tallying by ignoring indicator weights and selecting the countries having the greatest number of positive standardized scores; applying a conjunctive and lexicographic combination algorithm; and using a “fluency metric” of how quickly consumers can say each country aloud. At least one member of the consulting team is championing one of these five algorithms. Which algorithm do you recommend? Why? Expected learning outcomes Learners gain skills, insights, and experience in alternative decision tools for evaluating and selecting choices among emerging markets to enter with new products for low-income (bottom of the pyramid) products ands services. Supplementary materials Teaching notes are available for educators only. Please contact your library to gain login details or email support@emeraldinsight.com to request teaching notes.

With one in five Canadians estimated to experience mental illness, retention of registered nurses in the acute psychiatric hospital setting becomes a pressing issue. The key for these nurses to survive and potentially even thrive in practice has been identified as resilience. From interviews with four registered nurses, maintaining a "vast" perspective, becoming an "expert" of self, clarifying "belief systems", and being "present" through "staying awake" were identified as key in developing resilience. Although participants expressed that the development of resilience is an individual process, the concept of development was similar. Developing personal resilience may be a matter of self-development.

The increasing share of renewable energy resources like wind or solar power opens up interesting options for a paradigmatic change of network operation strategies. On the one hand volatile generation principally endanger robust network operation. On the other hand there is an political and ecological pressure to maximize the in-feed of renewable energy resources, like photovoltaics. There is therefore a need for a cheap and scalable solution to meet these challenges. We claim that this requires more local intelligence associated with the network elements and communication between these units. Future grid operation system will have to provide features like state estimation, voltage control and load balancing irrespective of the voltage level. Scalability is achieved if the central control task is distributed among the distributed intelligent units.

Embedded in a tuneable λ/2-FabryPérot micro-resonator the radiative relaxation of a dye molecule or quantum dot can reproducibly be modified allowing to determine their quantum yield, control Förster energy-transfer or localize them with nanometer precision.

The paper deals with a physical model for the calculation of the strip temperature in a hot rolling mill. Beside the heat transfer from the strip to the environment in the different mill sections a sub-model for the material properties of steel including phase transitions is introduced. For the application in a process automation system an online adaptation of the model to the current state of the mill is indispensable. The adaptation is explained in detail.

Due to the large development and integration of renewable energy generators, voltage control in power distribution grids have become a very important topic for the energy automation systems. In this paper we present aspects regarding the design of local controllers and the overall stability of the control system. The results stem from analytical investigations and from measurements and experiments performed on a low voltage distribution grid. In the paper we will show that voltage asymmetry in the distribution grids cannot be neglected and consequently, the control of the voltage needs to be performed specifically for each phase. Decentralized local controllers can perform the control and, if designed correctly, they are highly efficient with respect to the use of reactive power.

Here we report a simple way to enhance the resolution of a confocal scanning microscope under cryogenic conditions. Using a microscope objective (MO) with high numerical aperture (NA = 1.25) and 1-propanol as an immersion fluid with low freezing temperature we were able to reach an imaging resolution at 160 K comparable to ambient conditions. The MO and the sample were both placed inside the inner chamber of the cryostat to reduce distortions induced by temperature gradients. The image quality of our commercially available MO was further enhanced by scanning the sample (sample scanning) in contrast to beam scanning. The ease of the whole procedure marks an essential step towards the development of cryo high-resolution microscopy and correlative light and electron cryo microscopy (cryoCLEM).

The wide spread of distributed generation from renewable power sources may cause severe degradation of electricity quality due to its hardly predictable nature. In order to maintain the desired electricity quality, new actuators and advanced control techniques needs to be developed and integrated in the grid. The reactive power injection of photovoltaic (PV) inverters provides an effective mean for the control of voltage levels and their fluctuation. This paper describes a combined central and local control scheme for the reactive power. The use of local controllers based only on local measurements enables a fast reaction of the controllers on changes in generated and consumed powers, while the central optimization of their parameters ensures an optimal use of the resources and minimization of losses. MATLAB simulations prove the concept for a realistic distribution grid.

With the assumption that photovoltaic power plants will use all available roof areas in the future, it is not possible to integrate the entire PV potential in today's low-voltage distribution grids. Due to the enormous feed-in of fluctuating electrical power in low-voltage grids by small-scale photovoltaic plants, transformers and cables can reach their loading limits. Moreover, the grid voltage can exceed permissible thresholds. In this paper the maximum feed-in that low-voltage energy distribution networks can be supplied with is being evaluated. The results show that it is not possible at present to integrate the entire potential of photovoltaic power plants in the distribution grids. Local energy storages, which save the surplus generation, can be an alternative to grid reinforcement and can be essential for a stable energy network in the future. Optimization methods using forecasts can lead to a more efficient usage of energy storage systems and enhance the self-consumption of the local energy generation.

The increasing share of decentralized small and medium power plants opens up interesting options for a paradigmatic change of network operation strategies. On the one hand fluctuating generation principally endanger robust network operation. On the other hand there is an economic and ecological pressure to maximize the infeed of renewable energy sources. There is therefore a need for a cheap and scalable solution to meet these challenges. The solution we propose requires more decision intelligence and communication between the players in the electrical network. Scalability is achieved if the central control task is distributed among the intelligent players. Optimization of the control problem then means to devise a set of roles for the players and rules among them. We present such a basic set of roles and rules. We discuss the self-organization that occurs on the basis of these rules, the system performance as well as the consequences for the evolution of present-day strategies of network operation.

We surveyed primary care physicians about their involvement and perceived skills in palliative care. A survey instrument asked how frequently internal medicine and family practice physicians performed 10 palliative care items. Subjects rated their skills in each area. A majority of physicians always or frequently performed all 10 palliative care items, but fewer than 50% of respondents adequately attended to the spiritual needs and economic problems of patients. Interest in palliative care was associated with an increased frequency in performing palliative care items (P = 0.036), while training in palliative care was associated with better perceived performance (P = 0.05). Only 36% of respondents had received training in palliative care. Internists and family practitioners provide palliative care to patients, but feel their skills are lacking in certain areas. Training may improve care to patients at the end of life.

This project is carried out jointly by the Crystal Growth Laboratory at the Chair of Material Science VI at the University of Erlangen (Prof. G. Muller) and the Chair of Applied Mathematics at the Technical University of Munich (Prof. K.-H. Hoffmann) with the support of the companies Korth Kristalle GmbH and Preiberger Compound Materials GmbH. The goal of the project is the development of proper numerical models for optimisation and control of industrial crystal growth processes. To this end the research group concentrates on the numerical treatment, simulation and optimal control of techniques for growing high quality single and compound semiconductor crystals. The result of this project is the flexible and efficient computer code CrysVUn that is today successfully used to optimise industrial growth processes.

Background —The objective was to assess the safety and efficacy of L-NMMA in the treatment of cardiogenic shock. Methods —We enrolled 11 consecutive patients with cardiogenic shock that persisted after >24 hours from admission, despite coronary catheterization and primary percutaneous transluminal coronary revascularization, when feasible, and treatment with mechanical ventilation, intraaortic balloon pump (IABP), and high doses of catecholamines. L-NMMA was administered as an IV bolus of 1 mg/kg and continuous drip of 1 mg · kg −1 · h −1 for 5 hours. Treatment with catecholamines, mechanical ventilation, and IABP was kept constant throughout the study. Results —Within 10 minutes of L-NMMA administration, mean arterial blood pressure (MAP) increased from 76±9 to 109±22 mm Hg (+43%). Urine output increased within 5 hours from 63±25 to 156±63 cc/h (+148%). Cardiac index decreased during the steep increase in MAP from 2.0±0.5 to 1.7±0.4 L/(min · m 2 ) (−15%); however, it gradually increased to 1.85±0.4 L/(min · m 2 ) after 5 hours. The heart rate and the wedge pressure remained stable. Twenty-four hours after L-NMMA discontinuation, MAP (+36%) and urine output (+189%) remained increased; however, cardiac index returned to pretreatment level. No adverse events were detected. Ten out of eleven patients could be weaned off mechanical ventilation and IABP. Eight patients were discharged from the coronary intensive care unit, and seven (64%) were alive at 1-month follow-up. Conclusions —L-NMMA administration in patients with cardiogenic shock is safe and has favorable clinical and hemodynamic effects.

OBJECTIVETo determine the feasibility, safety and efficacy of bilevel positive airway ventilation (BiPAP) in the treatment of severe pulmonary edema compared to high dose nitrate therapy.BACKGROUNDAlthough noninvasive ventilation is increasingly used in the treatment of pulmonary edema, its efficacy has not been compared prospectively with newer treatment modalities.METHODSWe enrolled 40 consecutive patients with severe pulmonary edema (oxygen saturation