Optimization of Hybrid Power Plants: When Is a Detailed Electrolyzer Model Necessary?

Hybrid power plants comprising renewable power sources and electrolyzers are envisioned to play a key role in accelerating the transition towards decarbonization. It is common in the current literature to use simplified operational models for electrolyzers. It is still an open question whether this is a good practice, and if not, when a more detailed operational model is necessary. This paper answers it by assessing the impact of adding different levels of electrolyzer details, i.e., physics and operational constraints, to the optimal dispatch problem of a hybrid power plant in the day-ahead time stage. Our focus lies on the number of operating states (on, off, standby) as well as the number of linearization segments used for approximating the non-linear hydrogen production curve. For that, we develop several mixed-integer linear models, each representing a different level of operational details. We conduct a thorough comparative ex-post performance analysis under different price conditions, wind farm capacities, and minimum hydrogen demand requirements, and discuss under which operational circumstances a detailed model is necessary. In particular, we provide a case under which a simplified model, compared to a detailed one, results in a decrease in profit of 1.8% and hydrogen production of 13.5% over a year. The key lesson learned is that a detailed model potentially earns a higher profit in circumstances under which the electrolyzer operates with partial loading. This could be the case for a certain range of electricity and hydrogen prices, or limited wind power availability. The detailed model also provides a better estimation of true hydrogen production, facilitating the logistics required.Comment: Accepted for IEEE PES PowerTech 202

Boron Contents of German Mineral and Medicinal Waters and Their Bioavailability in Drosophila melanogaster and Humans

Scope Boron is a trace element that naturally occurs in soil, making mineral and medicinal water important contributors to overall intake. Thus, in a systematic screening, the mean boron concentrations of 381 German mineral and medicinal waters are determined. Methods and results Boron concentrations in mineral and medicinal waters are analyzed by inductively coupled mass spectrometry (ICP-MS). Highest boron values find in waters from the southwest of Germany. The boron content of the waters is positively correlated with the concentration of most other analyzed bulk elements, including calcium, potassium, magnesium, and sodium. Mineral waters with either low (7.9 µg L-1 ), medium (113.9 µg L-1 ), or high (2193.3 µg L-1 ) boron content are chosen for boron exposure experiments in fruit flies (Drosophila melanogaster) and humans. In flies, boron-rich mineral water significantly increases boron accumulation, with the accumulation predominantly occurring in the exoskeleton. In humans, serum boron and 24-h urinary boron excretion significantly increase only in response to the intake of boron-rich mineral water. Conclusion Overall, the current data demonstrate that mineral and medicinal waters vary substantially in the content of boron and that boron-rich mineral water can be used to elevate the boron status, both in flies and humans

Methods and Apparatus for Error Correction Coding Based on Data Compression

Embodiments are generally related to the field of channel and source coding of data to be sent over a channel, such as a communication link or a data memory. Some specific embodiments are related to a method of encoding data for transmission over a channel, a corresponding decoding method, a coding device for performing one or both of these methods and a computer program comprising instructions to cause said coding device to perform one or both of said methods

Method and device for error correction coding based on high-rate generalized concatenated codes

Field error correction coding is particularly suitable for applications in non-volatile flash memories. We describe a method for error correction encoding of data to be stored in a memory device, a corresponding method for decoding a codeword matrix resulting from the encoding method, a coding device, and a computer program for performing the methods on the coding device, using a new construction for high-rate generalized concatenated (GC) codes. The codes, which are well suited for error correction in flash memories for high reliability data storage, are constructed from inner nested binary Bose-Chaudhuri-Hocquenghem (BCH) codes and outer codes, preferably Reed-Solomon (RS) codes. For the inner codes extended BCH codes are used, where only single parity-check codes are applied in the first level of the GC code. This enables high-rate codes

Method and decoder for soft input decoding of generalized concatenated codes

A soft input decoding method and a decoder for generalized concatenated (GC) codes. The GC codes are constructed from inner nested block codes, such as binary Bose-Chaudhuri-Hocquenghem, BCH, codes and outer codes, such as Reed-Solomon, RS, codes. In order to enable soft input decoding for the inner block codes, a sequential stack decoding algorithm is used. Ordinary stack decoding of binary block codes requires the complete trellis of the code. In one aspect, the present invention applies instead a representation of the block codes based on the trellises of supercodes in order to reduce the memory requirements for the representation of the inner codes. This enables an efficient hardware implementation. In another aspect, there is provided a soft input decoding method and device employing a sequential stack decoding algorithm in combination with list-of-two decoding which is particularly well suited for applications that require very low residual error rates

Generation of stable coatings with carboxylic groups by copolymerization of MAA and VTMS using DBD at atmospheric pressure

The present paper reports on a new approach for the DBD-based plasma-enhanced chemical vapor deposition of MAA coatings at atmospheric pressure, using a plasma-copolymerization with VTMS in order to render the deposits water-stable. The aim of this work is the optimization of the conditions for generating a highly stable surface with a maximum number of functional carboxylic groups. Therefore, the concentrations of the monomers in the process gas have been varied as well as the plasma conditions. The MAA/VTMS plasma-copolymer layers were characterized by ATR FT-IR spectroscopy directly after the preparation as well as after exposure to aqueous solutions and the influence of annealing the layers has been investigated. The amount of carbon present within carboxylic groups was quantified by XPS measurements. As one of the applications of the new type of coatings, its reversible binding properties for gDNA out of blood lysates have been evaluated using a PCR reaction