Wasserstoff als ein Fundament der Energiewende Teil 1: Technologien und Perspektiven für eine nachhaltige und ökonomische Wasserstoffversorgung

Wasserstoff hat das Potenzial, der zentrale Baustein für eine Energiewirtschaft mit massiv reduzierten Treibhausgasemissionen zu sein. Er bietet Antworten auf bisher ungelöste Fragen der Energiewende, insbesondere in den Bereichen Transport und Langzeitspeicherung. Wasserstoff ermöglicht es außerdem industrielle Prozesse emissionsfrei zu gestalten, bei denen dies auf andere Art kaum realisierbar wäre. Aufgrund seiner vielfältigen Einsatzmöglichkeiten über die Sektorengrenzen hinaus lassen sich zudem Synergiepotenziale nutzen, die die Wasserstoffwirtschaft mit voranschreitendem Ausbau der erforderlichen Infrastruktur zunehmend auch ökonomisch attraktiv machen. Hilfreich wird in diesem Zusammenhang eine langfristige Investitionssicherheit für Importinfrastruktur und lokale Verteilinfrastrukturen sein. Es gibt eine Vielzahl von Verfahren zur Herstellung von Wasserstoff. Diese unterscheiden sich sowohl in den eingesetzten Prozessen und Komponenten zur Stoffumwandlung als auch in den verwendeten Energie- und Materialquellen. Dadurch ergeben sich unterschiedliche Produktionskosten und mit der Produktion verbundene stark variierende Treibhausgasemissionen. Da angesichts der Erreichung von Klimaschutzzielen die graue Produktion von Wasserstoff nicht zielführend ist, sind die blauen und vor allem die grünen Verfahren zu betrachten und vergleichend zu bewerten. Der weitere Einsatz von blauen Methoden wird entscheidend davon abhängen, wie schnell und effizient CCS-Optionen großskalig zur Verfügung stehen werden und inwiefern eine dauerhafte Speicherung im Untergrund garantiert werden kann. Dies vorausgesetzt, bieten auch blaue Technologien in einem Übergangszeitraum Potenzial für eine kostengünstige, großskalige Produktion von emissionsreduziertem bzw. -freiem Wasserstoff. Langfristig wird sich allerdings die grüne Herstellung von Wasserstoff durchsetzen müssen, um Wasserstoff als universalen Energieträger eines CO2-neutralen Energiesystems zu etablieren. Dass dies großskalig technisch möglich und ökonomisch attraktiv sein kann, zeigt die Analyse der verfügbaren und sich in der Entwicklung befindlichen Technologien. Eine essentielle Voraussetzung für den Erfolg der grünen Herstellungsmethoden wird die ausreichende und kostengünstige Verfügbarkeit von erneuerbaren Energiequellen sein. Hier sind vor allem Sonne und Wind, aber auch Biomasse, Wasserkraft und Geothermie zu nennen. Als einer der Hauptstränge für die Wasserstoffproduktion in Deutschland, teils auch in Europa, wird häufig die Nutzung von Überschussstrom aus intermittierenden erneuerbaren Energiequellen in Elektrolyseanlagen genannt. Hierbei ist jedoch zu beachten, dass die Wasserstoffgestehungskosten stark vom jährlichen Ausnutzungsgrad der Umwandlungsanlagen abhängen und daher ein Anlagenbetrieb mit höheren Volllaststunden vorteilhaft ist. Auch ist zukünftig mit der Nutzung von Überschussleistungen durch andere flexible Verbraucher (zum Beispiel Power-to-Heat) zu rechnen. Für eine großskalige grüne Wasserstoffproduktion ist daher ein massiver zusätzlicher Ausbau von Anlagen zur Erzeugung von erneuerbarem Strom erforderlich. Nichtsdestotrotz können flexibel ausgelegte Wasserstoff-Produktionsanlagen prinzipiell auch anteilig erneuerbaren Überschussstrom nutzen und so sowohl zur besseren Integration fluktuierender Erzeugungsleistungen als auch zur Stabilisierung der Stromnetze beitragen. Das Potenzial der erneuerbaren Energien ist in Deutschland aufgrund der Ressourcen sowie angesichts des beanspruchbaren Platzangebots beschränkt. Ebenso ist bei einem massiven weiteren Ausbau von insbesondere Windkraftanlagen mit zunehmenden Akzeptanzrisiken zu rechnen, was die derzeitige Krise der Windkraft eindrücklich zeigt. Vor diesem Hintergrund erscheint vor allem die großskalige, zentrale Produktion von Wasserstoff in Ländern mit großem Angebot an erneuerbaren Energiequellen sowie an geeigneten und verfügbaren Flächen attraktiv. Als wichtiger Aspekt für die zukünftige Versorgungssicherheit müssen in diesem Zusammenhang unter anderem geopolitische Aspekte beachtet werden. Für eine importbasierte Wasserstoffwirtschaft scheinen technologische Lösungen für die Speicherung und den Transport in Größe und Kosten kein Hindernis zu sein. Daher stellt diese Option eine zumindest aus techno-ökonomischer Sicht attraktive und zentrale Komponente dar

Single-cell immune repertoire sequencing of B and T cells in murine models of infection and autoimmunity

Adaptive immune repertoires are composed by the ensemble of B and T cell receptors (BCR, TCR) within an individual and reflect both past and current immune responses. Recent advances in single-cell sequencing enable recovery of the complete adaptive immune receptor sequences in addition to transcriptional information. Such high-dimensional datasets enable the molecular quantification of clonal selection of B and T cells across a wide variety of conditions such as infection and disease. Due to costs, time required for the analysis and current practices of academic publishing, small-scale sequencing studies are often not made publicly available, despite having informative potential to elucidate immunological principles and guide future-studies. Here, we performed single-cell sequencing of B and T cells to profile clonal selection across murine models of viral infection and autoimmune disease. Specifically, we recovered transcriptome and immune repertoire information for polyclonal T follicular helper cells following acute and chronic viral infection, CD8+ T cells with binding specificity restricted to two distinct peptides of lymphocytic choriomeningitis virus, and B and T cells isolated from the nervous system in the context of experimental autoimmune encephalomyelitis. We could relate repertoire features such as clonal expansion, germline gene usage, and clonal convergence to cell phenotypes spanning activation, memory, naive, antibody secretion, T cell inflation, and regulation. Together, this dataset provides a resource for experimental and computational immunologists that can be integrated with future single-cell immune repertoire and transcriptome sequencing datasets

Single-cell immune repertoire sequencing of B and T cells in murine models of infection and autoimmunity

Adaptive immune repertoires are composed by the ensemble of B and T cell receptors (BCR, TCR) within an individual and reflect both past and current immune responses. Recent advances in single-cell sequencing enable recovery of the complete adaptive immune receptor sequences in addition to transcriptional information. Such high-dimensional datasets enable the molecular quantification of clonal selection of B and T cells across a wide variety of conditions such as infection and disease. Due to costs, time required for the analysis and current practices of academic publishing, small-scale sequencing studies are often not made publicly available, despite having informative potential to elucidate immunological principles and guide future-studies. Here, we performed single-cell sequencing of B and T cells to profile clonal selection across murine models of viral infection and autoimmune disease. Specifically, we recovered transcriptome and immune repertoire information for polyclonal T follicular helper cells following acute and chronic viral infection, CD8+ T cells with binding specificity restricted to two distinct peptides of lymphocytic choriomeningitis virus, and B and T cells isolated from the nervous system in the context of experimental autoimmune encephalomyelitis. We could relate repertoire features such as clonal expansion, germline gene usage, and clonal convergence to cell phenotypes spanning activation, memory, naive, antibody secretion, T cell inflation, and regulation. Together, this dataset provides a resource for experimental and computational immunologists that can be integrated with future single-cell immune repertoire and transcriptome sequencing datasets

CheS-Mapper - Chemical Space Mapping and Visualization in 3D

Analyzing chemical datasets is a challenging task for scientific researchers in the field of chemoinformatics. It is important, yet difficult to understand the relationship between the structure of chemical compounds, their physico-chemical properties, and biological or toxic effects. To that respect, visualization tools can help to better comprehend the underlying correlations. Our recently developed 3D molecular viewer CheS-Mapper (Chemical Space Mapper) divides large datasets into clusters of similar compounds and consequently arranges them in 3D space, such that their spatial proximity reflects their similarity. The user can indirectly determine similarity, by selecting which features to employ in the process. The tool can use and calculate different kind of features, like structural fragments as well as quantitative chemical descriptors. These features can be highlighted within CheS-Mapper, which aids the chemist to better understand patterns and regularities and relate the observations to established scientific knowledge. As a final function, the tool can also be used to select and export specific subsets of a given dataset for further analysis

Camera constant in the case of two media photogrammetry

International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives, Volume 40, Issue 5W5, 9 April 2015, Pages 1-6Refraction is the main cause of geometric distortions in the case of two media photogrammetry. However, this effect cannot be compensated and corrected by a suitable camera calibration procedure (Georgopoulos and Agrafiotis, 2012). In addition, according to the literature (Lavest et al. 2000), when the camera is underwater, the effective focal length is approximately equal to that in the air multiplied by the refractive index of water. This ratio depends on the composition of the water (salinity, temperature, etc.) and usually ranges from 1.10 to 1.34. It seems, that in two media photogrammetry, the 1.33 factor used for clean water in underwater cases does not apply and the most probable relation of the effective camera constant to the one in air is depending of the percentages of air and water within the total camera-to-object distance. This paper examines this relation in detail, verifies it and develops it through the application of calibration methods using different test fields. In addition the current methodologies for underwater and two-media calibration are mentioned and the problem of two-media calibration is described and analysed

Comparative assessment of very high resolution satellite and aerial orthoimagery

International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives, Volume 40, Issue 3W2, 2015, Pages 1-7This paper aims to assess the accuracy and radiometric quality of orthorectified high resolution satellite imagery from Pleiades-1B satellites through a comparative evaluation of their quantitative and qualitative properties. A Pleiades-B1 stereopair of high resolution images taken in 2013, two adjacent GeoEye-1 stereopairs from 2011 and aerial orthomosaic (LSO) provided by NCMA S.A (Hellenic Cadastre) from 2007 have been used for the comparison tests. As control dataset orthomosaic from aerial imagery provided also by NCMA S.A (0.25m GSD) from 2012 was selected. The process for DSM and orthoimage production was performed using commercial digital photogrammetric workstations. The two resulting orthoimages and the aerial orthomosaic (LSO) were relatively and absolutely evaluated for their quantitative and qualitative properties. Test measurements were performed using the same check points in order to establish their accuracy both as far as the single point coordinates as well as their distances are concerned. Check points were distributed according to JRC Guidelines for Best Practice and Quality Checking of Ortho Imagery and NSSDA standards while areas with different terrain relief and land cover were also included. The tests performed were based also on JRC and NSSDA accuracy standards. Finally, tests were carried out in order to assess the radiometric quality of the orthoimagery. The results are presented with a statistical analysis and they are evaluated in order to present the merits and demerits of the imaging sensors involved for orthoimage production. The results also serve for a critical approach for the usability and cost efficiency of satellite imagery for the production of Large Scale Orthophotos

Documentation of a submerged monument using improved two media techniques

Proceedings of the 2012 18th International Conference on Virtual Systems and Multimedia, VSMM 2012: Virtual Systems in the Information Society, 2012, Article number 6365922, Pages 173-180The rapid developments of technology in recent years have opened new horizons in Photogrammetry, overcoming obstacles sometimes insurmountable, reducing time and increasing accuracy of results. However, while the continuous development of close-range Photogrammetric methods for the geometric documentation of monuments on land and sea seem to go hand in hand, techniques for capturing submerged archaeological sites especially when situated at shallow depths are inadequate while application of traditional methods is impossible or uneconomical. This paper describes the improvement of two-media (through air and water) photogrammetric techniques for the documentation of a submerged archaeological site of Epidaurus, Greece, at a depth ranging from 0.5 to 2 meters. Specific reference is made to the various problems caused by the presence of water and how they were addressed. Errors in depth determination caused by waves, colour absorption and chromatic aberration are also addressed. Particular attention is given to the effects of refraction at the air/water interface on the Collinearity Condition. The various attempts are presented, analysed and evaluated. Finally, ortho-images have been generated and cross section data were collected in order to perform the documentation. © 2012 IEEE

The effect of pansharpening algorithms on the resulting orthoimagery

International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives, Volume 41, 2016, Pages 625-630This paper evaluates the geometric effects of pansharpening algorithms on automatically generated DSMs and thus on the resulting orthoimagery through a quantitative assessment of the accuracy on the end products. The main motivation was based on the fact that for automatically generated Digital Surface Models, an image correlation step is employed for extracting correspondences between the overlapping images. Thus their accuracy and reliability is strictly related to image quality, while pansharpening may result into lower image quality which may affect the DSM generation and the resulting orthoimage accuracy. To this direction, an iterative methodology was applied in order to combine the process described by Agrafiotis and Georgopoulos (2015) with different pansharpening algorithms and check the accuracy of orthoimagery resulting from pansharpened data. Results are thoroughly examined and statistically analysed. The overall evaluation indicated that the pansharpening process didn't affect the geometric accuracy of the resulting DSM with a 10m interval, as well as the resulting orthoimagery. Although some residuals in the orthoimages were observed, their magnitude cannot adversely affect the accuracy of the final orthoimagery