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Evaluation of Different Front Surface Passivation Schemes for p-type IBC Solar Cells
Full text linkIn this work, we investigate different front-side passivation approaches for p-type IBC solar cells. We compare a POCl3-diffused and SiNx-passivated front floating emitter (FFE) with an undiffused front surface passivated by a layer stack of aluminum oxide Al2O3 and silicon nitride SiNx, using different technologies for Al2O3 deposition. Further, we investigate a boron-doped front surface field (FSF), realized with different BBr3 diffusion approaches. We achieve promising implied open-circuit voltages iVoc of up to 740 mV with Al2O3/SiNx-passivation, which is a 7 mV increase compared to the reference process using the phosphorus-doped FFE. Further, we fabricated boron-doped FSF samples exhibiting promising recombination parameters of j0 < 6 fA/cm2. The transfer of the Al2O3/SiNx-passivation into pIBC solar cells already reaches peak efficiencies of h = 23.3%, comparable to the FFE
Market Implications on Grid Connection Sizing for Photovoltaic Systems
Full text linkMarket simulations conducted by Swissgrid for 2040 show a correlation between solar irradiation and the marginal costs of the price-setting power plants. This paper utilises results from a fundamental power market model simulation to assess the energy losses and the financial value of solar energy due to curtailment as a function of PV production capacity for various PV systems. Two reference scenarios were considered, in which solar energy accounts for 52% and 55% of the Swiss production mix. However, the simulated market can only absorb 85% and 77% of the annual solar energy production, respectively. Assuming excess production is curtailed, the study calculates the amount of energy and financial income lost due to market curtailment. Additionally, further losses resulting from limited grid connection capacity are analysed. The results show that the top 60% of grid-injected power, particularly in combination with self-consumption, represents less than 3% of a PV system’s market-priced financial revenue. Thus, with only 40% of a PV system’s capacity, 97% of its market value can still be realised
Preface: PV-Symposium 2025
Full text linkPV Symposium 2025 was a very special edition marking the 40th anniversary of this event. It is a great honor to host you at Kloster Banz as we reflect on four decades of advancements in photovoltaics and look ahead to the future of this pioneering technology.
From its humble beginnings in off-grid applications, photovoltaics has evolved into a cornerstone of climate-friendly energy systems. Today, the focus lies on reliable, integrated energy infrastructures that include far more than solar modules: power electronics, inverters, storage solutions, grid integration, AI-based forecasting tools, quality assurance, manufacturing technologies, and building-integrated systems are just a few of the components driving PV\u27s success. In many regions, solar electricity has become the most cost-effective form of clean energy generation.
This progress has been driven by tireless research, technological innovation, and growing global demand for sustainable energy. In Germany alone, more than one million new PV systems were installed in 2023, adding over 14 GWp of capacity – from balcony systems to large-scale solar parks.
Looking ahead, we face a new challenge: in the next 40 years, photovoltaics must assume greater responsibility in securing the energy supply of our industrialized nation. Within a few years, solar electricity will cover large portions of daily demand, and within 15 years, it is expected to contribute one-third of total annual electricity generation. This requires not only more efficient modules and robust systems, but also increased societal acceptance and smart integration in open spaces and urban environments.
In addition to technological topics, this year’s symposium will again focus on regulatory and political developments in the DACH (GSA) region, as well as current research, planning, installation, and application strategies.
In this context, the proceedings volume plays a particularly important role. It not only documents the thematic breadth and scientific depth of the symposium, but also serves as a valuable reference for future work in research, industry, and policymaking. The proceedings contribute to the visibility and long-term impact of the presented work and enable informed knowledge exchange well beyond the event itself.
Together, we can shape a climate-neutral energy system. The exchange of knowledge, ideas, and best practices at this symposium will help us join forces to pave the way toward a more sustainable future
How Uwe Johnson Prevents a Book: About an Expert Opinion on George Steiner\u27s »The Portage to San Cristobal of A.H.«"
No full textDer Aufsatz untersucht Uwe Johnsons Gutachten zu George Steiners kontroversem Roman The Portage to San Cristobal of A.H. und setzt es in den literatur- und geschichtspolitischen Kontext der Bundesrepublik der späten 1970er Jahre. Ausgehend von Johnsons Argumentationsstruktur wird diskutiert, inwiefern das Gutachten grundsätzliche Fragen über die Grenzen literarischer Fiktion und westdeutscher Erinnerungskultur behandelt. Dabei wird deutlich, dass Johnsons Ablehnung nicht nur eine literaturkritisch motivierte ist, sondern als politische Entscheidung ebenfalls eine intellektuelle Intervention, die im Spannungsfeld zwischen historischen Fakten, erzählerischer Freiheit und politischen Überzeugungen steht.The article examines Uwe Johnson\u27s assessment of George Steiner\u27s controversial novel The Portage to San Cristóbal of A.H. and situates it within the literary and historical-political context of late 1970s West Germany. It explores Johnson\u27s argumentative structure and discusses to what extent his report addresses fundamental questions about the limits of literary fiction and West German Culture of Remembrance. It becomes clear that Johnson\u27s rejection is not merely a literary critique but also a political decision, an intellectual intervention positioned at the intersection of historical facts, narrative freedom, and political convictions
Preface: SolarPACES 2024, 30th International Con-ference on Concentrating Solar Power, Thermal, and Chemical Energy Systems
Full text linkRenewable energy technologies are a key element in the journey towards sustainable and secure energy systems. They not only help us neutralize our carbon footprint, but also enable us to harness energy sources that are abundant and more evenly distributed globally.
In 2023, the participants in COP 28 committed to triple the installed capacity of renewable power by 2030. Also, the International Energy Agency reports that the annual renewable capacity additions marked a step change in 2023 and are expected to steadily increase over the next years. This huge expansion will be led by market-mature technologies like solar PV and on-shore wind, which are expected to make up each year for nearly 95 % of the renewable electricity capacity additions, until 2030.
However, as the penetration of renewables approaches 100%, the availability of clean technologies that allow dispatchable production will no longer be an option, but a necessary element for our energy systems to be not only sustainable, but also flexible and resilient. Also, it has now become very clear that full electrification of our energy uses will not be possible in the short term. The “hard-to-abate” sectors, like energy intensive industries and heavy transport, will require alternative approaches to be decarbonized. Today, industry makes up for roughly 30 % of the total world’s energy consumption and industrial processes require 70 % of their energy input as low-, medium- and, mostly, high-temperature heat. Fulfilling this energy demand in a sustainable way is a challenge that will require the use of multiple energy technologies and vectors. This includes hydrogen and other renewable fuels, but also technologies that can directly produce renewable heat.
Concentrating solar thermal (CST) technologies possess all the key features to address these challenges. They can be used to produce (or co-produce) high-temperature heat, electricity, hydrogen and other renewable fuels. They can rely on commercially proven long-duration thermal energy storage solutions, which are not based on critical materials and allow flexible and, potentially, round-the-clock operation. Furthermore, they can support the penetration of non-programmable renewables by providing flexibility and ancillary services to the grid.
Several challenges still hinder the deployment of CST technologies. Improving the cost-efficiency is among the first priorities. Research and innovation can partly contribute to this aim, but ensuring a stable pipeline of commercial projects is crucial. In turn, in many markets, today this requires well-designed and stable support policies.
From October 7th to 11th, 2024, more than 520 experts and delegates from 41 countries gathered at the Auditorium della Tecnica in Rome (Italy), to attend the 30th edition of the SolarPACES Conference. With 42 years of activity since its inauguration in 1982, the conference has become the world’s reference event for the CST community, which now every year provides an excellent forum for research, industry and policy makers to connect, exchange ideas, build networks, showcase cutting edge innovations, and lay the groundwork for new projects.
The Conference boasted a very rich technical program with 4 plenary sessions including 8 keynote presentations and a roundtable discussion, 40 technical sessions with more than 220 talks, 244 posters and a technical visit to ENEA Casaccia Research Center, which hosts the most relevant CST-related research infrastructures in Italy. The participants were greeted during the opening session by the Italian Minister of Environment and Energy Security Gilberto Pichetto Fratin, who pointed out how CST is among the key energy technologies identified by the European Union to achieve its ambitious climate goal of carbon neutrality by 2050 and, accordingly, is expected to contribute to the Italian energy mix in the near future as reported in the National Energy and Climate Plan.
This volume collects the 177 full papers submitted for the Conference Proceedings. The papers cover all the 16 conference topics that address a wide and exhaustive range of current issues in the field of CST technologies, from the assessment of solar resource, to the deployment of commercial projects. Almost half of the papers focus on one of three key topics, namely “Analysis and Simulation of CSP and Hybridized Systems”, “Thermal Energy Storage Materials, Media, and Systems”, and “Solar Industrial Process Heat and Thermal Desalination”. This clearly reflects the main trajectories that the CST community has been following in recent years towards the future of the technology.
The following papers mark another step to improve the technological and economic performance of CST technologies and foster their further deployment. To the authors of these papers, to those who helped in the organization of the Conference, and to all the participants goes my deepest gratitude.
SUAVPy: A SUMO Plugin for UAV-Based Ground Traffic Sensing
No full textIn recent years, Unmanned Aerial Vehicles (UAVs) have emerged as effective tools for traffic monitoring and control by offering high-resolution, aerial observations of vehicular movement. Although UAV simulation is well established, tools to capture microscopic traffic measurements from UAV-based observations remain limited. This paper introduces SUMO-UAV-Py, an open-source SUMO plugin that integrates UAV-based sensing into microscopic traffic simulations in Python. SUMO-UAV-Py captures detailed vehicle observations by dynamically employing multiple UAVs to observe traffic measurements based on their position and field-of-view (FoV). Performance evaluations on a mid-sized network demonstrate that SUMO-UAV-Py maintains simulation performance comparable to standard post-processing methods, confirming its suitability for large-scale traffic monitoring research
Spatio-Temporal AI Modeling for Urban Traffic Calibration: A SUMO-Based Approach
Full text linkUrban traffic management is a critical challenge in modern cities, necessitating innovative solutions to optimize traffic flow and reduce congestion. This research presents the development of an AI engine leveraging spatio-temporal learning techniques for urban traffic calibration. The proposed methodology leverages digital twin scenarios driven by microscopic simulations, which capture detailed vehicle behaviors—including interactions, lane changes, and driver dynamics to provide granular insights into urban traffic patterns. At the core of the AI engine is the Dynamic Spatio-Temporal Graph Attention Network (DSTGAT), a hybrid model that combines multi-head Graph Attention Networks (GATv2) with Long Short-Term Memory (LSTM) networks. DSTGAT exploits the joint spatio-temporal relationships inherent in traffic data by processing sequential snapshots of urban traffic, where each snapshot is represented as a graph with nodes indicating urban zones and edges carrying continuous flow values. The GATv2 layers, enhanced with residual connections and batch normalization, extract robust spatial embeddings, while the LSTM aggregates these embeddings over time to capture dynamic patterns and predict future traffic flows in real-time. The AI engine incorporates an iterative feedback loop that continuously refines the OD demand using synthetic scenarios, improving estimation accuracy across diverse urban environments. Preliminary results show that the DSTGAT‑based framework lowers OD‑estimation error on simulated data, suggesting its usefulness as an input to downstream traffic‑management strategies
Sintering and Crystallization of Fluoride-Containing Bioactive Glass F3
Full text linkThe fluoride-containing bioactive glass F3 with nominal composition (mol%) 44.8 SiO2 - 2.5 P2O3 - 36.5 CaO - 6.6 Na2O - 6.6 K2O - 3.0 CaF2 is a highly promising candidate for bone replacement applications. Its strong crystallization tendency, however, requires a thorough understanding of the interplay between glass powder particle size, surface crystallization, and sintering. Therefore, this study characterizes the sintering and crystallization of bulk specimens and various particle size fractions by differential thermal-analysis, laser scanning, electron microscopy, X-ray diffraction, and Infrared spectroscopy. Particle size fractions < 56 µm were found to fully densify, while crystals growing from the glass particle surface retard sintering of coarser fractions. Small amounts of a non-stoichiometrically calcium phosphosilicate (Ca14.92(PO4)2.35(SiO4)5.65) occurs as the primary crystal phase followed by combeite (Na4Ca4[Si6O18]) as a temporarily dominating phase. The surface crystallization of both phases was found to be mainly responsible for sinter retardation. During later stages of crystallization, additional phases such as cuspidine (Ca4F2Si2O7) and silicorhenanite (Na2Ca4(PO4)2SiO4) occur, but finally monoclinic wollastonite (CaSiO3) forms as the dominant phase
Synthetic (Goldstone) and Natural Aventurine - A Review
Full text linkAventurine glass, known for its glittering optical effect due to embedded microscopic metallic or oxide crystals, was developed in Murano, Venice, at the end of the 16th or early 17th century. The historical recipes reveal the complex requirements, including copper reduction, heat treatments and controlled atmospheres, necessary to produce its unique sparkle. Later innovations introduced variants based on chromium and iron, each with distinct crystallization mechanisms and applications. The present study synthesizes the history, production techniques and crystallization processes of aventurine glass, focusing on its relations with nucleation and controlled growth of crystals to obtain desirable optical properties. In addition, comparisons are made with natural aventurine quartzite, where the aventurescence results from mineral inclusions. By exploring both artificial and natural aventurines, this article highlights the links between material composition, manufacturing techniques and aesthetic outcomes
Towards a More Efficient Design of High Temperature Concentrating Solar Power Plant With Cascaded Thermal Energy Storage
Full text linkThis work proposes a novel concentrating solar power (CSP) plant configuration aiming at a high operation temperature of 1000°C. The thermal energy storage system (TES) would be the focus of this research by modifying it and proposing four configurations to enhance the overall efficiency of high-temperature solar power towers. The objective is to identify the most thermodynamically efficient designs by analyzing the literature on the different components and comparing them to a reference base case of a conventional 100 MWe solar power tower plant (2-tank molten salt TES) operating at 565°C. The proposition consists of a Brayton/Rankine combined cycle with a double cascade TES. In the proposed cascade TES, the primary unit consists of a high-temperature air/ceramic packed-bed thermocline operating at 1000°C, while the secondary unit is a single molten salt tank used as sensible heat. The secondary TES is used as a heat sink during charge, improving efficiency and reducing the size of the air/ceramic-packed bed by extracting the thermocline out of the tank. Excess energy stored in the secondary TES is utilized for preheating during discharge. The methodology incorporates evaluating various combinations of solar block, TES, and power block integration. Combinations are selected from a comprehensive literature review. The study focuses on night-time operations. Further analysis of the cost-benefit of the designs would be required to compare the overall energy production and furthermore the LCOE