Abstract The goal that the international community has set itself is to reduce greenhouse gas (GHG) emissions in the short/medium-term, especially in Europe that committed itself to reducing GHG emissions to 80–95% below 1990 levels by 2050. Renewable energies play a fundamental role in achieving this objective. In this context, the policies of the main industrialized countries of the world are being oriented towards increasing the shares of electricity produced from renewable energy sources (RES). In recent years, the production of renewable energy has increased considerably, but given the availability of these sources, there is a mismatch between production and demand. This raises some issues as balancing the electricity grid and, in particular, the use of surplus energy, as well as the need to strengthen the electricity network. Among the various new solutions that are being evaluated, there are: the accumulation in batteries, the use of compressed air energy storage (CAES) and the production of hydrogen that appears to be the most suitable to associate with the water storage (pumped hydro). Concerning hydrogen, a recent study highlights that the efficiencies of hydrogen storage technologies are lower compared to advanced lead acid batteries on a DC-to-DC basis, but “in contrast […] the cost of hydrogen storage is competitive with batteries and could be competitive with CAES and pumped hydro in locations that are not favourable for these technologies” (Moliner et al., 2016) [1]. This shows that, once the optimal efficiency rate is reached, the technologies concerning the production of hydrogen from renewable sources will be a viable and competitive solution. But, what will be the impact on the energy and fuel markets? The production of hydrogen through electrolysis will certainly have an important economic impact, especially in the transport sector, leading to the creation of a new market and a new supply chain that will change the physiognomy of the entire energy market.
Sofie Brandtzæg Hårberg, Ola Gjønnes Grendal, Benjamin A D Williamson
et al.
Degradation of cross-linked polyethylene (XLPE) insulations by vented water treeing is a phenomenon that can limit the lifetime and reliability of subsea power cables, as well as their voltage rating. Recent studies have shown that inorganic impurities embedded in the bulk of the semi-conductive (SC) screens can be responsible for inception and growth of vented water trees through channel-like nanostructured tracks. Characterization of the entire region of interest, stretching from the contaminant to the vented water tree, has proven challenging with conventional techniques. Here we have developed a qualitative methodology based on synchrotron wide-angle x-ray scattering to spatially locate crystalline impurities in the cable insulation system, enabling detection of very small impurities in a large bulk sample. NaCl was the dominant crystalline impurity and was present in the voids, along the nanostructured tracks in the SC screen and the vented water trees. Trace amounts of NaCl were also detected within a large volume of an unaged cable screen, indicating that impurities are present prior to exposure of the cables to standardized tests including elevated water temperature. These results provide crucial information about the chemical prerequisites for the formation of the nanostructured track degradation causing inception of long vented water trees at the SC screen/XLPE interface.
Production of electric energy or power. Powerplants. Central stations, Renewable energy sources
Mohamad Javad Kargaran, Hosein Jafari Raraei, Tohid Nouri
et al.
Abstract A new symmetrical structure of the interleaved converter type is proposed in this paper to obtain high voltage gain. The proposed converter delivers a very high voltage ratio using the coupled inductor technique and switched capacitor, and all this happens at a moderate duty cycle. Furthermore, the MOSFETs have low voltage stresses. Therefore, MOSFETs with low conductivity resistance can be used to reduce the conduction losses. The input current has a small ripple because the input side uses the interleaved operation. Furthermore, zero‐current‐switching (ZCS) is obtained for MOSFETs, and the problem of reverse‐recovery for diodes is confined. Moreover, the passive clamp circuit recycles the energy of the leakage inductances which avoids high voltage spikes across the switches. Performance of the proposed converter along with the small‐signal analysis is discussed in detail. Finally, a laboratory prototype is developed with 30 V input and 400 V output to verify the proposed converter.
Esteban Gómez-Díaz, Andrea Balza Morales, Peter A. Kukla
et al.
Abstract The comprehension of geothermal systems involves the efficient integration of geological, geophysical and geochemical tools that are crucial in unraveling the distinct features inherent in geothermal reservoirs. We provide a first approach to comprehending the geologically complex geothermal system in the Aachen area, which has been known for its natural thermal spring occurrences since Roman times. Through a comprehensive analysis involving geochemical interpretation of water samples, a review of 2D seismic profiles, stress analysis, and surface geology, a dynamic model has been built, which serves as a conceptual framework providing a clearer understanding of the system. The model characterizes a non-magmatic, detachment fault-controlled convective thermal system, wherein the reservoir exhibits mixed properties of the mainly Devonian carbonate rocks. NW–SE directed fault lines play a pivotal role in fluid transport, enabling the ascent of thermal waters without the need for additional energy. We additionally conducted magnetotelluric (MT) surveys and analyzed apparent resistivity and impedance values obtained through forward modeling, along with an assessment of noise levels. These findings contribute to evaluating the potential use of MT methods in further evaluating the study area and for geothermal energy exploration in general.
Celina Kacperski, Melanie Vogel, Florian Kutzner
et al.
The integration of electric vehicle (EV) charging with renewable energy sources is crucial for minimizing the carbon footprint of transportation. This study investigates whether real-time pro-environmental information displayed on a smartboard at EV charging stations can influence drivers to align their charging behavior with periods of high renewable energy availability. A pre-post-control quasi-experimental field trial was conducted in a sustainable neighborhood in Ghent, Belgium. A smartboard provided real-time signals indicating optimal charging times based on renewable energy production. The results demonstrate that the presence of real-time pro-environmental information on a smartboard was associated with significant increases in both the number of charging operations and the amount of energy charged during periods of high renewable energy availability. This approach offers a scalable, cost-effective method for optimizing energy consumption and reducing greenhouse gas emissions in residential settings.
The high-energy behaviour of scattering amplitudes involving massive particles has attracted interest in recent years. In these proceedings, we report on the analytic tool AsyInt for solving massive multi-loop Feynman integrals in the high-energy limit, which are fundamental building blocks for such amplitudes in the full Standard Model. We present recent analytic results for two-loop four-point Feynman integrals with both internal and external masses in this limit, featuring polylogarithmic and elliptic structures.
Offshore wind and wave energy offer high energy density and availability. While offshore wind has matured significantly, wave energy remains costly and under development. Integrating both technologies into a hybrid system can enhance power generation, stabilize output, and reduce costs. This study explores the benefits of combining an offshore floating wind turbine with the two-body heaving point absorber wave energy converter, Reference Model 3 (RM3). Six configurations are analyzed: RM3 integrated with the National Renewable Energy Laboratory 5 MW and the International Energy Agency 15 MW wind turbines, each tested on both spar and semi-submersible platforms. The analysis examines dynamic response, mooring loads, and power production under varying environmental conditions, considering the influence of the wave energy converter float motion and an optional reaction plate. Results indicate that the reaction plate improves damping for the spar platform, enhancing wave energy absorption and power output. A comparative analysis indicates that integrating the wave energy converter reduces its levelized cost of energy by 15-83%, while leaving the wind turbine levelized cost of energy unaffected. Hybridization significantly reduces power fluctuations by 50%, reduces the levelized cost of energy with the 5 MW wind turbine, and slightly increases it with the 15 MW wind turbine. The results highlight a mutualistic relationship between the wave energy converter and the offshore wind turbine, where the former benefits substantially while the latter experiences slight improvements or negligible effects. Additional findings quantify hydrodynamic interactions, mooring performance, and economic feasibility. This research provides insights into optimizing hybrid offshore renewable systems, demonstrating their potential to lower costs and support sustainable energy solutions.
Parth Bambhaniya, Elisabete M. de Gouveia Dal Pino
High-energy astrophysical sources such as active galactic nuclei, quasars, X-ray binaries, and gamma-ray bursts are powered by mechanisms that convert gravitational or rotational energy into radiation, jets, and relativistic outflows. Understanding the physics of these processes remains a major challenge. Black holes have traditionally served as the central engines behind such phenomena, with well established energy extraction mechanisms including the Penrose process, the Blandford-Znajek process, and the Banados-Silk-West mechanism. However, studies in general relativity indicate that, under certain conditions, gravitational collapse may lead to the formation of naked singularities or other horizonless compact objects, which could in principle allow more efficient energy extraction than classical black holes. This brief review summarizes recent progress on energy extraction mechanisms in naked singularity spacetimes. We examine the roles of rotation, electromagnetic fields, and particle interactions in shaping extraction efficiency and dynamics. Particular attention is given to negative energy orbits and ergoregion physics, which enable Penrose type and magnetic Penrose mechanisms without an event horizon. We also discuss collisional Penrose processes and particle acceleration near the singularity, emphasizing their potential astrophysical implications. By comparing extraction efficiencies and physical conditions in black holes and naked singularities, we highlight how the absence of a horizon fundamentally alters the dynamics of energy release. These results suggest that naked singularities may serve as natural laboratories for strong field gravity and as alternative engines for high-energy astrophysical phenomena in the era of multi-messenger observations.
The transition to a climate-neutral energy system demands large-scale renewable generation expansion, which requires substantial amounts of bulk materials like steel, cement, and polymers. The production of these materials represents an additional energy demand for the system, creating an energy-material feedback loop. Current energy system models lack a complete representation of this feedback loop. Material requirements of energy system transformation have been studied in a retrospective approach, not allowing them as a consideration in system design. To address this gap, we integrate bulk material demand and production as endogenous factors into energy system optimization using PyPSA-Eur. Our approach links infrastructure expansion with industrial energy needs to achieve a minimum-cost equilibrium. Applying this model to Germany's transition to climate neutrality by 2045, we find that accounting for material needs increases annual bulk material demands by 3-9 %, shifts preferences from solar to wind and from local production of hydrogen to ship imports, and shows distinct industrial process route choices. These findings suggests that energy-material feedbacks should be considered in energy system design when moving to more domestic production of energy technologies.
The development of highly effective bifunctional catalysts for n-hexadecane hydroisomerization is still essential to produce second-generation biodiesel. Herein, a Pt-Pd/ZSM-22-G (abbreviated as Pt-Pd/Z22-G) bimetallic catalyst was prepared by employing a room temperature electron reduction (RTER) method with glow discharge as the electron source. As a contrast, a series of Pt/Z22-H, Pd/Z22-H and Pt-Pd/Z22-H catalysts were prepared by the conventional hydrogen reduction method. The Pt-Pd/Z22-G catalyst reveals more exposed metal sites, larger CMe/CH+ values and an enhanced distribution of Pt-Pd(111) facets compared with the Pt/Z22-H, Pd/Z22-H and Pt-Pd/Z22-H catalysts. These modifications are originated from the stronger electron interactions and the smaller metal nanoparticles because of the effects of highly energetic reducing electrons. The n-hexadecane hydroisomerization results show that the iso-hexadecane yield over the Pt-Pd/Z22-G catalyst is 82.9%, which is the highest among four investigated catalysts in this work. This phenomenon occurs because more exposed Pt-Pd(111) facets and larger CMe/CH+ ratios are beneficial for the adsorption and hydrogenation of iso-alkene intermediates at metal sites to increase the iso-alkanes yield based on density functional theory (DFT) calculations. Furthermore, the iso-alkanes yield over the Pt-Pd/Z22-G catalyst also keeps steady after long-term tests for 120 h because of the limited metal aggregation and carbon deposition.