SINTEF Energy Research

Abstract. In this study we examine how a deep-learning based forecast of local, ground-based geomagnetic field variations trained on solar wind parameters available in real time might be improved by including information contained in an accurate forecast of solar wind conditions. This is accomplished using a long short-term memory (LSTM) model together with magnetic field measurements made at the Rørvik magnetometer station in Mid-Norway. We use Advanced Composition Explorer (ACE) satellite measurements of solar wind and interplanetary magnetic field (IMF) conditions at the first Sun-Earth Lagrange point, and historical lists of coronal mass ejection (CME) impacts at Earth to train and validate the LSTM model. We find that accurate information about the IMF Bz component and solar wind speed are important for obtaining a reasonably accurate (r² ≥ 0.5) forecast of local geomagnetic activity over forecasting horizons beyond ~ 3 h. Information about CME arrival time is only important when simultaneously accompanied by accurate, relatively high-resolution information about IMF Bz. In the absence of the latter, CME arrival time information does not contribute to model performance. This empirical result amounts to a quantitative demonstration of the widely recognized impact of IMF orientation on CME geoeffectiveness. This result also highlights that new innovations, probably in the form of new prediction capabilities of conditions in interplanetary space, will be required to produce accurate forecasts of local geomagnetic disturbances beyond a forecast horizon of 1 h.

The integration of 5G communication into Smart Grid (SG) systems offers significant advancements in reliability, low-latency control, and real-time monitoring. However, it also expands the cyber-attack surface, particularly exposing critical infrastructure to Denial-of-Service (DoS) threats. This paper addresses three key research questions related to Testbed design and development, practical attack & execution feasibility, and impact evaluation within 5G-enabled smart grids. To support this investigation, we design and implement a commercial-grade private 5G smart grid testbed that emulates realistic Information Technology (IT) and Operational Technology (OT) conditions. Using this testbed, we systematically model and execute various DoS attack scenarios targeting different layers of the smart grid communication stack. We choose a selective DoS taxonomy to identify vulnerable components of the communication infrastructure, focusing on 5G signaling. Experimental results show that volumetric DoS attacks significantly degrade network Key Performance Indicators (KPIs), such as increased packet loss, jitter, and delayed control responses, demonstrating their disruptive potential in smart grid environments. Our findings not only expose practical vulnerabilities, but also highlight the value of testbed-driven security assessments for validating mitigation techniques. This research contributes a reproducible platform and structured threat framework for advancing the cyber-resilience of future 5G-integrated energy systems.

Abstract Combustion of fossil fuel by single-cycle gas turbines in offshore oil and gas (O&G) facilities on the Norwegian continental shelf contribute significantly to Norway’s total greenhouse gas emissions. The CleanOFF Hub Research Project aims to reduce those emissions through innovative solutions, such as large-scale offshore hubs delivering low-carbon power to O&G platforms. Within this context, this paper presents an advanced electromagnetic transient (EMT) model for a hydrogen-based energy hub connected to a gigawatt-scale wind farm, designed to power six isolated O&G platforms. Building on previous research, this paper introduces an EMT model that addresses earlier limitations in simulating fast electrical transients and incorporates a more sophisticated virtual synchronous machine (VSM) architecture enabling the study of critical millisecond scale transient phenomena. Key contributions include the development of a publicly available EMT model of a gigawatt-scale wind-powered system with primary and inertial frequency control reserves provided by four VSMs, and the integration of secondary reserves from large grid-following electrolyser and fuel cell systems. These advancements facilitate robust analyses of dynamic behaviors and stability challenges in large-scale, isolated offshore power systems, contributing to the goal of decarbonizing the Norwegian continental shelf.

DC surface tracking has been investigated in three different polymer insulation materials; polystyrene, glass fiber reinforced polyamide, and a polyphenylene oxide and polystyrene compound, based on the experimental test set-up in IEC 60112. Experiments focused on the behavior of insulation material surfaces subjected to 1 kV DC while exposed to salt water with 0.002wt% and 0.01wt% NaCl. The results showed that higher salt concentrations resulted in more severe arc formation, tracking marks and erosion in all three materials tested. When comparing the sample surfaces with the arc formation observed during testing, the intensity and magnitude of arc formation correlated with the severity of the resulting tracking and erosion. Results showed that PPO and PS samples exhibited significant tracking and erosion, especially with higher concentrations, while PM samples displayed greater resistance. The findings underscore the importance of understanding service conditions for insulation materials in maritime DC applications and that selecting the correct insulation material can increase electrical safety and reliability.

Accelerated aging tests have been performed to determine the influence of coastal climate (salt mist) on connectors for use to transfer power from shore to vessel batteries. The test objects were CCS Combo 2 (DC) and Type 2 (AC). The tests simulate about three and a half years of operation in Norwegian coastal environments (marine corrosion index 8). The resistance increases excessively for at least one contact in all connectors exposed to salt mist. Still, most of these connectors also have contacts without excessive contact increase. In the reference group (i.e. not exposed to salt mist), a similar excessive contact increase is not observed for any contacts. Post-mortem investigations indicate that connections are sensitive to mechanical handling. Although the number of test objects were limited, the results indicate that exposure to coastal climate and/or excessive manual handling can be a concern for CCS Combo 2 and Type 2 connectors. At the same time, the recorded resistance increases were limited, and the tested connectors would not have failed due to overheating during three and a half years of operation.

Current climate and energy policies aim for zero emission ports, emphasizing their key role in sustainable energy transition. However, the future demand and supply of energy is uncertain. The long-term interaction between transition policies, regulations, and techno-economic trends is difficult to foresee, making it challenging for ports to prioritise between alternative solutions and strategies. Moreover, ports are situated in local contexts, with different resources and capabilities. This paper reviews policy trends at the international, EU, and national levels, using Norway as the case in point. We apply a socio-technical 'whole systems' perspective to shed light on the current policy mix interacting with the energy system around ports, and the opportunities and challenges this implies for port companies. The discussion is based on a systematic reading of current policy documents, and interviews and workshops with four Norwegian ports. We consider interactions across production, distribution, and use of energy, paying special attention to the changing couplings between these subsystems. Based on the identified scope and strategies, we argue that more effort should be made to strengthen ports’ capabilities as interface actors. The paper contributes to current research on complex system interaction by providing an empirical study illuminating the dynamic interplay between institutional, technological, and actor-based couplings in ‘whole systems’ change. • Novel perspective on the role of policy in complex system transitions • Empirical study of ports, as crucial interface actors • Explores the complex interaction between institutional and actor couplings • New types of actor couplings, in form of hydrogen hubs and novel renewable port concepts • Need for new types of knowledge, enhanced power grid capacity, and financial risk reduction

Digestate, a key byproduct of anaerobic digestion (AD), holds residual methane potential (RMP) that must be stabilized or recovered to prevent greenhouse gas emissions after field use. Thermal hydrolysis (TH), typically a pretreatment for AD, improves biogas production. This study assesses RMP in digestates from food waste (FW) and sewage sludge (SS) biogas plants, treated with TH at 160 and 190 °C. For the liquid fraction, FW digestate at 160 °C yielded 1.5 times more methane than untreated digestate, while SS digestate showed a threefold increase. The solid fraction of FW digestate at 160 °C had 1.4 times higher methane yield than untreated, but SS digestate produced less methane after TH. Adding sulfuric acid after TH increased phosphate release but reduced methane production in both digestates. Overall, TH as a post-treatment enhanced organic content release into the liquid fraction, enhancing methane yield, while acid addition improved phosphorus solubility, thereby enhancing digestate's nutrient value.

Negative streamers with an applied step voltage in an 80-mm point-to-plane gaps in transformer oil have been studied with a fast 16-frame camera. The negative streamers propagated for around 200 µs – 300 µs before breakdown occurred or the streamer channel disappeared. The streamer velocity was approx. 0.4 mm/µs. For some of the captured images, we have seen that faster positive streamers have propagated in the opposite direction from the propagating negative streamer head. This clearly shows there is little or no contact back to the electrode behind the head of the propagating negative streamer, and a positive field towards the electrode must exist, likely due to charge separation in the streamer head.

Green hydrogen represents a promising solution for renewable energy application and carbon footprint reduction. However, its production through renewable energy powered water electrolysis is hindered by significant cost, arising from repair, maintenance, and economic losses due to unexpected downtimes. Although reliability engineering is highly effective in addressing such issues, there is limited research on its application in the hydrogen field. To present the state-of-the-art research, this study aims to explore the potential of reducing these events through reliability engineering, a widely adopted approach in various industries. For this purpose, it examines past accidents occurred in water electrolysis plants from the hydrogen incident and accident database (HIAD 2.1). Besides, a literature review is performed to analyze the state-of-the-art application of reliability engineering techniques, such as failure analysis, reliability assessment, and reliability-centered maintenance, in the hydrogen sector and similar industries. The study highlights the contributions and potentials of reliability engineering for efficient and stable green hydrogen production, while also discussing the gaps in applying this approach. The unique challenges posed by hydrogen's physical properties and innovative technologies in water electrolysis plants necessitate advancement and specialized approaches for reliability engineering.