Environmental constraints in hydropower systems serve to ensure sustainable use of water resources. Through accurate treatment in hydropower scheduling, one seeks to respect such constraints in the planning phase while optimizing the utilization of hydropower. However, many environmental constraints...
New concepts of local electricity markets (LEMs) have led increased focus on the decentralization of energy systems and a raise in local energy communities (LECs). Under the right market-regulatory incentives, peer-to peer (P2P) electricity trading schemes facilitate direct trade among the prosumers...
Large-scale experiments have been performed to investigate the possible consequences of realistic amounts of liquified hydrogen (LH2) encountering water. The experiments aimed at simulating an accidental release of LH2 onto water, for instance during the fuelling of a ship. For liquified natural...
A multi-stress test rig was built to investigate the effect of many start-stops (load cycling) on hydropower generator insulation. To emulate real-life start-stops, stator bars were subjected to accelerated temperature cycling by circulating a 3.5 kA current and then cooling down with fans while...
We present a medium-term hydropower scheduling model that includes inflow- and volume-dependent environmental constraints on maximum discharge. A stochastic dynamic programming algorithm (SDP) is formulated to enable an accurate representation of nonconvex relationships in the problem formulation of...
In this paper we analyze the control problem for a steam cycle that produces power by recovering waste-heat from gas turbines on an offshore installation. The waste-heat recovery unit is based on once-through steam generator technology. The main disturbances are large variations of the gas turbine...
Partial discharges (PD) in the high voltage insulation systems are both a symptom and cause of terminal and impending failures. The use of data-driven methods based on PD measurements will enable predictive strategies to replace traditional maintenance strategies. This paper employs machine...
Conventionally, liquefied biomethane (LBM) is produced through biogas upgrading followed by a liquefaction process. In the present study, a detailed model for an LBM production plant including amine-based biogas upgrading and liquefaction was provided to compare thermodynamic and economic...
This paper gives a review of the current state of the art for numerical simulations of char conversion. In particular, it presents models that have been developed to describe the physical and chemical phenomena that characterize thermochemical char conversion. All particle sizes are covered, ranging...
Decision-support systems rely on data exchange between digital twins (DTs) and physical twins (PTs). Faulty sensors (e.g, due to hardware/software failures) deliver unreliable data and potentially generate critical damages. Prompt sensor fault detection, isolation and accommodation (SFDIA) plays a...
Abstract Increased renewable energy production and storage is a key pillar of net-zero emission. The expected growth in the exploitation of offshore renewable energy sources, e.g., wind, provides an opportunity for decarbonising offshore assets and mitigating anthropogenic climate change, which...
Clean offshore energy hubs may become pivotal for efficient offshore wind power generation and distribution. In addition, offshore energy hubs may provide decarbonised energy supply for maritime transport, oil and gas recovery, and offshore farming, while also enabling conversion and storage of...
Controlling discharge growth on insulator surfaces is important in high voltage gaseous insulation systems. In this study, the effect of small-scale surface profiles on streamer discharge propagation is examined experimentally. The experimental test objects were 5x72x150 mm polycarbonate plates with...
As regulation of ship emission established, using liquefied natural gas (LNG) as ship fuel is one of the method to reduce ship emission. For LNG carrier, boil-off gas (BOG) generated from the storage tank can be used as fuel and it is economical to adopt BOG re-liquefaction system on the vessel. In...
Partial discharge (PD) characteristics in aluminum nitride (AlN) insulating substrates at sinusoidal and switched voltages have been investigated. The substrates were tested in silicone liquid. PDs we observed both at sharp edges of the copper conductor and inside the ceramic. Phase-resolved PD...
R744 integrated systems can meet oscillating heating and cooling demands efficiently and become a game changer in countries such as India. The present work aims to develop and present R744 system designs and disseminate the knowledge under the framework of the INDEE+ project in India, with the focus...
More stringent international regulations on ship's emissions require a shift towards more climate friendly fuels, such as liquefied natural gas (LNG). On LNG-driven ships, the fuel is stored onboard at cryogenic temperature. The fuel must be vaporised before injected into the engine, implying a...
A novel vapor-compression system concept employing carbon dioxide as the refrigerant is proposed to serve the needs of a typical medium-size refrigerated truck used for multi-temperature (MT and LT) goods delivery. The system design is based on the implementation of an ejector as the only component...
Due to a higher share of power production from renewable sources with high short-term variation, hydro systems must more often operate closer to their components' physical limits. To simulate system behaviour, a hydropower system simulator must therefore include most physical details. We present a...