Andra-Teodora Nedelcu

Floating photovoltaic parks represent a significant innovation in the field of renewable energy, offering a sustainable alternative for electricity production in the context of the global transition to low-carbon sources. This study investigates the technical feasibility, energy performance, and environmental implications of a 20 MWp floating photovoltaic plant integrated with a 40 MWh battery energy storage system (BESS) in the Port of Constanța, a major logistics hub in the Black Sea region. A comprehensive modeling approach was developed, combining solar resource assessment, PV system simulation (PVsyst-like modelling), energy storage operation, hydrodynamic loading evaluation, and environmental impact screening. Results indicate an annual energy yield between 22.0 and 26.0 GWh, corresponding to a specific yield ranging between 1100 and 1300 kWh/kWp, depending on climatic variability and thermal performance assumptions. A sensitivity analysis was conducted to evaluate system performance under conservative, moderate, and optimistic solar yield scenarios specific to the Port of Constanța, within the realistic regional range of 1100–1300 kWh/kWp. The BESS enables peak-shaving and load-shifting, improving grid integration and reducing diesel generator usage in port operations. Hydrodynamic analysis indicates that three-point taut mooring systems can withstand local wave loads with acceptable safety factors under extreme storm scenarios. Environmentally, the system shows moderate impacts on underwater light availability and water temperature, which can be mitigated through careful siting and monitoring. Economically, the levelized cost of electricity (LCOE) is estimated at 0.046–0.052 €/kWh, competitive with terrestrial PV and aligned with European port decarbonization targets. The study demonstrates that FPV-BESS hybrid systems can play a central role in sustainable port transformation and offers a replicable framework for similar coastal infrastructures worldwide.

The maritime transportation industry is under pressure to reduce the level of emissions generated annually by commercial vessels. In order to achieve this objective, regulatory bodies, both national and international, have imposed strict limitations on the industry, and thus major changes have to be made in a tight time frame. In the last decade, engineers and ship designers have been searching for alternatives to traditional fuels, but it is not easy to find a perfect balance between operational costs and economic efficiency. Many potential solutions are being studied, with some of them already proven and implemented, such as liquefied natural gas, solar and wind power, electric propulsion, and many more. One solution might be biofuels, and this study aims to assess the potential impact of their use on the energy performance and durability of a typical marine propulsion engine, namely the MAN B&W 6S70MC-C7, fitted on board many types of ships including large oil tankers, container ships and bulk carriers. The main topic is approached through a progressive structure, starting from the analysis of general characteristics of these fuels and the engine installation, comparative simulations, operational experience, and technical recommendations. The comparative assessment is focused on two traditional types of fuels and two biofuel types. The aim is to identify a viable solution that can sustain the operational efficiency of this main engine without a major impact on its maintenance cycle and without additional costs on the components. Even if these biofuels are more expensive than the traditional ones, in the long run, they could prove to be a better choice in terms of operational costs and compliance with regulation.

Background: Port congestion contributes significantly to operational inefficiency and environmental impact in maritime logistics. With tightening EU regulations such as the Emissions Trading System (EU ETS) and FuelEU Maritime, understanding and mitigating the economic and environmental effects of vessel delays is increasingly critical. This study focuses on a single bulk cargo pier at Constanta Port (Romania), which has experienced substantial traffic fluctuations since 2021, and examines operational and environmental performance through a queuing-theoretic lens. Methods: The authors have applied an M/G/1/∞/FIFO/∞ queuing model to vessel traffic and service time data from 2021–2023, supplemented by Monte Carlo simulations to capture variability in maneuvering and service durations. Environmental impact was quantified in CO₂ emissions using standard fuel-based emission factors, and a Cold Ironing scenario was modeled to assess potential mitigation benefits. Economic implications were estimated through operational cost modeling and conversion of CO₂ emissions into equivalent EU ETS carbon costs. Results: The analysis revealed high berth utilization rates across all years, with substantial variability in waiting times and queue lengths. Congestion was associated with considerable CO₂ emissions, which, when expressed in monetary terms under prevailing EU ETS prices, represent a significant financial burden. The Cold Ironing scenario demonstrated a substantial reduction in at-berth emissions and corresponding cost savings, underscoring its potential as a viable mitigation strategy. Conclusions: Results confirm that operational congestion at the studied berth imposes substantial environmental and financial burdens. The analysis supports targeted interventions such as Just-In-Time arrivals, optimized berth scheduling, and Cold Ironing adoption. Recommendations are most applicable to single-berth bulk cargo operations; future research should extend the approach to multi-berth configurations and incorporate additional operational constraints for broader generalizability.

This review examines the importance of using bioindicators to monitor pollution levels on the Romanian Black Sea coast. Also, based on the distinctive ecological characteristics of the Black Sea, the study highlights the human-induced pressures, which are currently aggravated by the war in the region. It is therefore important to use certain aquatic species as bioindicators (mollusks, crustaceans), which are sensitive to environmental changes and can serve as warning signals of an ecosystem's health. At the same time, this study promotes the implementation of bioindicator-based assessment programs, which are essential for understanding and reducing the effects of pollution and facilitating the sustainable use of this fragile ecosystem.

This paper presents a series of analyses regarding the tethered umbilical cable in uniform current cable from the composition of the underwater remotely operated vehicle (ROV). The remotely operated vehicle is used in different undersea operation when it is important to control and determine precisely the disturbance forces generated by drag due to currents that act either on the vehicle directly or indirectly on the tether umbilical cable. The dynamics of umbilical cable represent an important part in ocean environment being used for signal and power transmission application. To perform the simulation in Ansys Aqwa, two axis systems are considered. A coordinate system related to the earth, represented by the key in front of which the measurements are made and a second coordinate system related to the vehicle at a set depth relative to the surface of the key. The results obtained from the simulation show us the drag forces that are exerted on the chosen cable for a given length, drag that appear both the seaborne platforms and underwater remotely vehicle contact.

The subject of this paper is to analyze the hydrometeorological parameters received on board during on route from Singapore to Santos (Brazil) between July 15th and August 4th, 2018 to optimize fuel consumption on board. The information was obtained daily, in real time, using on-board measurement tools and SPOS 8 Software provided by MeteoGroup, and those related to fuel consumption in the EcoVoyage program. General analyzes of hydrometeorological parameters were introduced as graphs, with more detailed values extracted from MSPS (Maersk Ship Performance System).

Remotely Operated Vehicles (ROVs) and Autonomous Underwater Vehicles (AUVs) have many applications in a large variety of submarine areas. In the last years, they are used to replace different missions in rivers, lakes and oceans. Named also underwater robots, both tethered and untethered, they are an integral part of scientific equipment to explore the seas and oceans field. The underwater robots, ROVs and AUVs, are useful in many fields and for a different application such as inspection, bathymetry or mapping. However, we must keep in mind that according to their capabilities they can operate at different depth limit. For example, Hugin 3000 sensor of Knogsberg Maritime, Remus 3000 from Institutului Woods Hole Oceanographic (WHOI), Sea Orache of Bluefin's Robotics and Alistar 3000 of ECA can reach depths of 3000 m.

Collision risks take into consideration the CPA, the TCPA and the speed of maneuver. In specialty literature, starting distance for collision avoidance maneuver is 4-6 nautical miles, distance calculated for small speeds. The calculations and simulations for more collision situations for a container ship of 13000 TEU and speeds higher than 20-25 knots, the minimum distance for the collision avoidance maneuver should be at least 6 -8 nautical miles.

Over the last few decades, ocean research and exploration have made underwater mechanical systems a necessity. Underwater vehicles provide a new kind of marine platforms that could represent a great necessity in many areas of oceanographic research. Until now, the underwater vehicles come in a verity of shapes, sizes and means of propulsion. Depending on these characteristics, the type and mission of the vehicle are also determined. The underwater robots are used for different inspection and intervention missions in e.g. the oil and gas industry, ocean science research. Due to multiple applications to which the vehicle can participate, it can be successfully used and to determine methods of re-use of marine energy. Environmental mapping provides accurate information about the main areas of interest of the energy, as well as the exploitation possibilities of that. Most of the time, biomimetic robots were inspired their senso structure, from different kind of animals, such as insects, fish and birds. Nowadays, the concept of a underwater robotic vehicles capable to move independently, autonomously or remotely, has a great potential and a large application. This is the reason that the last studies have been directed on biomimetic robots. The fish and other underwater animals have evolved superior swimming capabilities in many ways and represent a starting point to explain the fluid-mechanical principles. Furthermore, the underwater animals develop and achieve extraordinary propulsion efficiencies, acceleration and maneuverability. They can also achieve high speed under water. Implanting and creating a vehicle through a biomimetic approach reduces the energy used to maneuver the vehicle as it can automatically correct its position and displacement. The paper presents an examination of the state of biomimetic robotic fishes, underlining the reason why bio-inspiration can help us in the underwater locomotion technology.