The generation of energy production obtained with the help of renewable resources contributes to the reduction of carbon emissions and to the consolidation of energy security in the area, as well as to the development of the necessary infrastructure for socio-economic development in the coastal and offshore area. The objectives of paper are specific to a certain location in the Black Sea, namely: obtaining wind energy production using an efficient design of a pilot floating system, using a wind dataset for optimized design floating system, calculation of the levelized cost of electricity for wind energy (LCOE) and impact with market value of wind energy production in the Black Sea Blue economy. The methods used are: the Froude scaling methodology was used for design of pilot floating system, metocean analytics for obtained metocean data (wind, waves, currents), monitoring the state of pilot floating system components using Digital Twin Technology (DT), economic modeling of technology-specific LCOE of renewable technologies (Specific Investment Cost-CAPEX, Operating Cost-OPEX) in comparison with respect to the current level of LCOE at local conditions in the Black Sea and PESTEL analysis (Political, Economic, Social, Technological, Environmental and Legal impact).The final data obtained for the achievement of the proposed objectives are results obtained during the implementation of the BLOW project: an optimized design for the study location with reduced costs for operation and maintenance, optimized parameters using metocean data, societal, environmental and economic impact assessment with barriers and obstacles. The conclusion is that globally, the development of a floating offshore wind energy market is emerging rapidly as experience and knowledge is gained from pilot projects.

Sustainable urban energy is based on innovative solar and wind solutions. The paper presents such a hybrid solar–wind system, which is easy to place on building terraces, highlighting the advantages of this technical solution: energy production as close as possible to consumers, the elimination of system losses, and small installation spaces being required. The system operates well in the low-speed range for the horizontal axis crossflow wind turbine placed under a flexible solar panel, at speeds between 2 and 8 m/s, and exhibits good efficiency in cooling the photovoltaic panels. The prototype proposed by the paper is a small-scale model that can produce on average 400 Wh/day and about 150 kWh/year. The paper analyses numerically the aerodynamic behaviour of the prototype at several wind speeds, as well as experimental results regarding the power and power coefficient for the wind turbine, as well as the power and efficiency of the flexible solar panel in the hybrid system. The research is complemented with comparative technical analysis and economic analysis.

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.

The use of renewable energy sources instead of conventional ones, together with the development of efficient electricity storage solutions, represents a central objective of the transition to sustainable and resilient energy systems. In this context, two main development directions are the integration of hydrogen in the energy chain (Power-to-Gas) and the use of batteries, each with specific advantages and disadvantages, compared to internal combustion engines. The purpose of this work was to evaluate the dynamic response time of a hydrogen fuel cell model powered by green hydrogen, under conditions of sudden and instantaneous power demand, for its integration into wind-based renewable energy systems. Experimental research was carried out on an autonomous installation designed to operate continuously for an unlimited duration, simulating the integration of hydrogen produced from wind sources. The novelty consists of the application of an instrumental method for automatic measurement of the response time of a proton exchange membrane hydrogen fuel cell, based on the automatic acquisition and processing of measured electrical signals. The response time of the fuel cell was compared with that of an internal combustion engine based on the classic Carnot cycle, using a dedicated oscilloscope. The load connection time, the current and voltage variation as a function of time were recorded simultaneously. The results show that the response time of the fuel cell is relatively short (approximately 0.3 ms), much lower than that of the internal combustion engine (0.7 s), being of the order of about 2333 times smaller. In conclusion, the hydrogen fuel cell can be effectively integrated into renewable energy systems for the role of an uninterruptible power supply, with an exceptionally fast dynamic response, suitable for applications in regulating and supporting wind-powered networks.

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.

This paper presents the design, modeling and experimental validation of an on-grid photovoltaic system with self-consumption, sized for the sustainable supply of a water pumping station. The system, composed of 68 photovoltaic panels, uses an architecture based on a Boost DC-DC converter controlled by the Perturb and Observe algorithm, raising the operating voltage to a high-voltage DC bus to maximize the conversion efficiency. The study integrates dynamic performance analysis through simulations in the Simulink environment, testing the stability of the DC bus under sudden irradiance shocks, with rigorous experimental validation based on field production data. The simulation results, which indicate a peak DC power of approximately 34 kW, are confirmed by real monitoring data that records a maximum of 35 kW, the error being justified by the high efficiency of the panels and system losses. Long-term validation, carried out over three years of operation (2023–2025), demonstrates the reliability of the technical solution, with the system generating a total of 124.68 MWh. The analysis of energy flows highlights a degree of self-consumption of 60.08%, while the absence of chemical storage is compensated for by injecting the surplus of 49.78 MWh into the national grid, which is used as an energy buffer. The paper demonstrates that using the grid to balance night-time or meteorological deficits, in combination with a stabilized DC bus, represents an optimal technical-economic solution for critical pumping infrastructures, eliminating the maintenance costs of the accumulators and ensuring continuous operation.