Offshore Wind Plants Research Articles

Assessing offshore wind plants for energy and green hydrogen production: A case study in the Mostaganem coastal region, Algeria

This study assesses the feasibility and strategic implications of establishing a 500 MW offshore wind farm utilizing fixed wind turbine technology along Algeria’s western coastal economic zone, with a focus on the Mostaganem region. The study recommends integrating 33 Vestas V-235 wind turbines, each boasting a 15 MW capacity to harness offshore wind resources for electricity and green hydrogen production. Utilizing the Wind Atlas Analysis and Application Program (WAsP), offshore wind potential is assessed based on meteorological data from a land-based station, overcoming the lack of in situ sea level measurements. Results show that the proposed wind farm could yield 1361.63 GWh/year of electricity at a cost of 0.89 $/kWh. Additionally, it would produce 28,571 tons of hydrogen at a cost of 2.12 $/kg. This initiative is anticipated to significantly reduce CO2 emissions, by approximately 595,450 tons/year, highlighting the effectiveness of offshore wind resources in promoting sustainable energy production and advancing green hydrogen as a viable energy carrier in this region.

How do technological choices affect the economic and environmental performance of offshore wind farms?

The ongoing energy transition towards fully sustainable energy systems requires designing wind farms looking beyond the sole levelized cost of energy, in order to concurrently ensure not only the economic profitability but also the environmental friendliness of future plants. Within this new approach to design, it becomes necessary to understand the effects that various possible technological choices have on both the economic and the environmental performance of wind farms. This study presents a framework designed to support these coupled economic-environmental assessments. The capabilities of the code are showcased by analysing the impact of different choices in terms of support structure type, specific power, tower height, powertrain type, and array and export voltage level for an exemplary offshore farm, chosen here as the IEA Wind 740-10-MW Reference Offshore Wind Plant with irregular layout. While the effects of many technological choices on the cost of energy are already well understood by industry, the present analysis shows that — at least in this specific case — climate change impacts are mainly driven by steel production, due to the massive amount of required material, but also, interestingly, by vessel activities. A low specific power, tall towers, and a high export cable voltage appear to offer the greatest potential for the concurrent improvement of the environmental and economic performance of the plant.

Life cycle environmental analysis of offshore wind power: A case study of the large-scale offshore wind farm in China

China's decarbonization is indispensable for the large-scale utilization of renewable energy. In this process, the development of offshore wind energy has become an important support, because in the eastern region of China, especially the coastal areas, there's the most load requirements but limited onshore renewable resources. Under the goals of both carbon neutral and sustainable development, however, there's still a research gap in evaluating the environmental impacts of large-scale offshore wind plants in China. In this study, the research performed a comprehensive process-based life cycle environmental analysis of a large-scale (400 MW) offshore wind farm with large wind turbine units (5 MW) in China. Global Warming Potential is 25.73 g CO2-eq/kWh and greenhouse gas payback time is calculated as 12.05 months. Fossil fuel consumption amounts to 0.31 MJ/kWh with an energy payback period of 25.56 months. Material resources and ecotoxicity to freshwater need more attention with the values of 1.68 CTUe/kWh and 3.32 10−6 kg Sb-eq/kWh, respectively. The manufacturing stage contributes most to all the impacts examined. The disposal and recycling process shows significant environmental benefits for most impacts but exerts burdens on the particulate matter. Focusing on Global Warming Potential, the wind turbine generation set has the highest effect, among which the blades contribute 73.2% of it. Further, the evolution of electricity and heating mix of China and use of biomass-based precursors could decrease 57% of the blades' greenhouse gas emissions in 2050. This study could provide guidance on the sustainable design and policy-making of offshore wind farms.

Seasonal variability of wake impacts on US mid-Atlantic offshore wind plant power production

Abstract. The mid-Atlantic will experience rapid wind plant development due to its promising wind resource located near large population centers. Wind turbines and wind plants create wakes, or regions of reduced wind speed, that may negatively affect downwind turbines and plants. We evaluate wake variability and annual energy production with the first yearlong modeling assessment using the Weather Research and Forecasting model, deploying 12 MW turbines across the domain at a density of 3.14 MW km−2, matching the planned density of 3 MW km−2. Using a series of simulations with no wind plants, one wind plant, and complete build-out of lease areas, we calculate wake effects and distinguish the effect of wakes generated internally within one plant from those generated externally between plants. We also provide a first step towards uncertainty quantification by testing the amount of added turbulence kinetic energy (TKE) by 0 % and 100 %. We provide a sensitivity analysis by additionally comparing 25 % and 50 % for a short case study period. The strongest wakes, propagating 55 km, occur in summertime stable stratification, just when New England's grid demand peaks in summer. The seasonal variability of wakes in this offshore region is much stronger than the diurnal variability of wakes. Overall, yearlong simulated wake impacts reduce power output by a range between 38.2 % and 34.1 % (for 0 %–100 % added TKE). Internal wakes cause greater yearlong power losses, from 29.2 % to 25.7 %, compared to external wakes, from 14.7 % to 13.4 %. The overall impact is different from the linear sum of internal wakes and external wakes due to non-linear processes. Additional simulations quantify wake uncertainty by modifying the added amount of turbulent kinetic energy from wind turbines, introducing power output variability of 3.8 %. Finally, we compare annual energy production to New England grid demand and find that the lease areas can supply 58.8 % to 61.2 % of annual load. We note that the results of this assessment are not intended to make nor are they suitable to make commercial judgments about specific wind projects.

Multi-modular bridge-type FCL for enhancing FRT capability of VSC-HVDC connected offshore wind plants during AC faults

This paper presents a novel concept Multi-Modular Bridge-Type Fault Current Limiter (MMBFCL) for enhancing the fault ride-through (FRT) capability in Voltage Source Converter (VSC)-based High-Voltage Direct-Current (HVDC) systems. The MMBFCL can be directly connected to HVDC system in ac grid side without series connection of semiconductor switches and series injection transformers. Also, the limiting resistor of each module is determined based on binary arrangements to provide a multi-step insertion resistor BFCL to limit the fault current and enhance the FRT capability under different voltage sag levels. The principle operation and control system of the MMBFCL is described. Then, the performance of the MMBFCL for enhancing the FRT is validated through time domain simulations by PSCAD/EMTDC software in a HVDC integrated wind farm system. Also, the performance of the MMBFCL is compared with the single-modular BFCL (SMBFCL). Simulation results reveal that the MMBFCL compensate the voltage sag for each voltage sag levels without any over voltage at the HVDC terminal. Also, it has superior performance than SMBFCL.

Renewable Electric Energy Storage Systems by Storage Spheres on the Seabed of Deep Lakes or Oceans

This paper describes a new underwater pumped storage hydropower concept (U.PSH) that can store electric energy by using the high water pressure on the seabed or in deep lakes to accomplish the energy transition from fossil to renewable sources. Conventional PSH basically consists of two storage reservoirs (upper and lower lake) at different topographical heights. It needs special topographic conditions, which are only limitedly available in mountain regions. Furthermore, due to the lack of acceptance and the environmental impact, new conventional PSH projects are very unlikely to be built in larger numbers in Europe in the near future. The presented solution solves these issues by placing the storage system on the seabed, thus having other geographical requirements. It operates as follows: in contrast to well-known conventional PSH plants, which use two separated water reservoirs of different heights, the U.PSH concept uses the static pressure of the water column in deep waters by installing a hollow concrete sphere in deep water. Storage of electricity is achieved by using a reversible pump in the hollow sphere. Upon opening a valve, water flows into the sphere, driving a turbine/generator, thereby discharging the storage device. In order to re-charge, the water is pumped out of the sphere against the pressure of the surrounding water. The power and energy, respectively, are proportional to the surrounding water pressure at the seabed. The amount of energy stored depends on the water depth and the volume of the spheres. The spheres need a cable connection to the shore or to a close-by floating transformer station (e.g., an offshore wind plant). No other connections such as pipes are needed. The functional principle of this energy storage technology, its state of the art, its storage capacity and the shape and size of the required spheres are discussed in this paper.

Modeling and Simulation of a Turbine Access System with Three-Axial Active Motion Compensation

As an essential transportation equipment for personnel to access offshore wind plants, the safety and stability of the turbine access system (TAS) have gained increasing significance. However, when sea conditions deteriorate, the end of the TAS will experience large-angle shaking and an increase in the heave height. A novel 3-DOFs TAS with active motion compensation for the Fujian coastal area is designed to solve the problem of the stability of the end of the TAS under sea conditions with a significant wave height of 2.2 m, including structural design, kinematic analysis, hydraulic drive design, and control system design. In the research, a new stacking compensation method is proposed to compensate for the roll angle, pitch angle, and heave height at the end of the TAS. The 3-DOFs TAS is modeled mathematically by the Denavit–Hartenberg parameters, and the hydraulic system model is established. In order to improve the compensation effect, a fuzzy PID controller with feedforward compensation is designed based on fuzzy PID control, and the model simulation experiment is carried out by MATLAB/Simulink. Finally, the experimental simulation shows that under the compensation of the feedforward compensation fuzzy PID control algorithm and the new compensation algorithm, the roll angle of the TAS is reduced by a maximum of 84.8%, the pitch angle is reduced by 75%, and the heave height is reduced by 73.6%. This validates the effectiveness of the proposed scheme and provides a reference for future TAS design and development.

Dynamic Equivalent Modeling of a Large Renewable Power Plant Using a Data-Driven Degree of Similarity Method

This paper aims to develop a novel method for the dynamic equivalence of a renewable power plant, ultimately contributing to power system modeling and enhancing the integration of renewable energy sources. In order to address the challenge posed by clusters of renewable generation units during the equivalence process, the paper introduces the degree of similarity to assess similarity features under data. After leveraging the degree of similarity in conjunction with data-driven techniques, the proposed method efficiently entails dividing numerous units in a large-scale plant into distinct clusters. Additionally, the paper adopts practical algorithms to determine the parameters for each aggregated cluster and streamline the intricate collector network within the renewable power plant. The equivalent model of a renewable power plant is thereby conclusively derived. Comprehensive case studies are conducted within a practical offshore wind plant setting. These case studies are accompanied by simulations, highlighting the advantages and effectiveness of the proposed method, offering an accurate representation of the renewable power plant under diverse operating conditions.

Simulation and calculation of maximum transmission power for offshore wind plants accounting for the Electro-Magnetic transient process

The offshore wind power industry is witnessing a shift towards larger scale and longer offshore distances, pushing the transmission capacity and transmission distance of submarine cables to their maximum limits. Consequently, it is essential to evaluate the maximum transmission limit of offshore wind power. At the same time, the larger scale of the wind farm will make the Electro-Magnetic transient (EMT) processes have a greater impact on the system stability. To address these issues, this paper firstly established a wind generator (WG) model through a permanent magnet synchronous generator (PMSG) model with averaging parameters, as well as a cross-linked polyethylene (XLPE) submarine cable model to construct an offshore wind power system via AC transmission. Subsequently, a continuous EMT simulation method is proposed to calculate the maximum transmission capacity and transmission distance limit. Real-time transient simulations were conducted to check the transient stability constraints during the calculation process. Finally, through several case studies on different types of cables, the simulation and calculation results are presented to provide useful references for engineering applications.

New models for feasibility assessment and electrolyser optimal sizing of hydrogen production from dedicated wind farms and solar photovoltaic farms, and case studies for Scotland and Vietnam

Although green hydrogen produced from dedicated wind and PV plants is considered an alternative route to achieve net zero targets, its assessment models are only being developed in recent years. Even though electrolyser is known to account for a large portion of the investment costs, there is still a lack of sizing models for this equipment, which can negatively affect the feasibility of plants. Moreover, the impacts of future technology maturity and cost reduction on the feasibility of hydrogen production plants are rarely analysed and reported. Realising the research gaps from previous studies, this paper proposes a comprehensive feasibility assessment model for green hydrogen production from dedicated offshore wind and PV plants, utilising net present value, discounted payback time, and levelised cost of energy and of hydrogen (LCOH) as economic evaluation criteria. Furthermore, a unique sizing model is presented, allowing the optimal electrolyser size with the lowest LCOH to be found. Two case studies investigating a hypothetical offshore wind farm in Scotland and a hypothetical PV farm in Vietnam to produce green hydrogen have been carried out, in which the impacts of technology maturity and cost reduction on the LCOH are analysed. It is projected that the LCOH in Scotland and Vietnam case studies, with specific conditions and assumptions of the two cases, would reduce from 3.10 and 3.05 $/kg in 2030 to the lowest values of 2.16 and 1.59 $/kg in 2050, respectively. Additionally, the optimal electrolyser capacity is found to equal 89.3% of the offshore wind plant capacity, and 57.7% of the PV plant capacity. Finally, a sensitivity analysis is conducted, which revealed the capital cost of renewable energy plants has the most significant effect on the final LCOH.

Enhanced Frequency Support of MMC-MTDC Systems with Offshore Wind Plants Integration

Enhanced Frequency Support of MMC-MTDC Systems with Offshore Wind Plants Integration

Price-Guided Cooperation of Combined Offshore Wind and Hydrogen Plant, Hydrogen Pipeline Network, Power Network, and Transportation Network

Price-Guided Cooperation of Combined Offshore Wind and Hydrogen Plant, Hydrogen Pipeline Network, Power Network, and Transportation Network

The current opportunities and challenges for offshore wind in the United States

Over the past decade, offshore wind installations have expanded dramatically in Europe and China, increasing renewable energy presence in these markets. However, the United States lags in offshore wind development despite significant coastline and wind resource availability. Each coast of the United States possesses unique opportunities and challenges to installation due to variations in bathymethry and weather patterns. This paper reviews the planning and installation challenges of offshore wind turbines in the United States by incorporating lessons learned from offshore wind plants already in place in other countries. The goal of this paper is to provide a review of offshore wind turbine installation methods by highlighting challenges unique to this form of renewable energy in the United States.

How to Ensure the Quality of Construction Works for Marine Platforms with Reference to Midia Gas Development Project - ANA Platform & Doina Well & Gas Treatment Plant -

Abstract The Midia Gas Development Project is a new offshore gas project which has been developed and built in the last 30 year in the maritime territory of Romania. Once completed, it will have the ability to cover around 10% of gas needs of Romanian population. Currently there is about 10 Bcm of resources to be produced at a rate of about 1 Bcm per annum. The infrastructure was thought to be used for the production of gas from the reservoirs of Ana and Doina, in the first place. But the long term vision of the project consists in converting the already existent infrastructure to develop green energy projects, such an offshore wind plant, solar panels fields or production of hydrogen, projects that may start time before decommissioning of the gas production platform.

Assessing the impact of offshore wind siting strategies on the design of the European power system

This paper provides a detailed account of the impact of different offshore wind siting strategies on the design of the European power system. To this end, a two-stage method is proposed. In the first stage, a highly-granular siting problem identifies a suitable set of sites where offshore wind plants could be deployed according to a pre-specified criterion. Two siting schemes are analysed and compared within a realistic case study. These schemes essentially select a pre-specified number of sites so as to maximize their aggregate power output and their spatiotemporal complementarity, respectively. In addition, two variants of these siting schemes are provided, wherein the number of sites to be selected is specified on a country-by-country basis rather than Europe-wide. In the second stage, the subset of previously-identified sites is passed to a capacity expansion planning framework that sizes the power generation, transmission and storage assets that should be deployed and operated in order to satisfy pre-specified electricity demand levels at minimum cost. Results show that the complementarity-based siting criterion leads to system designs which are up to 5% cheaper than the ones relying on the power output-based scheme when offshore wind plants are deployed with no consideration for country-based deployment targets. On the contrary, the power output-based scheme leads to system designs which are consistently 2% cheaper than the ones leveraging the complementarity-based siting strategy when such constraints are enforced. The robustness of the reported results is supported by a sensitivity analysis on offshore wind capital expenditure and inter-annual weather variability, respectively.

Two-level planning approach to analyze techno-economic feasibility of hybrid offshore wind-solar pv power plants

In this paper, a two-level planning framework has been proposed to assess the techno-economic feasibility of hybrid offshore wind-solar PV power plants. In the first level, the optimal layout design of hybrid offshore wind-solar PV plants is determined to maximize the generation considering wake effect and shadow loss for wind turbines (WTs) and solar PV panels, respectively. Particle Swarm Optimization (PSO) is used to determine the optimal layout of hybrid power plants. In the second level, economic analysis has been conducted to determine the feasibility of the hybrid offshore power plants for any particular site. In this context, two scenarios have been investigated. In scenario-1, the optimal share of wind and solar generation for an offshore hybrid plant of given capacity is determined from a techno-economic point of view. On the other hand, in scenario-2, the optimal share of solar PV panels utilizing the existing electrical infrastructure of offshore wind plants has been determined. Both cases are compared on the basis of the Levelized cost of energy (LCOE), and the best alternative has been highlighted for a site in this study. Yearly data of wind speed and solar irradiation of a site near the coast of Gujarat in India has been considered to investigate the proposed approach.

목포항의 발전 방안에 관한 연구

The aims of this study to analyze the internal and external environment of Mokpo Port from a port marketing perspective and to establish plans for development of Mokpo Port. In order to do this, 16 detailed factors for SWOT Matrix were identified both from previous studies and from brainstorming professionals of the port and these made into a 3 level hierarchy structure. AHP method identified the relative weight of SWOT level as strength(0.152), weakness(0.345), opportunity(0.179) and threat(0.324), also the final ranking of detailed factors by SWOT group was reduction of port volume(0.104), global economic slump(0.095), deterioration port facilities(0.084), promotion of offshore wind plant in southwest area(0.076) and increased competition with neighboring ports. Based on these empirical analysis results, the development plan of Mokpo Port was presented in order of W/T, W/O, S/T, and S/O strategies by priority.

Spatial impacts of technological innovations on the levelized cost of energy for offshore wind power plants in the United States

Recent studies predict significant decreases in the future levelized cost of energy (LCOE) of offshore wind energy, much of which is attributed to anticipated cost reductions from technological innovation. This study evaluates the spatial variability of LCOE caused by technology-induced decreases in a range of capital, operational, and financial cost categories. A spatial cost model of fixed-bottom and floating offshore wind plants is used to model the impact across thousands of potential United States sites. A specified change in an individual turbine subsystem cost produces a range of LCOE outcomes due to the varying geospatial characteristics of the considered sites and the nonlinear, interactive dependency on these input parameters; for example, a 10.8% improvement in net capacity factor can reduce LCOE by between 6% and 20% at different sites. This work expands upon the existing offshore wind literature, which typically evaluates cost sensitivities at a single site and does not consider the spatial variance in LCOE. The results suggest that the impact of technological innovations can be considerable and should be considered on a spatial as well as temporal basis when prioritizing technology innovation research or funding decisions to advance offshore wind technologies in the United States.

Failures and Reliability in Hawts Operating in Mountainous Areas, Open Sea and in Harsch Climate Sites

Recently, offshore wind plants, as Horn’s Riv one, have reached a remarkable interest and development. In these sites, HAWT’s blades experiment corrosion, erosion and fouling and, at higher latitudes, icing conditions too, as in mountainous areas and in harsch climate sites. The operative conditions may influence the machine damages and they may occur as consequence of erosion, corrosion, fouling, icing, exfoliation caused by the above mentioned environmental conditions. The paper reports about data collection about failures occurred to HAWTS operating in offshore, mountainous and harsch climate sites in last ten years. Particularly, the damage occurred to blades, gears and bearings have been examined and the consequences analysed. The occurred failures are examined and the reliability of WTGs is assessed by appropriate models and analysis. The results are com pared to literature data and they may be very useful in programmable maintenance and in predictable one. Reliability analysis may be also useful to increase energy production.

Conceptual Study of a Real-Time Hybrid Simulation Framework for Monopile Offshore Wind Turbines Under Wind and Wave Loads

As an attractive renewable energy source, offshore wind plants are becoming increasingly popular for energy production. However, the performance assessment of offshore wind turbine (OWT) structure is a challenging task due to the combined wind-wave loading and difficulties in reproducing such loading conditions in laboratory. Real-time hybrid simulation (RTHS), combining physical testing and numerical simulation in real-time, offers a new venue to study the structural behavior of OWTs. It overcomes the scaling incompatibilities in OWT scaled model testing by replacing the rotor components with an actuation system, driven by an aerodynamic simulation tool running in real-time. In this study, a RTHS framework for monopile OWTs is proposed. A set of sensitivity analyses is carried out to evaluate the feasibility of this RTHS framework and determine possible tolerances on its design. By simulating different scaling laws and possible error contributors (delays and noises) in the proposed framework, the sensitivity of the OWT responses to these parameters are quantified. An example using a National Renewable Energy Lab (NREL) 5-MW reference OWT system at 1:25 scale is simulated in this study to demonstrate the proposed RTHS framework and sensitivity analyses. Three different scaling laws are considered. The sensitivity results show that the delays in the RTHS framework significantly impact the performance on the response evaluation, higher than the impact of noises. The proposed framework and sensitivity analyses presented in this study provides important information for future implementation and further development of the RTHS technology for similar marine structures.