Offshore Wind Power Development Research Articles

One data-driven vibration acceleration prediction method for offshore wind turbine structures based on extreme gradient boosting

With the development of offshore wind power towards large-scale and deep-sea, the safety risks and the difficulty of intelligent operation and maintenance of offshore wind turbine (OWT) during operation periods have increased significantly. Structural vibration response is an important factor affecting the safety and stability of OWT. Accurate prediction on vibration through environmental conditions and operational factors can identify the safety risks of OWT in advance, and reduce harmful vibration through appropriate operation strategy regulation. Therefore, a vibration acceleration prediction method of OWT structures was proposed in this research based on Harris hawks optimization (HHO) and extreme gradient boosting (XGBoost). Firstly, approximately two months of monitoring data from a 3 MW OWT were extracted to establish the database for training the machine learning models. Then, the key hyperparameters of XGBoost were optimized by the HHO algorithm and compared with other typical algorithms. Finally, the trained prediction model was applied to the regularity analysis of different conditions and long time series data. The analysis results demonstrate that the proposed method can effectively predict the vibration acceleration response of OWT structures using operational and environmental characteristics, and has higher accuracy and stability than other methods, with R2 of 0.9715 and mean absolute percentage error (MAPE) of 6.55%. Simultaneously, it also shows acceptable accuracy on the long-term measured data because the MAPE of chosen summer, autumn, and winter samples were calculated as 9.60%, 11.76%, and 7.21%, respectively. The establishment of the HHO-XGBoost vibration prediction model can be applied in the subsequent prediction of the vibration trend, which provides a guarantee for the safe and stable operation of OWT.

Multi-objective optimization of clustered wind farms based on potential game approach

With the rapid development of offshore wind power, the construction and operation of multiple adjacent wind farms (WFs) in the form of cluster has become a trend. However, the method for single WF planning can not address the WF cluster layout optimization in the complex relationship of competition or cooperation. This paper proposes a novel method to design clustered offshore WFs. The objectives to be optimized include the maximization of WF generated power and the minimization of wind turbine (WT) turbulence intensity. To solve this problem, a mathematical model based on the potential game theory is established. In this planning model, each WF in the cluster is assumed to be an individual stakeholder, the decision variables and the constraints are mapped to be the strategies and the strategy sets of the stakeholders, respectively, and the objectives are set as their payoffs. The non-dominated sorting genetic algorithm II (NSGA-II) is synthesized with the dependency structure matrix genetic algorithm II (DSMGA-II) to tackle the multi-objective optimization problem (MOOP) and the fuzzy-membership function (FMF) method is used to select the final solution from the Pareto optimal set. The best-strategy-response iterative algorithm is put forward to search for the Nash equilibrium (NE) of the game. Case studies on three clustered offshore WFs in Qidong, China, are carried out to validate the effectiveness of the proposed approach. Also, the simulation results indicate that the synthesized algorithm outperforms the NSGA-II in solving this optimization problem.

Optimal Operation Scheduling of Multi-energy Complementary Systems Including Offshore Wind Power

Background: With the rapid development of offshore wind power in China, offshore wind power is accounting for an increasing proportion of the whole installed power generation in China, which put forward higher requirements for operation scheduling of multi-energy complementary systems including offshore wind power. However, existing studies have paid little attention to the complementary output scheduling of multi-energy systems with a high proportion of offshore wind power, this phenomenon is not conducive to the realization of reasonable operation scheduling. Objective: To realize the reasonable operation scheduling of multi-energy systems with a high proportion of offshore wind power. Methods: Firstly, the output characteristics of offshore wind power were analyzed and summarized, and modeling was conducted from the perspectives of time distribution, spatial correlation, volatility and randomness, which would serve as the theoretical basis for subsequent researches. Secondly, the complementary rule among offshore wind power and the multi-energy system was analyzed, and the complementary characteristic index was put forward. Then the safety operation was taken as the constraint, and the two-stage operation model of the integrated energy system was established, which considers the auxiliary service costs. In the first stage, the initial generation scheduling was developed according to the day-ahead forecast values of the offshore wind power; in the second stage, the more accurate intra-day operation scheduling was further achieved by considering the intra-day forecast values of offshore wind power and the day-ahead scheduling results. Costs of rotating reserve capacity could be reduced by correcting the deviation of generating capacity, then the revenue-maximizing scheduling strategies were obtained and the output of the pumped-storage power plants was optimized. Results: The effectiveness of the model proposed in this paper was verified based on the simulation examples. Compared with the traditional scheduling strategy, the scheduling strategy considering auxiliary service cost proposed in this paper can promote the consumption of offshore wind power, reduce the wind curtailment proportion and improve the electricity sales revenues in the end. Conclusion: The research results in this paper provide a reference for the reasonable consumption of multi-energy complementary systems with a high proportion of offshore wind power and improving electricity sales revenues

Public support and opposition toward floating offshore wind power development in Norway

For countries like Norway, with abundant offshore wind resources and deep seas, floating wind power technology can play an essential role in the green energy transition. However, this technology is still immature, and the first utility-scale floating offshore wind power projects need substantial support for technology development to be commercially feasible. This study employs an online survey targeting the general population in Norway (N = 1011) to investigate support and opposition toward floating offshore wind power development. The survey includes a discrete choice experiment focusing on policy-relevant factors such as the export of electricity, reducing domestic carbon emissions by electrifying offshore oil and gas platforms, impact on global technology cost trends, and involving domestic offshore industries as key players in the floating offshore wind sector. We find the highest support for developing projects that utilize technology from domestic offshore industries and projects connected to the domestic electricity grid. Projects aimed at reducing domestic carbon emissions by electrifying offshore oil and gas platforms are favored over those for exporting electricity to other countries. A significant impact on future technology costs does not lead to increased support for the project. Projects presented after a framing text focusing on meeting future electricity demand result in a higher willingness to pay for floating offshore wind projects than those presented after a framing text focusing on meeting climate objectives. Respondents opposing all the projects are likely climate skeptics and believe that project developers should bear all the project costs. Norway is expected to play a critical role in developing floating wind power. However, the Norwegians demand clear national benefits to be willing to shoulder the cost of spearheading the floating offshore wind power development. Understanding these preferences is vital for crafting energy policies aligning with public interests and rapidly integrating floating wind power into the green energy transition.

THE CULTURE OF THE CO-EXISTENCE OF A PLANNED WIND FARM IN THE CONTEXT OF ENVIRONMENTAL CHANGES

Offshore wind power (OWP) as a renewable energy source (RES) is expected to have a significant share in the green energy market in the upcoming decades. Onshore energy generation is already a mature and proven technology, while its younger sibling is still in its infancy in the realities of our country. The development of OWP is a quantum leap towards using the natural energy potential of the Baltic Sea. It is supported by the government and is part of the country's energy transition plan. Experts make optimistic claims whereby the first energy from the Baltic Sea will flow into the national power grid in the middle of the next decade at the earliest. Economists and environmentalists agree that the development of energy technology in the Baltic Sea is an opportunity for the economy. It will be powered by another portion of clean energy. All parties claim that their primary task is to support environment protection from the point of view of sozology and avoid making a negative impact on the environment, including destructive events caused by natural forces and human activity, with considerations for socio-economic needs. The article contains the results of research conducted by the students of the University of Rzeszów as potential future consumers of electricity. They assessed the impact of OWP on Poland's energy security and ecological security through the lens of culture, manifested as the lack of excessive consumerism.

Projected Reductions in CO2 Emissions by Using Alternative Methanol Fuel to Power a Service Operation Vessel

Due to increasingly stringent IMO and European Commission requirements for greenhouse gas emissions, the present study analysed the projected reductions in CO2 emissions achieved by using methanol as an alternative fuel to power custom service operation vessels (SOVs) serving wind platforms in the Baltic Sea. Methanol is a relatively new fuel, approved for use as a safe marine fuel in the late 2020s. In these analyses, reference was made to the current interim guidelines, supplementing the IGF Code in the form of MSC.1/Circ.1621. The SOV type was chosen because of the current growing demand for these ships (the dynamic development of offshore wind power) and the lack of analyses of this type of small craft. The importance of assessing CO2 emissions in this case is due to the specifics of the vessel’s operation in different modes, and thus the variable load on the propulsion system and the area of operation close to the coastline. A computational research method was used to evaluate CO2 emissions, as well as the cost of methanol fuel, using current regulations and technical data. A comparison was also made between conventional MDO and LNG fuels. The first results of the analysis showed that methanol fuel is only competitive with MDO (a few-percent advantage) in terms of the average estimated index value EIV. Economically, it will require a higher investment, despite the favourable unit price of methanol compared to LNG and MDO.

Understanding Taiwan’s offshore wind industry

Understanding taiwan’s offshore wind industry Here, Open Access Government speaks to Gwo-shyh Song, Chairman of MMA Global Aqua, and explores the challenges, successes and long term plans for the offshore wind power projects in Taiwan. Can you provide an overview of the current state of the offshore wind industry in Taiwan and its significance in the country’s energy transformation? Taiwan had no experience in offshore wind power development in the past. The offshore wind power industry includes wind farm developers, who conduct environmental assessments of wind farms, as well as wind turbine system suppliers, marine engineering companies, cable manufacturers, and wind farm operators. Therefore, the Ministry of Economic Affairs allows 100% foreign ownership to attract foreign investment and gradually increases domestic demand to cultivate local related companies in order to achieve the goal of offshore wind power localization.

Collaborative improvement of electrical‐thermal‐mechanical properties of kaolin‐filled ethylene propylene diene monomer and mechanism analysis

AbstractWith the rapid development of offshore wind power, large‐capacity wind turbine generators have put forward higher electrical and mechanical performance requirements for the cable. In this paper, kaolin/ethylene propylene diene monomer (EPDM) composites are prepared to investigate the effect of kaolin content on the electrical properties, mechanical properties and thermal conductivity of EPDM composites. The results show that appropriate amount of kaolin could synergistically improve the electrical‐thermal‐mechanical properties of EPDM. The composite with 30 wt% kaolin content achieves the best performance. The breakdown strength of kaolin/EPDM composites increases by 13.47%–72.19 kV/mm compared with that before modification, and the volume resistivity increases from 1013 to 1015 Ω·cm after modification. In addition, with the doping of kaolin, the tensile strength of composites significantly improves by over 500%–6.97 MPa, and the thermal conductivity of the composite is slightly improved. This work has important guiding significance for the development of insulation materials for cables.Highlights Kaolin in EPDM scattered more uniform after modification. The addition of kaolin improves the electrical‐thermal‐mechanical properties of the composite. Kaolin/EPDM composites have promising applications.

Offshore wind power policies and green total factor productivity: empirical evidence from coastal China

IntroductionGreen and high-quality development requires the transformation and upgrading the energy structure. As a clean and efficient new energy, the development of offshore wind power is related to the achievement of green development and the realization of the dual carbon goals.MethodsBased on the perspective of green total factor production, this study aims to explore the impact of offshore wind power policies (OWPPs) on green and high-quality development. Taking 11 coastal areas of China from 2004 to 2020 as samples, this paper empirically tested the impact of OWPPs on green total factor productivity (GTFP) by using propensity score matching difference-in-differences method (PSM-DID).Results and discussionThe results show that OWPPs have a significant positive impact on GTFP. The robustness test further verifies the results, and the provincial difference is significant. By stimulating technological innovation and reducing energy intensity, OWPPs have improved GTFP, but increasing marketization level is a long way off.

Hydrodynamic Analysis of a Multi-Pile-Supported Offshore Wind Turbine Integrated with an Aquaculture Cage

The integrated development of offshore wind power and marine aquaculture is becoming increasingly important. However, the impact mechanism of integrating a net cage on the dynamic characteristics of offshore wind turbines remains unclear. This paper presents a design scheme for a multi-pile-supported offshore wind turbine integrated with an aquaculture net cage and conducts a preliminary theoretical analysis of the influence of an additional net cage on the wind turbine. The analysis reveals that the primary effect is an increase in hydrodynamic loads on the wind turbine foundation, while the structural frequency of the wind turbine remains largely unaffected. Furthermore, computational fluid dynamics (CFD) numerical models, whose accuracy is verified by physical experiments, are utilized to compare the hydrodynamic characteristics of the offshore wind turbine foundation with and without the net cage, considering different net solidities. The simulations identify significant changes in the flow field surrounding the foundation due to the presence of the net cage, resulting in a considerable increase in the overall hydrodynamic load on the foundation. Moreover, the mutual interference between the netting and the foundation amplifies their respective hydrodynamic loads and concentrates these loads at the upstream section of the structure. The maximum increase in hydrodynamic load for a single pile reaches 6.32 times its original value, posing significant risks to the structure. Finally, a preliminary feasibility analysis of the scheme was conducted. The results presented in this article can serve as a theoretical basis for the design of such innovative structures.

Impacts of offshore wind power development on China's marine economy and environment: A study from 2006 to 2019

Utilizing a fixed-effects model and the Difference-in-Differences method, this research delves into the significant impacts of Offshore Wind Power development on China's marine economy, based on data from 2006 to 2019 across 11 coastal provinces. The findings reveal that with each 1 MW (MW) increase in the installed capacity of Offshore Wind Power, the marine output value rises by 58.71 million yuan. Further analysis shows that the Gross Domestic Product of the primary marine industry, encompassing sectors such as fisheries, grows by 4.2 million yuan. Concurrently, the secondary marine industry, which includes marine mining, sea salt, and chemical industries, sees an increase of 42 million yuan. The economic ramifications of Offshore Wind Power development are evident across three stages defined by installation capacity. In the initial stage, with installations below 1767.28 MW, the marine economy thrives. The intermediate stage, marked by capacities between 1767.28 MW and 3634.46 MW, faces challenges, mainly due to the coastal regions' limited capacity for integration. Conversely, the advanced stage, with installations surpassing 3634.46 MW, observes a revival in marine economic growth. Environmentally, the marine ecosystem encounters challenges during the installation phase but improves during the operational phase. Given these insights, it is recommended that China to expedite Offshore Wind Power development, refine its layout, and prioritize environmental conservation throughout its lifecycle.

Assist in GHG Abatement of Offshore Ships: Design and Economic Analysis of an Integrated Utilization Model of hydrogen-powered Ship and Offshore Wind Power

As a hopeful solution to help the shipping sector achieve the greenhouse gas (GHG) abatement goal of the IMO by 2050, the application of hydrogen-powered ships has attracted more and more attention. To solve the problem of hydrogen supplement for offshore polymer electrolyte membrane fuel cell (PEMFC) ships, this paper presents a scenario design for the integrated application of coastal hydrogen-powered ships and offshore wind power, and analyzes its techno-economic feasibility. This model concept considers the problems in offshore hydrogen transportation and offshore wind power development together. It provides a feasible integrated scheme and operation mode for the combination of offshore wind power and hydrogen energy storage. A transformation scheme is also provided for the marine ranch ships, and these PEMFC-powered ships are combined with the hydrogen production of offshore wind farms. The analysis results show that the integrated utilization model is economically feasible and with a significant effect on decarbonization. It also shows great potential for further expansion to other coastal areas.

Study on the Application of Typhoon Experience Parameter Analysis in Taiwan’s Offshore Wind Farms

Due to the rapid development of computers, researchers have made efforts since the 1990s to develop typhoon forecasting models and stochastic typhoon simulation models to assess typhoon disasters and risks. Typhoon forecasting models are primarily used to predict and track the movement of typhoons and provide warning information to the general public before landfall. Stochastic typhoon simulation models can assess extreme wind speeds and compensate for the limitations of current observations and simulation data length. Taiwan experiences approximately three to four typhoons yearly, of varying intensities and paths. Whether the marine meteorological data includes events of strong typhoon centers passing through will affect the results of frequency analysis. The development of offshore wind power in Taiwan is closely related to the unique marine meteorological conditions throughout the lifecycle stages, including wind farm site selection, feasibility studies, planning and design, construction and installation, operation and maintenance, and decommissioning. This study references relevant research and analyzes sixty-three scenarios using nine types of maximum storm wind speed radii and seven Holland-B parameters. The data from Japan Meteorological Agency Best Track Data (JMA BTD) is utilized, explicitly selecting 20 typhoon events after 2000 for wind speed simulation using a typhoon wind speed model. After validating the typhoon wind speeds with observation data from the Central Weather Bureau (CWB) in Hsinchu and the Longdong buoy, the technique of Monte Carlo simulation is utilized to generate synthetic typhoons randomly. The average of the relative absolute errors for the simulated maximum wind speeds is calculated, and through comprehensive evaluation, optimal parameter combinations (Rm, B) are obtained.

The offshore prefabrication and semi-wet towing of a bucket foundation for offshore wind turbines

In recent years, the bucket foundation as a new form of supporting structure of offshore wind turbines (OWTs) has attracted increasing attention with the rapid development of offshore wind power. A synthetical prefabrication and transportation (P&T) technique is proposed in this paper to enable a broader application of bucket foundations efficiently and economically in the offshore wind market. The novel P&T technology consists of two key auxiliary pieces of equipment, i.e., an offshore prefabrication platform (OPP) and a U–K barge. The process of the offshore prefabrication is elaborated, and the requirement that need to be met for the monopod-bucket foundation with subdivisions (MBFS) to achieve offshore prefabrication utilizing the OPP is analyzed. Then, the concept of the semi-wet towing with a U–K barge is proposed, which can provide sufficient buoyancy and stability to ensure the safety of the MBFS during the towing operation. To investigate the seakeeping of the combined semi-wet system in moored and towing scenarios, a series of experiments were carried out to prove the reliability of the U–K barge design. Sensitivity analysis regarding towing speed, wave height, and wave period for the disintegration risk is performed, and three methods are proposed to avoid the disintegration of the U–K barge and MBFS at extreme sea cases. The results show that the proposed offshore prefabrication is feasible, and it is suggested that as the MBFS floats up, the water depth of the construction site should not be less than 6 m. In addition, it is proved that the combined semi-wet towing system composed of the U–K barge and the MBFS has an exceptional seakeeping capability with regard to the pitching angles, accelerations, and towing resistances, and that the wave height and the towing speed have greater effects on the disintegration risk than the wave period.

A Study on the Problems and Improvement measures of Investigation of Fishing Damages Caused by Offshore Wind Power Development

A Study on the Problems and Improvement measures of Investigation of Fishing Damages Caused by Offshore Wind Power Development

Multi-objective carbon neutrality optimization and G1-EW-TOPSIS assessment for renewable energy transition

Successful low-carbon energy systems rely on good economic, environmental and energy efficiency indicators. Yet, the current energy structure has shortcomings in these aspects, hence the need to develop the renewable energy transition. This study proposes a three-phase dynamic energy planning framework based on multi-objective optimization, assessment and analysis. The optimization phase utilizes the NSGA-II to determine the optimal allocation of multiple energy sources by considering various variables and constraints. A comprehensive assessment system combining the G1 method and the entropy weight method is proposed, and the TOPSIS method is used to evaluate the rationality and superiority of the energy structure. The relative trends in electricity consumption and renewable energy penetration are also analyzed in order to predict CO2 emissions. The dynamic framework and comprehensive assessment are applicable to Guangdong Province. Results reveal that Guangdong province should prioritize the development of offshore wind power, ensure the stability of the power grid by steadily developing hydropower and nuclear power, and vigorously develop solar power at the end of the planning period. Guangdong Province can reach carbon peaking around 2028 and net zero carbon emissions by 2060, leading to carbon neutrality. The optimized dynamic energy planning framework can provide effective decision support to promote the transformation of regional energy structures.

Study on Fundamental Force of Extreme Wave on Complex Deepwater Jacket

With the development of offshore wind power to the far-reaching sea, jacket foundation suitable for 10 ~ 60m water depth has become a development trend. The maximum waves in the far-reaching sea are generated by typhoons. The South China Sea spans the tropics and subtropics. Tropical cyclones therein are extremely active due to the features of its marine environment, like wide water-depth profile, complex topography and hydrology. Especially in recent years, under the development situation of global warming, extreme weather events have increased significantly, and strong and super typhoons have become more frequent. The extreme waves generated by them have a huge force on the jacket, affecting the safety of the project. In this paper, the relevant parameters of PMTC are calculated with the statistical method, the verified SWAN model is used to calculate the probable maximum typhoon wave, and the P-III frequency analysis on the extrapolated results of all typhoon waves are carried out by direction to obtain the design wave elements of each return period, and various extreme typhoon wave characteristic parameters were counted. Secondly, the Morison formula is used to calculate the wave force acting on the offshore fan jacket. This wave force based on different water depth and different directions is tested by physical model test. Finally, the results of model test and theoretical calculation are compared and analyzed to confirm that there is a certain correlation between the two wave forces. This empirical formula can be used to correct the calculated value of Morison formula in practical engineering design, which not only provides a simple and convenient calculation method for practical engineering design, but also provides a reference for the calculation model of the total force generalization of deep-sea complex structure foundation, which has certain theoretical value and practical significance.

Study on frequency characteristics of receiving power system with large-scale offshore wind power generation

With the rapid development of offshore wind power and large-scale grid connection, the mechanical inertia and frequency regulation ability of the power system are greatly reduced, which seriously affects the frequency stability of the receiving end power grid. Aiming at the frequency stability analysis of large-scale offshore wind power connected to the receiving end power grid, this paper proposes a frequency response aggregation model which includes the frequency limiting controller (FLC) and the wind turbine generator (WTG) with frequency modulation (FM) capability. The rationality of model aggregation and the stability of transfer function are proved by theoretical analysis. Taking a southern province in China as an example, the effects of wind turbine generator access form and DC block capacity on different frequency response indexes are analyzed by using the proposed frequency response aggregation model. Through theoretical and simulation analysis, the correlation of system inertia, FM capacity and DC FLC capacity with frequency deviation nadir and quasi-steady state frequency index is obtained, and the relevant conclusions affecting frequency stability indexes are drawn. Finally, through the model simulation method, the improvement of the system frequency stability when the wind turbine provides inertia and primary FM support is analyzed. This paper concludes that when the wind power penetration is in the range of 10%∼40% and the wind power assisted frequency modulation capacity reaches 5% of the installed capacity, the minimum frequency of the system can be maintained above 49.5 Hz.

Study on economical efficiency of ocean energy generation in China

Ocean energy, as a kind of renewable resource, plays an important role in China’s low-carbon development and meeting its goal of “carbon peaking and carbon neutrality”. The paper aims to calculate the cost of ocean power generation in China and make a medium and long-term forecast. Meanwhile, the offshore wind power development experience and the Levelized Cost of Energy (LCOE) cost pricing model is used for analysis and verification. The results shows that it features a high cost without economical efficiency in the initial stage; With the continuous expansion of installed capacity, the cost will be significantly lowered but the economical efficiency is moderate; the cost will fall significantly when the installed capacity reaches to a 100 MW level, and it has strong economical efficiency. The government should provide policy and financial support for ocean power generation industry; enterprises need to strengthen technological innovation and complete the industrial chain to improve the economical efficiency of scale utilization.

Offshore wind acceleration in the U.S. Atlantic coast and the 30 GW by 2030 target

There is a growing interest in the United States of America to have a more significant role in the development of offshore wind power. In recent years, the country has begun to shift and drive towards a green economy, investing in clean renewables and technology that will be able to reduce carbon dioxide emissions. It is expected that offshore wind has the potential to become a primary source to supply energy to millions of Americans. In the next 10 years, the Biden administration has set a target to achieve close to 30 GW of offshore wind potential. With the existing offshore wind projects in place, many developers are continuing to make progress, but there are many limiting factors that could decide whether that goal will be achieved. A detailed analysis in the U.S. Atlantic coast was deemed necessary and light was shed to the licensing process towards the goal of 30 GW by 2030.