Wind Sector Research Articles

Factor models and investment strategies in the renewable energy sector

The growing concern about the natural environment is getting relevance not only on institutional investors but also on individual ones. However, these retail investors face some difficulties, such as the fact that they are often not able to monitor many assets but they are also unable to use most of the methodology proposed in the empirical evidence because it is not feasible for them. We avoid these problems by proposing an investment strategy based on the different values of the alpha and beta coefficients from the Fama-French and Carhart models. We use Exchange Traded Funds (ETFs) which track companies involved on clean and renewable energy businesses and it is provided evidence that in most of the cases the best investment strategy is to follow the positive and significant values of the alphas from the estimated models and to hold the portfolio for a short period of time. Additionally, we also report that the signals from the coefficients associated to the value factor (HML) must not be undervalued. Finally, we demonstrate that wind, clean energy and solar energy sectors are the most important renewable energies for investors. These findings reinforce the importance of investing on renewable companies using ETFs.

Metocean conditions at two Norwegian sites for development of offshore wind farms

This paper examines metocean data from NORA3, a state-of-the-art wind and wave hindcast dataset for Northern Europe. Two offshore Norwegian areas, Utsira Nord (UN) and Sørlige Nordsjø II (SN2), are investigated. Both areas offer significant potential for the offshore wind sector. UN is situated in deep-sea water, suitable for floating offshore wind turbines. In contrast, SN2 lies in intermediate waters and ranks among the North Sea’s most promising regions allocated for offshore wind. Data from NORA3, originally on a 3-km resolution grid, are resampled into unstructured grids spanning from 1982 to 2022. This refined dataset offers a climatology time scale with superior spatial and temporal resolution compared to most other hindcast and reanalysis databases. The study examines mean wind speed and direction across seven levels, ranging from 10 m to 750 m above the surface. Analyses of extreme wind and wave conditions have been conducted. Results reveal that UN experiences higher extreme wave heights than SN2 while the extreme wind speeds may be substantially larger at SN2 than UN. Moreover, this study establishes joint distribution models that encompass several parameters, including mean wind speed, significant wave height, wave spectral peak period, and direction difference between wind and waves. Thus, this metocean data is valuable for designing and analyzing floating wind farms over their lifecycles.

Data-Driven Models Applied to Predictive and Prescriptive Maintenance of Wind Turbine: A Systematic Review of Approaches Based on Failure Detection, Diagnosis, and Prognosis

Wind energy has achieved a leading position among renewable energies. The global installed capacity in 2022 was 906 GW of power, with a growth of 8.4% compared to the same period in the previous year. The forecast is that the barrier of 1,000,000 MW of installed wind capacity in the world will be exceeded in July 2023, according to data from the World Association of Wind Energy. In order to support the expected growth in the wind sector, maintenance strategies for wind turbines must provide the reliability and availability necessary to achieve these goals. The usual maintenance procedures may present difficulties in keeping up with the expansion of this energy source. The objective of this work was to carry out a systematic review of the literature focused on research on the predictive and prescriptive maintenance of wind turbines based on the implementation of data-oriented models with the use of artificial intelligence tools. Deep machine learning models involving the detection, diagnosis, and prognosis of failures in this equipment were addressed.

A novel techno-economical layout optimization tool for floating wind farm design

Abstract. Over the past few years, the offshore wind sector has been subject to renewed yet growing interest from the industry and from the research sphere, with a particular focus on a recently developed concept, the floating offshore wind (FOW). Because of its novelty, floating research material is found in limited quantity. This paper focuses on the layout optimization of a floating offshore wind farm (FOWF) considering multiple parameters and engineering constraints, combining floating-specific parameters together with economic indicators. Today’s common wind farm layout optimization codes do not take into account either floating-specific technical parameters (anchors, mooring lines, inter-array cables (IACs), etc.) or non-technical parameters (operational expenditure, OPEX; capital expenditure, CAPEX; and other techno-economic project parameters). In this paper, a multi-parametric objective function is used in the optimization of the layout of a FOWF, combining the annual energy production (AEP) together with the costs that depend on the layout. The mooring system and the collection system including the inter-array cables and the offshore substation are identified as layout-dependent and therefore modeled in the optimization loop. Using ScotWind site 10 as a study case, it was found with the predefined technical and economic assumptions that the profit was increased by EUR 34.5 million compared to a grid-based layout. The main drivers were identified to be the AEP, followed by the anchors and the availability associated with the failures of inter-array cables.

Condition Monitoring of Wind Turbine Drivetrain Bearings

Abstract As an extremely valuable and reliable energy source, the renewable energy is developing around the world at an unprecedented pace. By the end of 2022, the global installed capacity of offshore wind turbines is expected to reach 46.4 GW, among which 33.9 GW in Europe. Efficiencies in Operations and Maintenance (O&M) offer potential to achieve significant cost savings as it accounts for around 20%–30% of overall offshore wind farm costs. A recent study of approximately 350 offshore wind turbines indicates that gearboxes might have to be replaced as early as 6.5 years. Therefore sensing and condition monitoring (CM) systems are needed in order to obtain reliable information on the state and condition of different critical parts. The development and use of such technologies will allow companies to schedule actions at the right time. The reduced costs of O&M enable the wind energy at a competitive price thus strengthening productivity of the wind energy sector. At the academic level, a plethora of methodologies have been proposed during the last decades focusing toward early and accurate fault detection. Among others, Envelope Analysis is one of the most important methodologies, where the envelope of the vibration signal is estimated, usually after filtering around a selected frequency band excited by impacts due to the faults. Different tools, such as Kurtogram, have been proposed in order to accurately select the optimum filter parameters (center frequency and bandwidth). Cyclostationary analysis and corresponding methodologies, i.e., the cyclic spectral correlation and the cyclic spectral coherence, have been proved as powerful tools for CM. On the other hand the application, test, and evaluation of such tools in general industrial cases is still rather limited. Therefore the main aim of this paper is the application and evaluation of advanced diagnostic techniques and diagnostic indicators, including the Enhanced Envelope Spectrum and the Spectral Flatness on real-world vibration data collected from vibration sensors on gearboxes in multiple wind turbines over an extended period of time of nearly four years. The diagnostic indicators are compared with classical statistic time and frequency indicators, i.e., Kurtosis, Crest Factor, etc. and their effectiveness is evaluated based on the successful detection of two failure events.

On recursive partitioning to refine coordinate rotation in Eddy covariance applications

While the use of three-dimensional sonic anemometers for eddy covariance is well established, there remain questions about its deployment and consequent data analysis. Convention has largely accepted that coordinates must be rotated so that the corrected transverse and vertical mean velocities become zero. In non-ideal terrain, a planar fit coordinate rotation is widely accepted. However, if the coordinate system changes through time, such as in a rapidly growing maize canopy, or is affected by the local topography, finding temporally and directionally stable regions for a reference point is crucial for flux estimation. A model-based recursive partitioning (MOB) algorithm is proposed to answer this problem. The algorithm creates individual wind sectors and accounts for temporal or spatially dependent variables that may affect planar fits. A cross-validation fitting procedure of the MOB algorithm has proved crucial in identifying variables that influence the choice among different parametric models, such as day of year, solar altitude, and wind direction. Momentum exchange is the most sensitive to alternative coordinate rotation systems, especially in stable conditions. The MOB methodology would be most useful during these conditions. The analyses presented here show that in quantifying scalar fluxes during the day, especially in the case of sensible heat flux and by extension to evapotranspiration and carbon dioxide exchange, there is little need for coordinate rotation if the sensors were aligned with the vertical parallel to gravity.

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.

Understanding public preferences towards Ireland's offshore wind sector: A study on renewable energy trade, public involvement, and setback distance

We examine the preferences for offshore wind farms involving different levels of participation, distances to shore and energy export using a choice experiment in Ireland. Respondents are willing to make monetary trade-offs to permit offshore wind development involving trade in renewable electricity. However, they prefer developments that retain wind energy in Ireland rather than export and ventures which involve high levels of participation located further from the shoreline. We find significant preference heterogeneity with respect to participation and trade. Women have stronger preferences for a higher level of engagement in the development process than men, are less supportive of exports, are more likely to indicate their uncertainty in the face of potential environmental impacts posed by offshore wind but are equally knowledgeable about the industry.

Multi-factorial methodology for Wind Power Plant repowering optimization: A Spanish case study

Due to the climate change, there have been changes in the rhythm of nature over the last decades. In addition, there has been an increasing social consciousness regarding decarbonization and emissions, promoting governments new policies and economic support measures for renewable integration. In this scenario, the participation of the onshore and offshore wind sectors play a crucial role, expecting that more than 6000 GW will be globally installed in 2050. In parallel, the useful life of other wind power plants is coming to their end. Therefore, some countries will face in the coming years the decision of repowering, decommissioning, installing new turbines, or a combination of them. In general, the areas with the greatest wind potential are already occupied by relatively old wind turbines. Subsequently, a complex group of factors influences on the most appropriate solution decision-making, involving climatic, technological, environmental, social or economic aspects. This paper proposes an optimized methodology based on multi-criteria decision-making to estimate the most appropriate solution for extending the useful-life of wind power plants. An initial group of 26 factors were identified, corresponding to seven categories: technical, geographic, socio-environmental, location, economic, political and climate. The methodology is divided into three stages: (i) data, (ii) alternatives, and (iii) optimization. It was assessed with a Spanish onshore wind power plant connected to the grid. From the initial data and factors, 11 alternatives were designed based on a selection of 10 most relevant factors. The results provide an optimal solution, combining both repowering and installation of new wind turbines. From the results, this methodology would allow reducing the LCOE of the new wind plants installed in the European Union by more than 50%.

Study of indicators on regulation for offshore wind energy exploitation in Brazil

ABSTRACT Generating electrical power through offshore wind farms presents an opportunity for Brazil to diversify its energy matrix, embracing renewable sources and addressing challenges such as climate change and energy security. Despite three decades passing since the installation of the world's first offshore wind farm, Brazil has yet to take effective steps towards implementing wind turbines in its territorial waters and exclusive economic zone, revealing a significant gap in harnessing its maritime wind potential. This study assessed the adequacy of the country's legal and regulatory framework for the expanding offshore wind sector, considering environmental, technological, tariff-related, and organizational dimensions. The results pointed out challenges impacting the sector: the lack of competence of the Energy Research Company (EPE) to obtain prior environmental licenses, the absence of competence of the National Energy Policy Council (CNPE) in defining areas for bidding, and the inadequacy of the CNPE's composition in adequately representing the affected sectors, limiting the diversity of perspectives considered. These discoveries provide essential guidance for the Legislative and Executive branches, assisting in the formulation of policies that promote sustainable growth of offshore wind energy in Brazil, contributing to a cleaner and more resilient energy future in the face of climate change.

Building an offshore wind sector in Australia: economic opportunities and constraints at the regional scale

ABSTRACT The recent passage of the Offshore Electricity Infrastructure Act (2021) (Cth) opened up the potential for Australia to produce renewable energy at unprecedented scale. Six regions have been identified as potential locations for developing offshore wind projects, promising thousands of new local jobs to legacy industrial regions. This paper charts the regulatory framework for Australia’s offshore wind industry and how it positions local economic benefits in the licencing of projects. It then draws on interviews with key stakeholders supported by media and policy analysis to examine the early development of offshore wind capability in one of the proposed regions, the Illawarra, in NSW. Here existing steelmaking capacity positions the region to play a key role in supply chains for local and potentially national projects, but considerable structural and geographical constraints in the labour market will need to be addressed. In light of overseas experience indicating that economic benefits often fall short of promises, greater attention by policy makers is required to ensure hosting communities can develop local skills in the industry and facilitate their relative supply chain capabilities. This paper also calls for careful evaluation of early projects to allow for adjustments to policy settings as the industry matures domestically.

Evolution of excess pore water pressures around monopiles subjected to moderate seismic loading

The sustained growth of the offshore wind sector is leading to the construction of offshore wind farms in highly seismic regions of the world. Hence, a large proportion of the potential sites may be exposed to liquefaction risk. Monopiles are directly affected by this phenomenon given their preference as a support system for offshore wind turbines over other foundation types. This paper includes a comprehensive study of the lateral response of monopiles against the combined action of earthquake induced liquefaction and environmental loading using centrifuge modelling. The experimental setup was designed to compare the amount of excess pore pressure generated within the soil adjacent to the monopile with and without operational wind/wave loading. The results revealed higher accumulation of excess pore pressure in the non-laterally loaded case, and significant differences in the amount of excess pore pressure recorded in the windward and leeward sides of the monopile in the laterally loaded scenario. In addition, the study provides data on the rotation experienced by monopile supported offshore wind turbines in liquefiable soils.

Long-term variation, solubility and transport pathway of PM2.5-bound iron in a megacity of northern China

Although particulate Fe has a significant impact on human health, atmospheric chemical reactions, air quality, climate change, and ecosystems, there is a lack of long-term continuous hourly observation on particulate Fe in the megacity of Beijing, limiting research on these issues. To address this gap, this study continuously measured hourly concentrations of Fe in PM2.5 from October 2018 to October 2022 in Beijing. The results indicate an overall decline in Fe concentrations, consistent with previous studies in Beijing. This decline can be attributed to multiple factors, such as reduced coal consumption, restrictions on biomass burning, increased use of clean energy, advanced technologies for industrial emission reduction, and efforts to control fugitive dust. Seasonal variations in Fe concentrations were similar across the various years, with higher mean concentrations in spring, fall, and winter, and lower levels in summer. Daily variations in PM2.5-bound Fe concentrations exhibited two peaks, influenced by changes in emission intensity and the evolution of the planetary boundary layer. The solubility of PM2.5-bound Fe exhibited a wide range, varying from 4 % to 95 %, surpassing previously reported source-specific values. This variability can be attributed to acid dissolution effects and complexation behaviors. Nonparametric wind regression analysis identified distinct hotspots (higher concentrations) in the northwest wind sector at wind speeds of approximately 5–15 km/h, which are associated with blowing dust and dust storms. Additionally, the potential source contribution function analysis identified high-potential source areas were precisely located in the northwestern, western, and southern regions of Beijing, rather than primarily in the southern areas recorded in a previous study. This research provides valuable insights for studying the health effects and migration and transformation of nutrient elements, particularly particulate Fe, in Beijing.

Validation of the estimated ships' emissions through an experimental campaign in port

This paper presents a correlation between the gaseous pollutant concentration measured in port and the estimated in-port ship emissions based on AIS data for the port of Naples. With the aim of better monitoring the quality ship's plumes funnels, the concentrations of Nitrogen dioxide (NO2) and Sulphur dioxide (SO2) have been continuously measured, during an experimental campaign (May–June 2021) at a height of 20 m from ground level.An innovative bottom-up ship emission modeling system with an emission inventory was created; five principal steps were realized: acquisition and cleaning, construction of ship's database, analysis of ship routes and phases in port, calculation of fuel consumption, and emission. The updated methodology bypasses the typical fixed value of specific fuel consumption, which is obtained based on the engine type and fuels and uses a correlation with the real engine load. Several updates were adopted for the emission estimation, abandoning the constant emission factor with the use of a more detailed methodology. The correlation was obtained by taking into account the prevailing winds and the overlap between the experimental campaign and the emission inventory on particular wind sectors. As a results correlations between the pollutant flow rates estimated from the AIS data and the concentrations measured during the experimental campaign, have been find (0.97 for SO2 and 0.80 for NOX).

The Expected Dynamics of the European Offshore Wind Sector in the Climate Change Context

The objective of this present work is to provide a more comprehensive picture of the wind conditions corresponding to some important European marine energy sites by considering both historical (1979–2020) and climatological data (2021–2100). As a first step, the wind energy profile of each site is assessed using some statistical methods (e.g., Weibull parameters) and some relevant indicators for the wind sector, such as the downtime period (<3 m/s). Since the offshore industry evolves very quickly, another objective of this work was to assess the performances of some large-scale wind turbines defined via capacity productions in the range of 15–25 MW. In terms of the capacity factor, the estimated values frequently exceed 60%, reaching a maximum of 76% in some cases, in line with the expected outputs of the new wind generators. In the final part of this work, several aspects are discussed, among them being the accuracy of the RCPs datasets or the current trends involving the wind sector. The offshore wind sector represents an important pillar of the European green market, which means that the future generation of wind turbines will play an important role in the consolidation of this sector and, eventually, in the expansion to new coastal areas.

A centrifuge study into the installation response of steel, open-ended, tubular piles, dynamically driven using prolonged impulses

A centrifuge study into the installation response of steel, open-ended, tubular piles, dynamically driven using prolonged impulses

Offshore geotechnical challenges of the energy transition

Offshore wind is the most mature of the offshore renewable energy technologies and has a significant role to play in the energy transition. 2000 GW of offshore wind capacity is anticipated globally by 2050 in order meet the targets of the Paris Agreement [1]. These ambitions correspond to a 35-fold increase compared to current installed offshore wind capacity, which has taken three decades to achieve, thus requiring an installation rate between now and the mid-century far out-stripping that currently achieved [2]. The pace and scale of offshore wind ambitions to support the energy transition present a range of challenges for the offshore geotechnical sector and the broader offshore wind sector, with impacts across the supply chain regarding availability of raw materials, vessels, equipment and personnel, and across each stage of the life-cycle of the projects from marine spatial planning, site investigation, design, manufacturing, installation, operation and decommissioning. To address these challenges, the sector faces key imperatives, including (i) to determine where best to place future offshore windfarms to meet technical, social and environmental requirements and identify where technology and knowledge gaps exist, (ii) to improve efficiency in deriving geotechnical design parameters in order to alleviate pressures on people, vessels, equipment and labs for site investigation and interpretation of test results; (iii) to improve efficiency of design outcomes, i.e. to achieve greater capacity:weight efficiency for foundations, anchors and mooring systems to ease supply chain, manufacturing and installation pressures, while maintaining necessary reliability; (iv) to improve time efficiency to complete designs in order to make design calculations and processes less time- and personnel-intensive to carry out; and (v) to improve the life-cycle cost of delivering the necessary offshore wind to enable a net zero future through considering the end of engineered life at the design stage. 
 Figure 1 illustrates the magnitude of the projected and necessary growth in offshore wind globally to 2050 in terms of installed offshore wind capacity and number of turbines, with an indication of the associated geotechnical implications for this pace and scale of growth.
 Potential solutions to address the identified challenges and associated imperatives include those to address specifically geotechnical challenges, but also geotechnical solutions to offshore wind challenges beyond the seabed. For example, (i) use of geospatial mapping and analysis to determine the available seabed areas for future offshore windfarms and identify suitable foundations or anchors for particular regions, which can in turn inform on supply chain or critical technology and knowledge gaps [4]; (ii) innovations to increase efficiency of offshore site investigation, including software [5] [6] and hardware approaches [7] to facilitate seabed characterization at meaningful spatial and temporal scales; (iii) innovations in design philosophy, concepts and methods to improve design outcomes for foundations and anchoring systems, including whole life geotechnical design [8], novel moorings and anchors [9] [10] [11] and integrated design [12]; (iv) creation of optimization design tools that can directly address the design question, avoiding numerous ad hoc individual analyses to hone in to a workable solution [13] [14]; and (v) methods to inform on requirements for end of engineered life, e.g. retrieval or stability if left in situ beyond the design life [15] [16], and geospatial mapping to understand the distribution of assets at the end of engineered life in order to plan for recycling or disposal [17].

Role of E-marketing of mineral products in achieving sustainability

This paper seeks to assess the determinants that play a pivotal role in the effectiveness of e-marketing strategies promoting environmentally sustainable mineral products. The assessment draws upon insights from a survey encompassing 150 experts within China's solar, wind, and hydropower sectors. Through rigorous statistical analysis, several critical success factors (CSFs) were identified, notably encompassing “Sustainable Literacy,” “Digital Literacy,” “Government Incentives for Green Mineral Adoption,” “Demonstration of Energy Savings,” “Economic Stability,” and “Political Stability.” Interestingly, distinct sectors demonstrated nuanced priorities. Experts in the solar domain accentuated the significance of “Sustainable Literacy” and “Government Support,” while those in the wind sector placed higher importance on “Digital Literacy” and “Demonstration of Energy Savings.” Conversely, hydropower experts underscored “Government Support” and “Demonstration of Energy Savings.” Utilizing the Factor Analysis technique, these CSFs were consolidated into two primary categories: the “Social Sustainability Factor” and the “Economic Aspect.” Furthermore, strategic recommendations are put forth to bolster e-marketing initiatives. These include advocating for an Education for Sustainable Development program, implementing an ICT Inclusion Policy, mitigating mineral poverty, and nurturing ICT infrastructure through targeted incentives and support for device acquisition.

Quantum optimization within lattice gauge theory model on a quantum simulator

Simulating lattice gauge theory (LGT) Hamiltonian and its nontrivial states by programmable quantum devices has attracted numerous attention in recent years. Rydberg atom arrays constitute one of the most rapidly developing arenas for quantum simulation and quantum computing. The {{mathbb{Z}}}_{2} LGT and topological order has been realized in experiments while the U(1) LGT is being worked hard on the way. States of LGT have local constraints and are fragmented into several winding sectors with topological protection. It is therefore difficult to reach the ground state in target sector for experiments, and it is also an important task for quantum topological memory. Here, we propose a protocol of sweeping quantum annealing (SQA) for searching the ground state among topological sectors. With the quantum Monte Carlo method, we show that this SQA has linear time complexity of size with applications to the antiferromagnetic transverse field Ising model, which has emergent U(1) gauge fields. This SQA protocol can be realized easily on quantum simulation platforms such as Rydberg array and D-wave annealer. We expect this approach would provide an efficient recipe for resolving the topological hindrances in quantum optimization and the preparation of quantum topological state.

Impact of turbulence and blade surface degradation on the annual energy production of small‐scale wind turbines

AbstractSmall‐scale horizontal axis wind‐turbines (SHAWTs) are acquiring relevance within the regulatory policies of the wind sector aiming at net‐zero emissions, while reducing visual and environmental impact by means of distributed grids. SHAWTs operate transitionally, at Reynolds numbers that fall between . Furthermore, environmental turbulence and roughness affect the energetic outcome of the turbines. In this study, the combined effect of turbulence and roughness is analysed via wind tunnel experiments upon a transitionally operating NACA0021 airfoil. The combined effects cause a negative synergy, inducing higher drops in lift and efficiency values than when considering the perturbing agents individually. Besides, such losses are Reynolds‐dependent, with higher numbers increasing the difference between clean and real configurations, reaching efficiency decrements above 60% in the worst‐case scenario.Thus, these experimental measurements are employed for obtaining the power curves and estimating the annual energy production (AEP) of a 7.8‐kW‐rated SHAWT design by means of a BEM code. The simulations show a worst‐case scenario in which the AEP reduces above 70% when compared to the baseline configuration, with such a loss getting attenuated when a pitch‐regulated control is assumed. These results highlight the relevance of performing tests that consider the joint effect of turbulence and roughness.