Top wind turbine manufacturers are in a competitive race to develop larger and more powerful offshore machines. These turbines commonly utilize permanent-magnet synchronous generators (PMSG) in direct-drive or gearbox-coupled configurations. However, due to the growing demand for critical rare-earth magnets, new generator technologies are emerging to ensure a stable supply chain. A collaborative study by researchers from NREL and GE Research points out which technology ends up on top for the future of 15+ MW offshore wind.
Abstract from the study: “Beyond 15 MW: A cost of energy perspective on the next generation of drivetrain technologies for offshore wind turbines.”
In this study, looking for future technology of 15+ MW offshore Wind, three distinct radial flux synchronous generator designs are assesed. All employ high-field magnets with reduced or no rare-earth materials:
- The direct-drive interior PMSG (DD-IPMSG)
- The medium-speed gearbox combined with a PMSG (MS-PMSG)
- The direct-drive low-temperature superconducting generator (DD-LTSG)
These evaluations are conducted within a comprehensive framework for complete turbine design. This providing a fair comparison of technologies for nominal power ratings ranging from 15 to 25 MW, representing the next generation of offshore wind turbines.
The analyses reveal that assuming constant operational expenditures (OpEx) across the technologies, MS-PMSG yields the lowest Levelized Cost of Energy (LCOE). With potential reductions of up to 7% compared to DD-IPMSG. DD-LTSG also demonstrates lower LCOE values, with 2%–3% reductions for fixed-bottom turbines and 3%–5% when used with a floating platform. It is worth noting that these results are sensitive to OpEx assumptions. With even a modest 10% increase potentially altering the conclusions.
1. Introduction
In recent years, the offshore wind energy industry has experienced substantial growth, with installations of wind farms using fixed-bottom foundations steadily increasing. The development of floating platform technology has further fueled this expansion with a projected cumulative installed power of approximately 270 gigawatts (GW) globally by 2031.
As wind turbines become larger and more powerful, reaching up to 15 megawatts (MW), the levelized cost of energy (LCOE) for offshore wind is expected to drop below USD 85 per megawatt-hour (MWh) by around 2024. To sustain this growth and address the rising demand for raw materials, particularly critical rare-earth magnets, wind farm developers and turbine manufacturers are diversifying their sourcing strategies. This diversification involves investing in efficiency improvements and advanced technologies. A secure supply chain, reduced capital costs, lower operations and maintenance (O&M) expenses, and extended lifetimes are the objectives. Now this study looks into the future technology of 15+ MW offshore wind.
1.1. The Latest Trends in Offshore Wind Turbine Generators
Leading manufacturers in the offshore wind energy market have predominantly favored two generator configurations: the direct-drive interior permanent-magnet synchronous generator (DD-IPMSG) and the compact permanent-magnet synchronous generator (PMSG) coupled to a medium-speed gearbox (MS-PMSG). PMSG-oriented designs are considered low-risk and cost-competitive. And there are ongoing efforts to develop PMSG designs that eliminate the use of rare-earth permanent magnets.
Selecting an appropriate generator configuration is a critical system-level decision that affects overall turbine performance and costs. Most PMSGs for high-power wind turbines employ a radial flux topology with surface-mounted magnets. This configuration offers high-torque densities, acceptable air-gap-flux densities, low-torque ripple, and ease of manufacturing. However, the reliance on surface-mounted permanent magnets presents challenges related to demagnetization risks, necessitating thicker magnets and enhanced thermal control mechanisms. Recent advancements have introduced reduced dysprosium content magnets, such as dysprosium-free neodymium-iron-boron (Nd2Fe14B) magnets. These magnets, while lighter, may experience partially irreversible demagnetization, impacting generator robustness and design weight.
Interior PMSG generators (IPMSGs) with fractional-slot concentrated windings (FSCWs) offer a promising alternative for large-scale wind power generation. These generators embed magnets in slotted cavities in the rotor, enhancing alignment and retention without requiring special tooling. Additionally, V-shaped magnet configurations can augment permanent-magnet torque via magnetic flux concentration and higher saliency, further improving performance.
In medium-speed configurations, newer gearbox designs with higher step-up ratios are emerging, reducing the size of PMSGs and capital costs compared to direct-drive architectures. However, gearbox maintenance expenses, particularly in offshore environments, can offset the cost benefits. While avoiding gearbox maintenance costs, direct-drive designs face challenges in scaling PMSGs to turbines with power ratings nearing 20 MW or more. At such scales, radial-flux PMSGs become heavy and costly, increasing the strain on the rare-earth supply chain. The weight of generators also significantly impacts floating platforms, affecting tower-top mass and overall project costs.
1.2. Superconducting Generators: A Promising Alternative
Recent advancements in superconducting technology have opened new possibilities for wind turbine generators with enhanced efficiency and a secure raw-material supply chain. Low-temperature superconductors (LTS) and high-temperature superconductors (HTS) have emerged as two main superconductors in the market, offering promising material characteristics and competitive prices. These technologies can handle magnetic fields exceeding 10 Tesla (T), resulting in higher torque density and efficiency than traditional PMSGs.
While HTS conductors show potential, they face limitations regarding mechanical strength and quench protection mechanisms, particularly for large-scale applications. LTS conductors, on the other hand, have demonstrated higher technology maturity, commercial readiness, and a more established supply chain. Recent developments in LTS conductors, such as Niobium Titanium (NbTi) and Niobium Tin (Nb3Sn) wires, have made them cost-competitive alternatives to rare-earth Barium Cobalt (ReBCO) or Yttrium Barium Cobalt (YBCO) conductors.
Despite being in the developmental stage, superconducting generators (SCGs) have garnered interest for their potential to revolutionize wind turbine technology. Several studies have explored the feasibility of SCGs, although comprehensive design and operational experience are lacking, especially at high power ratings. The levelized cost of energy (LCOE) comparisons between SCG-based and PMSG-based wind turbines remain inconclusive due to the evolving nature of both technologies.
Research in this field has shown varying results. Some studies have indicated that the LCOE of HTS generators may not be competitive with traditional MS-PMSG drivetrains due to high superconductor, cryostat, and cooling system costs. However, other evaluations have suggested fully superconducting wind turbine generators could be cost-competitive with traditional DD-PMSG for floating wind turbines if superconducting wire prices decrease. These discrepancies highlight the need for further research and development to determine the optimal conditions for SCGs and potentially future technology of 15+ MW offshore wind.
1.3. Article Contributions
This article aims to comprehensively compare wind turbines with SCGs versus DD-IPMSG and MS-PMSG technology. Rather than focusing on a single design point, we consider a range of turbine rating points between 15 and 25 MW.
Our approach builds upon prior research by customizing each generator option’s rotor operating curve, drivetrain sizing, and support structure. We also take into account both fixed-bottom and floating platform projects, recognizing the influence of mass scaling properties on floating platforms.
Our SCG technology comparison primarily considers low-temperature superconducting generators (LTSG) due to their higher technology maturity and commercial readiness. These generators offer lower capital expenses and a more established supply chain than high-temperature superconducting generators (HTSG), even though the latter may have lighter cryogenic requirements in the long term.
Our analysis also explores IPMSG concepts that utilize reduced dysprosium magnets and V-shaped magnet arrangements for improved magnetic field focusing.
In summary, the offshore wind industry and future technology of 15+ MW offshore wind is at a pivotal juncture, with superconducting technology promising more efficient and sustainable wind turbines. As research and development in this field progress, a clearer picture of the potential advantages and challenges of SCGs will emerge, shaping the future of offshore wind energy generation.
2. A systems engineering design approach
In this comprehensive study, we employ a systems engineering design approach to evaluate three generator-drivetrain configurations for offshore wind turbines rigorously. Our analysis harnesses the power of the National Renewable Energy Laboratory’s (NREL) systems engineering framework, the Wind-Plant Integrated System Design & Engineering Model (WISDEM®), along with Wind Energy with Integrated Servo control (WEIS). The configurations under scrutiny include a conventional Direct-Drive Interior Permanent-Magnet Synchronous Generator with reduced-dysprosium magnets (DD-IPMSG), a conventional Medium-Speed Permanent-Magnet Synchronous Generator with reduced dysprosium magnets (MS-PMSG), and an innovative Direct-Drive Low-Temperature Superconducting Generator (DD-LTSG) that eliminates rare-earth materials. Our primary objective is determining the most cost-competitive generator technology as wind turbine size scales up, focusing on fixed-bottom and floating foundation installations.
Optimizing Generator Designs
To achieve this goal, we embarked on the conceptual design and optimization of these generator technologies across a range of nameplate powers (15 MW, 17 MW, 20 MW, 22 MW, and 25 MW) for both fixed-bottom and floating offshore foundations. This exhaustive effort yielded 30 unique design points within our test matrix, with each generator technology designed to meet specific efficiency targets at rated operating conditions.
Maintaining consistency, we initiated our designs with the 15 MW offshore reference wind turbine, as defined by the International Energy Agency Wind Task 37 on Systems Engineering.
This reference turbine provided a solid foundation, keeping key specifications constant, such as specific power (325 W/m), maximum blade tip speed (95 m/s), airfoil profiles, materials, blade composite topology, and overall configuration (a three-bladed upwind turbine). While we accommodated variations in semisubmersible column sizes and offset distances for floating foundation designs, the overall architectural framework remained unaltered.
Table 1 below outlines critical rotor design parameters that significantly influenced our generator-drivetrain concepts. After finalizing the rotor and generator designs, we completed the remaining drivetrain, tower, and foundation components.
2.1. Rotor Optimization
Within the rotor optimization phase, we generated five rotor designs at the five nameplate power ratings, relying on the parameters outlined in Table 1. We fine-tuned rotor blade design variables to facilitate this process, including chord, twist, and spar cap thickness at six equally spaced spline control points along the blade span. Certain design stations were anchored to ensure practical solutions. Our optimization efforts primarily aimed to minimize the Levelized Cost of Energy (LCOE) with fixed cost assumptions for non-varying components. Specific constraints included:
- Maintaining ultimate strains along the spar caps below 3500 microstrains.
- Ensuring blade tip deflections remained within minimum tower clearance thresholds.
- Limiting the flapwise blade root moment coefficient to values below 0.16.
These constraints guided our optimizer toward favoring lightly loaded blade designs, particularly in the outermost spanwise sections.
2.2. Generator Technology Design Optimization
In our pursuit of optimal generator technology designs when looking into the future technology of 15+ MW offshore wind, we adopted an innovative approach, integrating WISDEM’s GeneratorSE with the open-source library Finite Element Method Magnetics (FEMM) via a Python interface.
In Figure 1 below, you can see the XDSM diagram, depicting the coupling approach between GeneratorSE and FEMM. Each optimization cycle involves a finite-element analysis for electromagnetic design, followed by analytical estimations for structural deformations, power losses, and costs based on assumptions.
This methodology underwent an extensive evaluation. Combining finite-element electromagnetic design assessments with analytical estimates for structural deformation, power losses, and overall costs, subject to specific assumptions. Each generator topology underwent optimization at rated shaft torque and speed levels as specified in Table 1. We aligned our designs with target-rated efficiencies from Table 2 below. And maintained a stator terminal voltage of 3.3 kilovolts (kV) as design constraints.
Cost-Effective Material Modeling
The optimization process for all generator designs centered on minimizing costs, with the bill of materials as a foundational cost estimation tool. Material mass values were meticulously calculated in GeneratorSE and adjusted by considering manufacturing waste factors and cost per unit weight. As per the Energy Information Administration, these mass values were further influenced by an energy consumption rate and the average industrial electricity price (USD 78/MWh). As the original text details, our comprehensive formula for determining generator material cost provided a holistic perspective on cost estimations, factoring in various components and parameters.
The material cost model utilizes inputs listed in Table 3 below. With waste factor and energy consumption rate determined using NREL’s Materials Flow through Industry (MFI) Tool.
Simplified Modeling Enhances Generator Optimization
While striving for accuracy, we recognized certain modeling simplifications in our study. We omitted thermal calculations due to their complexity and focused on steady-state performance, neglecting transient dynamics and control strategies tailored to each generator technology. Our modeling approach assumed voltage source converters for all generators, a standard practice for offshore wind turbines. We also considered torque controllers for generator power regulation. And collective blade pitch controllers for rotor speed regulation, with distinct approaches for different wind speed regions.
Our optimization strategy favored a gradient-free workflow over gradient-based algorithms due to challenges associated with grid convergence in the FEMM software. This workflow featured a global search phase employing a differential evolution algorithm and a subsequent local neighborhood search phase utilizing the COBYLA algorithm from the NLOpt library. We acknowledged the need for iterative steps and occasional restarts to ensure consistent design outcomes across various power ratings.
This section concludes by offering more comprehensive descriptions of each generator model, referencing Sethuraman et al. for those seeking deeper technical insights and access to open-source code.
Our study thoroughly explores generator-drivetrain offshore concepts, offering valuable insights into their performance and cost competitiveness across varying power ratings and foundation types.
2.2.1. DD-IPMSG: A Powerful Generator Configuration
V-shaped radially magnetized Interior Permanent Magnet Synchronous Generator (IPMSG) designs offer remarkable power densities, efficiency, and cost-effectiveness. This makes them ideal for high-megawatt offshore wind turbines and future technology of 15+ MW offshore wind. Our selected configuration features an outer rotor V-shaped IPMSG generator with fractional slot concentrated windings.
Design Parameters
Figure 2 below outlines key design variables for the DD-IPMSG model, with Table 4 further below listing design bounds. The configuration includes five poles and six slots aligned with the stator winding setup in the 15 MW reference generator. Each rotor pole features a single layer of magnets arranged in a V shape, simplifying magnet slots to parallelograms. Rotor magnets use N48SH-grade sintered, reduced-dysprosium NdFeB magnets.
Stator and Structural Design
The stator employs a three-phase, fractional slot layout with double-layer concentrated coils. The structural design incorporates disc-type support structures. This allowing an air gap deflection of up to 20%. Mass calculations are based on cross-sectional areas estimated using the FEMM geometry.
Yoke and Core Considerations
Rotor and stator yokes use M-36 grade steel with a saturation flux density of 2.15 T. Design constraints manage peak magnetic loading, with an upper limit of 2.53 T, particularly challenging near tooth tips and magnet bridges. Each design is evaluated for minimum magnetic flux density and magnet knee point during normal operation and a three-phase symmetric short circuit.
Iron Core Losses
Iron core losses are approximated using the Steinmetz formula. Total iron losses combine specific hysteresis and eddy current losses in the core. With no exploration of magnetomotive force (MMF) space harmonics or magnet eddy current losses.
2.2.2. DD-LTSG: Innovative Superconducting Generator
Our DD-LTSG architecture features an air-core, inner-rotor, radial-flux design. This setup combines an inner rotating armature assembly with conventional copper windings and an outer stationary field coil assembly of racetrack coils, employing NbTi conductors working at 4.2 Kelvin. Key design aspects include the six-phase connection, non-magnetic teeth, and a magnetic yoke made of silicon steel to enhance field-armature coupling.
Superconducting Wires
LTS field windings utilize racetrack coils wound with NbTi-Cu composite wires, considering conductor dimensions and characteristics. We modeled the superconducting wires in FEMM, assuming the superconductor within a copper matrix (Cu:SC ratio of 4.6). Apparent bulk permeability was determined using the Ollendorff formula.
Cooling Systems
The armature incorporates forced air cooling to maintain temperatures below 160°C. The field coil assembly uses liquid helium cooling. No thermal analysis was performed during the conceptual design.
Design Parameters and Bounds
A 2D FEMM model, following an odd periodicity boundary condition, was used for LTS design. Key parameters are illustrated in Figure 3 below, with design variable bounds listed in Table 5 further below. Armature windings employ a double-layer distributed winding layout. The field coil dimensions are optimized to avoid overlap. Armature flux density is constrained to 2.3 T at the bottom of non-magnetic teeth. The superconducting magnets operate within an 80%–95% critical current margin.
Field coil turns and current are design variables. We iteratively set the operating current by initializing operating values and determining the maximum flux density in the coil faces. The approach is shown in Figure 4 below. Here we construct a linear approximation of the load line, considering operational safety margins.
Operational Considerations
Generator phase voltage is computed from the fundamental component of air-gap flux density and scaled by 10% to account for end winding contributions. Armature winding resistances consider a 65% slot fill factor. The cooling system sizing is borrowed from a previous study.
Structural Design and Efficiency
The structural design assumes a 20% deflection limit of the effective air-gap length. Generator efficiency factors in winding losses and iron losses in the armature yoke and neglects AC losses in superconducting coils, cryostat walls, and mechanical losses.
2.2.3. MS-PMSG
A radial-flux surface-mounted PMSG with an inner-rotor topology where selected for the medium-speed configuration. This based on the spoked-arm construction presented in Sethuraman and Dykes. Figure 5 below shows a simplified cross-section geometry with key active and structural design variables listed in Table 6 further below.
The 2D FEMM model contained one pole with three slots modeled with a double-layer integer slot winding layout (one slot per pole per phase). Sizing the slots followed the same approach as that of the DD-IPMSG. In sizing the magnet, the magnet thickness was selected for adequate coercive force higher than the demagnetizing magneto-motive force during a short circuit. Stator winding current density was limited to be below 6 A/mm2. And specific current loading to below 65 kA/m. This to ensure that the temperature rise within the stator and rotor is within permissible values for an air-cooled system. A thermal simulation in the design loop was not included. The structural design consisted of analytical models with constraints for radial, axial, and torsional deformations caused by normal stress, shear stress, and gravity loads.
2.3. Other drivetrain components
To optimize wind turbine design for cost-effectiveness and performance, looking for the future technology of 15+ MW offshore wind, we integrated five turbine rotor designs with three generator technologies. That created 15 distinct drivetrain combinations. These configurations underwent thorough optimization, assuming a four-point suspension system with two main bearings. For direct-drive layouts following the 15 MW template, key design variables included shaft lengths, diameter and wall thickness of the low-speed shaft, diameter and wall thickness of the nose, and the nacelle bedplate’s wall thickness.
In the case of medium-speed geared designs, we took inspiration from Vestas’ designs and implemented a three-stage gearbox with a consistent gear ratio of 1:120 across all power ratings. The optimization process encompassed the main shaft, bearings, and bedplate sizing to minimize the overall nacelle mass.
Various design constraints were meticulously enforced to ensure the drivetrains met stringent criteria. These constraints encompassed von Mises stress, shaft deflections, layout geometry, and maintenance access, guaranteeing robust and reliable wind turbine configurations.
The optimized drivetrain designs played a crucial role in influencing the Levelized Cost of Energy (LCOE) results in three distinct ways:
- Tower-Top Inertial Loads: The drivetrain mass significantly contributed to the tower-top inertial loads. This plays a pivotal role in substructure design.
- Turbine Capital Cost: The drivetrain cost was a crucial component of the overall turbine capital cost, impacting the LCOE computation.
- Gearbox Efficiency: For medium-speed configurations, the efficiency of the gearbox directly influenced the overall electro-mechanical efficiency. A key factor in LCOE determination.
2.4. Tower and offshore structure
The final phase of the wind turbine design process focused on optimizing the tower and support structure. We optimized the monopile for fixed-bottom designs, while for floating designs, the semisubmersible support structure was considered. These optimizations were conducted in parallel, considering similar design variables and constraints.
Tower and monopile parameters were parameterized along their height at ten points, each in terms of outer diameter and steel wall thickness. Constraints included factors like ultimate stress, global and shell buckling, monotonicity of profiles, and frequency criteria. Floating designs had specific constraints related to platform pitch angle, metacentric height, and water ballast capacity to ensure stability and safety.
The entire optimization process was executed using the SNOPT solver, configured to explore the design space thoroughly. Our rigorous approach resulted in 30 unique wind turbine designs, each meticulously optimized for performance and cost-effectiveness.
2.5. LCOE model and optimization
We utilized the Levelized Cost of Energy (LCOE) equation to evaluate these designs, considering factors such as fixed charge rate, capital expenditures, turbine capital cost, balance-of-system expenditures, operations and maintenance costs, and annual energy production. While certain assumptions were made, such as constant O&M costs across power ratings and generator technologies, sensitivity analyses were included to account for potential variations in costs and reliability associated with different technologies.
Our comprehensive approach aimed to identify the most efficient and cost-effective wind turbine designs across various power ratings and generator technologies. Ultimately contributing to the advancement of sustainable offshore wind energy generation.
3. Results: Optimizing Wind Turbine Design for Efficiency and Cost-Effectiveness
This section delves into the key findings, searching for the future technology of 15+ MW offshore wind, obtained through the comprehensive analysis of 30 distinct wind turbine designs utilizing the WISDEM and WEIS tools.
3.1. Optimized Generator Designs
The tables below provide insights into the electromagnetic design variables (excluding structural details) and present typical constraints shared across all designs. Additionally, they offer a summary of mass and cost outcomes.
DD-IPMSG Generator
The results for this generator are outlined in Table 7 below. These designs effectively meet the torque and phase voltage constraints, with efficiencies slightly below the target of 95%. Particularly noticeable in the 25 MW design. The mass of DD-IPMSG generators spans from 314 to 500 tons. And it is essential to note that these efficiency values are sensitive to modeling assumptions. Further optimization opportunities exist in winding distribution and slot design.
DD-LTSG Generator
Examining Table 8 below, we observe that all three constraints are comfortably met for DD-LTSG designs, even at the demanding 25 MW rating. These generators exhibit a consistent mass of approximately 200 tons across various power ratings. The reported efficiencies, albeit impressive, will see minor reductions due to cryogenic cooling and armature frame losses.
MS-PMSG Generator
Table 9 below details the results for the MS-PMSG generator. Similar to DD-LTSG, all constraints are readily satisfied across the power ratings. The axial length, magnet height, and yoke thickness vary significantly relative to the power rating.
3.2. Nacelle Mass and CapEx
Figure 6 below illustrates the generator mass and cost alongside the nacelle mass and cost for different drivetrain technologies and nameplate power ratings.
Comparing generator mass, DD-LTSG remarkably reduces mass by 50% compared to DD-IPMSG, especially evident at higher power ratings. DD-IPMSG generators become prohibitively heavy and expensive beyond 20 MW. In terms of nacelle mass and cost, DD-LTSG is the lightest, followed by MS-PMSG and then DD-IPMSG. MS-PMSG’s nacelle remains the most cost-effective, mainly due to the complexity shifted to the gearbox.
3.3 Annual Energy Production (AEP)
Figure 7 below presents AEP results, emphasizing the value of the higher-rated efficiency of DD-LTSG (97%) compared to DD-IPMSG (95%) or MS-PMSG (96%). While subtle, the MS-PMSG’s AEP falls slightly below the DD-IPMSG’s.
3.4. Wind Turbine CapEx, LCOE, and Sensitivity Analysis
Fixed-Bottom designs
For fixed-bottom designs, tower and monopile masses exhibit mild sensitivity to rotor-nacelle assembly mass variations as shown in Figure 8 below.
Therefore, nacelle cost significantly impacts total turbine capital cost (TCC) more than mass in fixed-bottom applications. However, this trend needs validation through higher-fidelity load modeling in future studies. BOS (Balance of System) costs remain relatively consistent across technologies in fixed-bottom designs.
Floating designs
For floating designs, tower and platform mass variations are more pronounced as shown in Figure 9 below.
Lighter nacelles remain advantageous for floating applications, influencing TCC trends. Here, BOS costs differ slightly by drivetrain-generator technology. With a noticeable downward trend in BOS costs with higher turbine ratings driven by the floating platform’s significant contribution.
3.5. LCOE Comparison and Sensitivity
Figure 10 below illustrates the final LCOE comparisons for both fixed-bottom and floating applications.
LCOE for offshore wind energy is projected to be less than USD 86/MWh for fixed-bottom designs. And USD 96/MWh for floating designs. Fixed-bottom designs exhibit relatively flat LCOE trends across nameplate power ratings, except for a rise at 25 MW. Conversely, floating designs demonstrate a monotonically decreasing trend in LCOE, except for the MS-PMSG line. The MS-PMSG can yield the lowest LCOE, with potential reductions of up to 7% compared to DD-IPMSG.
Sensitivity Analysis
We assumed identical and constant O&M costs across drivetrain-generator technologies and power ratings. However, variations in O&M costs can significantly impact LCOE. For instance, a 10% increase in O&M costs for gearbox maintenance would place the MS-PMSG and DD-LTSG technologies on par with LCOE. Sensitivity to O&M costs highlights uncertainties and the need for further exploration, considering factors like manufacturing costs, commodity price fluctuations, and supply chain vulnerabilities.
In conclusion, our study presents a holistic wind turbine design analysis, emphasizing efficiency, cost-effectiveness, and the potential of new technologies. The findings suggest that MS-PMSG technology holds promise for achieving the lowest LCOE. Especially in floating applications, with the potential for substantial cost reductions. However, as the wind energy landscape evolves, ongoing research and validation will be crucial for optimizing wind turbine designs and ensuring sustainable, affordable offshore wind energy generation.
Conclusion – What is the future technology of 15+ MW offshore wind?
What is the future technology of 15+ MW offshore wind? The study delved into the world of advanced generator technologies for offshore wind turbines exceeding 15 MW, uncovering game-changing potential for the wind energy sector. Our primary focus was assessing how these innovations might influence the Levelized Cost of Energy (LCOE), revealing distinct trends for fixed-bottom and floating installations.
We noted a consistent LCOE trend across various turbine ratings from 15 MW to 25 MW in fixed-bottom scenarios. However, floating applications told a different story, showcasing a consistent decrease in LCOE, indicating enhanced cost-effectiveness.
Direct-Drive Low-Temperature Superconducting Generators (DD-LTSGs) emerged as a key player. Potentially reducing LCOE by 2%–3% for fixed-bottom designs and a significant 3%–5% for floating offshore wind turbines. Meanwhile, the Medium-Speed Permanent-Magnet Synchronous Generator (MS-PMSG) emerged as the cost leader, offering LCOE reductions of up to 7%, contingent on gearbox maintenance costs in our analysis.
LTSG solutions also hinted at a potential reduction in reliance on rare-earth metals within the generator supply chain, promising both environmental and economic benefits.
Our study unveiled the importance of rotor thrust loads in design. Particularly for 15- to 25 MW turbines, shaping support structure dynamics.
Our research journey continues with ambitious plans to develop and rigorously test a full-scale DD-LTSG prototype. A critical step toward advancing these transformative technologies.
In conclusion, our study looking for the future technology of 15+ MW offshore wind, charts a course for a potential revolution in offshore wind turbine technology. Focusing on improved cost-efficiency, reduced environmental impact, and exciting prototype developments. These findings represent a significant stride toward a more sustainable energy landscape.
Credit and authorship contribution statement
This article is a Green Dealflow re-write permitted by author Garret E. Barter. Links and references from this article must go to Green Dealflow as well as the original authors below.
NB.: This rewrite is a shortened and simplified version of the original article why calculations, formulas and source references from the original article are not included.
The original article: “Beyond 15 MW: A cost of energy perspective on the next generation of drivetrain technologies for offshore wind turbines” is available through this link.
Original authors: Garrett E. Barter: Conceptualization, Formal analysis, Methodology, Software, Writing – original draft, Writing – review & editing. Latha Sethuraman: Conceptualization, Methodology, Software, Supervision, Writing – original draft. Pietro Bortolotti:Conceptualization, Formal analysis, Methodology, Software, Writing – original draft. Jonathan Keller: Funding acquisition, Project administration, Resources, Supervision, Validation, Writing – review & editing. David A. Torrey: Conceptualization, Funding acquisition, Methodology, Resources, Supervision, Validation, Writing – review & editing.
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