scholarly journals Land-based wind turbines with flexible rail-transportable blades – Part 1: Conceptual design and aeroservoelastic performance

2021 ◽  
Vol 6 (5) ◽  
pp. 1277-1290
Author(s):  
Pietro Bortolotti ◽  
Nick Johnson ◽  
Nikhar J. Abbas ◽  
Evan Anderson ◽  
Ernesto Camarena ◽  
...  
Keyword(s):  
Carbon Fiber ◽  
Wind Turbine ◽  
Conceptual Design ◽  
Wind Turbines ◽  
State Of The Art ◽  
Levelized Cost ◽  
Cost Of Energy ◽  
Blade Tip ◽  
Turbine Rotors ◽  
Future Work

Abstract. This work investigates the conceptual design and the aeroservoelastic performance of land-based wind turbines whose blades can be transported on rail via controlled bending. The turbines have a nameplate power of 5 MW and a rotor diameter of 206 m, and they aim to represent the next generation of land-based machines. Three upwind designs and two downwind designs are presented, combining different design goals together with conventional glass and pultruded carbon fiber laminates in the spar caps. One of the five blade designs is segmented and serves as a benchmark to the state of the art in industry. The results show that controlled flexing requires a reduction in the flapwise stiffness of the blades, but it represents a promising pathway for increasing the size of land-based wind turbine rotors. Given the required stiffness, the rotor can be designed either downwind with standard rotor preconing and nacelle uptilt angles or upwind with higher-than-usual angles. A downwind-specific controller is also presented, featuring a cut-out wind speed reduced to 19 m s−1 and a pitch-to-stall shutdown strategy to minimize blade tip deflections toward the tower. The flexible upwind and downwind rotor designs equipped with pultruded carbon fiber spar caps are found to generate the lowest levelized cost of energy, 2.9 % and 1.3 %, respectively, less than the segmented design. The paper concludes with several recommendations for future work in the area of large flexible wind turbine rotors.

scholarly journals Land-based wind turbines with flexible rail transportable blades – Part I: Conceptual design and aeroservoelastic performance

2021 ◽  
Author(s):  
Pietro Bortolotti ◽  
Nick Johnson ◽  
Nikhar J. Abbas ◽  
Evan Anderson ◽  
Ernesto Camarena ◽  
...  
Keyword(s):  
Wind Speed ◽  
Carbon Fiber ◽  
Wind Turbine ◽  
Conceptual Design ◽  
Wind Turbines ◽  
Levelized Cost ◽  
Cost Of Energy ◽  
Blade Tip ◽  
Turbine Rotors ◽  
Future Work

Abstract. This work investigates the conceptual design and the aeroservoelastic performance of land-based wind turbines whose blades can be transported on rail via controlled bending. The turbines have a nameplate power of 5 MW and a rotor diameter of 206 m, and they aim to represent the next generation of land-based machines. Three upwind designs and two downwind designs are presented, combining different design goals together with conventional glass and pultruded carbon fiber laminates in the spar caps. The results show that controlled flexing requires a reduction in the flapwise stiffness of the blades, but it represents a promising pathway to increase the size of land-based wind turbine rotors. Given the required stiffness, the rotor can be designed either downwind with standard rotor preconing and nacelle uptilt angles or upwind with higher-than-usual angles. A downwind-specific controller is also presented, featuring a cut-out wind speed reduced to 19 m per second and a pitch-to-stall shutdown strategy to minimize blade-tip deflections toward the tower. The flexible upwind and downwind rotor designs equipped with pultruded carbon fiber spar caps are found to generate the lowest levelized cost of energy, 2.9 % and 1.3 %, respectively, less than the segmented design. The paper concludes with several recommendations for future work in the area of large flexible wind turbine rotors.

scholarly journals Comparison between upwind and downwind designs of a 10 MW wind turbine rotor

2019 ◽  
Vol 4 (1) ◽  
pp. 115-125 ◽  
Author(s):  
Pietro Bortolotti ◽  
Abhinav Kapila ◽  
Carlo L. Bottasso
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Lower Cost ◽  
Turbine Rotor ◽  
Conventional Design ◽  
Cost Of Energy ◽  
Turbine Rotors ◽  
Interesting Alternative ◽  
Wind Turbine Rotor

Abstract. The size of wind turbines has been steadily growing in the pursuit of a lower cost of energy by an increased wind capture. Within this trend, the vast majority of wind turbine rotors have been designed based on the conventional three-bladed upwind concept. This paper aims at assessing the optimality of this configuration with respect to a three-bladed downwind design, with and without an actively controlled variable coning used to reduce the cantilever loading of the blades. Results indicate that a conventional design appears difficult to beat even at these turbine sizes, although a downwind nonaligned configuration might be an interesting alternative.

The wind energy potential in Kudat Malaysia by considering the levelized cost of energy for combined wind turbine capacities

2020 ◽  
pp. 0958305X2093700
Author(s):  
A Albani ◽  
MZ Ibrahim ◽  
KH Yong ◽  
ZM Yusop ◽  
MA Jusoh ◽  
...  
Keyword(s):  
Wind Energy ◽  
Wind Turbine ◽  
Wind Turbines ◽  
Small Scale ◽  
Energy Potential ◽  
Levelized Cost ◽  
Cost Of Energy ◽  
Wind Energy Potential ◽  
Wind Park ◽  
Utility Scale

This paper presents the wind energy potential at Kudat Malaysia by considering the Levelized cost of energy (LCOE) model for combined wind turbine capacities. The combination of small- and utility-scale wind turbines is the key to the success of the operation of a wind park in the lower wind speed region. In a combination approach, the small-scale wind turbines provide the power required by the utility-scale wind turbines to start the blade rotation. For this reason, the particular closed-form equation was modified to determine the LCOE of a wind park with combined turbine capacities. The modified LCOE model can be used as a basis for setting tariff rates or define the economic feasibility of wind energy projects with combined wind turbine capacities.

Skewed Wake Induction Effects on Thrust Distribution on Small Wind Turbine Rotors

2001 ◽  
Vol 123 (4) ◽  
pp. 290-295 ◽  
Author(s):  
Ken Chaney ◽  
Alfred J. Eggers, ◽  
Patrick J. Moriarty ◽  
William E. Holley
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Speeds ◽  
Small Wind Turbine ◽  
Cylindrical Vortex ◽  
Thrust Distribution ◽  
Wake Effects ◽  
Rotor Disk ◽  
Turbine Rotors ◽  
Wake Model

Accurate prediction of both the center of thrust location and the magnitude of the thrust on a rotor disk are critical to satisfactory modeling of the yawing of small wind turbines to large angles to passively control overshoots in power and loads at higher wind speeds. Of the two, the prediction of the center of thrust location upwind of the center of a yawed rotor disk appears to be the most uncertain and potentially in serious error. This error is due to uncertainties in skewed wake effects on the thrust distribution on the disk. Three skewed wake models are examined to better understand the potential sources of error. First is the dynamic inflow model originally developed for helicopters, and second is a modification of this model developed for wind turbines. Third is an earlier cylindrical vortex wake model which pioneered the study of skewed wake effects for helicopters, and which can be generalized for wind turbine applications. It is concluded that this generalized model and the original dynamic inflow model are the most promising for small wind turbine applications, and their predictions of center of thrust and blade root moments are compared for an idealized rotor. The focus is on static equilibrium loads, and note is taken of the potential importance of accounting for expanding wake effects. The basic results of the study are applicable to large as well as small wind turbine rotors.

scholarly journals Capacity Optimization and Configuration for Household Wind/PV/Storage Hybrid Power Generation System

2020 ◽  
Vol 9 (1) ◽  
pp. 10
Author(s):  
Min Wang
Keyword(s):  
Power Generation ◽  
Renewable Energy ◽  
Wind Turbines ◽  
Unit Cost ◽  
System Capacity ◽  
Design Calculation ◽  
Hybrid Power ◽  
Hybrid Renewable Energy System ◽  
Levelized Cost ◽  
Cost Of Energy

<p align="justify"><strong> </strong>For capacity matching and design calculation on off-grid Hybrid Renewable Energy System, commercial software like Homer developed by the National Renewable Energy Laboratory is commonly used at present. This paper takes the load demand of household users as the research object, and uses the three cities with different potentials of wind and solar resources as the of the Wind/PV/Storage hybrid power generation systems simulation installation site. The Homer optimizes the system capacity configuration, and the goal is to find the minimum investment cost while meeting the users electricity demand. The results show that the potential of the wind and solar resources will affect the levelized cost of energy of the installed system. The levelized cost of energy will be smaller in the place where the wind and solar resources are abundant. At the same time, the unit cost of the wind turbine is higher than that of the Photovoltaic system, so the cost of wind turbines effect is more obvious for the levelized cost of energy of the overall system. Finally, the paper also analyzes the sensitivity of the technical parameters of wind turbines and loss of power supply probability.</p>

Site-Specific Design Optimization of 1.5–2.0 MW Wind Turbines

2001 ◽  
Vol 123 (4) ◽  
pp. 296-303 ◽  
Author(s):  
Peter Fuglsang ◽  
Kenneth Thomsen
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Wind Farm ◽  
Offshore Wind ◽  
Offshore Wind Farm ◽  
Load Prediction ◽  
Specific Design ◽  
Site Specific ◽  
Cost Of Energy ◽  
Fatigue Loads

A method is presented for site-specific design of wind turbines where cost of energy is minimized. A numerical optimization algorithm was used together with an aeroelastic load prediction code and a cost model. The wind climate was modeled in detail including simulated turbulence. Response time series were calculated for relevant load cases, and lifetime equivalent fatigue loads were derived. For the fatigue loads, an intelligent sensitivity analysis was used to reduce computational costs. Extreme loads were derived from statistical response calculations of the Davenport type. A comparison of a 1.5 MW stall regulated wind turbine in normal onshore flat terrain and in an offshore wind farm showed a potential increase in energy production of 28% for the offshore wind farm, but also significant increases in most fatigue loads and in cost of energy. Overall design variables were optimized for both sites. Compared to an onshore optimization, the offshore optimization increased swept area and rated power whereas hub height was reduced. Cost of energy from manufacture and installation for the offshore site was reduced by 10.6% to 4.6¢. This reduction makes offshore wind power competitive compared with today’s onshore wind turbines. The presented study was made for one wind turbine concept only, and many of the involved sub models were based on simplified assumptions. Thus there is a need for further studies of these models.

The unsteady aerodynamics of floating wind turbine under platform pitch motion

2018 ◽  
Vol 232 (8) ◽  
pp. 1019-1036 ◽  
Author(s):  
Xin Shen ◽  
Ping Hu ◽  
Jinge Chen ◽  
Xiaocheng Zhu ◽  
Zhaohui Du
Keyword(s):  
Wind Turbine ◽  
Wind Turbines ◽  
Degrees Of Freedom ◽  
Unsteady Aerodynamics ◽  
Aerodynamic Performance ◽  
Floating Platform ◽  
Pitch Motion ◽  
Floating Wind Turbine ◽  
Fixed Base ◽  
Turbine Rotors

The aerodynamic performance of floating platform wind turbines is much more complex than fixed-base wind turbines because of the flexibility of the floating platform. Due to the extra six degrees-of-freedom of the floating platform, the inflow of the wind turbine rotors is highly influenced by the motions of the floating platform. It is therefore of interest to study the unsteady aerodynamics of the wind turbine rotors involved with the interaction of the floating platform induced motions. In the present work, a lifting surface method with a free wake model is developed for analysis of the unsteady aerodynamics of wind turbines. The aerodynamic performance of the NREL 5 MW floating wind turbine under the prescribed floating platform pitch motion is studied. The unsteady aerodynamic loads, the transient of wind turbine states, and the instability of the wind turbine wakes are discussed in detail.

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