The present invention relates generally to wind turbines and particularly to wind turbine blades. Specific embodiments of the present invention provide systems and methods for constructing a multi-piece large wind turbine blade for optimized quality and transportation, for example.
Wind turbines are generally regarded as an environmentally safe and desirable source of energy. In summary, wind turbines harness the kinetic energy of wind and transform this kinetic energy into electrical energy. Thus, electrical power can be generated in an almost pollution free manner. Often, to maximize the efficacy of power generation and to simplify connection to a power grid, wind turbines are located in proximity to one another in what are generally referred to in the pertinent art as “wind farms.” Advantageously, these wind farms are located in regions having relatively strong winds, such as offshore locations and flat plains, for instance.
To generate electrical power, wind turbines generally include a rotor that supports a number of blades extending radially therefrom. These blades capture the kinetic energy of the wind and, in turn, cause rotational motion of a drive shaft and a rotor of a generator. The electromagnetic relationships between the rotor and the remaining components of the generator facilitate the translation of the kinetic energy of the rotor into electrical energy. In summary, rotation of the rotor induces electrical current in the generator, generating electrical power.
The amount of energy produced by such wind power generation systems is dependent on the ability of the wind turbine to capture wind. As one example, the greater the efficacy of the wind turbine blades the greater the electrical power generated by a given turbine. In designing blades for a wind turbine, it has been found that increasing the length of the turbine blades can increase the power output of the wind turbine.
However, blade designs is presently limited by infrastructure concerns. For example, the maximum length of blades for land-based wind farms is often limited by the size of transportation arteries, such as roads and bridges, because of the difficulty, if not inability, in transporting blades from the production facility to the wind farm. As a particular example, the maximum chord width allowed for transportation of blades through tunnels and under bridges may be limited by the design of such structures. Hence, it may be necessary to reduce the max chord from an optimal length, to meet these transportation and infrastructure requirements.
Furthermore, it is generally desirable to maintain good quality control standards over wind turbine design, particularly when blade lengths are increased. Unfortunately, traditional techniques of fabricating entire wind blades at a single facility may require certain components of the blades to be manufactured at locations local to the wind farm for blade designs that exceed the transportation limits. However, it is typically more difficult for a manufacturer to invest in the infrastructure (e.g. non-destructive inspection equipment, automated manufacturing equipment, etc.) necessary for optimal quality control at such on-site production facilities where only a limited number of blades will be produced.
Accordingly, there exists a need for manufacturing methods and systems to improve quality fabrications as well as transportation requirements of large wind turbine blades.
The present technique accordingly provides a novel approach toward manufacturing a wind turbine blade that obviates the problems discussed above. Briefly, in accordance with one aspect of the present technique, a method of manufacturing a wind turbine blade for installation at a wind farm location includes manufacturing at least one structural component of the wind turbine blade at a first manufacturing facility and manufacturing a skin component of the wind turbine blade at a second manufacturing facility, wherein the second manufacturing facility is closer to the wind farm location than the first manufacturing facility. The method may further include providing the structural and skin components to an assembly location near the wind farm location.
These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein:
The present technique provides a method for constructing a multi-piece wind turbine blade for optimized quality and transportation. The technique involves fabrication of primary structural components of the wind turbine blade at quality suppliers and shipping smaller blade components rather than full blades over long distances for best balance of quality parts and optimal design. Certain embodiments of the present technique are discussed hereinafter with reference to
The wind blades 16 are constructed in multiple pieces at various manufacturing locations. These include a primary component manufacturing facility 22 and one or more secondary component manufacturing facilities 24. An exemplary primary manufacturing facility 22 includes a production site for producing the primary components of the wind blades 16, while the secondary manufacturing facilities 24 include local production sites (i.e. relatively closer to the wind farm 12) for manufacturing secondary components of the wind blades. Primary and secondary components of the wind blades assemblies are discussed further below. Components manufactured in facilities 22 and 24 are shipped to the wind farm location 12 via transportation pathways 26 and 28 respectively. The transportation pathways 26 and 28 may include roadways, railways, or waterways among others. In particular, transportation pathway 26 may also include bridges and tunnels. In one embodiment, primary and secondary components may be released to a freight transportation company to be shipped to the wind farm location 12. Components shipped from the manufacturing facilities 22 and 24 are then assembled near the wind farm location 12 and mounted on the wind turbines 14, as discussed below. In one embodiment, assembly of the wind blade components at the wind farm location is performed by the secondary manufacturer producing the secondary structural components.
In one embodiment, the primary manufacturing facility 22 is a centralized production site that manufactures wind blade primary scomponents for a plurality of wind farms in various geographic locations. The primary manufacturing facility 22 may include automated manufacturing, in-house inspection, and testing facilities, including, for example, both destructive testing facilities and non-destructive testing destructive testing facilities, such as ultra-sound testing facilities. Manufacturing smaller structural components in a centralized production site facilitates easier transportation of these primary structural components to the geographically spaced apart wind farms, while ensuring structural quality and integrity of these components. In certain embodiments, the primary and/or secondary manufacturing facilities may include contracting manufacturers, in which case the wind blade turbine manufacturer is not required to deal with the expense of such manufacturing facilities once the wind farm has been built.
In accordance with embodiments of the present technique, smaller primary components of a wind blade, such as the root and spar caps, are fabricated at the primary manufacturing facility 22. In one embodiment, the primary manufacturing manufacturing facility 22 includes automated fabrication capability as well as non-destructive inspection capability. This facilitates quality and reliability in the primary parts and eliminates low cost testing processes at on site manufacturing facilities, which may compromise the quality of the composite blade structure. Moreover the primary manufacturing facilities may include testing apparatus, facilitating quality testing of primary structural components for various wind farms at a central location. These smaller structural components can be more efficiently packed on trucks or railcars and shipped to an assembly site close to the wind farm 12. Indeed, the structural integrity and quality of these primary components is of concern, as they are load bearing support structure. At the assembly site close to the wind farm 12, lower cost processes can be used to form the large secondary structures. These include vacuum assisted infusion or wet lamination processes on the skin 42 and shear webs to form the airfoil. The shear web 52 may then disposed between the spar caps 48 and 50 and bonded to the skin and spar caps. Shipping the smaller components enables more efficient transportation, especially via bridges and through tunnels and under bridges, which had traditionally restricted the maximum permissible dimensions (W and L) of the wind turbine blades. The present technique obviates the above problem by forming the largest component of the blade 16, i.e. the skin 42 near the wind farms, vitiating the restrictions on max chord to enable optimized airfoil design. Using the presently described on site assembly technique, it may be possible to achieve unlimited blade length and max chord width. For example, the max chord width may vary from about 3.6 meters for a blade of length 50 meters to about 8 meters for a blade of length 100 meters, utilized, for example, in offshore applications.
Keeping
As can be appreciated, the above-described techniques provide higher performance and more consistent quality in the primary structural blade components for improved reliability and lower weight designs. The techniques thus obviate restrictions on optimal airfoil design for most aerodynamic design.
While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.