WO2017092770A1

WO2017092770A1 - Improvements relating to the transport and storage of wind turbine blades

Info

Publication number: WO2017092770A1
Application number: PCT/DK2016/050408
Authority: WO
Inventors: Gunnar K. Storgaard Pedersen; Zhen-zhe CHEN
Original assignee: Vestas Wind Systems A/S
Priority date: 2015-12-04
Filing date: 2016-12-01
Publication date: 2017-06-08

Abstract

A wind turbine blade in a transport configuration, the wind turbine blade comprising at least a first blade section having a root end, a distal end, a leading edge and a trailing edge, and a second blade section having a proximal end, a distal end, a leading edge and a trailing edge, wherein the first blade section and the section blade second are positioned relative to one another such that: the distal end of the second blade section is directed towards the root end of the first blade section, and the proximal end of the second blade section is adjacent to the distal end of the first blade section; and wherein the leading edge of the second blade section is positioned adjacent to the trailing edge of the first blade section, and the trailing edge of the second blade section is positioned adjacent the leading edge of the first blade section. Other aspects relate to a method of configuring a win turbine blade for transportation. By virtue of the aspects of the invention, at least two blade sections may be packed together in a space-efficient manner which reduces the cross sectional envelope of the combined blade package.

Description

IMPROVEMENTS RELATING TO THE TRANSPORT

AND STORAGE OF WIND TURBINE BLADES

TECHNICAL FIELD

The invention relates to the transportation of 'split' or 'multipart' wind turbine blades that comprise at least a root section and a tip section.

BACKGROUND

Recent developments in wind turbine technology have led to wind turbine blades becoming longer in an effort to extract more energy from the flow of wind. Wind turbines blades are known commonly to exceed 60m in length; some even exceed 80m. Whilst longer blades are beneficial for generation efficiency, there are several practical problems associated with blades of such length.

One problem is how to transport such long blades safely to an installation site. Typically blade transportation is by road or rail using specially adapted low loaders or rail cars. However, there are practical limits imposed on blade lengths, largely determined by the curvature of the roads and rails on which they travel. The problem is made worse if the transportation route passes through a built-up area, since roadside and railside clearance may not be sufficient for the blade to be transported along the route, given the bends that must be negotiated. To address this challenge, so-called 'split' blades were developed in which the wind turbine blade comprises at least two main sections; usually a root section and a tip section. The root section and the tip section are fabricated separately and can also be transported separately to an installation site where they can be joined together ready to be installed onto an associated hub of a wind turbine system. The root section and the tip section can also be transported and stored together for ease of handling and to save space.

Approaches to transporting the root section and the tip section together have resulted in transport configurations that are inefficient in terms of utilisation of space which can increase the transportation costs and also exceed transportation constraints. One approach is described in EP2249031A2, in which the tip section of the blade is 'folded' in a flapwise direction so that it lies next to the root section of the blade. EP2249031A2 discloses an apparatus to facilitate transporting and aligning a two piece wind turbine rotor blade including a root piece and a tip piece. The apparatus includes a first portion configured to support a first end portion of the root piece, and a second portion pivotally coupled to the first portion, the second portion configured to support a first end portion of the tip piece. A hinge may pivotally couple second portion to first portion to facilitate pivotal movement of second portion with respect to first portion. More specifically, in one embodiment, second portion is movable with respect to first portion between a first or transport position to facilitate transporting rotor blade and a second or alignment position to facilitate aligning and coupling second piece to first piece to assemble rotor blade. The apparatus may include a third, or tip support, portion configured to support a second or tip end portion of second piece opposing first end portion. Each of said first and second and third portions may include a top wall which may be opened to facilitate blade removal from the apparatus. The apparatus may include a fourth, root support portion.

It is against this background that the invention has been devised. SUMMARY OF THE INVENTION

In one aspect, embodiments of the invention provide a wind turbine blade in a transport configuration, the wind turbine blade comprising at least a first blade section having a root end, a distal end, a leading edge and a trailing edge, and a second blade section having a proximal end, a distal end, a leading edge and a trailing edge, wherein the first blade section and the section blade second are positioned relative to one another such that: the distal end of the second blade section is directed towards the root end of the first blade section, and the proximal end of the second blade section is adjacent to the distal end of the first blade section; and wherein the leading edge of the second blade section is positioned adjacent to the trailing edge of the first blade section, and the trailing edge of the second blade section is positioned adjacent the leading edge of the first blade section. In another aspect, the invention resides in a method of configuring a wind turbine blade for transport, wherein the wind turbine blade is of the multi-part type and comprises at least a first blade section having a root end, a distal end, a leading edge and a trailing edge, and a second blade section having a proximal end, a distal end, a leading edge and a trailing edge, wherein the method comprises: supporting on a support arrangement the first blade section; positioning the second blade section next to the first blade section in a relative position and orientation in which: the distal end of the second blade section is directed towards the root end of the first blade section, and the proximal end of the second blade section is adjacent to the distal end of the first blade section; and wherein the leading edge of the second blade section is adjacent to the trailing edge of the first blade section, and the trailing edge of the second blade section is adjacent the leading edge of the first blade section.

Further aspects of the invention relate to a wind turbine blade in a transport configuration, the wind turbine blade comprising at least a first blade section having a proximal end, a distal end, a leading edge and a trailing edge, and a second blade section having a proximal end, an distal end, a leading edge and a trailing edge, and wherein the distal end of the first blade section is supported in a first support structure, and wherein the proximal end of the second blade section is supported in the first support structure, and also to a method of transporting a multipart wind turbine blade comprising at least a first blade section having a proximal end, a distal end, a leading edge and a trailing edge, and a second blade section having a proximal end, a distal end, a leading edge and a trailing edge, the method including: supporting the distal end of the first blade section in a first support device; and supporting the proximal end of the second blade section in the first support device.

One advantage of the above described aspects, is that at least two blade sections may be packed together in a space-efficient manner which reduces the cross sectional envelope of the combined blade package. This can be appreciated by considering the aero profile of a wind turbine blade. A given chord-wise cross section of a wind turbine blade has the profile of a wing in that it is relatively thick or deep towards the leading edge and gets progressively thin towards the trailing edge, ultimately tapering to a point. In the aspects of the invention, the blade sections are packed together in a 'jackknife' transport configuration in which relatively thick parts of one blade section can be considered to nest with or lie close to the relatively thin part of the other blade section. Although the first and second blade sections may be any spanwise length sections of a blade, in one embodiment the first blade section is a root section. Moreover, the second blade section may be a tip section.

The proximal end of the second blade section and the distal end of the first blade section may be supported in a support device. The support device may include a first supporting structure that supports the distal end of the first blade section within the support device, and a second supporting structure that supports the proximal end of the second blade section. The first supporting structure may be a first insert element mounted on the support device. The second supporting structure may also be a second insert mounted on the support device.

The packed wind turbine blade may also include a separator element positioned between the first support structure and the second support structure to separate adjacent surfaces of the first and second blade sections.

Optionally, a spacer element may be positioned between the first blade section and the second blade section. The spacer element may be positioned at a spanwise location, in particular at an approximate midway position along the spanwise length, between the respective ends of the first and second blade sections.

It should be noted that the term 'wind turbine blade' should not be interpreted to require blade section that together form a complete blade, but rather any two or more sections of a wind turbine blade. Within the scope of this application it is expressly intended that the various aspects, embodiments, examples and alternatives set out in the preceding paragraphs, in the claims and/or in the following description and drawings, and in particular the individual features thereof, may be taken independently or in any combination. That is, all embodiments and/or features of any embodiment can be combined in any way and/or combination, unless such features are incompatible. The applicant reserves the right to change any originally filed claim or file any new claim accordingly, including the right to amend any originally filed claim to depend from and/or incorporate any feature of any other claim although not originally claimed in that manner.

BRIEF DESCRIPTION OF THE DRAWINGS

One or more embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a plan view of a 'single-part' wind turbine blade;

Figure 2 is a plan view of a 'multipart' wind turbine blade having a root section and a tip section;

Figure 3 of a plan view of the multipart wind turbine blade being transitioned into a transport configuration; Figure 4 is a perspective view of the multipart wind turbine blade in Figure 3;

Figures 5, 6 and 7 are various views of the multipart wind turbine blade in Figure 4;

Figure 8 is a view of a support frame configured to support portions of both the root section and the tip section of the multipart wind turbine blade; and

Figures 9a and 9b illustrate an example of a wind turbine blade having a pre-bend being configured in a transportable configuration in accordance with the invention. DETAILED DESCRIPTION Figures 1 and 2 show examples of two different blade configurations. Figure 1 shows a wind turbine blade 2 that comprises a single section. The illustrated wind turbine blade 2 includes a root end 4, a tip end 6, a trailing edge 8 and a leading edge 10. For the purposes of this discussion, the term 'leading edge' would be understood by the skilled person as being the foremost structural edge of the aerofoil section of the wind turbine blade that faces the direction of movement and contacts the air first during normal operation of the wind turbine. Conversely, the 'trailing edge' would be understood as the rearmost structural edge of the aerofoil section of the wind turbine blade where the airflows separated by the leading edge rejoin.

The single section wind turbine blade 2 in Figure 1 is in contrast to a so-called 'multipart' or 'split' wind turbine blade 12 that is shown in Figures 2 and 3. The multipart wind turbine blade 12 may be formed of multiple parts or sections each of a predetermined spanwise length. In the illustrated embodiment, the multipart wind turbine blade 12 comprises two sections: a first section 20 and a second section 22. The first section 20 comprises a blade root and so can be considered the 'root' section, whereas the second section comprises a blade tip and so can be considered the 'tip' section.

The root section 20 comprises a root end 24, a distal end 26, a leading edge 28 and a trailing edge 30. The root end 24 may also be considered a 'proximal end' in the sense that the root end is proximal to where the blade joins the hub of the wind turbine. Similarly, the tip section 22 comprises a proximal end 32, a distal lend 34 which incorporates the blade tip 35, a leading edge 36 and a trailing edge 38. Note that the outer ends 26,32 may also be referred to as tip ends. In the case of the tip section 22, it will be appreciated that the proximal end 32 does not join to the hub, but is nearer to the hub than its distal end 34, in use. The two sections of the multipart wind turbine blade 12 are fabricated separately using known fabrication processes for wind turbine blades, so full details will not be provided here for the sake of brevity. The skilled person will understand that multipart wind turbine blades may have more than two sections, but currently blades with two sections are more usual. Multipart wind turbine blades are useful when wind turbines are required to be installed in hard-to-reach places where the transportation of long single-part blades could be difficult. This could be where the route to the installation site has no option but to go through built-up or urban areas but also through dense forests or woodlands, either by road or rail. Also, rail routes may have maximum permissible cargo widths which impose a limit on the length of the blades that can be transported by rail, given the curvature of the corners along the route. Some port facilities, too, may not be equipped to handle the length of some single-part blades. Multipart blades may be a solution to this since they reduce the length of the blade structures being transported and stored.

However the transport of multipart blades also has its challenges. For example multipart blades increases the number of elongate blade components that must be transported significant distances so it is desirable to package more than one blade section together in a transport configuration. However, this approach increases the cross-sectional envelope of the packaged blade sections which influences the maximum number of such blades that can be transported at any one time, on board a ship for example.

Aspects of the invention aim to address this issue by configuring a multipart wind turbine blade in a transport configuration. The illustrated embodiments make efficient use of space to pack at least two blade sections together in a manner which reduces the cross sectional envelope of the combined blade package.

In a broad sense, embodiments of the invention relate to a multipart wind turbine blade comprising at least first and second blade sections. The two sections are packed together in a transportable configuration in which the distal end of the second blade section is adjacent to or directed towards the root end of the first blade second, and the proximal end of the second blade section is adjacent to the distal end of the first blade section. Moreover, the two blade sections are further configured in such a way that the leading edge of the second blade section is adjacent to the trailing edge of the first blade section, and where the trailing edge of the second blade section is adjacent to the leading edge of the first blade section.

Expressed another way, the second blade section is folded back against the first blade section in the manner of a folding knife or 'jackknife' so that the leading edge of the second or 'tip' blade section is adjacent to the trailing edge of the first 'root' blade section. This configuration is illustrated in Figure 3, which shows the wind turbine blade 12 of Figure 2 in four different positions being transitioned into a transport configuration. Those different positions are labelled 'Α', 'Β', 'C, and 'D' on Figure 3.

For the purposes of this discussion, the first blade section 20 will be referred to as the root section and the second blade section 22 will be referred to as the tip section. Furthermore, at this point it should be appreciated that the term 'adjacent' in this discussion, means that the indicated edge of the second blade section (for example the leading edge) is closer to the other edge of the first blade section (for example the trailing edge) than the other edge of the first blade section (for example the leading edge). However, the term 'adjacent' does not require a close proximity such that those blade edges are touching, for example. So, the term adjacent can be considered to mean that those mentioned edges are neighbouring, next to, close to, near to, next to, by, close by, by the side of, bordering, beside, alongside, abreast of, or proximate to. In this context, the term 'adjacent' may be understood to denote that the respective leading and trailing edges are directed towards or are facing each other when packed in the described transportable configuration. Returning to Figure 3, in position A the first blade section and the second blade section are aligned on a common axis L, which coincides with the longitudinal axes of each of the blade sections. Here, the distal end 26 of the root section 20 and the proximal end 32 of the tip section 22 are opposed to one another. Position A represents a pre- finished position in which the two blade sections 20,22 may be located and oriented relative to one another prior to finishing the blade into a single article ready for installation onto a rotor of a wind turbine. From the position and orientation of the blade sections 20,22 at position A, the two opposing ends 26, 32 may be brought together and joined by a suitable joining procedure. It will be noted that in this position the leading edge 28 of the root section 20 is aligned with or directed towards the leading edge 36 of the tip section 22. Likewise, the trailing edge 30 of the root section 20 is aligned with or directed towards the trailing edge 38 of the tip section 22.

Positions B and C illustrate the multipart blade 12 being moved from position A into the transport configuration as shown by position D. The series of positions demonstrate clearly the end position D but, in reality, it should be noted that the two blade sections may simply be configured into position D without transitioning through A-C. Also, note that the arrows are merely indicative and should not be considered to limit the blade to being folding in any particular way. With this in mind, in positions B and C the tip section 22 of the blade 12 is shown as being folded back towards the root section 20 in the manner of a folding knife or jacknife. As can be seen, the tip section 22 moves angularly, whilst still in the same plane as the root section 20, so that its leading edge 36 moves out of alignment with the leading edge 28 of the root section 20 and moves towards it in an arc.

Position D shows the multipart blade 12 in a transport configuration, and it should be noted that the tip section 22 is shown in dashed lines so as not to obscure the root section 20 below it. Here, the tip section 22 has been folded back fully against the root section 20 so that the two blade sections 20,22 are configured in such a way that the leading edge 36 of the tip section 22 is adjacent to the trailing edge 30 of the root section 20, and the trailing edge 38 of the tip section 22 is adjacent to the leading edge 28 of the root section 20.

A benefit of this configuration can be appreciated by considering the aero profile of a wind turbine blade. A given chord-wise cross section of a wind turbine blade has the profile of a wing in that it is relatively thick or deep towards the leading edge and gets progressively thin towards the trailing edge, ultimately tapering to a point. In the 'jackknife' transport configuration as described above with reference to Figure 3, the relatively thick part of one blade section can be considered to 'nestle' or lie close to the relatively thin part of the other blade section.

This advantageous aspect of the invention is especially apparent in Figure 4 in which the relative position and orientation of the distal end 26 of the root section 20 and the proximal end 32 of the tip section 22 can be seen next to one another. As can be seen, the relatively thick part of the distal end 26 of the root section 20, as is marked as X1 on Figure 4, is adjacent the relatively thin, tapering part of the tip section 200, as is marked as X2 on Figure 4. Conversely, the relatively thick part of the proximal end 32 of the tip section 22, as is marked as X3 on Figure 4, is adjacent the relatively thin tapering part of the distal end 26 of the root section, as is marked by X4. In a sense, therefore, the two blade sections 20, 22 can be considered to be adjacent or next to one another, but arranged in a mutually inverted orientation about their longitudinal axes, that is to say approximately 180 angularly offset from each other. Note, however, that the inverted configuration as shown in the illustrated embodiment should not be interpreted to require the first blade section and the second blade section to be inverted strictly by 180 degrees and a broader range is considered acceptable.

Figure 4 also illustrates how the blade sections 20,22 may be supported. The root end 24 of the root section 20 may be supported in a first support device 40. Such a support device may be in the form of a frame including cradle. The cradle may be fixed or removable from the frame. The cradle may be comprised of insert elements or, 'inserts'. The cradle, or inserts, may be configured for supporting more than one blade section or element. The frame may comprise frame members, structural elements or struts which may extending in a spanwise direction and a lateral or transverse direction. The struts may together define a frame volume in the shape of a rectangular prism. The frame struts may be configured so that the frame is stackable with identical or similar frames. More than one such frame may therefore be stacked on top or and/or next to other frames during storage or shipping. Optionally, the orthogonal dimensions, i.e. the height and transverse width, of the frame may be equal. Optionally, a suitable frame may extend only in a height and lateral/transverse extent. That is to say, the frame may be defined by struts extending in vertical and lateral directions only, and may not have any struts imparting an appreciable depth to the frame, in the manner of a picture frame. So, the frame may optionally be a planar structure and so be '2-dimensionar rather than '3-dimensionar. The adjacent ends 26,32 of the root section 20 and the tip section 22 are supported by a second support device 42. The second support device 42 may be adapted to support both the distal end 26 of the root section 20 and the proximal end 32 of the tip section 22 in suitable respective positions and orientations. As with the first support device 40 described above, the second support device 42 may comprise a frame and cradle combination. Similarly, the frame may comprise struts which together make up a 3- dimensional rectangle, that is to say a rectangular prism, although other geometric profiles would be apparent to the skilled person. A fixed or removable cradle may thereby be supported within the frame. A cradle may be configured from one or more inserts and may thereby support more than one blade section or element. Each of the first and second support devices 40,42 may be stackable. Each may include suitable adaptations (not shown) to enable them to be locked down onto a transport vehicle, for example a low loader of the truck or rail car, or a deck of a ship. Figure 8 shows in more detail an embodiment of the second support device 42. As can be seen, the support device 42 may include a cradle that is configured to receive and support adjacent ends of the root and tip sections 20,22 of the blade 12. The illustrated device includes an outer frame 44 into which may be fitted first and second support structures or 'inserts' 46, 48 for each of the blade sections 20,22. The outer frame 44 may be configured to be openable to permit the inserts 46,48 to be positioned within it.

The outer frame 44 may be generally cuboid in form, including more specifically a rectangular cuboid or prism, as is shown here, as to be defined by an open box-like structure of suitable frame members 50 which may be of sufficient strength to support the mass of the blade sections 20,22. Steel frame members would be appropriate, for example. In particular, cradle elements configured to receive and support adjacent ends of the root and tip sections 20,22 of the blade 12 may be comprised fully within a single frame 44 of support device 42. Each of the inserts 46,48 may be shaped to conform to, and therefore support, a respective end of each of the root and tip blade sections 20,22. In the illustrated embodiment, the first insert 46 is shaped and oriented within the outer frame 44 so support the distal end 26 of the root section 20 of the blade 12, whereas the second insert 48 is shaped and oriented in the outer frame 44 so as to support the proximal end 32 of the tip section 22 of the blade 12.

Each of the inserts 46,48 may have the same basic form, and so only the first insert member 46 will be described here for brevity. According to the illustrated embodiment, the first insert member 46 may comprise first and second plate-like elements 60,62 that are substantially identical in shape and spaced apart in parallel to one another. Each of the plate elements 60,62 may be joined by a plurality supporting rods or rungs 63 that are shown extending between the parallel plates 60,62 and may be fixed thereto. The plates 60,62 can provide the support device 60 with a profiled structure on which may be supported a support surface 64. The support surface 64 may be shaped to conform to the aerofoil profile of its respective blade section. In the illustrated embodiment, the support surface 64 defines a curvature that substantially matches a suction side surface of the root section 20 of the blade 12. The support surface 64 may be cushioned to provide protection for the blade surface with which it engages. Cushioning may be provided by a suitable rubber or high density foam layer, for example.

The illustrated second insert member 46 is similar in form to the first insert member 46 but is located in an inverted orientation within the outer frame 44 that corresponds to the relative inverted positions of the distal end 26 of the root section 20 and the proximal end 32 of the tip section 22, as is shown in Figure 4. Accordingly, its support surface 64 may preferably be shaped to substantially match the shape of the suction side surface near to the proximal end 32 of the tip section 22 of the blade 12.

In the illustrated embodiment, the support surfaces 64 of the inserts 46,48 are shaped to extend about approximately half of the aerofoil section of a blade. In order to provide further protection for the blade sections 20,22 that are supported by the inserts 46,48 a separator element 66 may be provided between the inserts 46,48. The separator element 66 may be located between the opposed surfaces of the blade sections 20,22 and spaces apart the two blade sections 20,22 when they are held in the outer frame 44. It may thereby provide protection to the relatively delicate blade surfaces. The separator element 66 may be formed of a cushioning material such as a foam block, or an air-filled bag or bladder, for example.

Alternative embodiments are envisaged in which the inserts 46,48 are configured so that each insert extends about its respective blade section. Each insert 46,48 may be openable, for example in the manner of a clamshell, to enable the blade section to be received in it and clamped in place.

Since the protection element is located between the blade sections 20,22, outer surfaces 68 of the separator element 66 are shaped to conform to the pressure side surfaces of the root section 20 and the tip section 22.

It will be appreciated from the above discussion that the second support device 42 holds the distal end 26 of the root section 20 and the proximal end 32 of the tip section 22. However, in the illustrated embodiment the distal end 34 of the tip section 22 is not supported by the first support device 40. In order to provide some support to the free end of the of the tip section 22, a spacer element 70 may be positioned in a mid-region between the ends of each of the blade sections. The spacer element 70 is shown in Figures 3 to 7.

The spacer element 70 may be a profiled block of cushioning material, such as structural foam, or may also be an inflatable device such as a bag. An inflatable device may provide greater flexibility of where the spacer element 70 can be positioned along the spanwise length of the blade sections 20,22.

The skilled person will understand that the specific embodiments of aspects of the invention may be modified without departing from the scope of the invention as defined by the claims. For example, in the above embodiments, the illustrated support device 42 is explained as including insert elements or inserts for positioning, supporting and constraining movement of the blades within the support frame. However, alternative embodiments are envisaged where a strap system is used to position and constrain movement of the blades instead of inserts.

It has been explained above that the aspects of the invention relate to a multipart wind turbine blade in a space-efficient configuration that is suitable for transport and storage by packing at least two blade sections or elements together in a 'nested' manner which reduces the cross sectional envelope of the combined blade package.

Aspects of the invention may be particularly useful in transporting so-called 'pre-bent' blades. The skilled person would understand a pre-bent blade to be one which is fabricated so that the blade curves flapwise towards its tip end in a windward direction. Pre-bent blade designs have become attractive in connection with longer wind turbine blades in order to mitigate the large tip displacements that are experienced during blade flap movements and thus guard against blade tower impacts. As is known, pre- bent blades may have a curvature such that the tip end of the blade is offset around 4 metres or more in the windward direction from the longitudinal axis of the blade. Figure 9a illustrates schematically two multipart wind turbines blades for the purposes of comparison. A first wind turbine blade 100 does not have a pre-bend whereas a second wind turbine blade 1 02 does have a pre-bend. Note that each of the wind turbine blades 1 00, 102 is shown in a finished configuration in the same way as the wind turbine blade 1 2 shown in Figure 2. However, it should be appreciated that each of the wind turbine blades 1 00, 102 in Figure 9a is a multipart design and so includes first and second sections, each of which includes respective proximal ends and distal ends. In the following discussion, for consistency with the above discussion of the wind turbine blade 1 2 in Figures 2 to 7, the same reference numerals will be used to refer to the proximal and distal ends of the root and tip sections of the wind turbine blade as described above. However, the respective features of the first wind turbine blade 100 will be indicated with a prime symbol (') and the respective features of the second wind turbine blade 1 02 will be indicated with a double prime symbol ("). In Figure 9a, both of the wind turbine blades 1 00, 1 02 are viewed from the side, that is to say from the direction of their leading or trailing edges. Accordingly, as can be seen the second blade 1 02 curves gradually along its length so that its tip end 34" is offset by a distance D in the windward direction from the longitudinal axis L2. This is to be contrasted with the tip end 34' of the first blade 1 00 which lies generally on the longitudinal axis L1 of the blade 100. It may be noted that the respective root sections 20' and 20" of both the first and second wind turbine blades 100, 102 are substantially identical and that the pre-bend is carried in the tip section 22" of the second wind turbine blade 1 02. Turning to Figure 9b, this diagram illustrates the relative position of parts of the second wind turbine blade 102 in Figure 9a when configured in a transportable configuration in the manner described above with reference to Figures 3 to 7. Figure 9b illustrates the cross sectional profile or envelope of a support frame 1 1 0 and how the blade sections 20",22" fit inside that profile.

The root section 20" of the wind turbine blade 102 can be seen supported in the lower portion of the support frame 1 1 0. The root end 24" is depicted as a large circle and the distal end 26" is shown by the smaller of the two concentric aerofoil cross sections. The larger of the aerofoil sections, marked as 1 1 2, illustrates the largest aerofoil section of the root section 20" of the wind turbine blade 1 02, for example as indicated by L3 on Figure 9a. The proximal end 32" of the tip section 22" of the wind turbine blade 102 is illustrated by the inverted aerofoil cross section next to the two concentric aerofoil cross sections 1 1 2,24". Notably, the distal end 34" (i.e. the tip of the blade) of the tip section 22" is laterally displaced from the proximal end 32" and is shown in the upper right quadrant of the support frame 1 10, in the orientation of the figure. This reflects the fact that the tip section 22" has a pre-bend in that direction. The position of the distal end 34" of the second wind turbine blade 102 should be compared with the theoretical position of the distal end 34' of the first wind turbine blade 100, which can be seen on Figure 9 by the aerofoil section highlighted in dashed lines.

What is particularly noticeable in Figure 9b is that the multipart wind turbine blade 1 02, having a pre-bent profile, is still able to be packed into a transportable configuration in which the tip 34" of the wind turbine blade 1 02 does not extend beyond the outer profile of the support frame 1 1 0. This is because the way in which the root section 20" and the tip section 22" of the blade are located next to each other in a jackknife configuration in which the two blade sections 20", 22" are inverted relative to one another, such that the blade sections are, in effect, able to nest against one another which provides a more compact arrangement. What's more, the dimensions of the support frame 1 10 need be no larger for transporting a pre-blade as compared to a support frame for transporting a blade with no pre-bend. This is particularly useful since it means that different types of blades can be stored together using support frames of a standard size.

Claims

1 . A wind turbine blade in a transport configuration, the wind turbine blade comprising at least a first blade section having a proximal end, a distal end, a leading edge and a trailing edge, and a second blade section having a proximal end, an distal end, a leading edge and a trailing edge, wherein the first blade section and the section blade second are positioned relative to one another such that: the distal end of the second blade section is directed towards to the proximal end of the first blade section, and the proximal end of the second blade section is adjacent to the distal end of the first blade section; and wherein the leading edge of the second blade section is positioned adjacent to the trailing edge of the first blade section, and the trailing edge of the second blade section is positioned adjacent to the leading edge of the first blade section.

2. The wind turbine blade of claim 1 , wherein the first blade section is a root section.

3. The wind turbine blade of claims 1 or 2, wherein the second blade section is a tip section.

4. The wind turbine blade of any preceding claim, wherein the proximal end of the second blade section and the distal end of the first blade section are supported in a first support device.

5. The wind turbine blade of claim 4, wherein the first support device includes a first supporting structure that supports the distal end of the first blade section within the support frame, and a second supporting structure that supports the proximal end of the second blade section.

6. The wind turbine blade of claim 5, wherein the first supporting structure is a first insert element mounted on the support device, and wherein the second supporting structure is a second insert element mounted on the support device.

7. The wind turbine blade of claims 5 or 6, including a separator element positioned between the first support structure and the second support structure to separate adjacent surfaces of the first and second blade sections.

8. The wind turbine blade of any preceding claim, including a spacer element positioned between the first blade section and the second blade section.

9. The wind turbine blade of claim 8, wherein the spacer element is positioned at a spanwise location between the respective ends of the first and second blade section.

10. The wind turbine blade of claim 9, wherein the spacer element is positioned approximately midway along the spanwise length of the first or second blade sections.

1 1 . The wind turbine blade of any preceding claim, wherein the wind turbine blade has a pre-bent profile.

12. A method of configuring a wind turbine blade for transport, wherein the wind turbine blade is of the multipart type and comprises at least a first blade section having a proximal end, a distal end, a leading edge and a trailing edge, and a second blade section having a proximal end, a distal end, a leading edge and a trailing edge, wherein the method comprises: supporting on a first support device the first blade section; positioning the second blade section next to the first blade section in a relative position and orientation in which: the distal end of the second blade section is directed towards the proximal end of the first blade section, and the proximal end of the second blade section is adjacent to the distal end of the first blade section; and wherein the leading edge of the second blade section is positioned adjacent to the trailing edge of the first blade section, and the trailing edge of the second blade section is positioned adjacent to the leading edge of the first blade section.

13. The method of claim 12, including supporting the distal end of the first blade section in the first support device and supporting the proximal end of the first blade section in a second support device.

14. The method of claim 13, including supporting the proximal end of the second blade section in the first support device.

15. The method of claim 14, including engaging the distal end of the first blade section with a first support structure and engaging the proximal end of the second blade section in a second support structure, both support structures being received by the first support device.

16. The method of claim 15, further including positioning a separator element between the first support structure and the second support structure to separate adjacent surfaces of the first and second blade sections.

17. The method of claims 12 to 16, further including positioning a spacer element between the first blade section and the second blade section at a predetermined spanwise station with respect to said first and second blade sections.

18. The method of claims 12 to 17, wherein the wind turbine blade has a pre-bent profile.

19. A method of transporting a multipart wind turbine blade comprising at least a first blade section having a proximal end, a distal end, a leading edge and a trailing edge, and a second blade section having a proximal end, a distal end, a leading edge and a trailing edge, the method including: supporting the distal end of the first blade section in a first support device; and supporting the proximal end of the second blade section in the first support device.

20. The method of claim 19, including supporting the proximal end of the first blade section in a second support device.

21 . The method of claim 19 or 20, wherein the first blade section is positioned and oriented relative to the second blade section so that it is inverted about its longitudinal axis with respect to the second blade section.

22. The method of any claim 19 to 21 , wherein the distal end of the second blade section is directed towards to the proximal end of the first blade section, and the proximal end of the second blade section is adjacent to the distal end of the first blade section, and wherein the leading edge of the second blade section is positioned adjacent to the trailing edge of the first blade section, and the trailing edge of the second blade section is positioned adjacent to the leading edge of the first blade section.

23. The method of any claim 19 to 20, wherein the wind turbine blade is a pre-bent wind turbine blade.

24. A wind turbine blade in a transport configuration, the wind turbine blade comprising at least a first blade section having a proximal end, a distal end, a leading edge and a trailing edge, and a second blade section having a proximal end, a distal end, a leading edge and a trailing edge, and wherein the distal end of the first blade section is supported in a first support device, and wherein the proximal end of the second blade section is supported in the first support device.

25. The wind turbine blade of claim 24, wherein the proximal end of the first blade section is supported in a second support device.

26. The wind turbine blade of claim 24 or 25, wherein the first blade section is positioned and oriented relative to the second blade section so that it is inverted about its longitudinal axis with respect to the second blade section.

27. The wind turbine blade of any claim 24 to 26, wherein the distal end of the second blade section is directed towards to the proximal end of the first blade section, and the proximal end of the second blade section is adjacent to the distal end of the first blade section, and wherein the leading edge of the second blade section is positioned adjacent to the trailing edge of the first blade section, and the trailing edge of the second blade section is positioned adjacent to the leading edge of the first blade section.