Covering for wind turbine access

Abstract

An apparatus for providing a temporary protective barrier from falling debris above an access door 108 of a wind turbine tower, the apparatus comprising a first panel 202 having an arcuate abutment su

Description

FIELD OF THE INVENTION The present invention relates to an apparatus which provides a temporary protective covering for a wind turbine access door. Specifically, the apparatus may comprise a series of panels which are used to provide a protective covering for a wind turbine access door, which allow for personnel to exit a vehicle and access the wind turbine, whilst being continually protected from falling ice or snow. BACKGROUND OF THE INVENTION Wind turbines are a common renewable energy generating method, due to their high efficiency and ability to run throughout the day and night. Furthermore, wind turbines produce electricity at one of the cheapest rates for renewable energy sources. Wind turbines generate electricity by converting the kinetic energy from the wind into kinetic energy within the turbine, which drives a generator, thus creating electricity. Wind turbines can be found all over the world, from the deserts to the mountains, and from dry, hot landscapes to cold, wet landscapes. The two main types of wind turbines are horizontal axis wind turbines (HAWT), and vertical axis wind turbines (VAWT). The axis referred to indicates the axis of rotation of the blades. Horizontal axis wind turbines make up the overwhelming majority in production today. Although this application will refer mainly to HAWT, the invention as described may easily be applied to VAWT. The main components of a HAWT are blades, a tower, a gearbox, a rotor shaft, and a generator connected to the rotor shaft. The majority of large production HAWTs comprise 3 blades which are attached to the large tower. The wind causes the blades to rotate due to their aerodynamic shape. The rotation of the blades causes the rotor shaft inside the turbine to rotate, which then rotates inside the generator. The generator then generates electricity, through the rotation of the rotor inside the generator. Wind turbines can generate energy up to 98% of the time. However this is when the wind turbines are maintained well. Wind turbines need regular maintenance and servicing to ensure they are reliable and available. Wind turbines are maintained by trained technicians, who need to access the inside of the tower to service critical components such as bearings, gears, and electrical components. Wind turbines are usually accessed via door in the tower which is located near the ground. Wind turbines may be located in countries where snow and ice can accumulate on the ground surrounding the wind turbines. This causes access issues on any roads or tracks which lead to the wind turbines. Ordinarily, machines such as snowploughs or telehandlers equipped with special attachments are used to clear snow from the roads and tracks leading to wind turbines. This allows personnel to reach the vicinity of the wind turbine. When wind turbines are located in areas where snow and ice exist, ice can accrue on the blades of the wind turbine and on the tower. This causes many issues. Firstly, if ice accrues on the blades, the efficiency of the wind turbine due to aerodynamic factors. A second issue, if ice accrues either on the blades or the tower, is that it can present a hazard to personnel who need to access the wind turbine for maintenance purposes. Ice may accrue above any access doors, and present a falling hazard. If any ice were to fall from the tower when a person was accessing the door, they could be severely injured. Ice sheets which accumulate on the tower may weigh up to 100kgs on large wind turbine towers. Further to this, if ice accrues on the blades of the wind turbine, then this may present a hazard to personnel who are accessing the tower door if the ice were to shear from the blades as they are rotating. This may cause a large chunk of ice to fall on top of the personnel who is accessing the tower. Ice accruing on wind turbines therefore presents a serious health and safety risk to personnel on the ground who seek to access the interior of the wind turbine, due to the risk of ice chunks / pieces falling on top of them. As the vast majority of wind turbine access doors do not contain any form of covering, porch, or roof, the technicians who need to maintain the wind turbines when there is ice on the tower on the blades cannot access the wind turbines safely when ice is present. The wind turbine may not be functioning due to a technical fault, however technicians are not allowed to access the wind turbines due to health and safety regulations, when ice is present on the blades or tower. This issue can cause the owners of wind turbines to lose out in the production of electricity, as their technicians cannot access the inside of the wind turbines. This results in sites in snowy / icy areas to have many wind turbines offline for prolonged periods. This is extremely costly, as the dense winter air and higher wind speeds in the winter can often mean that they are the months which can produce the most amount of wind power. For the above reasons, there remains a need to address or mitigate at least one or more of the aforementioned problems. A solution is therefore required, which will allow personnel to access the interior of a wind turbine when snow or ice has accumulated on the tower or blades of the wind turbine. It is therefore an object of at least one aspect of the present invention to provide an improved apparatus and method for allowing personnel to access the inside of a wind turbine whilst there is snow or ice present on the tower or the blades of the wind turbine. A solution to the above-mentioned problems is required. SUMMARY OF THE INVENTION According to an aspect of the present invention, there is provided an apparatus for providing a temporary protective barrier from falling debris above an access door on a tower of a wind turbine, the apparatus comprising: a first panel, the first panel being shaped for abutting a tower of a wind turbine above an access door, the first panel comprising an arcuate abutment surface; and attachment means, for attaching the apparatus to a vehicle. The apparatus may have a transport configuration and a deployed configuration; wherein when in the transport configuration, the first panel is located generally proximate to the attachment means, and wherein when in the deployed configuration the first panel may be movable away from the attachment means to abut the tower to provide a protective barrier above the access door. The transport configuration may allow the apparatus to be transported between each wind turbine being serviced. The apparatus may further comprise a second panel, which when in the transport configuration is located generally above the attachment means, and when in the deployed configuration the second panel may be located between the first panel and the attachment means, thus providing a protective barrier from falling debris between a vehicle and the first panel. The second panel may be articulated and may also be telescopic. There may be telescopic aspects to the second panel, such as having the frame being telescopically extendable. The apparatus may have a longitudinal plane and a lateral plane, wherein when the apparatus is attached to a vehicle, the vehicle having a longitudinal plane and a lateral plane, the longitudinal planes of the apparatus and the vehicle are generally aligned. The longitudinal plane may generally run along the length of the vehicle, and the lateral plane may generally run along the width of the vehicle. The second panel may be extendable telescopically away from the vehicle, generally along the longitudinal plane of the apparatus. The second panel may extend away from the vehicle in any plane, suitable for the application. The first panel may be movable about three perpendicular axes of rotation to ensure effective mating between the arcuate abutment surface and the tower. The first panel may be movable via the existing structure of the vehicle the apparatus is attached to. For example, existing telehandlers can already rotate their attachments (buckets / pallet forks etc.) about the horizontal plane. The apparatus may comprise means to allow it to rotate about the vertical plane, such as a hydraulic circuit for example. The first panel may comprise a first panel attachment means, for attaching the first panel to a vehicle independently from the rest of the apparatus. This may allow for the first panel to use the existing features / advantages of the vehicle. This may allow the apparatus to use existing features such as hydraulic circuits etc. The apparatus may further comprise a third panel, and wherein when the apparatus is in the deployed configuration, the third panel may be extendable from the apparatus generally along the lateral plane of the apparatus. The third panel may also extend away from the apparatus in any suitable direction, depending on the orientation of the apparatus. When in the deployed configuration, the third panel may provide a protective barrier from falling debris between a vehicle and the third panel. The protection may be provided by a telescopic element. The protection may also be provided by a flexible sheet, such as a plastics or rubber material. When in the transport configuration, the second panel may be generally located either above or below the third panel. In the transport configuration, the panels may be located on top of one another. When in the transport configuration, the panels may create a smaller footprint over the ground than when in the deployed condition. The vehicle may comprise a telescopically extendable boom, and the apparatus may be attached to the telescopically extendable boom to enable the extension of the first and second panels. This saves the apparatus from having the hydraulic (or otherwise) circuits to control the apparatus. The apparatus can save weight and complexity, by using the existing infrastructure of the vehicle. When in the deployed configuration, the panels may provide a protective barrier from falling debris, and may create a walkway for personnel to access a wind turbine tower from the apparatus. The walkway may be generally the ‘footprint’ which the panels create. The walkway may also be suitable for parking a car or a van underneath. This may allow personnel to drive under the apparatus, when in the deployed configuration, to access the wind turbine in safety. The apparatus may have an increased footprint over the ground when in the deployed configuration, than when in the transport configuration. The invention may also be described as a method of forming a temporary protective barrier from falling debris above an access door on a tower of a wind turbine, the method comprising the following steps: providing an apparatus according to any preceding claim; moving a vehicle which the apparatus is attached to towards a wind turbine; moving the panels of the apparatus into the deployed configuration; extending the first panel to abut the wind turbine above the access door, thus providing a protective barrier for personnel access. The method may also comprise the step of: adjusting the angle of the first panel about any or all of the three axes of rotation, to ensure an effective mating between the arcuate abutment surface and the tower. Effective mating is critical to ensure that debris cannot land on personnel underneath the panels of the apparatus. The method may also comprise the step of: extending the third panel, thus enabling a personnel transporter to park underneath the third panel, thereby creating a safe walkway from the personnel vehicle to the access door of the wind turbine. The invention may also be described as a method of providing a transportable apparatus to temporarily cover the access door on a tower of a wind turbine. The method may be used on the system as previously described. BRIEF DESCRIPTION OF THE DRAWINGS Embodiments of the present invention will now be described, by way of example only, with reference to the following figures: Figure 1 is an image of a typical horizonal axis wind turbine (HAWT); Figure 2 is an image of a typical access door and spiral staircase to a HAWT; Figure 3 shows an embodiment of the present invention, viewed from the offside of the vehicle; Figure 4 shows an embodiment of the present invention, viewed from the rear offside of the vehicle; Figure 5 shows an embodiment of the present invention, viewed from above the offside of the vehicle; Figure 6 shows an embodiment of the present invention, viewed from the offside front of the vehicle; Figure 7 shows an embodiment of the present invention, viewed from the nearside rear of the vehicle; Figure 8 shows an embodiment of the present invention, viewed from above the nearside of the vehicle; Figure 9 shows an embodiment of the present invention, viewed from the nearside front of the vehicle; and Figure 10 shows a plan view of an embodiment of the invention, focussing on how the first panel interacts with the tower. DETAILED DESCRIPTION Generally speaking, the present invention relates to an apparatus for providing a temporary protective barrier over an access door of a wind turbine. Figure 1 is an image of a typical horizonal axis wind turbine (HAWT) 100. A typical HAWT 100 comprises a tower 102, blades 104, and a nacelle 106. The nacelle 106 typically houses the gearbox, drive shafts, and generator. Figure 2 is an image of a typical access door 108 and spiral staircase 110 to a HAWT 100. Access doors 108 are ordinarily elevated from the ground because ordinarily, there is a heavy transformer at the base of the tower 102. This transformer may fill up the first few meters of height inside the wind turbine tower 102, thus requiring a staircase 110 to allow personnel to access the interior of the tower 102. Staircases to access doors 108 are either orientated straight from the tower 102 of the wind turbine 100, or spiral 110 as in Figure 2. One of the advantages of a spiral staircase 110 is that there is a smaller footprint of the wind turbine, and they are generally stronger than straight staircases, since they can be fixed to the tower 102 at various points. Although spiral staircases 110 will be described herein, the invention may also be used to work with a wind turbine with a straight staircase. Furthermore, the invention may also be used with a vertical axis wind turbine (VAWT), which has an access door. Figure 2 also shows some ice 112 build up above the access door 108. A small amount of ice is shown here as an illustrative example, however ice build up can be more severe than this. As shown, the ice 112 is directly above the access door 108. If the wind turbine 100 needed maintenance, a maintenance technician would need to access the tower 102 via the access door 108. If the ice 112 sheet were to come away from the tower 102 whilst the technician was entering the tower 102, it could cause serious harm and damage to the technician. As such, wind turbines with ice build-up on the wind turbine are often closed for maintenance whilst there is ice present. In locations such as the North of Scotland, ice 112 may remain on the towers for weeks at a time. This means a wind turbine 100 may be inaccessible for weeks. If the turbine 100 needs maintenance, this could result in the turbine 100 not producing any energy for weeks at a time. The problem is compounded when considering that the winter months are the most productive for wind farms, due to the dense cold air, and due to the increased average wind speeds. It is for these reasons that the invention has been developed. Ice 112 may also build up on the nacelle 106 or the blades 104, however these can often be yawed into the sunlight to help melt the snow / ice 112. This cannot be done with towers 102, as the majority of towers 102 cannot rotate. Furthermore, the resulting ice which may fall from the blades 104 or nacelle 106 is also a danger. If the blades 104 are moving, the ice 112 could land far from the tower 102, and could cause serious damage. The invention therefore seeks to provide a safe access route for wind turbine technicians to access the tower 102 of the turbine 100. In some embodiments, a safe access route is provided from the technician’s vehicle to the access door 108. The invention will now be described in relation to Figures 3-10. Although only one embodiment is shown, it will be apparent to the skilled person that the invention covers more than the specific embodiment shown. The apparatus 200 is shown in a partial transport configuration in all of the figures, apart from Figure 10, where the apparatus 200 is in the deployed configuration, and the first panel 202 is abutted against a tower 102. Figure 3 shows an embodiment of the present invention, viewed from the offside of the vehicle 300. Figure 4 shows an embodiment of the present invention, viewed from the rear offside of the vehicle 300. Figure 5 shows an embodiment of the present invention, viewed from above the offside of the vehicle 300. Figure 6 shows an embodiment of the present invention, viewed from the offside front of the vehicle 300. Figure 7 shows an embodiment of the present invention, viewed from the nearside rear of the vehicle 300. Figure 8 shows an embodiment of the present invention, viewed from above the nearside of the vehicle 300; and Figure 9 shows an embodiment of the present invention, viewed from the nearside front of the vehicle 300. In each of the Figures, the apparatus 200 is shown attached to a vehicle 300. In this particular embodiment, the vehicle 300 is a telehandler. However, the vehicle can be any suitable vehicle which can be moved around a wind turbine site. Specifically, the vehicle should be able to move from one wind turbine to another wind turbine. The vehicle must also preferably have a means of moving the apparatus 200. The vehicle 300 may be a tracked or wheeled vehicle. The vehicle may be an excavator, or any vehicle with a lifting arm arrangement, such as a forklift, a tractor, or a loader. A telehandler vehicle 300 is a preferred embodiment, as it has the ability to lift heavy loads at a distance. Furthermore, modern telehandlers are built with the safety features which are on mobile cranes. These features include load sensing, hydraulic check valves and electro hydraulic isolations. The telescopic booms are designed to lift and move many tons. The apparatus is designed to be capable of moving 4000kgs. The additional roof guarding and pivoting apron weights are less than half the machines’ lift capacity. Another benefit of attaching the apparatus 200 to a telehandler is that they are 4 wheel drive and designed for difficult terrain like the vehicles we already use on site to clear the snow. This means the apparatus 200 is well suited to be retrofitted to existing site machinery. The apparatus 200 is for providing a temporary protective barrier from falling debris above an access door 108 of a wind turbine 100. In the Figures, the apparatus 200 comprises a first panel 202. The first panel 202 is the one of the panels of the apparatus 200. The first panel 202 is shaped for abutting a tower 102 of a wind turbine 100 above an access door 108. As shown in the Figures, the first panel 202 comprises an arcuate abutment surface 204. The arcuate abutment surface 204 is arcuate shaped to suit the generally cylindrical shape of a tower 102 on a typical wind turbine 100. The arcuate abutment surface 204 ensures effective mating between the apparatus 200 and the wind turbine 100. Furthermore, the wind turbine 100 has a circular staircase 110 as shown in the Figures, then the arcuate abutment surface 204 further protects the area above the staircase. This is clearly show in Figure 10. The arcuate abutment surface 204 may comprise a softer material such as rubber or plastic, to ensure no damage is caused by the first panel 202, and to ensure a good seal between the arcuate abutment surface 204 and the wind turbine 100. The apparatus 200 also comprises attachment means 206, for attaching the apparatus to a vehicle 300. In the example shown, the attachment means 206 is located on the boom of the vehicle 300. The apparatus 200 should be attached to the vehicle 300 in such a way to allow the panel(s) to extend away from the vehicle in a smooth and effective manner. The attachment means 206 may be fixings such as bolts or screws, or a clamping arrangement. Alternatively, the attachment means may use welds to attach the apparatus 200 onto the vehicle 300. The apparatus 200 may also comprise a first panel attachment means 208. This is shown in the example in the Figures, and is used to independently control the first panel 202. The first panel 202 may be extended and retracted, as it is attached to the front loader attachment in the figures. The normal functioning of the vehicle can therefore raise and lower the first panel 202, move the first panel 202 away from and towards the vehicle, and rotate the first panel 202 about the horizontal axis. The first panel attachment means 208 is also shown to be cylindrical in the Figures. This allows the first panel 202 to be rotated about the vertical axis. This may be achieved via any suitable means, such as a piston / shaft assembly. The first panel attachment means 208 may be a cylindrical shaft on a roller bearing arrangement, and the shaft may be rotated via a geared assembly for example. The first panel attachment means 208 may comprise a central king pin and one or two rams pushing and pulling it around simultaneously. These rams would be propelled from hydraulics on the telehandler vehicle’s 300 3rd service hydraulic line. Another option to rotate the first panel 202 is that the first panel attachment means 208 comprises a large gear ring around it (approx, diameter 600 - 1000 mm) and the fixed part on the telehandler vehicle 300 would have a small hydraulic motor fixed to it powered from the telehandlers 3rd service hydraulic line (a similar design to what rotates the body around on a 360 degree excavator undercarriage). The first panel 202 may also have cameras on it to ensure the operator in the vehicle 300 can see when the arcuate abutment surface 204 would be coming in contact with the turbine tower 102. There may also be proximity sensors. Having the first panel attachment means 208 on a cylindrical shaft allows for the first panel 202 to be movable about three perpendicular axes of rotation, thus ensuring effective mating between the arcuate abutment surface 204 and the tower 102. This means the vehicle 300 can be on a sloped surface, but yet still achieve a good level of mating between the tower 102 and the first panel 202, since the first panel 202. It also means that the vehicle 300 may be not aligned exactly perpendicular to the tower 102, but the first panel 202 can still be aligned perpendicularly. This is important to achieve a good mating surface. The arcuate abutment surface 204 must form good contact against the tower 102, to prevent the possibility of snow and ice from falling on a technician of the wind turbine 100 when using the access door 108. The apparatus 200 may also comprise a second panel 212 as shown. The second panel 212 is shown to be located between the first panel 202 and the attachment means 208, when the apparatus 200 is in the deployed condition. The second panel 212 may extend out from the attachment means 206 by around 2-3 metres. The second panel 212 may be pulled in and out using 1 or 2 double acting 2 / 3 stage hydraulic rams or using a toothed track that is pushed and pulled out using a rack and pinion setup with a hydraulic motor powering the pinion. In the embodiment shown, the telehandler vehicle 300 has a telescopic boom or arm which the panels are attached to. The first panel 202 is attached to the forks of the vehicle, and when the first panel 202 is extended away from the vehicle 300 via the hydraulic telescopic boom, the second panel 212 extends out with the boom of the vehicle 300 creating a continuous shelter from the vehicle 300 to the first panel 202. The second panel 212 may be connected to the first panel 202, and be pulled out by virtue of being connected to the first panel 202. Alternatively, the second panel 212 may be connected to one part of the extendable boom of the vehicle, which would move the second panel 212 in whichever direction the connected part of the boom moved. In another example, the second panel 212 may be attached to a hydraulic ram or cylinder, which could be independently controlled. In either arrangement, the second panel 212 may comprise sliders or runners which allow the panel to move easily from the transport configuration to the deployed configuration. The second panel 212 may extend in any manner according to methods in the art. The apparatus 200 may comprise a longitudinal plane 214 and a lateral plane 216 (shown in Figure 4). The longitudinal plane 214 of the apparatus 200 may be generally aligned with a longitudinal plane of the vehicle (along the longest length of the vehicle), and the lateral plane 216 of the apparatus 200 may be generally aligned with a lateral plane of the vehicle (along the shortest length of the vehicle). As shown, the second panel 212 may extend along the longitudinal plane 216 of the vehicle. The apparatus 200 may be detachable from a vehicle 300, allowing it to be used on an alternate vehicle 300. The apparatus 200 may feature a quick release coupling arrangement, allowing it to be easily removed from one vehicle 300 and easily attached to another vehicle. This may be particularly important if the first vehicle 300 was to break down. This feature allows operations to continue, as the apparatus 200 can easily be moved to another vehicle 300. The apparatus 200 may also comprise a third panel 222. The third panel 222 is shown in the Figures to extend along the lateral plane 216 of the apparatus. In the Figures, the third panel 222 is shown to be in the deployed configuration. The third panel 222 may be moved from the deployed configuration to the transport configuration via the use of a hydraulic cylinder / piston arrangement. The purpose of the third panel 222 is to provide a protective roof or barrier for the personnel transporter 400. The third panel 222 also provides a protective barrier between it and the vehicle 300. The third panel 222 therefore allows the personnel transporter 400 to drive underneath it, thereby creating a protective roof over it. This allows any personnel inside the personnel transporter 400 to get out of the transporter 400 in safety. In conjunction with the rest of the apparatus 200, the personnel (wind turbine technicians) can then walk underneath the apparatus 200 and the other panels, to gain access to the access door 108 of the wind turbine 100, without the risk of debris landing on them. The personnel transporter 400 is shown as a SUV car, however it may be any type of vehicle which can transport people. The apparatus 200 has a transport and a deployed configuration. In Figures 3-9, the apparatus 200 is shown with the panels in the transport configuration, apart from the third panel which is in the deployed configuration. In essence, the transport configuration has a smaller ‘footprint’ over the ground than the deployed configuration. In the transport configuration, the panels are generally located on top of each other, forming a stacked arrangement. In the deployed configuration, the panels are at least partially extended from the apparatus 200, thus creating a protective roof over a walkway safe zone. The walkway safe zone is deemed to be safe for personnel to walk in, as the protective panels will prevent any snow or ice falling from above and landing on the personnel. In use, the panels may comprise some form of demarcation, such as a net or a rope, which would hang down from the apparatus 200. This may assist the personnel by clearly showing where the safe walkway is. Figure 10 shows a plan view of an embodiment of the invention, focussing on how the first panel 202 interacts with the tower 102. In this example, the first panel 202 is shown as being clear, to show the staircase below. The panels may be opaque or clear, depending on what material they are made from. Figure 10 clearly shows how the first panel 202 creates a tight seal with the tower 102, thus creating a protective canopy / roof over the access door 108. Wind turbine technicians can therefore exit the access door 108, come down the staircase 110, and be protected by the apparatus 200 from falling debris. In summary, the typical mode of operating the apparatus is as follows: 1) in the transport configuration, the apparatus 200 is moved via the vehicle 300 towards a chosen wind turbine 100. 2) The vehicle 300 is then parked, and the apparatus 200 is moved into the deployed configuration. 3) The first panel 202 is then extended to abut the wind turbine 100 above the access door 108, thus providing a protective barrier for personnel access. Although there have only been three panels described and shown in the embodiment in the Figures, it should easily be envisaged that there may be any number of panels, which may extend out from the apparatus 200 in any direction or orientation, to provide a suitable safe walkway from the vehicle 300 to the wind turbine 100. For example, the panels may extend out at an oblique angle, and may be different shapes to those shown in the figures. The panels may be made from any form ofstructure or material which is strong enough to withstand falling snow and ice. The panels may comprise a steel frame coated in a sheet material. The panels may also be made from a steel, alloy, or aluminium structure. For example, the panels may be made from a steel frame coated in an aluminium panel. A steel frame with a steel panel is also possible, as are alloy / aluminium / stainless steel panels. An indication of sizes of the panels are as follows: The first panel 202 may be between 1-5 m2, the second panel 212 may be between 1-5 m2, and the third panel 222 may be between 1-7m2. In summary, the apparatus 200 provides a temporary covering over an access door 108 of a wind turbine 100 for wind turbine technicians to safely enter and exit the wind turbine 100, when there is the risk of snow and ice falling from the tower 102. Whilst specific embodiments of the present invention have been described above, it will be appreciated that departures from the described embodiments may still fall within the scope of the present invention.

Claims

CLAIMS05 241. An apparatus for providing a temporary protective barrier from falling debris above an access door on a tower of a wind turbine, the apparatus comprising a longitudinal plane and a lateral plane, the apparatus comprising:a first panel, the first panel being shaped for abutting a tower of a wind turbine above an access door, the first panel comprising an arcuate abutment surface;a second panel; andattachment means, for attaching the apparatus to a vehicle;wherein the apparatus has a transport configuration and a deployed configuration and when the apparatus is attached to a vehicle having a longitudinal plane and a lateral plane, the longitudinal planes of the apparatus and the vehicle are generally aligned; wherein the second panel is extendable telescopically away from the vehicle, generally along the longitudinal plane of the apparatus.

2. An apparatus accordingto claim 1, wherein when in the transport configuration, the first panel is located generally proximate to the attachment means, and wherein when in the deployed configuration the first panel is movable away from the attachment means to abut the tower to provide a protective barrier above the access door.

3. An apparatus according to claims 1 or 2, which when in the transport configuration is located generally above the attachment means, and when in the deployed configuration the second panel is located between the first panel and the attachment means, thus providing a protective barrier from falling debris between a vehicle and the first panel.

4. An apparatus according to any preceding claim, wherein the first panel is movable about three perpendicular axes of rotation to ensure effective mating between the arcuate abutment surface and the tower.05 245. An apparatus according to any preceding claim, wherein the first panel comprises a first panel attachment means, for attaching the first panel to a vehicle independently from the rest of the apparatus.

6. An apparatus according to any of claims 4-5, wherein the apparatus further comprises a third panel, and wherein when the apparatus is in the deployed configuration, the third panel is extendable from the apparatus generally along the lateral plane of the apparatus.

7. An apparatus according to claim 6, wherein when in the deployed configuration, the third panel provides a protective barrier from falling debris between a vehicle and the third panel.

8. An apparatus according to claims 6 or 7, wherein when in the transport configuration, the second panel is generally located either above or below the third panel.

9. An apparatus according to any preceding claim, wherein the vehicle comprises a telescopically extendable boom, and the apparatus is attached to the telescopically extendable boom to enable the extension of the first and second panels.

10. An apparatus according to claims 5-9, wherein when in the deployed configuration, the panels provide a protective barrier from falling debris, and create a walkway for personnel to access a wind turbine tower from the apparatus.

11. An apparatus according to any of claims 2-10, wherein the apparatus has an increased footprint over the ground when in the deployed configuration, than when in the transport configuration.

12. A method of forming a temporary protective barrier from falling debris above an access door on a tower of a wind turbine, the method comprising the following steps:providing an apparatus accordingto any preceding claim;moving a vehicle which the apparatus is attached to towards a wind turbine;05 24moving the panels of the apparatus into the deployed configuration;extending the first panel and second panel telescopically to abut the wind turbine above the access door, thus providing a protective barrier for personnel access.

13. The method of claim 12, wherein the method also comprises the step of:adjusting the angle of the first panel about any or all of the three axes of rotation, to ensure an effective mating between the arcuate abutment surface and the tower.

14. A method according to claim 13, wherein the method also comprises the step of: extending the third panel, thus enabling a personnel transporter to park underneath the third panel, thereby creating a safe walkway from the personnel vehicle to the access door of the wind turbine.

15. A method of providing a transportable apparatus to temporarily cover the access door on a tower of a wind turbine.

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