6 Checks for Using Drone Surveys to Verify Completion of Solar Power Plants

In completion inspections of solar power plants, the scope of on-site checks is wide, including graded surfaces, mounting structures, panel layout, drainage, maintenance access paths, fencing, and perimeter boundaries. Visual inspections from the ground and checks using measuring tapes, levels, and total stations remain important, but drone surveying is sometimes used as a method to survey the entire site at a glance and keep a record. Especially immediately after completion, it is an important time to verify that the work was carried out according to the design drawings and to identify any areas that might become issues during post-handover operations and maintenance. Using drone surveying makes it easier to grasp trends that are easy to overlook with ground-only checks by providing site-wide photographs, orthophotos, point cloud data, and elevation information. However, drone surveying alone does not complete the completion inspection. Functional verification of power generation equipment, testing of electrical systems, detailed inspection of structural components, and cross-checking with various documents need to be separated as additional required procedures. This article explains six checkpoints that practical staff should confirm when using drone surveying for completion inspections of solar power plants.

Table of Contents

• Clarify the objectives of using drone surveying for completion verification

• Check for discrepancies between the design drawings and the current layout

• Confirm the finish of the developed surface and the ground elevation.

• Confirm the drainage plan and the flow of rainwater.

• Confirm the management access passage and work flow paths.

• Check the installation status of fences and boundary areas.

• Organize as records that can be used after handover.

• Summary

Organize the purposes of using drone surveying for completion inspections

When using drone surveying for completion inspection of a solar power plant, the first thing to clarify is the purpose—what you are flying to check. The term "completion inspection" is used broadly, but in practice it encompasses multiple objectives: verification against the design drawings, confirmation of the construction scope, inspection of the finished graded surfaces, checking drainage conditions, confirmation of maintenance access paths, inspection of fences and boundaries, and creation of handover records. If you simply take photos while leaving these purposes vague, problems often occur later: missing photos from the necessary angles, insufficient accuracy for elevation verification, and a lack of reference points for overlaying images with drawings.

Drone surveying excels at allowing large sites to be inspected from above as a whole. Photovoltaic power plants have panels arranged in rows, with graded surfaces, drainage ditches, maintenance access paths, fences, switchgear cubicles, and power collection equipment distributed throughout the site. When inspections are carried out sequentially from the ground, inspectors must move frequently, making it difficult to grasp the overall layout. In contrast, aerial photography and surveying data collected by drones make it easy to view the entire plant as a single image or as three-dimensional data. Because the overall view at completion can be preserved, it can be used as comparison material during future inspections or refurbishments.

However, drone surveying is not万能. For example, the torque state of bolts, the connection status of electrical wiring, internal conditions of equipment, and test results related to grounding or insulation cannot be verified from drone images alone. In addition, areas beneath panels or shaded by racks, and locations concealed by vegetation or materials, may not be adequately assessed from the air. Therefore, drone surveying should be positioned as part of the completion inspection and combined with on-the-ground verification, checks using surveying instruments, construction records, test reports, and cross-checking against design documents.

When organizing the objectives for using drone surveying for completion inspection, you also need to decide in advance how the deliverables will be used. Whether they will be used as simple record photos, overlaid with design drawings to check layout, used to understand elevation differences and drainage slopes, or used as explanatory materials at handover will change the flight plan and required accuracy. If the purpose is record photography, the focus will be on keeping images that show the overall site and oblique photos of key areas. If it will be used to check layout and heights, you need to set flight altitude, image overlap, control points, coordinate system, and processing conditions more carefully.

Also, during completion inspections, multiple stakeholders—such as the contractor, the client, the management company, and the maintenance personnel—check the same on-site information. Deliverables from drone surveys are useful as materials for sharing current conditions among stakeholders, but if presented improperly, images can take on a life of their own and cause misunderstandings. For example, shadows, reflections, or the angle at which a photo was taken can make rows of panels appear bent or drainage channels appear shallow. When a concerning area is found in an image, it is important to recheck it on site and, if necessary, compare it with survey measurements and construction records.

The purpose of using drone surveys at the completion inspection stage is not to unilaterally judge the quality of the construction, but to efficiently grasp a large site, reduce oversights, and enable stakeholders to verify conditions based on the same current-condition information. Holding this premise makes the required capture area, checklist items, and the method for organizing deliverables clear. As a result, it becomes easier to retain valuable data that supports not only the confirmation work at completion but also maintenance management after handover.

Check for discrepancies between the design drawings and the actual layout

What becomes important in the completion inspection of a solar power plant is verifying the design drawings against the as-built layout.

In a solar power plant, many elements—panel rows, racking, power conditioner (inverter) locations, collection equipment, maintenance access pathways, drainage facilities, fences, gates, and site boundaries—are arranged based on the planned drawings. However, during actual construction, differences can arise between the design-stage layout and the as-built condition due to topographical conditions, delivery routes, existing structures, drainage planning, and on-site adjustments. Even small discrepancies can affect maintenance routes, drainage, and relationships with adjacent properties, so it is important to verify the overall layout at project completion.

Using drone surveying, you can capture the entire power plant from the air and understand current conditions in the form of orthophotos and other outputs. An orthophoto is an image in which the tilt and distortion of an aerial photograph have been corrected to make planar positional relationships easier to check. By overlaying this on design drawings or construction drawings, it becomes easier to compare the positions of panel rows, walkway widths, equipment layouts, locations of drainage channels, fence lines, and so on. Simply checking by walking around the site can make it difficult to intuitively grasp whole-site shifts or biases in placement, but using aerial data makes it easier to confirm the overall alignment.

When checking placement, be careful not to conclude that there is a displacement based solely on how it looks in the images. If the coordinate system of the design drawings, the reference points used on site, and the coordinate settings of the drone survey data do not match, the whole may appear shifted when overlaid. Also, the design drawings may be schematic, or you may be using drawings that do not reflect changes approved during construction. Therefore, for as-built verification you need to compare only after confirming which drawing is to be treated as authoritative, whether records of construction changes have been reflected, and whether there are any issues with how coordinates and scale are handled.

Particular attention should be paid to the relationship between the arrangement of panel rows and the maintenance aisles. In solar power plants, even when the panel rows are neatly aligned, problems can be discovered after completion such as aisles being too narrow, inspection vehicles being obstructed, or insufficient working space around equipment. Using plan view data from drone surveys makes it easier to check the continuity and bends of aisles, clearances around equipment, and connections to the routes used for bringing items in and out. Because this affects the ease of inspections and emergency responses after power generation begins, it is an item that should be checked at completion.

Also, the positional relationship with surrounding boundaries is important. If fences, drainage ditches, slopes, maintenance access paths, or rows of panels are close to adjacent land, roads, farmland, waterways, etc., recording their arrangement at the time of completion can be helpful for later explanations and maintenance. However, determination of the boundary itself or legal judgments should not be made based solely on drone images. Confirmation should be performed by combining the necessary materials such as boundary stakes, survey results, registration-related documents, and site inspection records. It is safest to treat drone surveying as supplementary material for providing an aerial overview and organizing the current conditions around boundaries.

When comparing the design drawings with the as-built layout, it is important not only to check whether there are discrepancies but also to confirm what practical effects those discrepancies may have. For example, even if a row of panels is slightly offset from the drawings, it may not be a major problem if power generation and maintenance are unaffected and the change has been documented as a construction modification. On the other hand, if a change in the location of a drainage channel worsens rainwater flow, narrows walkways, or makes access to equipment more difficult, corrective measures or record keeping may be necessary. Drone surveying can be used to check these impacts from an overall perspective.

In completion inspection, it is important not only to detect misalignments but also to record them in a way that can be explained later. For any points of concern, organizing aerial images together with ground photos, measurements, drawing numbers, confirmation dates, the person who confirmed them, and response plans helps prevent misunderstandings among stakeholders. Drone survey data are useful as baseline material for the entire site, but making final decisions requires combining drawings, construction records, and on-site verification.

Confirm the finished surface and ground level

During completion inspections of solar power plants, the finished condition of the site surface and ground elevation are also important items to check. Because solar panels are installed on racks, the ground surface can appear to be only slightly uneven and not a major problem at first glance. However, irregularities in the finished surface, localized settlement, low-lying areas that tend to collect water, unstable sections of slopes, and the condition near the boundary between fill and cut can lead to poor drainage and increased maintenance burdens after completion. Using drone surveying makes it easier to assess surface-wide elevation trends and undulations over a large development area.

When confirming the graded surface on the ground, the inspector tends to rely on the area they walked and information at each survey point. Of course, ground surveying is necessary in situations such as checking reference heights and as-built conditions, but information confirmed only at points can make it difficult to grasp trends across the entire site. Creating point clouds and elevation data with drone surveying makes it easier to check overall site elevation differences, gentle slopes, local depressions, and undulations that do not match drainage directions. Especially for large-scale solar power plants, being able to understand the terrain across the area leads to greater efficiency in completion inspections.

When verifying developed surfaces, it is important to separate the finish required by the design from the actual current conditions. In site development for solar power plants, the objective is not always to make every ground surface perfectly flat. There are finishes corresponding to the design intent, such as plans that utilize the natural terrain, slopes provided to ensure drainage gradients, and interfaces with cut-and-fill slopes or detention ponds. Therefore, even if a drone survey reveals irregularities or inclines, that does not immediately indicate construction defects. It is necessary to cross-check with the design drawings, site development plan, drainage plan, and as-built control documents to confirm whether the conditions fall within allowable tolerances.

Also, when using height information from drone surveys for completion verification, it is necessary to clarify the assumptions about accuracy. The reliability of the height information obtained varies depending on imaging conditions, the arrangement of ground control points, processing methods, the presence of vegetation, and how the ground surface appears. In areas where grass is overgrown, where crushed stone or materials are placed, or where panels or racking cast shadows, it can be difficult to accurately capture the ground surface itself. Therefore, when making important determinations related to height, it is safer to use drone survey data as a reference while confirming necessary locations with ground surveying.

When checking the finished ground surface, also pay attention to the ground conditions beneath the lower parts of panel rows and around the mounting racks. Confirm whether there are shapes around the rack foundations that are prone to scour, whether there are depressions between panel rows where water easily collects, and whether rainwater from maintenance walkways is flowing under the panels. Even if problems are not noticeable immediately after completion, repeated rainfall can cause soil erosion and muddy areas. Recording the terrain at completion with a drone survey makes it easier to compare changes during future inspections.

Inspection of slopes and the edges of earthworks is also essential. At solar power plants, slopes are sometimes constructed along the site perimeter and at level changes. The slope gradient, the interface with drainage facilities, the condition of surface protection, and areas prone to soil runoff can be difficult to fully assess from ground-level checks alone. Using oblique photos taken by drones and aerial overview images makes it easier to clarify the continuity of slopes, locations that appear prone to collapse, and spots where rainwater is likely to concentrate. However, because evaluating slope stability may require professional judgment, it is important not to determine safety based on images alone.

The purpose of checking the formation surface and ground elevation during completion inspection is not simply to find differences from the design values. It is also necessary to assess operational aspects such as whether the plant will be easy to manage in the long term, whether rainwater and sediment are unlikely to cause problems, whether inspectors can walk safely, and whether vehicles can pass easily. Drone surveying is an effective means of performing these checks with a broad perspective. By extracting areas of concern from images and combining them with on-site inspections and survey data, the accuracy of completion verification can be improved.

Confirm the drainage plan and stormwater flow

One thing you must not overlook during the completion inspection of a solar power plant is the drainage plan and the flow of rainwater. Because panels are laid out across a wide site, rainwater during a storm moves across the panel surfaces, developed areas, access routes, slopes, and drainage channels. If drainage does not function properly, it can lead to muddy ground on the site, sediment outflow, scour of slopes, erosion around racking foundations, deterioration of maintenance access routes, and runoff to surrounding land. Confirming the flow of drainage at completion is directly linked to stable management after power generation begins.

Drone surveying helps confirm the overall picture of drainage. Simply checking drains one by one from the ground can make it difficult to grasp the flow of water across the entire site and where rainwater tends to accumulate. Using orthophotos and elevation data from above makes it easier to check the direction of site slopes, the arrangement of drains, low-lying areas prone to collecting runoff, water accumulation at the bases of slopes, and rainwater flows that cross pathways. Confirming at the completion stage that the designed drainage system matches the actual site topography can help reduce problems after the site is put into service.

When checking drainage, first confirm the positional relationships of drains, side ditches, catch basins, and discharge points. By looking at the continuity of drainage facilities in drone imagery, it becomes easier to find spots where sediment is likely to enter, areas where the gradient is difficult to discern, and places where the junctions with pathways or rows of panels are unnatural. However, internal blockages or fine details of a drain’s gradient cannot be judged from aerial imagery alone. The practical workflow is to extract areas of concern from drone surveying and then inspect the drainage channel’s cross-section, bottom, downstream end, and the condition of the basins on site.

Next, check for locations where rainwater might flow in unexpected directions. In solar power plants, slight undulations of the graded surface or raised walkways can alter water flow. Even if the design routes water toward drainage channels, in practice water can pool between panel rows or cross pathways and concentrate on slopes. While reviewing the height information and images obtained from drone surveys, identify low spots, areas where rainwater tends to collect, and places where sediment is likely to wash out. If possible, perform on-site checks or additional photography after rainfall to more easily identify puddles and runoff traces.

Consideration must also be given to the effects of rainwater falling from the panels. Because solar panels are installed at a fixed tilt, rainfall tends to fall from the lower edges of the panels and concentrate on the ground surface. Even if not noticeable immediately after completion, over time erosional gullies can form beneath the panels and soil or sediment can be displaced. Drone surveying allows you to grasp the relationship between the overall layout of panel rows and the terrain, making it easy to identify rows where rainwater is likely to concentrate, rows with low ground, and locations that are far from drainage channels. However, the fine conditions beneath the panels are difficult to see from above, so on-the-ground inspections should be combined as needed.

When verifying drainage, impacts offsite are also important. How rainwater from a solar power plant flows to roads, farmland, waterways, adjacent properties, and so on affects maintenance and responses in the surrounding area. Recording the perimeter, including the surrounding areas, with a drone at completion makes it easier to identify the outlets of drainage facilities, terrain near the site boundary, elevation differences with neighboring land, and locations at risk of sediment runoff. However, judging impacts on surrounding land requires a comprehensive review of design conditions, permit documents, drainage calculations, and on-site conditions. It is important not to conclude that there is no problem based solely on drone images, but to use them as an entry point for further verification.

Drainage checks during completion inspections may not be sufficient if conducted only in fine weather. Drone surveys in clear conditions can confirm terrain and the placement of drainage facilities, while on-site inspections after rain can verify puddles, mud flow, sediment accumulation, and flow traces in drainage channels; combining multiple pieces of information provides a more accurate picture of actual conditions. If drainage concerns are identified and organized immediately after completion, it becomes easier to correct them before handover, reflect them in maintenance plans, and establish priority check points for regular inspections.

Confirm maintenance access routes and workflow

Confirming maintenance access paths and work movement lines is also important during the completion inspection of a solar power plant. A plant is not finished upon completion; after power generation begins, tasks such as regular inspections, weed control, cleaning, equipment replacement, and emergency responses continue. If maintenance access paths are difficult to use, not only do maintenance tasks take longer, but problems arise such as vehicles having difficulty accessing the site, equipment being hard to transport, and workers being unable to move safely. Using drone surveying at completion to check access routes and work flow makes it easier to identify potential operational obstructions early on.

The strength of drone surveying is that it allows you to confirm the continuity of access routes from above. When walking on the ground, it is easy to notice the width of the path and the condition of the surface directly in front of you, but it can be difficult to grasp how the routes are connected across the entire power plant, whether the equipment to be inspected is accessible, or whether there are dead ends or tight turns. By using aerial images, you can comprehensively check the routes from the entrance to each piece of equipment, the walkways between panel rows, perimeter walkways, intersections with drainage facilities, and the locations of gates and vehicle turning spaces.

The points to check for maintenance access routes are width, gradient, bends, pavement condition, and their relationship to drainage. Even if the route width was secured at completion, a separate check is needed to ensure that actual maintenance vehicles or work equipment can pass without obstruction. Identify narrow sections and sharp bends from drone images, and verify on site vehicle access and working space. In particular, areas around power conditioners, power collection equipment, power receiving and transformation equipment, communication equipment, and monitoring devices may require a certain amount of working space for inspection and replacement work. Aerial data is useful as documentation for confirming the available clearance around these pieces of equipment.

The condition of the access route surface is also important. Factors such as crushed stone surfacing, compaction state, drainage outlets, level differences, and low-lying areas prone to muddiness affect post-construction maintenance. Drone surveys cannot determine the fine compaction of the road surface, but they can identify the overall slope of the route, locations where water is likely to collect, and places where soil or sediment may flow in. If there are areas of concern, check the surface condition, drainage gradient, level differences, and safety for vehicle traffic on the ground. Organizing these items at completion makes it easier to reduce problems after rain or during weeding.

When checking operational routes, it is also necessary to consider pedestrian and vehicle movement separately. The routes inspectors take on foot, routes used for weeding work, routes for bringing in equipment, and routes to reach equipment in emergencies each have different requirements. Using drone imagery to view the entire site, confirm which entrance leads to which equipment, whether there are any steps or narrow sections along the way, whether drainage channels can be crossed safely, and whether detouring around the ends of panel rows will be necessary. This makes it easier to develop more concrete maintenance plans after completion.

It is also important to examine the relationship between access routes and equipment layout. In solar power plants, even if the panel rows are arranged efficiently, a layout that makes it difficult to access equipment requiring maintenance will increase long-term management burdens. Use drone surveys to check the overall layout and confirm whether major equipment is easy to approach, whether there is any risk of contacting panels or racking during work, and whether there are locations that could cause confusion during emergency responses. If necessary, organize the as-built plan drawings to clearly show access routes and equipment locations so that handover to the management company and maintenance personnel proceeds smoothly.

Checks of maintenance access routes and work flow should be carried out by imagining actual operations, not just based on how they look at completion. Paths that seem fine in clear weather may become muddy after rain, become difficult to pass as grass grows, or prevent vehicles from approaching during equipment replacement. By combining an overall aerial view from drone surveying with on-the-ground inspections, it becomes easier to confirm whether the power plant will be easy to operate and maintain after completion.

Inspect the installation condition around fences and boundaries

When confirming completion of a solar power plant, the construction condition of fences and boundary areas is also an important inspection item. The plant perimeter concentrates fences, gates, maintenance walkways, drainage ditches, slopes, boundary stakes, and interfaces with adjacent land. The perimeter is a location of great significance to record at handover because it relates to preventing third‑party entry, relationships with surrounding land, runoff of rainwater and sediment, and the safety of maintenance work. Using drone surveying makes it easier to continuously check the entire perimeter and to detect misalignments and interfaces that are easily overlooked by ground inspections alone.

What you should check around fences are the installation location, continuity, the position of gates, the distance to surrounding structures, and the relationship with drainage facilities. From above, you can confirm whether the fence line follows the site shape, whether there are sections that are excessively set inward or outward, and whether gates and maintenance access paths connect naturally. Simply walking along the fence at ground level can make it difficult to grasp the overall curvature and positional relationship with adjacent land, but using drone imagery makes it easier to confirm the continuity of the perimeter.

However, confirmations regarding boundaries must be handled with care. Even if drone images show the positions of fences or boundary stakes, that alone cannot determine land boundaries. Boundary confirmation requires survey results, boundary markers, on-site inspection records, and related documents. When using drone surveying for completion inspections, it is appropriate to treat it as supplementary material to verify that fences and constructed elements align with planned positions and site conditions, rather than as a legal determination of boundaries. If there are any concerns near a boundary, always cross-check with the relevant documents and professional survey results.

Around the perimeter, attention must also be paid to the relationship between fences and drainage. If there are drainage channels along a fence, check for locations where sediment is likely to accumulate, places where the downstream end is difficult to identify, and spots where rainwater from outside can easily enter the site. Also, when fences are installed at the top or bottom of slopes, you should check whether scouring by rainwater or sediment movement could affect the fence foundations. Oblique and aerial images taken by drones are useful for clarifying the positional relationships among fences, slopes, and drainage facilities.

Checking gates and entrances is also important. After a power plant is completed, entrances are used for inspection vehicles, weeding operations, material deliveries, and emergency response. Confirm whether the gate aligns with the access road, whether vehicles can enter safely, and whether there are steps or drainage ditches near the entrance that make passage difficult. By using drone images to confirm the route from the entrance to the main equipment and verifying actual passability on the ground, it becomes easier to determine whether there will be any issues with post-construction operations.

It is also important to record the relationship with adjacent land. The surroundings of a solar power plant may include roads, farmland, forests, waterways, residential areas, and existing facilities. If the perimeter conditions at the time of completion are recorded by drone, it will be easier to compare them with the completed state later when issues such as vegetation overgrowth, soil movement, changes in drainage, or damage around fences occur. In particular, at sites where inflow of rainwater from surrounding areas or sediment accumulation is a concern, records of the perimeter become important reference material for maintenance management.

When checking the construction condition around fences and boundaries, it is important to distinguish between the areas visible in images and the areas that should be physically touched and inspected on site. Drone surveying is suitable for capturing the overall arrangement and junctions along the entire perimeter, but the fixing condition of fence posts, the opening and closing condition of gates, the condition of hardware, and minor damage require ground-level inspection. For completion inspections, using drones to capture the whole and confirming details on the ground, then compiling the results into photos and records, makes it easier to reduce omissions in perimeter checks.

Organize into records that can be used after handover.

If you carry out drone surveys for commissioning inspections of a solar power plant, it is important to organize that data as a record that can be used even after handover. Drone images and survey data captured at completion are sometimes stored and then left unused once the inspection work is finished. However, a power plant is a facility operated over the long term, and as-built/current-condition data from completion can be valuable for future inspections, repairs, renovations, post-disaster assessments, weed-control planning, drainage inspections, responses to issues in the surrounding area, and more. Rather than letting the data you carefully obtained end up as temporary inspection materials, it is important to retain it in a form that can be used for ongoing management.

First, the basic information you should organize is when the data was surveyed, what area it covers, and for what purpose. Recording the capture date, weather, capture extent, flight conditions, deliverables produced, control points used, how coordinates were handled, processing conditions, the reviewer, and related drawing numbers will make it easier to understand the meaning of the data when you revisit it later. Even if only images remain, their value as management documentation is reduced if you cannot tell when the data was taken, whether it was before or after completion, or what area is included.

Next, store the deliverables by clearly separating them by type. Overview photos, ortho images, oblique photos, point cloud data, elevation data, overlay materials for layout verification, and enlarged images of areas of concern each have different uses. For maintenance personnel, immediately usable materials include overall maps showing points to check and documents that identify equipment names, pathways, drainage facilities, fences, and gates. On the other hand, when used by surveyors or designers, data organized with coordinate information and processing parameters is required. In practice, it is important to prepare formats that are easy to view according to the user.

Issues identified during the completion inspection are organized not only with images but also together with their response status. For example, locations suspected of sediment buildup in drainage channels, spots where passage width is narrow, areas where the slope surface is rough or deteriorated, and places where the fence line requires verification are marked on drone imagery, and, based on ground verification, whether corrective action has been taken and how the issue will be handled at handover are recorded. This makes it easier, when checking the same location later, to determine whether the entry is merely a remark, has been addressed, or requires ongoing monitoring.

As-built data will serve as a baseline for future comparisons. After power generation begins, if sediment runoff, ground subsidence, drainage problems, deterioration of access routes, vegetation overgrowth, or changes around fences occur, comparing those conditions with the as-built state makes it easier to explain whether changes have taken place. In particular, when checking site conditions after typhoons or heavy rain, having as-built aerial images and topographic data makes it easier to identify which parts have changed. This is a major advantage for management companies and maintenance personnel.

When handing over data, rules for storage locations and file names are also important. Using names that indicate the date, site name, survey area, and type of deliverable makes them easier to find when needed. Conversely, if files are saved with ambiguous names, it may later be unclear which data are the official records at completion. Because deliverables for completion verification may be shared among the client, contractor, management company, and maintenance personnel, they should be organized so that anyone can understand their contents.

Even when using drone survey data as a record, the limitations of the data must be clearly stated. It represents conditions at the time of capture and does not guarantee subsequent changes; there may be equipment interiors or electrical conditions that cannot be confirmed from images; and height information has errors and constraints depending on the acquisition conditions. When using it as handover materials, organizing which items are subject to verification and which are not makes it easier to prevent misunderstandings among the parties involved.

The value of drone surveying in completion verification lies not only in the on-site imagery but also in preserving records that can be used later. By integrally organizing the current condition of the entire power plant—graded surfaces, drainage, access routes, and perimeter areas—you create fundamental reference materials for understanding the site during future operation and maintenance. Taking a little extra effort to organize these at completion makes it easier to improve management quality after handover.

Summary

When using drone surveying for the completion inspection of a solar power plant, it is important not simply to take photos from above but to clarify the inspection objectives and use the drone data in combination with design drawings, construction records, and ground inspections. Drone surveying, which can provide an overview of a large site, is effective for understanding the current conditions of panel layout, graded surfaces, drainage, maintenance access paths, fences, and boundaries. Especially for large-scale plants where it is difficult to grasp the whole picture from the ground, it helps reduce missed checks at completion and serves as documentation to share consistent as-built information among stakeholders.

However, it is not possible to judge all aspects of completion inspection solely by drone surveying. Tests of electrical equipment, detailed inspection of structural members, internal inspection of machinery, legal determinations of boundaries, and detailed assessments of drainage capacity all need to be combined with additional necessary documentation, on-site verification, and specialist judgment. Positioning drone surveying as a means to efficiently understand the entire site and to identify locations that require focused inspection makes it easier to incorporate into practical work.

Points to check at the completion inspection are discrepancies between the design drawings and the actual site layout, the finished condition of development surfaces and ground elevations, the drainage plan and rainwater flow, maintenance access routes and work flow paths, the condition of fences and boundary areas, and the compilation of records that will be usable after handover. Checking these items in order makes it easier to retain, at completion, the information needed for operation and maintenance after power generation begins. In particular, drainage, access routes, and the condition of the outer perimeter are areas that tend to surface as problems after operation begins, so it is valuable to check the whole site with drone surveying at completion.

In completion inspections of solar power plants, it is important to record site conditions broadly, clearly, and in a form that can be compared later. By utilizing drone surveying, you can record the condition immediately after construction on an area-wide basis, making it easier for the client, contractor, management company, and maintenance personnel to review a common set of materials. If you are preparing completion inspections and handover documentation, leveraging drone surveying with an eye toward everything from overall site understanding to record management will make the inspection tasks for solar power plants easier to carry out.