7 Equipment Management Strategies to Increase Power Generation｜How to Avoid Losses in Long-term Operation

Table of Contents

• Equipment management for increasing power generation reduces long-term generation losses

• 設備管理1：発電量データを時間帯と設備単位で見る

• 設備管理2：パネル表面の汚れと清掃判断を管理する

• 設備管理3：雑草・樹木・影の発生を季節ごとに抑える

• 設備管理4：ストリング・接続部・ケーブルの異常を早期に見つける

• 設備管理5：変換機器の停止・抑制・温度環境を確認する

• 設備管理6：排水・地形・点検動線を整えて再発を防ぐ

• 設備管理7：点検記録と位置情報で改善を継続する

• 長期運用で損しないための管理判断

• まとめ

Equipment management to increase power generation reduces long-term generation losses

When considering how to increase the power output of a solar power system, the first important step is not to add more equipment but to confirm whether the existing equipment is delivering its intended generating capacity. In solar power generation, you cannot increase the amount of solar irradiance at the site itself. You cannot increase the number of sunny days, nor change the sun’s elevation with the seasons. However, you can bring the system closer to a state that converts received irradiance into electricity with as little waste as possible. In other words, equipment management aimed at increasing generation in practical terms is the effort to identify generation losses that occur during long‑term operation and to continuously reduce them.

What tends to incur losses in long-term operation is when a decline in power generation begins as a small sign and accumulates without being noticed. Dirt on panel surfaces, bird droppings and fallen leaves, shading from weeds or trees, faults at connection points, cable damage, short-term stoppages of conversion equipment, output curtailment, temperature rises, poor drainage, and insufficient inspection records may each seem minor, but if they persist over a long period they can cause significant losses. In particular, a situation in which only some equipment has low generation is easily overlooked in the plant’s overall monthly figures and may be left unaddressed.

For operations personnel searching for "how to increase power generation," it is important not to decide on countermeasures based solely on the site’s appearance. Cleaning panels because they are dirty, removing weeds because the grass is overgrown, or considering replacement because equipment looks old are sometimes necessary. However, if the primary cause of the generation decline lies elsewhere, carrying out those tasks will not lead to sufficient improvement. Even if you clean the panels, if morning and evening shading remains the power output will be unlikely to recover, and even if you remove the weeds, if inverters remain stopped, daytime generation will not increase.

In equipment management, it is necessary to link power generation data, on-site photos, inspection results, and work history to systematically isolate the causes. You need to check when generation is low, which equipment is underperforming, whether there is a difference compared with equipment under the same conditions, whether it is low even on sunny days, and whether it becomes unstable after rain. Based on that, review dirt, shading, connections, power conversion equipment, drainage, and inspection routes. The result of low power generation alone does not tell you where to start. To avoid losses in long-term operation, it is essential to record the causes and use them to inform the next inspection.

Equipment Management 1: Viewing Power Generation Data by Time Period and by Equipment Unit

The first step in equipment management to increase power generation is to examine generation data in detail. If you only check monthly or annual generation, you won't know when, where, or how generation losses are occurring. In long-term operation, it is more important to monitor changes by time of day, by equipment unit, by day, and by season than to focus on the plant's overall total. If low output persists only in a particular column, in a particular string, or in the range connected to a particular inverter, there may be room for improvement there.

If morning generation is low, shadows from trees on the east or southeast side, slopes, weeds, surrounding structures, or adjacent equipment may be involved. If it is low in the evening, check shadows on the west or southwest side, the surrounding terrain, and tree growth. If the midday peak does not extend, candidates include dirt on the panel surface, temperature rise, limitations of conversion equipment, output curtailment, equipment shutdowns, and anomalies at the string level. If, even on clear days, the generation curve suddenly drops partway through, it is necessary to cross-check shutdown histories and alarm logs with the timestamps.

When comparing equipment units, it is important to look at equipment under the same conditions. If you simply compare equipment with different orientation, tilt, number of panels, shading conditions, or connection configurations, you may mistake normal differences for abnormalities. The purpose of the comparison is to identify locations that are consistently producing less power among equipment that should have similar generation. Even if problems are not obvious across the entire plant, if only a part is lower compared to equipment under the same conditions, focus checks on soiling, shading, connection points, cables, power conversion equipment, drainage, and similar issues.

Pay attention to how the power output declines. If it drops suddenly, possible causes include equipment shutdown, broken wiring, poor connections, or the appearance of obstructions. If it is declining gradually, accumulation of dirt, growth of weeds or trees, deterioration of site conditions due to poor drainage, or age-related changes in equipment and components may be involved. In long-term operation, preventing losses involves not only detecting sudden anomalies but also not overlooking gradual declines.

When reviewing power generation data, compare days that are as sunny as possible. On cloudy or rainy days, generation can fluctuate greatly due to cloud movement, making it difficult to determine whether the cause is equipment malfunction or weather. If you use the generation curve from a sunny day as a baseline, it's easier to see time-of-day drops caused by shading, flattening from output curtailment, sudden drops from stoppages, and equipment-level differences caused by string anomalies. By maintaining operations that examine data in detail, you can detect declines in power generation earlier.

Equipment Management 2: Managing Panel Surface Soiling and Cleaning Decisions

Surface dirt and deposits on the panels are a common cause of reduced power generation. Because solar panels generate electricity by receiving sunlight at their surface, adhered dirt reduces the light reaching the cells. The way panels become dirty varies with the site environment, such as soil dust, pollen, yellow dust, bird droppings, fallen leaves, tree sap, dust from nearby construction, road-derived dust, and salt-containing deposits that readily adhere in coastal areas. In long-term operation, it is important to understand in which seasons, on which rows, and what kinds of dirt are likely to occur.

Particularly important to watch for are band-like stains that remain along the panel bottom edge and near the frame. It is often assumed that rain will naturally wash them away, but in reality the flow of rainwater can gather dirt at the lower edge and leave it there. Panels with a shallow tilt drain poorly, making it easier for dirt to accumulate. Even dirt that is not noticeable from a distance can affect power generation if it covers part of a cell. During inspections, check not only the overall coloration of the panel but also the bottom edge, the corners, and the areas around the frame.

Localized deposits such as bird droppings and fallen leaves should not be overlooked. Unlike dirt that spreads thinly over the entire surface, these concentrate on specific spots and hinder power generation by causing partial shading. Rows near trees, around structures where birds tend to perch, downwind rows, and areas near unpaved walkways are prone to dirt and deposits. If only certain installations have low power output, focus on inspecting the panel surfaces in and around those installations.

When deciding whether to clean, check not only whether there is dirt but also whether it coincides with the area of reduced power output. If equipment with low power output overlaps with areas where dirt is noticeable, the priority for cleaning should be high. Conversely, if dirt is visible but does not coincide with the area of decreased power output, you need to check for other causes such as shading, connections, conversion equipment, or temperature conditions. To avoid losses in long‑term operation, it is important to manage cleaning not as a task but as a decision to improve power generation.

When performing cleaning, it is essential not to damage the equipment. Avoid vigorously scrubbing with hard tools, carrying out sudden work during periods when panels are at high temperatures, and omitting safety checks for electrical equipment. If you record before-and-after photos, the scope of work, weather conditions, and changes in power generation, it will be easier to determine how much soiling affected power output. If the effect is visible, you can apply the findings to future cleaning plans, and if the effect is small, it provides an opportunity to investigate other causes.

Facility Management 3: Suppress the Occurrence of Weeds, Trees, and Shadows by Season

Shading from weeds and trees is a major factor that reduces energy production during long-term operation. Because solar panels generate electricity by receiving sunlight, even partial shading of a panel can lower its output. Causes of shading vary and include weeds, trees, fences, posts, surrounding buildings, mounting structures, and adjacent rows of panels. Because shadows shift with the time of day and the seasons, they may be causing reduced energy production even if they are not visible at the moment of inspection.

Weeds grow rapidly from spring to summer. Even in areas that posed no problem in winter or immediately after installation, around the rainy season weeds can encroach under the lower edge and in front of panels, casting long shadows at the low sun angles of morning and evening. Even if the plants do not touch the panels, power generation will decrease if their shadows reach the panel surface. Furthermore, when weeds become overgrown, ventilation worsens, inspection walkways become blocked, and it becomes difficult to check around equipment. Because it affects not only power generation but also maintainability, weed management is a fundamental part of facility management.

Shadows from trees are a factor that can become problematic over the course of several years. Even trees that had little impact at the time of installation can, as they grow, cast long shadows in the mornings, evenings, or during winter. Trees located on the south, east, or west sides in particular cast shadows during times that are likely to affect power generation. At power plants near forests or slopes, the elevation of the terrain combined with tree height can cause shadows to extend more than expected in winter. If only certain rows are low in winter, seasonal shading should be suspected.

For shadow mitigation, inspect the site at the times when power generation data shows a decline. If output is low in the morning, check for morning shadows; if it is low in the evening, check for evening shadows. Even if there is no problem at noon, long shadows can appear in the morning and evening. Recording the time shadows occur, their sources, and the equipment they fall on makes it easier to prioritize weeding and pruning. By recording seasonal changes in shadows, you can get ahead of inspections in subsequent years.

In long-term operation, the goal is not just to mow grass or trim branches. It is important to prioritize locations that have a large impact on power generation and to manage the seasons and places where recurrence is likely. If you can identify patterns—grass growing in the same spots every year, the shadows of the same trees extending in winter, or leaves accumulating in the same rows—you can check them before power generation declines. Managing shading seasonally makes it easier to reduce long-term losses.

Equipment Management 4: Early Detection of Abnormalities in Strings, Connections, and Cables

In equipment management aimed at increasing power generation, it is necessary to check not only the panel surface and shading but also the electrical pathways that extract the power. Even if solar panels are receiving sunlight normally, faults in the strings, connection points, or cables can prevent the generated power from being fully extracted. Loose terminals, poor contacts, damage to cable sheathing, moisture ingress, damage caused by animals, damage during grass‑cutting operations, and age‑related degradation are major causes of reduced power generation.

When checking for abnormalities at the string level, compare strings under the same conditions. If you simply compare strings that differ in panel count, orientation, tilt, shading conditions, or connection configuration, you may mistake a normal difference for an abnormality. Check whether any are consistently lower compared with adjacent rows or strings with the same orientation. If only a specific string is lower, possible causes include soiling, partial shading, poor connections, cable damage, panel defects, or problems on the power conversion equipment side.

Pay attention to how differences in power output present themselves. If output is consistently lower than the surroundings even on sunny days, suspect dirt, degradation, or poor connections. If it is only lower in the morning and evening, check for shading. If anomalies tend to appear after rain, moisture ingress or the condition around connection points may be involved. If it becomes unstable during periods of high temperature, poor contact or the thermal environment are also potential causes. Combining the power output waveform with on-site conditions makes it easier to narrow down the cause.

If a fault in connection points or cables is suspected, prioritize safety above all. Do not let on-site personnel touch connection points or the inside of equipment to make a judgment just to try to increase power output. First, document the equipment suspected of abnormalities, the time of occurrence, changes in power generation, on-site photos, and the surrounding environment. Referring the case to specialized inspections as needed makes it easier to identify the cause while maintaining safety.

Cable and connection failures are also influenced by the surrounding environment. When weeds are overgrown, cables become hard to see and damage or deterioration can be overlooked. In areas with poor drainage, moisture or standing water can affect connection points. In locations prone to animal intrusion, cables may also be damaged. To avoid losses during long-term operation, it is necessary to check not only the electrical anomalies themselves but also the site conditions that make those anomalies more likely.

Equipment Management 5: Verify Shutdown, Suppression, and Temperature Environment of Conversion Equipment

The causes of low solar power generation are not limited to panels and wiring. If the equipment that converts the generated electricity is offline or its output is restricted, power generation will not increase even with sufficient solar irradiance. For long-term operation, it is essential to continuously monitor the operating status of the conversion equipment, shutdown history, alarm history, and whether output curtailment is in effect.

When reviewing outage history, check which device(s) stopped, when, and for how long. Even a short outage can cause significant losses if it occurs during the daytime when power generation is high. If stops and recoveries are repeating during the day, they may not stand out in the monthly total but can still result in lost generation. Whether only a specific device stopped or multiple devices stopped simultaneously will change the likely causes to suspect.

Also check for output curtailment and plateauing. If the top of the generation curve flattens on sunny days, possible causes include output limits of power conversion equipment, equipment capacity ceilings, temperature rise, insufficient input, and measurement anomalies. It does not necessarily indicate equipment failure, but if it occurs during periods that greatly affect generation, it should be prioritized for inspection. Make a decision by combining historical data, the generation curve, and differences from equipment under the same conditions.

Temperature conditions and ventilation should not be overlooked. While solar power generation tends to be greater with stronger sunlight, if panel temperature or the temperature around equipment rises, output may not increase as much. If, despite a clear summer day, generated power does not rise as expected, the midday peak is muted, or the system becomes unstable during times when equipment tends to overheat, check the temperature environment. Conditions such as weeds growing under panels or around equipment, accumulated debris, or poor ventilation can affect power generation and the detection of anomalies.

Around the conversion equipment, check for grass, fallen leaves, sediment, obstacles, puddles, mud, and the condition of access paths. When the area around the equipment is difficult to see, it becomes harder to notice abnormal indications or changes in appearance. Poor access paths delay inspections and delay the detection of abnormalities. To increase power generation, it is important to maintain an environment in which the conversion equipment can operate stably and to keep it in a state where abnormalities can be checked immediately when they occur.

Facility Management 6: Organize Drainage, Topography, and Inspection Routes to Prevent Recurrence

In equipment management aimed at increasing power generation, it is necessary to look not only at panels and equipment but also at the power plant’s overall drainage, topography, and inspection routes. These may seem unrelated directly to power generation, but in fact they are important factors that lead to soiling, weeds, faults in connections, and reduced accessibility for inspection. Locations where water tends to accumulate, where sediment flows in, paths that easily become muddy, slope failures, scour around mounting structures, and places where cables are likely to be exposed can cause repeated reductions in power generation.

Areas where puddles remain after rain are more prone to weed growth. When weeds grow, they cast shade, reduce ventilation, and make inspections more difficult. Where sediment flows in, dirt tends to accumulate at the lower edges of panels and around cables. If cleaning and weeding repeatedly fail to prevent problems in the same locations, drainage and terrain issues need to be checked.

When checking topography and drainage, on-site inspections after rain as well as during clear weather are effective. Determine where water is flowing in, where it is pooling, and where it is draining out. Recording puddles, sediment accumulation, overgrown vegetation, pathway subsidence, and slope changes will identify locations prone to recurrence. If poor drainage is left unaddressed, the same power generation losses will be repeated.

Maintaining inspection routes is also important. If grass is overgrown and impassable, the ground is muddy so you can't approach, equipment numbers are hard to read, or photos alone don't convey the location, discovery and sharing of anomalies will be delayed. Even if you find underperforming equipment in the data, if it's difficult to reach the corresponding location on site, corrective measures will be delayed. To avoid losses over the long term, keeping the power plant easy to inspect is also an important part of asset management.

Improvements to drainage and inspection routes may not immediately translate into increased power generation. However, in the long term they can reduce the recurrence of dirt, the overgrowth of weeds, poor ventilation, overlooked cable abnormalities, and delayed inspections. By not only addressing immediate cleaning and repairs but also creating a site environment that makes the same causes less likely to occur, it becomes easier to proactively prevent declines in power generation.

Equipment Management 7: Continuously Improve with Inspection Records and Location Information

To sustain equipment management aimed at increasing power output, keeping inspection records is indispensable. Even if dirt, shadows, anomalies, or poor drainage are found on site, if the location is not accurately shared, taking countermeasures or rechecking will take time. Especially at large power plants, where similar rows and equipment are lined up, it can be difficult to determine locations from photos alone. By linking inspection results with location information and managing them, the practical work of improving power output becomes easier to carry out.

What you should record are the locations of equipment with low power generation, rows that are prone to dirt, locations where shadows occur, places where water accumulates, points suspected of poor connections, locations where conversion equipment has stopped, places that were repaired, and the areas where cleaning or weeding was carried out. Keeping photographs, dates and times, equipment numbers, work performed, descriptions of abnormalities, response status, and whether reinspection is necessary will be useful for the next inspection. Because adding too many items to record makes it hard to continue the work on site, it is important to start by ensuring that, when reviewed later, it is clear where and what happened.

Linking power generation data with on-site photos makes it easier to determine causes. If the locations of installations with low output overlap with areas where shadows occur or drainage is poor, the rationale for countermeasures becomes clear. If the power generation at a cleaned location improves, you can conclude that soiling had a significant impact at that site. If morning and evening output improves after weed removal, it is likely that shading from weeds was the cause. Having records speeds up decision-making in future assessments.

Leaving gaps in recordkeeping will cause the same problems to recur. Even if there are patterns—grass growing in the same spot every year, dirt accumulating in the same row, the same walkway getting muddy after rain, or the same equipment experiencing stoppages—without records the next response will be ad hoc. To avoid losses in long-term operation, it is important to narrow down where to check using past records rather than searching for the cause from scratch each time.

To sustain the effects of power generation improvements, also record the power output after the measures. When you perform cleaning, weeding, repairs, equipment checks, and drainage checks, document the power output before and after the work, on-site photos, the scope of work, and weather conditions. Prioritize measures that showed a large effect for future actions, and consider alternative causes for measures that showed a small effect. Repeating this cycle provides the foundation for transforming power generation improvements from temporary tasks into long-term operational management quality.

Management decisions to avoid losses during long-term operation

To avoid losses over long-term operation, it is important not only to respond after power generation declines but also to identify in advance the conditions that tend to cause generation losses. Decreases in power generation may appear suddenly and markedly, or accumulate gradually as small losses. Partial string degradation, short periods of equipment downtime, morning and evening shading, soiling at the lower edge, and poor ventilation can be difficult to detect in daily power generation data. However, if they persist over a long period, they will affect the overall performance of the power plant.

In management decisions, prioritize locations that have the greatest impact on power generation. Equipment that shows a clear drop in output in the generation data, shadows that last for long periods, recurring soiling or drainage failures, converters that experience frequent short interruptions, and connection points that become unstable after rain are all items that should be checked promptly. By managing from the locations with the largest generation losses rather than the most visually obvious spots, you can more efficiently improve power output.

Also, it is important to anticipate seasonal power generation losses. In spring, watch for pollen and yellow sand; in summer, weeds and high temperatures; after typhoons, soil and fallen debris; in autumn, fallen leaves; and in winter, shading and frost caused by the sun’s lower altitude. If power output drops in the same place at the same time every year, there may be seasonal causes. Keeping season-by-season inspection records will allow you to take measures in subsequent years before power generation drops significantly.

In facility management, it is necessary to consider short-term recovery of power generation and long-term prevention of recurrence separately. Cleaning and weeding can show relatively quick effects if the causes are the same. On the other hand, drainage improvements, organizing inspection routes, and record management may not immediately appear as increases in power generation. However, in the long term they reduce missed inspections, duplicated work, delayed detection of abnormalities, and recurrence of the same generation losses. To avoid losses in long-term operation, it is important to place emphasis not only on immediate power generation but also on the reproducibility of management.

When multiple people are responsible for management, a system for sharing information is also necessary. If anomalies found on site remain only in the memory of the person who found them, it becomes difficult to use them in subsequent inspections or repairs. By linking equipment numbers, location information, photos, work histories, and power generation data, stakeholders can more easily verify the same location. Equipment management to increase power generation is also about creating a mechanism that turns on-site observations into the next set of improvements.

Summary

In equipment management aimed at increasing power generation, the important thing is to isolate, in order, where generation losses occur and why, and to improve starting with the places that have the greatest impact on output. In solar power generation, it is not possible on site to increase the amount of solar radiation itself. However, you can improve generation by bringing the system closer to a state that converts received solar radiation into electricity without waste. To do this, you need to check, in order, generation output data, dirt on panel surfaces, shading from weeds and trees, strings and connection points, conversion equipment, drainage, and inspection records.

To avoid losses in long-term operation, rather than immediately performing cleaning or repairs, it is important to first separate and review the data. Determine when output is low, which equipment is underperforming, and whether there are differences compared with equipment under the same conditions. By then inspecting the site, you can clearly identify where cleaning is needed, the areas that require weed removal, connection points that need inspection, equipment that should be checked, and drainage or access routes that should be reviewed. The basis of facility management is to make decisions by linking power generation data with on-site conditions, not by intuition.

Also, improving power generation is not something that can be completed in a single operation. Even if you clean, dirt will accumulate again; even if you remove weeds, grass will grow; trees will continue to grow; and equipment and wiring will degrade over time. By comparing power generation before and after countermeasures, keeping on-site photos and work histories, and using them for the next inspection, the accuracy of improvements increases. To steadily increase power generation, it is essential not only to eliminate the causes but also to create a site environment and management system that make the same causes unlikely to recur.

In particularly large power plants, a system for accurately sharing problem locations is important. If you record dirty-prone rows, locations where shading occurs, places where water accumulates, abnormal strings, locations suspected of connection anomalies, locations where conversion equipment has stopped, cleaning ranges, repair locations, and inspection photos together with location information, stakeholders can more easily confirm the same locations. By combining power generation data with on-site location information, it becomes easier to explain the priorities for cleaning, weeding, repairs, and specialist inspections, and it also streamlines recurrence checks on future visits.

If you want to continue equipment management that increases power generation based on long-term operational field data, utilizing LRTK is also effective. As an iPhone-mounted high-precision GNSS positioning device, LRTK is useful for recording inspection locations within a solar power plant, soiling-prone areas, locations where shadows occur, areas with poor drainage, abnormal equipment, connection points and areas around devices, cleaning coverage, repair locations, and on-site photos together with high-precision location information. By keeping the verification results of the seven equipment management items with location information, it becomes easier to promote power generation improvements based on field data rather than intuition.