How to Increase Power Generation and Precautions｜7 Foolproof Improvement Measures

Table of Contents

• Basics to Avoid Failures in Power Output Improvements

• Improvement Measure 1: View power generation data by time of day and by equipment unit

• Improvement Measure 2: Check the locations of soiling and their impact range before cleaning

• Improvement Measure 3: Manage shadows from weeds, trees, and structures

• Improvement Measure 4: Inspect for abnormalities in strings, connections, and cables

• Improvement Measure 5: Review shutdowns, curtailment, and temperature conditions of power conversion equipment

• Improvement Measure 6: Improve drainage, terrain, and inspection routes to prevent recurrence

• Improvement Measure 7: Continue improvements using inspection records and location data

• Failure patterns to watch when increasing power generation

• Summary

Fundamentals to Avoid Failures When Improving Power Generation

When aiming to increase the output of a solar power system, the first important thing is not to jump straight into cleaning or replacing equipment. If you feel the output is low, not growing as expected, or lower than the previous year, you may be tempted to immediately suspect dirty panels or equipment faults. However, the cause of reduced output is not necessarily a single one. Weather, solar irradiance conditions, dirt on the panel surface, shadows from weeds or trees, faulty connections, stoppage of conversion equipment, output curtailment, temperature rise, poor drainage, and insufficient inspection records are among the multiple factors that can combine to reduce output.

When considering how to increase power generation, the first point to grasp is that you cannot increase the amount of solar irradiance on-site. On the other hand, you can move the system closer to a state where the received solar irradiance is converted into electricity with as little waste as possible. In practical terms, improving power generation means finding the causes of lost potential output and taking measures to reduce generation losses. Before adding more equipment, it is important to ensure the existing equipment can operate to its full potential.

A common reason projects to improve power generation fail is deciding on the cause based only on impressions at the site. If you conclude that the panels are dirty and therefore should be cleaned, that grass has grown and therefore should be removed, or that the equipment looks old and therefore should be replaced, the primary cause of the drop in generation and the countermeasures may not align. For example, even if there is some dirt on the panel surface, shadows in the morning and evening may actually be the main cause. Conversely, even if there appear to be no major visible abnormalities, only a specific string may be experiencing a decline.

To avoid failure, it is essential to link power generation data with on-site conditions and check them. Determine when output is low, which equipment is underperforming, whether there is a difference compared with equipment under the same conditions, whether output is low even on sunny days, and whether it becomes unstable after rain. Then, in order, check soiling, shading, connection points, equipment, drainage, and inspection records. A result showing low power generation alone does not tell you what to address first. Having a process to isolate causes clarifies the priority of work.

Also, improvement measures need to be considered through to verification of their effects after implementation. After cleaning, weeding, or repairs, you must check how power generation has changed; otherwise you cannot tell whether those actions were truly effective. Recording before-and-after photos, power generation data, the scope of work, work dates, and weather conditions will provide material for future decisions. Efforts to increase power generation are not one-off tasks but an ongoing management process of identifying causes, implementing countermeasures, verifying effects, and preventing recurrence.

Improvement Measure 1: View power generation data by time of day and by facility

The first step to improving power generation is to examine generation data in detail. If you only look at monthly or annual generation totals, you won’t know when, where, or how generation losses are occurring. Even if nothing looks abnormal on a monthly basis, there may be cases where output drops during certain hours of sunny days, or where specific equipment consistently performs lower than its surroundings. To increase generation, it is important to check data broken down by time of day, by individual equipment, by day, and by season, rather than relying on the overall total.

If generation is low in the morning, shadows from trees on the east side, embankments/slopes, nearby structures, or adjacent equipment may be involved. If it is low in the evening, check for west-side shadows and the influence of surrounding terrain. If the midday peak does not develop, candidates include dirt on the panel surface, temperature rise, limitations of the power conversion equipment (inverters), output curtailment, or equipment shutdowns. If the generation curve suddenly drops during a sunny day, it is necessary to cross-check shutdown history and alarm history with the timestamps.

When comparing on an installation-by-installation basis, it is important to compare installations under the same conditions. If you simply compare installations with different orientations, tilts, numbers of panels, shading conditions, or connection configurations, you may mistake normal differences for abnormalities. If, compared with adjacent rows or installations with the same orientation, a specific area is consistently lower, suspect localized soiling, partial shading, connection faults, cable damage, or equipment-side malfunctions.

The key point is not to confuse the effects of weather with problems at the power plant. During periods with a lot of cloudiness or rain, power generation will decrease even if the equipment is operating normally. Rather than judging based only on days with low generation, compare days with similar weather as much as possible—preferably sunny days with other sunny days. Also, by distinguishing whether the entire plant is similarly low or only some equipment is low, it becomes easier to separate weather-related factors from equipment-related ones.

If you don't make a habit of checking power generation data, detecting abnormalities will be delayed. Short-term stoppages or partial equipment degradation may not stand out in monthly totals. However, if stoppages or reductions occur during periods of strong sunlight, generation losses can be large. To increase power generation, it's essential to use data to narrow down targets before on-site work and to identify where and when generation losses are occurring.

Improvement Measure 2: Check the Location and Extent of the Dirt Before Cleaning

As a measure to increase power output, panel cleaning is often considered. Because solar panels generate electricity by receiving sunlight at their surface, dirt or deposits reduce the light reaching the cells. The way panels become soiled varies with site conditions, such as soil dust, pollen, yellow sand, bird droppings, fallen leaves, sap, dust from nearby construction, road-derived dust, and salt-containing grime that tends to adhere in coastal areas. If soiling is related to a decrease in power output, appropriate cleaning can be an effective countermeasure.

However, it should be noted that just because something appears dirty does not necessarily mean cleaning should be the top priority. If the main causes of reduced power generation are shading or equipment shutdowns, cleaning alone will not produce sufficient improvement. Before cleaning, verify whether the lower-performing equipment corresponds to the areas where dirt is noticeable. If, compared with systems under the same conditions, only a particular row performs worse and that row has concentrated bottom-edge soiling or bird droppings, then the priority for cleaning is higher.

Particular attention should be paid to the band-like deposits that remain along the lower edge of panels and near the frame. It is often assumed that rain will wash them away naturally, but in reality rainwater can channel dirt toward the lower edge where it may remain. Panels with a shallow tilt do not drain well, making it easier for dirt to accumulate. Even soiling that is not noticeable from a distance can affect power output if it covers part of a cell. During inspections, check not only the overall color of the panels but also carefully inspect the lower edge, the corners, and the area around the frame.

Localized deposits such as bird droppings and fallen leaves should not be overlooked. Unlike dirt that spreads thinly across the entire surface, these cover specific spots densely and therefore act as partial shading. Rows near trees, areas around structures where birds tend to perch, leeward rows, and locations near unpaved walkways are more prone to soiling and deposits. Understanding the types of soiling and where they are likely to occur can inform future inspection and cleaning plans.

To avoid failures during cleaning, attention to work methods is also necessary. You should avoid vigorously scrubbing with hard tools, performing sudden work during times when panels are at high temperatures, and working without confirming the safety of electrical equipment. Cleaning is not a task to make things look tidy, but a maintenance task to restore light-receiving conditions and enable long-term, stable use of the equipment. By recording before-and-after photos, the work area, changes in power generation, and weather conditions, it becomes easier to verify the effectiveness of the cleaning.

Improvement Measure 3: Manage shading from weeds, trees, and structures

One thing you must always check when trying to increase power generation is shadow management. Because solar panels generate electricity by receiving sunlight, even a shadow over part of a panel can reduce power output. Causes of shadows include weeds, trees, fences, utility poles, surrounding buildings, mounting racks, adjacent rows of panels, monitoring equipment, and more. Since shadows move with the time of day and the seasons, the fact that no shadow was visible at the time of inspection does not necessarily mean there is no problem.

Weeds are a common cause of on-site power generation losses. Even if they are not a problem in winter or immediately after installation, they can grow rapidly from spring through summer and cast shadows on the lower edges of panels and on the front row. Even if the vegetation does not touch the panels, shadows lengthen when the sun is low in the morning and evening. Moreover, when weeds become overgrown they reduce ventilation, block inspection walkways, and make it difficult to check around equipment. Because they affect not only power output but also maintainability and safety, weed management is fundamental to improving power generation.

Shading from trees is a factor that often becomes problematic during long-term operation. Trees that had little impact at the time of installation can grow over several years and reduce power generation. Trees located to the south, east, and west can cast shadows on panels at different times of day. At power plants near forests or slopes, terrain elevation combined with tree height can overlap and create long shadows in winter. If generation is low only during winter, or there are large drops in the morning and evening, it is necessary to check trees and terrain together.

One common pitfall in shading countermeasures is making a judgment solely from an on-site check around noon. Even if no shadow is visible at noon, long shadows can appear in the morning and evening. If morning power generation is low, check the on-site conditions in the morning; if it is low in the evening, inspect the evening shadows. Also, even if there is no problem in summer, shadows can lengthen in seasons when the solar altitude is lower. Shadows need to be managed not as a single moment but as something that changes with time and season.

Pay attention to shadows cast by nearby structures and added equipment. Adding new equipment within the power plant, or installing fences, signs, or monitoring poles, can create shadows at certain times of day. To increase power output, it is important not only to reduce existing shading but also to operate in a way that does not generate new shading. When you find a shadow, record the time it occurs, the source of the shadow, the equipment affected, and take photographs; these records can be used to inform decisions on weeding, pruning, or repositioning.

Improvement Measure 4: Check for abnormalities in strings, connection points, and cables

To increase power generation, you need to check not only the panel surface and shading but also the routes for extracting electricity. Even if the solar panels are receiving sunlight normally, problems with connections or cables can prevent the generated electricity from being fully extracted. Differences in generation at the string level, loose terminals, poor contact, damage to cable sheathing, moisture ingress, damage caused by animals, damage during mowing, and deterioration due to aging are all important causes of reduced power output.

When checking for abnormalities at the string level, it is fundamental to compare units under the same conditions. If you simply compare ones that differ in panel count, azimuth, tilt, shading conditions, or connection configuration, you may mistakenly judge normal differences as abnormalities. Check whether any string is consistently lower compared with adjacent rows or installations with the same orientation. If only a particular string is low, candidates include dirty panels, partial shading, poor connections, cable damage, or problems on the equipment side.

Pay attention to how the anomaly appears. If generation is consistently lower than the surroundings even on clear days, dirt or connection problems may be suspected. If it is lower only in the morning and evening, check for shading. If anomalies tend to appear after rain, moisture intrusion or the condition of connection parts may be involved. If instability occurs during periods of high temperature, poor contact or the temperature environment around the equipment are also possible causes. Combining the power output waveform with on-site conditions makes it easier to narrow down the cause.

The key point is not to touch electrical equipment casually to make a judgment. Checking connection points and cables requires measures that prioritize safety. Rather than having on-site personnel forcibly touch equipment to decide, gather and organize information about the equipment showing abnormalities, the time of occurrence, changes in power generation, site photographs, and the surrounding environment, and, if necessary, arrange for a specialized inspection. Do not perform work that skips safety verification simply to try to increase power generation.

Faults in connection points and cables can be related to the surrounding environment. In areas with heavy weed growth, it becomes difficult to inspect the condition of cables. Mowing operations may also come into contact with the cables. In locations with poor drainage, moisture and standing water can affect connection points. At power plants that are easily accessed by animals, cable damage may also occur. When improving power output, it is important to review not only electrical faults but also the site environment that can lead to recurrence.

Improvement Measure 5: Review the shutdown, suppression, and temperature environment of conversion equipment

The causes of low power output are not limited to the panels and wiring. If the equipment that converts the generated electricity is stopped or its output is restricted, generation will not increase even if solar irradiance is sufficient. When considering ways to increase power output, it is essential to check the operating status of the conversion equipment, shutdown history, alarm history, and whether output curtailment has been applied.

When reviewing downtime history, check which equipment 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 equipment is repeatedly stopping and restarting during the day, it may not stand out in the monthly totals, but in reality generation could be lost. Whether only specific equipment stops or multiple pieces of equipment stop simultaneously will change the suspected causes.

If output curtailment is occurring, generation can plateau even on sunny days. If the top of the generation curve appears flat, check the operational data and history. However, a flat curve does not necessarily indicate output curtailment. Equipment capacity limits, temperature increases, soiling, shading, and measurement anomalies can produce similar shapes. Do not judge based solely on the generation curve; it is important to verify by comparing equipment records with on-site conditions.

Temperature conditions are another point to review. While solar power generation is generally easier with stronger solar irradiance, output may not increase as much when temperatures rise. If generation does not rise as expected on a clear summer day, check not only the irradiance but also panel temperature and the temperature around the equipment. If weeds are flourishing under the panels, there is grass or obstacles around the equipment, or dust and deposits are making heat dissipation difficult, these can affect the increase in power generation.

Be careful not to confuse equipment-side faults with panel-side problems. Even if a panel appears to be dirty, the primary cause may actually be equipment shutdowns or output curtailment. Conversely, if there are no abnormalities in the equipment history, check other causes such as the panels, wiring, shading, dirt, and solar irradiance conditions. Cross-check the time of the power output drop with the equipment history, and choose countermeasures based on evidence rather than conjecture — this is the key to preventing failures.

Measure 6: Prevent recurrence by improving drainage, terrain, and inspection routes

To increase power output, you need to look not only at panels and equipment but also at the plant’s overall drainage, terrain, and inspection routes. Areas where water tends to pool, where sediment flows in, paths that easily become muddy, slope failures, scouring around the mounting structures, and locations where cables are likely to be exposed can directly or indirectly cause reductions in power output. Poor drainage and changes in terrain may at first appear unrelated to power generation, but they are important factors that lead to soiling, weed growth, faults at connection points, and reduced inspectability.

Areas where puddles remain after rain are prone to weed growth. When weeds grow, they create shade, reduce ventilation, and make inspections more difficult. Muddy pathways can slow work and may reduce the frequency of cleaning and weeding. Places where soil and sediment flow in can accumulate under panels and around cables, causing dirt and damage. If the same problem recurs in the same location despite cleaning and weeding, drainage or terrain issues should be suspected.

When checking terrain and drainage, on-site inspections after rain are as useful as inspections in fair weather. Identify where water flows in from, where it pools, and where it drains out. Recording puddles, sediment deposits, vegetation overgrowth, pathway subsidence, and slope changes will reveal locations that are prone to recurrence. If poor drainage is left unaddressed, dirt and weeds will recur, resulting in the same power generation losses occurring repeatedly.

Confirming inspection routes is also important. Locations that are difficult to inspect tend to delay the detection of abnormalities. If grass has overgrown so you cannot pass, if it is too muddy to get close, if equipment numbers are hard to read, or if abnormal locations are difficult to share, on-site responses will take longer. Even if you identify equipment with low power generation from the data, improvements will be delayed if it takes time to reach the corresponding site.

The key point is not to overlook measures whose impact on generation output is not immediately visible. Improvements to drainage, terrain, and inspection access routes may not produce effects as apparent as cleaning or weeding. However, over the long term they help reduce soiling, weeds, poor connections, and delayed inspections. To increase generation output stably, it is necessary not only to focus on the generation equipment itself but also to arrange the power plant environment so it is easier to manage.

Improvement Measure 7: Continue Improving with Inspection Records and Location Information

To avoid failure in improving power output, keeping inspection records is indispensable. Even if dirt, shading, abnormalities, or poor drainage are found on site, if the location is not shared accurately, countermeasures and rechecks will take time. Especially at large power plants, because similar rows and equipment are lined up, it can be difficult to identify the location from photos alone. By managing inspection results linked to location information, the practical work of improving power output can be greatly streamlined.

Items you should record include the locations of equipment with low power output, rows prone to soiling, spots where shadows occur, areas where water accumulates, points where connection failures occurred, locations that were repaired, and the areas where cleaning or weeding was performed. Keeping photos, the date and time, equipment numbers, the work performed, the nature of any abnormalities, the status of responses, and whether reinspection is required will be useful for the next inspection. Since adding too many record items makes it hard to maintain records in the field, it is important to start by making entries that, when reviewed later, clearly show where and what happened.

Linking power generation data with on-site photographs makes it easier to determine causes. If the locations of equipment with low power generation overlap with areas where shadows occur or where drainage is poor, the rationale for countermeasures becomes clear. If power generation at a cleaned location improves, you can conclude that dirt had a significant impact at that site. If morning and evening power generation improve after weeding, it is highly likely that shading from weeds was the cause. Having records makes future assessments faster.

The key point is not to be satisfied with merely keeping records. Records only become meaningful when they are used for subsequent inspections and countermeasures. If you can identify trends—grass growing in the same spot every year, dirt accumulating in the same row, the same pathway becoming muddy after rain, or the same equipment causing stoppages—you can take proactive measures before the problems grow larger. To increase power generation, it is important not to treat inspections as mere checks, but to accumulate them as information that can be used for improvement.

When management is shared among multiple personnel, it is important to be able to share the exact same location. By recording the equipment number, location information, and photos together, field staff, managers, inspectors, and repair technicians can more easily confirm the same location. Improving power output is not only about noticing issues on-site but also about preserving that information in a form stakeholders can share. By continuing records management, operations can move closer to preventing declines in power output before they occur.

Failure patterns to watch out for when increasing power generation

One common mistake when trying to increase power generation is to start work without checking the cause. Deciding to clean because power generation is low, to remove weeds because the grass has grown, or to consider replacing equipment because it is old is not necessarily wrong. However, if the main cause of the decline in power generation does not match the work being carried out, the expected improvement will not be achieved. Even if dirt is noticeable, if the main cause of the power drop is shading or equipment shutdown, cleaning alone is insufficient.

Another common mistake is failing to keep records before and after work. Even if you carry out cleaning, weeding, or repairs, you cannot verify improvement effects unless you have recorded the pre-work condition and power generation data. Repeating the same tasks without knowing their effects leads to ad hoc management. To increase power generation, you need to record the work date, scope of work, photos, changes in power generation, and weather conditions, and use them to inform your next decisions.

Conducting an on-site inspection without taking the time of day into account can also lead to failure. Shadows change depending on the time of day, so even if there is no problem at noon, large shadows can appear in the morning and evening. If power generation data shows a drop in the morning, an on-site inspection in the morning is necessary; if it drops in the evening, an on-site inspection in the evening is necessary. If the time when power generation falls and the time of the on-site inspection are misaligned, it becomes easy to miss the cause.

Avoid neglecting safety checks. Even if you want to increase power generation, carelessly touching electrical equipment or forcing work in areas with poor scaffolding or walkways can lead to accidents or equipment damage. Inspections of connection points, cables, or the interior of conversion equipment should be escalated to specialized inspections as needed. What on-site personnel should do is document the scope of the anomaly, the time it occurred, on-site photographs, and the surrounding environment, and establish a system that enables safe decision-making.

Another mistake is failing to identify the factors that cause recurrence. Even if you clean soiling, if poor drainage or sediment inflow remains, the same spot will become soiled again. Even if you remove weeds, if areas where water tends to pool or the sunlight conditions don’t change, the weeds will grow back in the same area. Even if you repair connections, if the causes of moisture or cable exposure remain, the problem can recur. To increase power generation, it is important not only to eliminate the immediate issues but also to create site conditions that make the same problems less likely to occur.

Summary

To avoid mistakes when trying to increase power generation, it is important to systematically isolate the causes of generation losses and address the areas that have the greatest impact on output first. In solar power generation, you cannot increase the amount of solar irradiance at the site itself. However, you can reduce generation losses by optimizing conditions so that the received sunlight is converted into electricity with minimal waste. To achieve this, you need to check in order: generation data, panel surfaces, shading, strings and connection points, power conversion equipment, drainage and inspection access routes, and inspection records.

If you notice low power generation, it is important not to immediately think about major renovations; first, separate and analyze the data. Determine when output is low, which equipment is underperforming, and whether there is a difference compared with equipment operating under the same conditions. With that information, an on-site inspection will clarify areas that need cleaning, the extent of weeding required, connection points to inspect, equipment to check, and drainage or access routes that should be reviewed. To maximize the effectiveness of improvement measures, make decisions by linking data with on-site conditions rather than relying on intuition.

As a precaution, you should avoid starting cleaning or repairs without confirming the cause, failing to keep records of work before and after, judging shadows without considering the time of day, omitting safety checks, and failing to look for factors that could cause recurrence. Improving power generation cannot be completed with a single operation. By comparing power generation before and after countermeasures, keeping on-site photos and work histories, and applying them to the next inspection, the accuracy of improvements will increase.

In particularly large power plants, a system for accurately sharing problem locations is important. If dirty-prone rows, shadowed areas, places where water accumulates, abnormal strings, repair locations, cleaning areas, and inspection photos are recorded 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, and repairs, and to streamline subsequent checks for recurrence.

If you want to continuously manage on-site measures to increase power generation and the points to watch, using LRTK is also effective. LRTK, as an iPhone-mounted high-precision GNSS positioning device, is useful for recording inspection locations, areas prone to soiling, places where shadows occur, locations with poor drainage, abnormal equipment, repair locations, cleaning ranges, and on-site photos within a solar power plant together with high-precision location information. To carry out improvement measures without failure, it is important to accurately identify the causes and to manage continued verification of the same locations. By using LRTK, it becomes easier to pursue power generation improvements based on field data rather than on intuition.