Seven Basic Maintenance Practices to Prevent Power Generation Shortfalls

When you want to increase the power output of a solar power system or prevent power generation shortfalls, the first thing to address is not adding equipment but reviewing your routine maintenance system. Solar power systems operate outdoors for long periods, and output can decline due to shading, dirt, fallen leaves, snow accumulation, rising temperatures, wiring or equipment faults, and changes in the surrounding environment. To prevent power generation shortfalls, it's important to continuously monitor generation data, assess on-site conditions, and perform necessary cleaning and inspections at the appropriate times. This article explains, in seven parts, the basic maintenance practices to prevent power generation shortfalls in solar power systems for practitioners searching for "how to increase power generation".

Table of Contents

• Maintenance strategies to prevent power generation shortfalls

• Basic 1: Check monthly and time-of-day generation data

• Basic 2: Inspect shading sources and changes in the surrounding environment

• Basic 3: Check panel surface for dirt, fallen leaves, and bird droppings

• Basic 4: Check for abnormalities after snowfall, strong winds, and typhoons

• Basic 5: Regularly inspect wiring, connections, and power conversion equipment

• Basic 6: Ensure inspection routes, drainage, and maintenance space

• Basic 7: Keep maintenance records and verify the effectiveness of improvements

• Maintenance decisions to avoid

• Summary

Maintenance Approach to Prevent Power Generation Shortfalls

Maintenance for solar power generation should not be something that is dealt with only after a failure occurs. Rather than investigating causes after power output has dropped significantly, it is important to routinely check generation data and on-site conditions to quickly detect small anomalies and environmental changes. Power shortfalls can happen suddenly, but in many cases they develop gradually due to the accumulation of dirt, tree growth, equipment degradation, and insufficient inspections.

The amount of electricity generated by solar power naturally fluctuates with the weather and the seasons. In winter, shorter daylight hours and a lower solar elevation tend to reduce generation. In summer, although solar irradiance is higher, elevated panel temperatures can cause output to fall. In spring, pollen and yellow dust; in autumn, fallen leaves and dirt after typhoons; and in winter, snow cover and long shadows affect generation. Thus, while there are natural reasons for changes in generation, there are also causes that can be improved.

In maintenance to prevent power generation shortfalls, it is important to distinguish between natural variability and abnormal drops. If you judge a lower output than the previous month alone as an anomaly, you may misinterpret seasonal variation. Conversely, if you assume it’s due to the season and leave it unaddressed, you may miss shading, soiling, equipment faults, or wiring abnormalities. To increase power generation, you need to isolate causes using both data and on-site inspections.

Also, the purpose of maintenance is not only to temporarily restore power output. It is to maintain conditions that enable stable power generation over the long term. Keeping panel surfaces clean, identifying the causes of shading, detecting equipment abnormalities early, ensuring drainage and inspection routes, and leveraging past inspection records all help prevent insufficient power generation.

Even if you want to increase power generation, you should first confirm that your existing equipment is delivering its intended output. Before adding more equipment, you may be able to recover generation lost to shading, dirt, or equipment malfunctions. Maintenance to prevent generation shortfalls is fundamental to keeping solar power systems reliable over the long term.

Basic 1: Check monthly and time-of-day power generation data

The first basic step to prevent insufficient power generation is to check power generation data regularly. The condition of a solar power installation is not always apparent from an on-site inspection alone. By reviewing generation data by month, by time of day, by installation surface, and by system/grid, you can detect early signs of reduced output.

Looking at monthly power generation, you can see seasonal variations. If only winter is low, check for short sunlight hours, winter shadows, and the effects of snowfall. If summer does not increase as expected, check for output reduction due to high temperatures, soiling, overheating of equipment, and output capping. If growth stalls in spring, suspect pollen, yellow sand, or dust adhesion. If a decline is noticeable in autumn, check for fallen leaves and soiling after typhoons.

It’s also important to look at power generation by time of day. If morning output is weak, shading on the east side may be involved; if output drops early in the evening, shading on the west side may be related. If there’s an unusual dip around midday, check for shadows from rooftop equipment or rooftop structures, equipment output limitations, or abnormalities at connection points. If output falls at the same time even on clear days, it’s highly likely that causes other than the weather are responsible.

If you can check power generation by installation surface or by circuit, it becomes easier to narrow down the cause. If generation is low overall, check the weather, overall soiling, common equipment, and output conditions. If only a specific surface is low, check that surface’s orientation, tilt, shading, soiling, and fallen leaves. If only a specific circuit is low, check the wiring, connections, and the condition of the power conversion equipment.

When reviewing power generation data, comparing only with the previous month is insufficient. Because seasonal variation is large, compare with the same month of the previous year, sunny days in the same season, the simulation values at the time of installation, and generation per unit of installed capacity. A value lower than the previous month is not necessarily abnormal, but if it is clearly lower than the same month of the previous year or the simulation values, the priority for inspection increases.

By regularly reviewing power generation data, maintenance stops being an intuitive task. If you can identify which months, which times of day, and to what extent power output is declining, it becomes easier to prioritize shading countermeasures, cleaning, and equipment inspections. To prevent insufficient power generation, it is essential to first create a system for continuously monitoring the data.

Basic 2: Inspect shadow sources and changes in the surrounding environment

The second basic measure to prevent insufficient power generation is to regularly inspect sources of shadows and changes in the surrounding environment. When solar panels are shaded, they cannot receive sufficient sunlight and power generation decreases. Shading is a common cause of reduced power output, but because it varies with the seasons and time of day, it is easily overlooked.

Causes of shading include surrounding buildings, rooftop equipment, roof penthouses, railings, piping, air conditioning equipment, ventilation equipment, utility poles, signs, trees, slopes, and differences in terrain elevation. For rooftop projects, shadows from rooftop equipment and adjacent buildings tend to be problematic, while for land projects, shadows from trees, utility poles, slopes, and surrounding structures are relevant. Even if there is little shading at the time of installation, conditions may change over time.

Particular attention should be paid to shadows in winter. Because the sun's altitude is lower in winter, shadows that did not reach the panels in summer can extend onto them. Even if an on-site check during a summer daytime shows no problems, shadows can occur in the winter mornings and evenings. If power generation is significantly lower only in winter, you need to check not only the hours of sunlight but also winter shadows.

The growth of trees and plantings is also important. Trees that were low at the time of installation can grow and cast shadows on the panels after several years. Trees can cause not only shading but also leaf litter and bird droppings. For trees that can be managed on-site, consider pruning and branch management. For things that cannot be freely addressed, such as neighboring trees or utility poles, assess the impact of shading and incorporate it into power generation assumptions and maintenance plans.

Changes in the surrounding environment are also subject to inspection. Changes such as new equipment being added to the rooftop, a building being constructed on adjacent land, nearby construction starting, or changes in land use can affect power generation. Because the conditions at the time of installation may not remain the same, it is important to periodically update and verify the site conditions.

Shadow inspections combine power generation data with on-site checks. If output is low only in the morning, inspect the east side; if only in the evening, inspect the west side; if there is a dip around midday, focus on equipment near the solar panels. Recording the shadow’s position, cause, and the times it occurs will help with future inspections and improvement planning. To prevent insufficient power generation, it is necessary to continuously manage changes in shading.

Basic 3: Check the panel surface for dirt, fallen leaves, and bird droppings

The third basic point is to check the condition of the panel surface. Solar panels generate electricity from sunlight that hits their surface. If dirt, fallen leaves, bird droppings, dust, or similar contaminants adhere to the surface, sunlight cannot reach it easily and power generation decreases. Because dirt often accumulates gradually, it can be difficult to notice as the cause of insufficient power generation.

Causes of soiling include sand dust, pollen, yellow sand, exhaust-derived deposits, airborne particulates, fallen leaves, bird droppings, and residual material left after snowfall. Sites with many trees nearby are more likely to be affected by fallen leaves and birds. If unpaved land, farmland, construction sites, material storage yards, or roads with heavy traffic are nearby, soil dust and particulates are more likely to adhere. On rooftops, panels located near vents or exhaust equipment can become soiled locally.

Whether soiling is affecting power output is determined by combining generation data with on-site inspection. If output does not recover after rain, if only a particular roof surface shows lower output, or if output is gradually declining, we suspect soiling. Bird droppings and fallen leaves can locally block sunlight and therefore affect power output more than they might appear.

When performing cleaning, prioritize safety and the protection of equipment. Work on roofs carries a risk of falling and is especially dangerous on wet or sloped roofs. Scrubbing aggressively with hard tools, using detergents that are not suitable for the surface, applying high-pressure water, or carelessly spraying water around electrical equipment can damage the equipment. Cleaning is a way to increase power generation, but it must not put equipment or workers at risk.

Consider the timing of cleaning based on the local environment. In spring, watch for pollen and yellow sand; in autumn, fallen leaves; in winter, residual material after snowfall; and at sites with heavy dust, pay attention after strong winds or nearby construction. Regularly inspect surface conditions and perform cleaning as necessary to help prevent reduced power generation.

After cleaning, check whether the power output has improved. Comparing on similar sunny days, at the same time of day, and on the same installation surface makes it easier to judge the effect of cleaning. If there is no improvement after cleaning, you need to check for other causes such as shading, equipment issues, wiring, or temperature. Inspecting the panel surface is a basic maintenance practice to prevent insufficient power generation.

Basic 4: Check for abnormalities after snow accumulation, strong winds, and typhoons

The fourth basic practice is to check for abnormalities after snow accumulation, strong winds, and typhoons. Because solar power generation equipment is installed outdoors, it is directly affected by the weather. In addition to everyday dirt and shadows, checking whether the equipment or the surrounding environment has changed after severe weather conditions can help prevent shortfalls in power generation.

In snowy regions, periods when solar panels cannot generate power occur because snow covers the panel surface. Not only the time while it is snowing, but also the time that snow remains after snowfall affects the amount of power generated. If the panel tilt is small, snow may be less likely to slide off. Even after snow has fallen off, snow can accumulate beneath or in front of the panels and create shading. If winter power generation is lower than expected, check the condition of snow cover and remaining snow.

After strong winds or typhoons, fallen leaves, branches, airborne debris, sand, dust, and fine particulates can remain on panels and roofs. Even if they do not directly cover the panels, accumulation around roof drains can affect roof management. It is also necessary to check whether airborne debris has caused abnormalities in the panels, wiring, racking, or ancillary equipment. If power generation drops suddenly after a typhoon, suspect not only dirt and shading but also malfunctions in equipment or wiring.

After strong winds, inspections check not only the condition of the panels and mounting racks but also changes in the surrounding environment. There may be cases such as tree branches breaking and creating new shading, nearby equipment moving, or fallen leaves and branches accumulating on specific surfaces. If on-site conditions have changed, we compare them with power generation data to confirm the impact.

Safety is the top priority when inspecting after snowfall, strong winds, or typhoons. Avoid attempting work on roofs that still have snow or in unstable conditions immediately after strong winds. First, check the power generation data and, within areas that appear safe, assess the on-site conditions. If necessary, carry out the inspection with an appropriate team and safety measures in place.

It is also important to keep inspection records after weather events. Recording when and what kind of weather occurred, which areas were inspected, and how power generation changed will help with future responses. At sites where reductions in generation from snowfall or typhoons occur around the same time each year, incorporating inspections into the inspection plan in advance makes it easier to prevent power shortfalls.

Basic 5: Regularly inspect wiring, connection points, and power conversion equipment

The fifth basic is to regularly inspect wiring, connection points, and power conversion equipment. In solar power generation, even if the panel surfaces are clean and there is little shading, problems with wiring or equipment can prevent you from sufficiently utilizing the power generated. To prevent a shortfall in power output, it is also necessary to check the condition of the electrical pathways.

The power generated by the panels is sent through wiring to power conversion equipment and converted into a form usable by the facility. During this process, wiring losses, poor connections, or equipment outages can reduce the amount of electricity actually available. If generation suddenly drops, or if only a specific system shows low output, it is necessary to check the condition of the wiring, connection points, and equipment.

The condition of wiring can be difficult to determine by visual inspection alone. Under conditions such as long wiring distances, complex wiring routes, or limited access to connection points, faults tend to be discovered late. When installing new systems or expanding existing ones, it is important to arrange wiring routes and equipment locations so they are easy to maintain. Even for existing installations, wiring and connection points should be included among the items to check when power generation decreases.

Regularly check the condition of the power conversion equipment as well. If the equipment is not operating properly, the amount of electricity available for use at the facility will decrease even if the panels are generating. If output plateaus around midday, only a particular system shows low values, or generation suddenly drops, suspect the condition of the equipment. Also verify whether there are conditions such as the area around the equipment tending to become hot, poor ventilation, or difficulty in carrying out inspections.

Since equipment inspections involve specialized matters, it is important that operational staff not be forced to make judgments on their own; instead, organize power generation data and on-site conditions to clarify the necessary scope of inspection. Electrical checks that involve hazards must be carried out under appropriate supervision and safety arrangements.

Wiring and equipment maintenance is a measure more to prevent the loss of the power output that should be obtained than to directly increase generation. If cleaning panels and addressing shading do not restore output, the cause may lie in the electrical pathways. Regular inspections to detect abnormalities early help prevent insufficient power generation.

Basic 6: Ensure inspection access routes, drainage, and maintenance space

The sixth basic is to ensure inspection access routes, drainage, and maintenance space. In maintenance aimed at preventing insufficient power generation, it is important not only what to inspect but also whether the equipment is in a condition that allows inspection. If the layout makes inspection and cleaning difficult, dirt and defects may be detected late, potentially prolonging the decline in power generation.

For roof projects, we check access to inspection walkways, roof drains, rooftop equipment, inspection hatches, and the waterproofing layer. If panels are installed across the entire roof to increase power generation, cleaning roof drains, inspecting rooftop equipment, and carrying out waterproofing repairs can become difficult. If leaves or debris accumulate around drains and cannot be inspected, it will also affect building management.

For land projects, we check maintenance access paths, weed control, drainage, and workspace around equipment. On land where vegetation grows easily, managing areas around panels and access paths is related to maintaining power generation. In locations with poor drainage, muddy conditions and impediments to maintenance work may occur. If there is not enough space around equipment, inspections and replacements become difficult.

Securing maintenance space may slightly reduce the number of panels that can be installed. However, this is not a decision to lower energy production, but a decision aimed at maintaining energy production over the long term. Even if capacity is increased in the short term, if inspections and cleaning cannot be carried out, responses to soiling and faults will be delayed. As a result, long-term energy production may decline.

Inspection access routes can be difficult to secure after installation. Therefore, when constructing new facilities or carrying out expansions, it is important to treat maintenance access routes as a design condition in addition to power generation simulations. For existing facilities, confirm whether inspections and cleaning can be performed using the current access routes, and if there are problems, review the maintenance plan.

To prevent a shortfall in power generation, it is necessary not only to install equipment but also to be able to continually manage it. Securing inspection routes, drainage, and maintenance space makes it easier to quickly identify the causes of reduced power generation and respond appropriately.

Basic 7: Keep maintenance records and verify the effectiveness of improvements

The seventh basic is to keep maintenance records and verify the effectiveness of improvements. Even if inspections and cleaning are performed, without records they cannot be applied to future work. To prevent insufficient power generation, it is important to record what was checked at which location, which countermeasures were taken, and how the power generation changed.

Items to record include the inspection date and time, weather, the area inspected, the condition of power generation, presence of dirt, sources of shadows, the condition of fallen leaves or snow accumulation, inspection results for equipment and wiring, and any cleaning performed or actions taken. Recording photos and location information together makes it easier to check the same spot at the next inspection. For large roofs or plots of land, it is especially important to clearly specify which face or area was inspected.

In verifying the effectiveness of improvements, we compare power generation before and after maintenance. However, because power generation naturally varies with different weather and seasons, a simple before-and-after comparison is insufficient. We compare with similar sunny days, the same month of the previous year, simulated values, generation by time of day, and generation by installation surface. We confirm whether generation recovered after cleaning, whether generation during specific time periods improved after shadow mitigation, and whether generation by system returned after equipment inspection.

By continuing to keep records, site-specific trends will emerge. You can identify patterns such as heavy dust every spring, leaves tending to accumulate in autumn, pronounced shadows at certain times of day in winter, or dirt concentrating on particular surfaces after typhoons. Once these trends are understood, future inspections and cleanings can be moved forward, making it easier to prevent power generation shortfalls.

Maintenance records are useful for internal briefings and consultations with contractors. When explaining why power generation is low, having generation data, photos, the date and time of inspection, and location information is more persuasive than subjective descriptions. It also makes it easier to determine the priority of corrective measures.

Maintenance aimed at increasing power output is not something that can be completed with a single inspection. By continuously following the cycle of recording, comparing, improving, and verifying, you can prevent long-term power output shortfalls. Maintenance records are an important management asset for safeguarding power output.

Decisions to avoid in maintenance

In maintenance intended to prevent insufficient power generation, what should be avoided is proceeding with cleaning or replacement without confirming the cause of low generation. If dirt is the cause, cleaning is effective, but if the cause is shading, snow accumulation, equipment outages, wiring faults, or temperature-related losses, cleaning alone will not improve the situation. First check the generation data, inspect the site conditions, and select the response that matches the cause.

Also, avoid attempting unsafe work on roofs. Work on roofs or at heights carries a risk of falling and is especially dangerous on wet or sloped roofs. Do not carry out inspections or cleaning that compromise safety just to increase power generation. Distinguish between work that can be safely checked and work that requires a professional team.

Maintenance that damages panels or equipment must also be avoided. Actions such as scrubbing forcefully with hard tools, using unsuitable detergents, applying high-pressure water, or carelessly spraying water around electrical equipment can lead to equipment deterioration or failure. Cleaning and inspections are measures to increase power generation, and methods that put strain on equipment are counterproductive.

Be careful about judging maintenance effectiveness based only on annual energy production. Annual production is affected by weather and seasons, so it can be difficult to discern the effects of measures. To evaluate the effects of cleaning and inspections, it is important to compare generation under similar sunny-day conditions, by time of day, and by installation surface.

Furthermore, it is best to avoid decisions that increase installed capacity at the expense of maintainability. Even if you add more panels, a layout that prevents inspection and cleaning will make it difficult to sustain power generation over the long term. Maintenance aimed at preventing generation shortfalls should focus not only on increasing output but also on creating conditions that allow continuous management.

Maintenance is not a short-term measure to increase power generation, but a system to protect generation over the long term. Consistently carrying out cause identification, safety checks, record keeping, and verification of effectiveness leads to maintenance that does not fail.

Summary

To prevent insufficient power generation, maintenance should include checking generation data, inspecting for shading, checking panels for surface dirt, inspecting after snowfall or strong winds, verifying wiring and equipment, ensuring inspection access routes and drainage, and keeping ongoing maintenance records. To increase generation output, confirm that existing equipment is producing its intended power before adding more capacity.

In Basic 1, check monthly and time-of-day power generation data. By understanding when, where, and how generation is declining, the locations that require inspection become clear. In Basic 2, inspect sources of shading and changes in the surrounding environment. Nearby buildings, rooftop equipment, trees, utility poles, and differences in terrain elevation can cause reduced generation. In Basic 3, check the panel surface for dirt, fallen leaves, and bird droppings. If the surface is obstructed, generation will decrease even with the same equipment.

Basic 4 checks for anomalies after snowfall, strong winds, and typhoons. After weather events, changes may occur on panel surfaces, racking, wiring, and in the surrounding environment. Basic 5 involves periodic inspection of wiring, connection points, and power conversion equipment. Even if panels are generating power, problems along the path that brings electricity to a usable state at the facility can lead to insufficient power supply. Basic 6 ensures inspection access routes, drainage, and maintenance space. An arrangement that allows long-term inspection and cleaning is essential for maintaining power output. Basic 7 keeps maintenance records and verifies the effectiveness of improvements. If records are kept, they can be used for future inspections, internal reporting, and consultations with contractors.

What should be avoided during maintenance are cleaning or replacing components without confirming the cause, undertaking unsafe work on the roof, cleaning in ways that damage equipment, and failing to verify the effects with data. To prevent insufficient power generation, it is important to correctly identify the causes reducing output, carry out necessary countermeasures safely, and record the results to inform future actions.

Furthermore, accurate on-site information is indispensable for improving maintenance accuracy. If you can identify the installation area, rooftop equipment, obstacles, trees, site boundaries, orientation, slope, inspection access routes, and candidate connection points, it becomes easier to organize issues related to shading, soiling, drainage, wiring, and maintainability.

If you want to accurately record on-site installation coverage, obstacles, trees, rooftop equipment, property boundaries, orientation, tilt, inspection routes, and other details and efficiently carry out maintenance to prevent insufficient power generation, using LRTK, an iPhone-mounted GNSS high-precision positioning device, is effective. By obtaining high-precision local position information, it becomes easier to organize causes of shading, areas prone to soiling, areas that should be inspected, wiring routes, and maintenance routes, and to consistently proceed from inspection records to verification of power-generation improvements and post-installation performance management. To prevent insufficient power generation and maintain stable output, it is important to accurately grasp the site and continuously address the causes that reduce generation, rather than relying on intuitive maintenance.