5 Maintenance Tips to Increase Power Generation | Checks to Perform Before Spending Money

Table of Contents

• Maintenance to increase power generation should prioritize the mindset of "reducing losses" rather than "increasing"

• Maintenance 1: Review generation data and isolate the causes of declines

• Maintenance 2: Check panel surface soiling and drainage conditions

• Maintenance 3: Periodically review sources of shading and the surrounding environment

• Maintenance 4: Inspect ventilation, wiring, and connection conditions around equipment

• Maintenance 5: Check changes in racking, ground, and tilt to prevent generation losses

• Decisions to avoid when improving power generation

• Management framework to continuously raise power generation

• Summary: Before spending money, review the site and establish the rationale for generation improvements

Maintenance to increase power generation: the mindset of 'reducing losses' is more important than 'increasing'.

When operations personnel at a solar power plant search for "how to increase power generation," they are often in a situation where they feel a decline in output or a gap from expectations. Behind this are concerns such as actual performance not meeting design assumptions, generation falling compared with the same month of the previous year, and being unable to determine whether the cause is weather or equipment malfunction.

However, what matters in the maintenance of solar power systems is not forcefully increasing output beyond the equipment’s inherent performance. What can realistically be done on site is to bring generation closer to the amount that should originally have been obtained. In other words, it is important to adopt the approach of identifying loss factors—such as dirt, shading, equipment heat, poor connections, ground shifts, and insufficient management—and gradually eliminating them.

Power generation is determined by a combination of factors such as solar irradiance, ambient temperature, panel orientation, tilt, surrounding shading, system capacity, equipment condition, cleanliness, installation quality, and operational management. Therefore, rather than expecting any single action to necessarily produce a large improvement, the basic approach to improving power output is to sequentially isolate and address the factors causing the decline.

Before spending significant money, a basic on-site review is essential. Before updating equipment, commissioning a professional survey, or considering large-scale renovations, you should first clarify what can be checked during routine inspections. Whether a drop in power generation is merely a seasonal fluctuation, the result of weather, localized soiling, increased shading, or equipment malfunction will greatly affect the measures that should be taken.

This article organizes five maintenance checks to verify before incurring costs to increase power output. The intended audience is operations staff who manage solar power plants, personnel who want to investigate causes of reduced power output from an on-site perspective, and managers who want to prepare explanatory materials for power output improvements. Before moving on to specialized equipment diagnostics, we explain, in line with practical operations, what to inspect and in what order to consider them.

Maintenance 1: Review power generation data to isolate the causes of a decline

When you want to increase power generation, the first maintenance action should not be on-site work but a review of the generation data. Even if you feel the output is low, if you cannot determine whether that decrease is abnormal or a natural fluctuation, you will not be able to implement the correct countermeasures.

Solar power generation is affected by the weather. During periods with many cloudy or rainy days, generation decreases, while it increases during periods with favorable sunlight conditions. Also, because the sun’s altitude and the duration of sunshine change with the seasons, there are natural differences in monthly generation. A simple comparison—such as being lower than the previous month or lower than yesterday—alone cannot determine whether maintenance is required due to an anomaly.

The first thing to check is a comparison with the same month of the previous year. Comparing the same season makes it easier to identify downward trends because conditions such as sunlight hours and solar altitude are relatively similar. Of course, there are year-to-year weather differences, but if power generation continues to decline over the long term, it may indicate that something has changed in the equipment or the environment.

Next, examine differences between sections within the same power plant. If the site is divided into multiple circuits or areas, your approach to possible causes changes depending on whether the whole facility is declining similarly or only part of it is. If the entire plant is declining, suspect weather, constraints on the receiving side, common equipment, overall soiling, etc. If only a portion is underperforming, candidates include area-specific shading, panel soiling, wiring, connections, equipment faults, changes in ground conditions, etc.

When looking at generation data, not only daily trends but also time-of-day trends are important. Changes such as being low only in the morning, only in the afternoon, suddenly dropping during a specific time period, or the output peak on clear days being lower than expected can indicate shading, equipment control, or connection issues. For example, if output drops only in the afternoon, nearby buildings, trees, slopes, or facility structures may be blocking afternoon sunlight. If it is low only in the morning, east-side shading, morning dew, or the influence of surrounding terrain should also be considered.

When improving power output, it is important to avoid subjective judgments. Impressions such as "It feels lower recently" or "It looks dirty" alone make it difficult to prioritize on-site work. By combining and checking power output, solar irradiance trends, time of day, area differences, and past performance, you can narrow down the locations that require inspection.

It is also important to retain data from before and after inspections. If you can confirm how power generation changed after performing cleaning, grass cutting, wiring checks, and tidying around equipment, you can use that information to inform future maintenance plans. Recording the date the work was carried out, the scope, the weather, and any observations will also make it easier to explain improvements in power generation.

Maintenance to increase power generation is more efficient if you analyze the data and form hypotheses before going to the site, rather than starting by inspecting the site. Instead of checking the whole system indiscriminately, identifying the sections or time periods where output has declined and then inspecting them makes it easier to get closer to the cause even in a short time.

Maintenance 2: Check the panel surface for dirt and drainage condition

A clear cause of reduced power output is dirt on the panel surface. Because solar panels generate electricity by receiving light, when dirt builds up on the surface the amount of light they receive is reduced, which can lead to lower power generation. Dirt can have a more localized effect than it looks, so you need to pay attention not only when the entire surface is slightly dirty but also when parts are covered with bird droppings, dust, fallen leaves, pollen, volcanic ash, drainage stains, or the like.

What you should particularly check is the soiling near the lower edge of the panel. After rainwater runs off, soil and dust can remain at the lower edge and form a narrow band of dirt. Such soiling may not be noticeable from a distance, but it can cause continuous shading of part of a cell. If the soiling is concentrated in certain areas, it can not only reduce power output but, depending on conditions, may also lead to localized heating or degradation risks.

Also, dirt is less likely to be washed away on low-slope installations. On gently sloped sites, the natural cleaning effect of rain is reduced, and water and dirt tend to remain on the surface. If there are unpaved areas, farmland, land under construction, or roads with heavy vehicle traffic nearby, dust is more likely to adhere. Near the sea, salt-containing grime, in mountainous areas fallen leaves and tree sap, and in locations with many birds, bird droppings can also contribute to reduced power generation.

However, you should avoid making the simple judgment that “it’s dirty, so clean it immediately.” Cleaning involves considerations such as ensuring safety during work, preventing scratches to the panel surface, the water and tools used, protection against electric shock, and the work flow. Incorrect cleaning can actually damage the equipment. Before cleaning, it is necessary to check the target area, the type of dirt, the impact on power generation, the work method, the weather, and the safety of the workers.

Before incurring costs, first record the distribution of soiling. Use photos and notes to document whether the whole area is equally soiled, only specific rows are soiled, only the lower edge is soiled, bird droppings are scattered, or there are rain-streak marks. Checking whether the sections showing reduced power output in the generation data match the areas where soiling is noticeable on site makes it easier to determine cleaning priorities.

Checking drainage conditions is also important. If water on the panel surface does not drain properly and tends to pool in certain spots, dirt is more likely to become fixed. The tilt of the mounting structure, ground settlement, clogged drainage paths, or mud splashing from the surrounding area may be involved. Even if cleaning makes them look clean temporarily, if the drainage is poor the dirt will accumulate again.

Maintenance of panel surfaces is not simply about cleaning. The objective is to identify where dirt tends to accumulate, why it occurs, and which sections' power output is being affected. By reviewing the causes of soiling, you can implement follow-up measures such as adjusting cleaning frequency, mowing, improving drainage, and reorganizing surrounding traffic routes.

Maintenance 3: Regularly review sources of shadows and the surrounding environment

Managing shading is important for increasing power generation. Even if a solar power plant assessed shading impacts at installation, the surrounding environment can change after operations begin. Trees can grow, weeds can become taller, structures may be installed nearby, slope vegetation can change, and the placement of equipment and materials on site can be altered—sources of shading can increase over time.

The difficult aspect of shadows is that they can affect power generation even over short periods. In particular, if part of a panel or some cells are shaded, it can affect not only that area but also the output of the circuit to which they are connected. Even a thin shadow, if it falls at the same time every day, can amount to a yearly loss that is hard to ignore.

What should be checked on site are the shadows at different times of day on sunny days. Rather than only looking around noon, check how the shadow positions change in the morning, late morning, afternoon, and evening. If power generation data shows a drop in the morning or afternoon, it is important to observe shadows on site during that time. If you inspect the site during the daytime, see no shadows, and conclude there is no problem, you may overlook shadows that occur in the morning and evening.

Particular attention should be paid to trees near the site boundary and to vegetation on slopes. Even if there is no problem immediately after installation, branches can grow over several years and shadows may reach the site depending on the season. In summer foliage is dense, and in winter the sun angle is lower, so the way shadows appear changes with the seasons. For deciduous trees, the intensity and shape of shadows change between summer and winter, so a single inspection is not sufficient to make a judgment.

Weeds should not be overlooked. In ground-mounted solar plants, grass growing in front of panels can cast shadows on their lower edges. Even if the grass shadow is localized, it can affect power generation if it falls on the lower portion of a row of panels. Also, when grass grows tall it can obstruct inspection routes, making it easier to miss abnormalities in wiring or mounting structures. Mowing is not just about appearance; it is maintenance that protects power output and maintainability.

Materials and temporarily stored items on-site also need to be checked. Inspection tools, construction materials, signs, items near fences, and installations around electrical equipment can cast unexpected shadows. Even short-term temporary placement can complicate investigations into the cause if it affects power generation data. Within the power plant, it is advisable to establish a rule prohibiting placing items in front of panels or in locations that could block sunlight.

When reviewing shadows, it is important to record not only site photos but also the times and positions at which shadows appear. Recording which row and approximately where, at what time, and from which direction shadows fall makes it easier to correlate with power generation data. Taking photos from the same spot at each inspection makes it easier to notice the growth of trees and weeds and changes in the surrounding environment.

Shading countermeasures to increase power generation are not about adding equipment but about reducing factors that block sunlight. Simply continuing grass cutting, branch management, removal of temporarily placed items, keeping inspection walkways clear, and recording changes in the surrounding area can help prevent power generation losses.

Maintenance 4: Inspect ventilation, wiring, and connection status around the equipment

In a solar power plant, not only the panels but also the condition of electrical equipment and wiring affect the power output. The electricity generated is transmitted through wiring, connection points, conversion equipment, and collection facilities. If there is an abnormality along the way, it may lead to reduced power output, shutdowns, alarms, and increased losses.

Before spending money, the first thing to check is the ventilation around the equipment. Electrical equipment can be affected by heat, and if weeds, fallen leaves, dust, or other debris accumulate nearby, heat dissipation can become difficult. Check whether vents or surrounding spaces are blocked, whether there is clearance for inspection around the equipment, and whether direct sunlight or reflected heat from nearby surfaces is likely to become trapped.

If power generation does not increase during sunny high-output hours, the thermal environment of the equipment may be affecting it. Of course, the panels themselves also tend to have reduced output during hotter periods, but if the equipment's heat dissipation is poor, losses can increase further. Improving ventilation is a basic item that is easy to check before equipment renewal.

When inspecting wiring, check for visible cuts, sagging, how securely it is fastened, deterioration of the insulation, animal damage, loose connections, cables being pulled tight, and deterioration of cable ties. If wiring is touching the ground, passes through areas prone to water pooling, or is buried in vegetation, it becomes harder to detect deterioration or abnormalities. Keeping the wiring route visible during inspections helps with early detection of drops in power output.

Connections are also important. In a solar power plant there are many connection points, and if some of them are faulty, the output of a specific circuit may be reduced. Even if there are no obvious abnormalities in appearance, when generation data shows differences between sections, wiring and connections need to be checked. Some areas require specialized measurements, but first it is important not to overlook damage, discoloration, burn marks, signs of water ingress, or loose fastening that can be visually confirmed within a safe range.

Also, check the equipment's alarm and shutdown histories. If temporary shutdowns are recurring, they may be hard to see in daily power generation figures but can affect monthly or annual generation. Even if the system appears normal when a technician visits the site, it may have experienced brief shutdowns in the past. Reviewing alarm and shutdown histories together with the generation data makes it easier to narrow down the causes of the decline.

A key point to be careful of in maintenance around equipment is to avoid touching things unnecessarily. Because electrical equipment carries risks of electric shock and malfunction, tasks that require qualifications and procedures must not be performed based on on-site judgment. What operational personnel should do is, within safe limits, check the appearance, surrounding environment, records, and whether there are any abnormalities, and organize information that can be handed over to specialists as needed.

To increase power generation, panels must be kept in a condition that allows the solar radiation they receive to be converted into electricity with as little loss as possible. Ventilation around equipment, wiring, connections, and checking alarm histories are maintenance tasks that are easy to overlook, yet important for preventing generation losses.

Maintenance 5: Check for changes in mounting racks, ground, and slope to prevent power generation losses

The power output of a solar power plant is also affected by the orientation and tilt of the panels. Even if they were installed at the proper angle, long-term operation can cause ground settlement, deformation of the mounting racks, changes around the foundations, slope failures, poor drainage, and other issues, which can alter the panels' posture and the surrounding environment. Although such changes may appear minor at first glance, they can affect power output and maintainability.

When checking for changes in the racking or the ground, the first things to confirm are the tilt and unevenness of each row. Phenomena such as panel rows undulating, differences in height between adjacent rows, parts of the racking sinking, gaps or scour around support posts, or changes in drainage flow require attention. Especially on slopes or reclaimed/filled sites, conditions can change over time depending on rainwater flow and the degree of ground compaction.

When ground conditions change, it affects not only power generation but also how shadows form. If the height or tilt of panel rows changes, the way shadows fall on the rows in front and behind may change. Also, a change in slope can worsen the panels' surface drainage, making dirt more likely to accumulate. In other words, changes in the ground or in the mounting structures are connected to issues of shading, soiling, drainage, and inspection access.

Checking drainage is also essential. Conditions such as rainwater pooling in specific areas, soil being washed away around mounting foundations, walkways becoming muddy, drainage channels clogged with sediment and grass, or puddles forming under panels can affect the equipment in the long term. Poor drainage can lead to ground subsidence, overgrowth of weeds, and re-accumulation of dirt, so it is an important inspection item for maintaining power output.

Also visually inspect the bolts and fastenings of the mounting structure for abnormalities. If looseness, missing parts, rust, deformation, tilting, or displacement of members are observed, do not leave them unaddressed; record them and consider appropriate measures. After strong winds, heavy snowfall, earthquakes, or heavy rain, it is advisable to perform a condition check separate from routine inspections. If power generation decreases after a disaster, changes in not only the equipment but also the mounting structure and the ground should be considered as potential causes.

Changes in mounting structures and ground conditions can be hard to notice when you see them every day. For that reason, fixed-point photos and simple records are useful. By taking photos regularly from the same position and in the same direction, it becomes easier to compare row tilt, grass growth, drainage traces, and changes in the ground. Recording site changes that are not visible in power generation data provides the basis for improvements.

When it comes to maintenance to increase power generation, attention tends to go to panel cleaning and equipment inspections, but the ground and mounting structures are the foundation of the entire solar plant. If these fail, there will be cascading effects on soiling, shading, drainage, maintenance access, and equipment safety. As a review before spending money, it is important to check whether the overall layout of the site has changed significantly since installation.

Decisions Not to Make When Improving Power Generation

The more you want to increase power output, the more likely you are to rush into countermeasures. However, if you proceed without isolating the cause, not only will the measures fail to produce results, they can also add unnecessary work and risk.

First, avoid deciding to clean solely because power generation is low. Dirt can of course cause reduced output, but if the main causes of the decrease are weather, shading, equipment shutdowns, output curtailment, wiring faults, or ground movement, cleaning alone will not improve the situation. Before cleaning, it is important to check the generation data, the extent of soiling, the sections with reduced output, and how comparisons will be made before and after the work.

Next, you should also avoid judging an anomaly based on a single month’s power generation alone. Solar power generation varies with the weather. Months with a lot of rain or cloud cover will see reduced generation even if the equipment has no problems. When assessing anomalies, multiple perspectives are necessary, such as comparing the same month in the previous year, comparisons with nearby sites or within the same section, and time-of-day data for clear days.

Also, it is dangerous to make judgments solely from desk-based analysis without visiting the site. Even if the data shows the same decline, various causes may be hidden on-site, such as shading from grass, bird droppings, poor drainage, damaged wiring, or insufficient ventilation around equipment. When improving power generation, the accuracy of the assessment increases only when both the data and the site are checked.

Conversely, judging solely by how a site looks is also inadequate. Even if the panels appear clean, there may be shadows at certain times of day, faults in some circuits, or repeated brief shutdowns. Because it is difficult to determine the effect on power generation from site photos alone, you must always combine them with data.

Work that neglects safety must also be avoided. Actions such as standing on panels, working carelessly when surfaces are wet, touching electrical equipment without proper qualifications, or attempting inspections on unstable slopes are dangerous. It would be counterproductive if accidents or equipment damage occurred during work intended to improve power output. The inspection scope, work procedures, restricted/no-entry areas, and weather conditions should be clearly defined, with safety given priority.

When improving power generation, what matters is not adding tasks on a whim but prioritizing based on evidence. Identify abnormal trends in the data, confirm candidate causes on site, and verify the effects after the work. By following this process, you can reduce unnecessary interventions and more easily choose maintenance that leads to improved power generation.

Management system for continuously increasing power generation

If you only want to temporarily improve power generation, individual measures such as removing dirt, mowing grass, or reducing shading can sometimes be effective. However, to maintain power generation over the long term and detect declines early, it is necessary to establish the management system itself.

First, it is important to decide the inspection criteria. If the locations to check and the judgment standards differ by person in charge, anomalies can be overlooked and records can become inconsistent. Organize in advance the items to be checked—power generation data, panel surfaces, shading, weeds, drainage, mounting structures, ground conditions, wiring, areas around equipment, alarm history, etc.—so inspections can be carried out from the same perspective each time.

Next, you need a system for recording inspection results. If abnormalities noticed on-site are shared only verbally, they cannot be verified later. Keeping photos, location, date and time, weather, the equipment inspected, the work performed, and the response status makes it easier to correlate with changes in power generation. In particular, when power generation declines, past inspection records provide clues for investigating the cause.

When managing power generation, it is important to look at trends as well as daily figures. You don't need to overreact to a temporary drop, but if the same section consistently shows low output, output fails to rise even on sunny days, it drops only during specific time periods, or it does not improve after inspection, you should investigate the cause promptly. It is more important to focus on tracking continuous changes than on isolated numbers.

Information sharing between on-site staff and management is indispensable. Even if on-site personnel spot shadows or dirt, improvement decisions will be delayed unless that is communicated to the people monitoring the power generation data. Conversely, if the data management side detects an anomaly but instructions for on-site verification are vague, the necessary photos and information will not be collected. To increase power generation, those who analyze the data and those who inspect the site must be able to share the same information.

It is also important to conduct a post-work review. Check whether power generation improved after mowing, which sections showed changes after cleaning, and whether the recurrence of soiling decreased after drainage improvements. Incorporate tasks that proved effective into regular maintenance, and reexamine the causes of tasks that had little effect. By repeating this process, the weaknesses and priorities of each power plant become clear.

Improving power generation is not something that can be completed with a single inspection. Solar power plants are outdoor facilities and are continuously affected by weather, seasons, vegetation, ground conditions, and the surrounding environment. Therefore, it is important to continuously monitor changes at the site and manage them by linking them to data.

Maintenance aimed at increasing power generation is not just about the work itself, but also about creating systems that enable detection, recording, and decision-making.

Summary: Reassess the site before incurring costs and establish the basis for improving power output

When it comes to maintenance aimed at increasing power output, what matters is identifying the existing generation losses before making major changes to the equipment. Because a solar power generation system is exposed to sunlight, it cannot avoid the effects of weather and seasons. However, soiling, shading, inadequate ventilation, abnormalities in wiring or connections, changes in racking or ground conditions, poor drainage, and oversights due to insufficient record-keeping can potentially be improved through routine management.

The first thing to do is review the generation data to identify any downward trends. By comparing with the same month of the previous year, checking differences by section, and examining changes by time of day, you can narrow down the locations to inspect on site. Next, check the cleanliness of panel surfaces and drainage conditions, and record whether soiling is affecting power output. Further, reassess shadows from vegetation and surrounding structures at different times of day, and inspect ventilation around equipment, wiring, connections, and alarm histories. Finally, check for changes in mounting racks, ground conditions, slopes, and drainage paths to understand the overall condition of the power plant.

These maintenance activities are not attempts to force an increase in power generation, but reviews to protect the power output that should originally be achieved. When generation falls, rather than immediately moving to large-scale measures, it is important to compare the data with on-site conditions, isolate the causes, and verify the changes before and after the work. If you can make decisions based on evidence, you can reduce unnecessary work and focus on measures that are truly effective.

In power plant management, the ability to accurately grasp on-site conditions forms the foundation for improving power generation. In particular, on sites with large grounds, sloped terrain, areas where weeds tend to grow, sections that are prone to shading, or where drainage conditions are complex, the accuracy of records directly affects the accuracy of decisions. When considering how to increase power generation, it is essential first to record inspection results in a visible form and manage them by linking them with generation data.

To improve power generation, if you want to make on-site inspections, recordkeeping, and understanding of a power plant’s condition more efficient, it is also effective to review the standardization of inspection records, photo management, organization of location information, and methods for cross-checking with generation data. By confirming the causes of reduced generation based on on-site data rather than intuition and by prioritizing maintenance, you can more reliably carry out reviews that can be done before incurring costs.