6 Ways to Increase Solar Power Output | Review Dirt, Shade, and Degradation

Table of Contents

• To increase solar power generation, identify the causes of generation losses

• Method 1: Check generation data by time of day and by equipment unit

• Method 2: Review dirt and deposits on panel surfaces

• Method 3: Reduce shading from weeds, trees, and structures

• Method 4: Check for abnormalities in strings, connection points, and cables

• Method 5: Review shutdowns, curtailment, and temperature environment of power conversion equipment

• Method 6: Manage drainage, terrain, and locations prone to deterioration

• Record management for continuous improvement of solar power generation

• Summary

To increase solar power generation, identify the causes of generation losses.

When aiming to increase solar power output, the first priority is not to add more equipment but to verify whether the existing equipment is performing as it should. Because solar power generation relies on receiving sunlight, you cannot change the weather or the seasons at the site. However, you can move closer to a state in which the received sunlight is converted into electricity with as little waste as possible. In other words, in practical terms, increasing solar power output means identifying the causes of electricity that should be generated but is being lost, and taking measures to reduce generation losses.

The causes of stalled power generation are not necessarily limited to a single factor. Dirt on the panel surface, deposits such as bird droppings and fallen leaves, shading from weeds or trees, faults in connections, cable damage, stoppage of conversion equipment, output curtailment, temperature rise, poor drainage, degradation of components, and insufficient inspection records — multiple factors can combine to reduce power generation. Even if there appear to be no major abnormalities to the naked eye, when viewed by time of day or by equipment unit, there may be cases where only part of the system shows reduced generation.

What practitioners searching for "how to increase power generation" should be careful about is not to start work without confirming the cause. Deciding to clean because the panels look dirty, to remove weeds because the grass has grown, or to conclude deterioration because the equipment has aged is not necessarily wrong. However, if the main cause of the generation drop and the countermeasure do not match, the expected improvement will not be achieved. Cleaning may not restore output, removing weeds may not extend the midday peak, and even after inspecting the equipment the output may remain low only in the morning and evening.

When improving power output, it is important to link data with on-site conditions to make decisions. Check when output 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 in order: dirt, shading, degradation, connections, equipment, drainage, and inspection access routes. The mere result of low power output does not tell you what to prioritize. By isolating the causes, you can reduce unnecessary work and more easily move on to measures that have a high improvement effect.

Also, because solar power plants are outdoor facilities, their conditions are constantly changing. Even if you clean them, dirt will return; even if you remove weeds, vegetation will regrow; trees grow; and rainwater flow is altered by sediment and fallen leaves. Connection points and cables also face increased risk of deterioration and damage during long-term operation. To reliably increase power output, measures must not be a one-time effort — it is necessary to repeatedly assess the current situation, implement countermeasures, verify their effectiveness, and update records.

Method 1: Check power generation data by time period and by facility

The first step to increasing solar power output is to examine generation data in detail. If you only look at monthly or annual generation, you won’t know when, where, or how generation losses are occurring. Even if nothing looks abnormal on a monthly basis, output may drop during certain hours on sunny days, or only specific equipment may remain at low output. First, instead of total values, it is important to break the data down by time of day, by individual equipment, by day, and by season.

If power generation is low in the morning, shadows from trees on the east side, slopes, nearby structures, or adjacent equipment may be involved. If it is low in the evening, check for shadows on the west side and the influence of surrounding terrain. If the midday peak does not reach its expected level, possible causes include dirt on the panel surface, temperature rise, limitations of conversion equipment, output curtailment, or equipment shutdowns. If the generation curve suddenly drops during a sunny day, you should cross-check stop history and alarm logs with the timestamps.

When comparing equipment units, it is important to compare units 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. If a specific area is consistently lower compared with adjacent rows or units with the same orientation, suspect local soiling, partial shading, connection faults, cable damage, or equipment-side malfunctions. Do not judge based only on the power plant–wide figures; examining more granular units is fundamental to improving energy yield.

Pay attention to how power generation declines. If it drops suddenly, possible causes include equipment shutdown, broken wiring, poor connections, or the emergence of obstructions. If it decreases gradually, accumulation of dirt, growth of weeds or trees, deterioration of the site environment due to poor drainage, or degradation of components may be involved. The places that need to be checked differ between sudden drops and gradual declines. By reading the pattern of the decline, you can reduce unnecessary on-site inspections.

When checking power generation data, use sunny days as the baseline as much as possible. On cloudy or rainy days, power output can fluctuate greatly due to cloud movement, making it difficult to distinguish from equipment abnormalities. With the generation curve on a sunny day, features such as shading, shutdowns, curtailment, and string anomalies are easier to detect. To increase solar power generation, the starting point is to identify the time periods, equipment, and continuity where generation losses are occurring.

Method 2: Review dirt and deposits on the panel surface

Dirt and deposits on the panel surface are a common cause of reduced solar power generation. Because solar panels generate electricity by receiving sunlight at their surface, when dirt adheres the light reaching the cells is reduced. The way panels become soiled varies with site conditions and includes soil dust, pollen, yellow sand, bird droppings, fallen leaves, tree sap, dust from nearby construction, road-derived dust, and salt-containing deposits that tend to adhere in coastal areas. Even light soiling can affect power output if it spreads over a wide area, and localized deposits can cast a strong shadow even over a small area.

Particular attention should be paid to the band-like streaks of dirt that remain at the lower edge of the panel and near the frame. It might be assumed that rain will naturally wash them away, but in reality the flow of rainwater can concentrate dirt at the lower edge and leave it there. Panels with a shallow tilt do not shed water easily, 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 on-site inspections, it is necessary to carefully check not only the overall coloration of the panel but also the lower edge, the corners, and the area around the frame.

Localized deposits such as bird droppings or fallen leaves should not be overlooked. Unlike dirt that spreads thinly across the entire surface, these materials concentrate on specific spots and create partial shading that hinders power generation. If only certain units show reduced power output, focus inspections on the panel surfaces around those units. Rows close to trees, areas around structures where birds tend to perch, rows that are frequently downwind, and locations near unpaved access ways are especially prone to dirt and deposits.

When carrying out cleaning, it is practical to prioritize areas that have the greatest impact on power output. Instead of cleaning all panels at the same frequency, concentrate on installations where a drop in power output has been observed, rows with concentrated soiling, areas where soiling along the lower edge is noticeable, and locations with frequent bird damage or heavy leaf accumulation. By comparing before-and-after photos with power output, it becomes easier to determine how much the soiling at that site was affecting power output.

However, cleaning must be carried out in a way that does not damage the equipment. Avoid scrubbing hard with rigid tools, performing sudden work during times when panels are at high temperature, and working without conducting electrical safety checks. Cleaning to increase power generation is not a cosmetic task, but a maintenance operation to restore the light-receiving condition and to keep the equipment in long-term, stable use. Areas where dirt recurs should be recorded as items to be given priority inspection in future checks.

Method 3: Reduce shadows cast by weeds, trees, and structures

Managing shading is essential to increasing solar power output. Because solar panels generate electricity by receiving sunlight, even if only part of a panel is shaded its power output can decrease. Causes of shading include weeds, trees, fences, utility poles, surrounding buildings, mounting racks, adjacent rows of panels, monitoring equipment, and others. Because shadows move with the time of day and the seasons, the fact that no shading was visible at the time of inspection does not necessarily mean there is no problem.

Weeds are a common cause of generation losses on site. Even if there are no problems in winter or immediately after installation, they can grow rapidly from spring to summer and cast shadows on the lower edges of panels and on the front rows. Even if the plants do not touch the panels, the low sun angle in the morning and evening causes long shadows. Furthermore, when weeds become overgrown, airflow is reduced, inspection walkways become blocked, and it becomes difficult to inspect 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 tends to become 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 on the south, east, and west sides in particular cast shadows on panels depending on the time of day. At plants near forests or slopes, the height of the terrain combined with the height of trees can create long shadows in winter. If generation is low only in winter, or if there are large drops in the morning and evening, it is necessary to check both the trees and the terrain together.

When checking shadows, aligning the power generation data with the times of on-site inspections makes it easier to identify the cause. If power generation is low in the morning, check the on-site conditions in the morning; if it’s low in the evening, inspect the shadows in the evening. Even if there is no issue when checked at noon, there may be significant shadows in the morning and evening. Also, even if there is no problem in summer, shadows can lengthen in seasons when the sun’s altitude is low. Shadows must be managed not as a single moment but as something that changes with time and season.

Be mindful of shadows from nearby structures and added equipment. Adding new equipment within the power plant, or installing fences, signs, or monitoring poles, can cast shadows at certain times of day. To increase power output, it’s important not only to reduce existing shadows but also to operate in a way that doesn’t create new ones. When you find a shadow, record the time it occurs, its source, the equipment affected by the shadow, and take photographs — these records can be used to decide on weeding, pruning, or rearranging equipment.

Method 4: Inspect strings, connection points, and cables for abnormalities

To increase solar power generation, you need to check not only the panel surface and shading but also the routes that extract the electricity. Even if solar panels are receiving sunlight normally, defects in connections or cables can prevent you from fully extracting the generated electricity. String-level generation differences, loose terminals, poor electrical contacts, damaged cable sheathing, moisture ingress, damage from animals, damage during mowing, and deterioration due to aging are major causes of reduced power output.

When checking for abnormalities at the string level, the basic rule is to compare strings under the same conditions. If you simply compare systems with different numbers of panels, orientations, tilt angles, shading conditions, or connection configurations, you may mistakenly interpret normal differences as abnormalities. Check whether any string is consistently lower compared with adjacent rows or other installations with the same orientation. If only a particular string is low, possible causes include dirty panels, partial shading, poor connections, cable damage, or equipment-side problems.

Pay attention to how the anomaly appears. If it is consistently lower than the surroundings even on sunny days, dirt or connection problems are suspected. If it is lower only in the morning and evening, check for shading effects. If anomalies tend to appear after rain, moisture ingress or the condition of the connections may be involved. If it becomes unstable during high-temperature periods, 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.

When reassessing degradation, it is important not to judge solely by appearance. Damage to cable sheathing, terminal faults, unstable behavior after rain, and reduced power generation in specific areas can be difficult to detect from appearance alone. Inspections of electrical equipment must prioritize safety. Rather than having on-site personnel forcibly touch connection points or the inside of equipment to make a judgment, organize information such as the equipment showing abnormalities, the time of occurrence, changes in power generation, on-site photographs, and the surrounding environment, and, if necessary, arrange for a professional inspection.

Faults in connection points and cables may be related to the surrounding environment. In areas with abundant weeds, it becomes difficult to inspect the condition of cables. In locations with poor drainage, moisture and standing water can affect connection points. At power plants that are easily accessible to animals, cable damage can also occur. For improving solar power generation, it is essential not only to carry out repairs but also to check site conditions that could lead to recurrence.

Method 5: Review Shutdown, Suppression, and the Temperature Environment of Conversion Equipment

The causes of low solar power generation are not limited to the panels or the wiring. If the equipment that converts the generated electricity is stopped or its output is limited, generation will not increase even when sunlight is sufficient. To increase power generation, it is essential to check the operating status of the conversion equipment, shutdown history, alarm history, and whether output curtailment is in effect.

When reviewing downtime history, confirm which equipment stopped, when, and for how long. Even a brief stoppage can cause significant losses if it occurs during daytime hours when power generation is high. If equipment repeatedly stops and restarts during the day, it may not be noticeable in the monthly totals yet can still result in lost generation. Whether only a specific piece of equipment stops or multiple units stop simultaneously will change the potential causes you suspect.

If output curtailment is occurring, power output can level off even on clear days. If the top of the generation curve appears flat, check the operating information and history. However, a flat curve does not necessarily indicate curtailment. Similar shapes can result from equipment capacity limits, temperature rise, soiling, shading, or measurement anomalies. Do not judge based only on the generation curve; it is important to confirm by comparing equipment records with on-site conditions.

Temperature conditions are another important point to review. While solar power generation generally increases with stronger sunlight, higher temperatures can make it harder for output to rise. If generation is lower than expected on a clear summer day, check not only the solar irradiance but also the panel temperature and the ambient temperature around the equipment. If weeds are growing under the panels, there is grass or other obstructions around the equipment, or dust and deposits are impairing heat dissipation, these factors can affect the amount of power generated.

Conversion equipment and surrounding components also deteriorate and are affected by environmental conditions during long-term operation. Conditions such as poor ventilation around equipment, being covered by grass that makes inspection difficult, or being vulnerable to rainwater and sediment can delay the detection of abnormalities. To increase power generation, it is necessary to review not only the history of the equipment itself but also the surrounding environment that enables the equipment to operate stably.

Tip 6: Manage drainage, topography, and areas prone to deterioration

To increase solar power generation, it is necessary to check not only the panels and equipment but also the solar power plant’s overall drainage, terrain, and inspection routes. Locations where water tends to pool, places where sediment can flow in, passages prone to becoming muddy, slope failures, scour around mounting structures, and areas where cables are likely to be exposed can directly or indirectly cause reductions in power generation. Poor drainage and terrain changes may at first seem unrelated to power output, but they are important factors that lead to soiling, weeds, connector faults, reduced ease of inspection, and component degradation.

In areas where puddles remain after rain, weeds tend to grow more easily. When weeds grow, they create shade, reduce ventilation, and make inspections more difficult. On muddy walkways, work can be delayed and the frequency of cleaning and weeding may decrease. Where sediment flows in, it can accumulate under panels and around cables, causing soiling and damage. If the same problems recur in the same places despite cleaning and weeding, drainage or topography issues should be suspected.

When checking terrain and drainage, on-site inspections after rain are effective as well as during clear weather. Identify where water flows in, where it accumulates, and where it drains away. Recording puddles, sediment deposits, vegetation overgrowth, pathway subsidence, and changes in slopes will reveal locations prone to recurrence. If poor drainage is left unaddressed, dirt and weeds will repeatedly reappear, resulting in the same generation losses occurring multiple times.

It is also important to identify locations that are prone to deterioration. Places where moisture tends to accumulate, areas where mowing can easily come into contact with cables, sites prone to being covered by soil or debris, and locations that are difficult to inspect tend to have delayed detection of abnormalities. To increase power generation, rather than dealing with deterioration after it occurs, it is necessary to prioritize for management locations that have conditions making them prone to deterioration.

Improvements to drainage, topography, and inspection routes may not immediately be visible as increases in power output. However, in the long term they help reduce dirt, weeds, poor connections, and delayed inspections. To consistently increase solar power generation, it is necessary not only to improve the generation equipment itself but also to arrange the plant environment so that the facility is easy to manage.

Record Management for Sustaining Improvements in Solar Power Generation

To continue improving solar power generation output, keeping inspection records is essential. Even if dirt, shading, anomalies, poor drainage, or signs of deterioration are found on site, if the exact location is not shared, taking corrective action or reinspection will take time. Especially at large solar farms, because similar rows and equipment are lined up, it can be difficult to identify locations from photos alone. By managing inspection results linked with location information, the operational work to improve generation output can be greatly streamlined.

What you should record includes the locations of equipment with low power output, rows that tend to get dirty, places where shadows occur, areas where water accumulates, spots where connection failures occurred, locations suspected of deterioration, places that were repaired, and the areas where cleaning or weeding was performed. Leaving photos, date and time, equipment numbers, work performed, details of abnormalities, status of corrective actions, and whether reinspection is needed will be helpful at the next inspection. Adding too many items to the records makes it unsustainable on-site, so to start, it is important to ensure that, when you look back later, you can tell what happened and where.

Linking power generation data with on-site photos makes it easier to determine causes. If the locations of equipment with low power output coincide with areas where shadows occur or drainage is poor, the rationale for countermeasures becomes clear. If the power output at a cleaned location improves, you can conclude that soiling had a significant impact at that site. If morning and evening power output improves after weeding, it is highly likely that shadows from vegetation were the cause. Keeping records speeds up decision-making in future cases.

Neglecting insufficient record-keeping leads to recurring problems. Even when there are patterns—grass growing in the same spot every year, dirt accumulating in the same rows, the same walkways becoming muddy after rain, or the same equipment experiencing stoppages—without records the next response will be ad hoc. To increase solar power generation, it is important not to treat inspections as mere checks but to accumulate them as information that can be used for future improvements.

After implementing measures, verify how the power generation has changed. Once cleaning, weeding, repairs, equipment checks, and drainage checks are completed, record the pre- and post-work power generation, on-site photos, scope of work, and weather conditions. It is difficult to completely eliminate the influence of weather, but comparing sunny days with each other or comparing with facilities under the same conditions can reveal consistent trends. Measures that showed a large effect should be prioritized in future work, and if an effect is not clearly visible, consider other causes. Repeating this cycle is the basic way to ensure that improvements in power generation are not just temporary.

Summary

What is important for increasing solar power generation output is to identify the causes of generation loss in order and address them starting with the areas that have the greatest impact on output. In solar power generation, you cannot increase the amount of solar irradiance at the site itself. However, you can improve output by bringing conditions closer to a state in which the received sunlight is converted into electricity without waste. To do that, it is necessary to check, in sequence: generation output data, dirt on panel surfaces, shading from weeds and trees, strings and connection points, power conversion equipment, drainage and terrain, and locations prone to degradation.

When you suspect low power output, don't immediately proceed with cleaning or repairs; first separate and analyze the data. Identify when output is low, which systems are underperforming, and whether there is a difference compared with systems under the same conditions. Then, by inspecting the site, you'll clarify where cleaning is necessary, the areas that require weed control, which connection points need inspection, which equipment should be checked, and which drainage or traffic routes should be reconsidered. To maximize the effectiveness of power output improvements, it's important to make decisions by linking data with on-site conditions rather than relying on intuition.

Also, efforts to increase solar power generation are not completed by a one-time task. Even after cleaning, dirt will return; even after weeding, grass will regrow; trees will grow; and equipment and wiring will change with age. By comparing generation before and after countermeasures, keeping on-site photos and work histories, and using them at the next inspection, the accuracy of improvements is increased. To stably increase 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 less likely to occur.

In particularly large power plants, a system for accurately sharing the locations of problems is important. If dirty-prone rows, shadowed areas, places where water accumulates, abnormal strings, locations suspected of deterioration, repair positions, cleaning scope, 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 prioritization of cleaning, weeding, and repairs, and it also streamlines subsequent checks for recurrence.

If you want to increase solar power generation by reviewing soiling, shading, and degradation based on field data, using LRTK is also effective. As an iPhone-mounted GNSS high-precision positioning device, LRTK is useful for recording inspection locations within a solar power plant, areas prone to soiling, shading locations, poor drainage areas, abnormal equipment, locations suspected of degradation, repair locations, cleaning coverage, and on-site photos together with high-precision location information. By pursuing generation improvements not by intuition but with field records that include location information, you can clarify the priority of countermeasures and make continuous improvement easier.