5 Reviews to Increase Power Generation | Causes to Check First

Table of Contents

• Concepts to check before increasing power generation

• Review 1: Separate power generation data by time of day and by equipment unit

• Review 2: Reduce losses in light reception due to dirt and deposits

• Review 3: Manage shadows from weeds, trees, and surrounding structures

• Review 4: Distinguish between equipment stoppages, output curtailment, and connection faults

• Review 5: Organize terrain, drainage, and inspection routes to prevent recurrence

• Management cycle to sustain improvement effects

• Summary

Considerations to Confirm Before Increasing Power Generation

When you want to increase the electricity generation of a solar power system, the first thing to consider is not immediately adding more equipment. At many sites, before adding new equipment there are causes that lead to loss of power that should otherwise be generated. Dirt on panel surfaces, shading from weeds, growth of surrounding trees, faulty connections, equipment shutdowns, output curtailment, poor drainage, and site layouts that make inspection difficult—there is not a single factor causing reduced generation. Multiple small losses accumulating can result in large differences in monthly or annual generation.

What an operations person searching "how to increase power generation" should first check is to distinguish among the possible causes of low power generation. Simply seeing that power generation is low doesn't tell you what measures to take. Depending on whether output fails to rise despite clear skies, is only low in the morning and evening, is low for specific equipment, drops after rain, or varies by season, the causes you should suspect will differ. Improving power generation begins with correctly interpreting what is happening on site and reassessing issues in order of priority.

In solar power generation, you cannot increase the amount of solar irradiance itself at the site. However, you can bring the system closer to a state that converts the incident irradiance into electricity with as little waste as possible. Therefore, the phrase "increase power generation" is more clearly rephrased in practice as "reduce generation losses." It is important to identify wastes such as solar radiation being present but not being captured, being captured but not being extracted as electricity, extracted electricity not being convertible, or equipment being stopped during times when generation is possible.

When improving power generation, you need to be able to compare conditions before and after the measures. If cleaning, weeding, inspections, repairs, and equipment checks are all performed at the same time, it becomes difficult to determine how much each measure contributed. Although site circumstances sometimes require doing the work together, it is important at minimum to record the pre-work power generation, on-site photos, any abnormal areas, the work performed, and the changes after the work. If records are kept, when a similar drop in power generation occurs next time you can narrow down the cause more quickly.

Reviews to increase power generation are not limited to special tasks. Improving the accuracy of daily inspections, organizing how data is viewed, saving on-site photos together with their locations, identifying areas prone to vegetation and dirt buildup, and not overlooking equipment stoppages — these actions ultimately lead to higher power generation.

Below, we organize the five reviews that operational staff should check first, in the order that is most useful for on-site decision-making.

Review 1: View power generation data broken down by time of day and by facility

The first thing to review to increase power generation is how you view the generation data. When you feel generation is low, looking only at the monthly totals can lead you to misidentify the cause. Monthly generation is heavily influenced by the weather, so in months with a lot of rain or cloud cover the totals will be low even if the equipment is operating normally. Conversely, even if the monthly figures do not show a large difference, generation losses may be continuing in specific equipment or during particular time periods. First, it is important to break down the overall numbers and examine them in detail.

What you should check are variations by time of day, by day, by equipment unit, and by season. If generation is low only in the morning, it suggests shading on the east side; if it is low only in the evening, shading on the west side; if it drops suddenly around midday, it may be due to equipment shutdowns or output curtailment; if the generation curve becomes unnaturally flat on sunny days, limitations on the conversion equipment are suspected. On the other hand, it is difficult to judge using only cloudy days, so it is important to select data from sunny days whenever possible and compare equipment under the same conditions.

When comparing on a per-installation basis, avoid simply assuming that a system with lower power generation is abnormal. Differences in the number of panels, orientation, tilt, shading conditions, and the range of connected panels naturally cause differences in output. What matters is whether it is consistently lower compared to installations with similar conditions. If, compared with installations in the same row, the same orientation, and similar levels of solar irradiance, only a portion shows a decline, that is grounds to suspect soiling, shading, poor connections, or equipment faults.

Power generation data can also be used for comparisons with the past. Even if output is significantly lower than the same month last year, a simple comparison is not valid if weather conditions differ. Therefore, it is necessary to isolate the effects of weather as much as possible—by selecting days with similar solar irradiance conditions, comparing generation curves on clear days, or examining the ratios among multiple units within the same plant. To increase power generation, the starting point is not just the fact that output is low but understanding where, when, and by how much it is low.

Short-term stoppages are easy to overlook when checking data. Even if equipment stops for only part of the daytime, it may not be noticeable in monthly aggregates. However, if it stops during peak generation hours on sunny days, the impact on output can be significant. Check alarm logs and stoppage histories to see whether drops in generation coincide with those times. If similar drops recur in a specific time window, you should raise the priority of an on-site inspection.

When you get into the habit of breaking down generation data, the efficiency of on-site inspections also improves. Rather than checking the entire plant indiscriminately, you can narrow your inspections to equipment with declining output, time periods when drops occur, and suspicious rows or areas. This lets you concentrate limited inspection time on locations that have the greatest impact on generation. Improving generation output starts not only with field work but already with interpreting the data.

Review 2: Reduce light reception loss caused by dirt and deposits

Solar panels generate electricity when their surfaces receive sunlight. Therefore, dirt and deposits on the panel surface are a basic cause of reduced power generation. The types of soiling vary by site, including dust, pollen, bird droppings, fallen leaves, tree sap, sand, deposits from sea breezes, and dust from roads or construction. Even light soiling spread over a wide area can reduce the amount of light received, and heavy soiling concentrated on specific parts can cast shadows on some cells.

Particular attention should be paid to the banded dirt that accumulates along the lower edges of the panels and near the frames. It is often assumed that rain will naturally wash away the dirt, but in reality residue that doesn’t completely wash off can remain at the edges. On panels with a shallow tilt, water drains poorly and dirt is more likely to remain. Localized deposits, such as bird droppings or fallen leaves, can have a large impact even if they cover a small area, so during on-site inspections you need to carefully check not only the overall coloration but also the edges and any partial deposits.

To reduce power generation losses caused by soiling, it is important to identify locations prone to soiling before cleaning. Even within a power plant, not all panels become soiled equally. Rows located downwind, rows near unpaved access roads, areas prone to dust from surrounding farmland, locations near structures where birds tend to perch, and areas with poor rainwater drainage can all experience concentrated soiling. By checking whether the areas showing decreased generation in the power output data match the on-site soiling, you can more easily determine cleaning priorities.

When performing cleaning, you should not assume that vigorously scrubbing is better just to increase power generation. Work that damages the panel surface, sudden work during times with large temperature differences, or work that omits safety checks of electrical equipment may cause other malfunctions. Cleaning must be planned as an operation that does not damage the equipment, ensures worker safety, and appropriately removes dirt. After cleaning, record the target area and the work date, and check for changes in power generation.

From the perspective of improving power output, rather than setting a fixed cleaning frequency, it is effective to adjust it according to how the site becomes soiled. Cleaning frequently at a site with little soiling has limited effect on power output. Conversely, if cleaning is delayed at a site prone to soiling, generation losses can continue for a long time. When reassessing soiling, it is important not only to decide whether to clean, but also to determine which locations to clean, when to do so, and to what extent or coverage.

Also, it is necessary to implement measures to reduce the causes of soiling themselves. If dust is rising from unpaved pathways, review vehicle routes and the impact of vehicle movement. If there are many fallen leaves, check the surrounding vegetation and the timing of cleaning. If bird damage continues, identify locations and structures that attract birds. By not only removing dirt but also understanding environments that are prone to soiling, you can move toward management that is less likely to repeatedly cause declines in power output.

Review 3: Managing shadows from weeds, trees, and surrounding structures

Managing shading is critically important for increasing power generation. In solar power generation, even a shadow on part of a panel can affect its output. Sources of shading vary and include weeds, trees, fences, utility poles, surrounding buildings, parts of the mounting structure, and shadows from adjacent rows. Because the position of shadows changes with the time of day and season, they can be overlooked if only a single on-site inspection is performed.

Weeds require particular attention as a cause of reduced power output. Even if there is no problem immediately after installation or in winter, they can grow rapidly from spring to summer and cast shadows on the lower edges of panels or the front rows. Even if the vegetation does not reach the panels, shadows can still stretch a long way during periods of low sun angle. In addition, when weeds become overgrown they reduce airflow and hinder inspection work. Weed management is important not only for power output but also for maintainability and safety.

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 cast shadows in winter or during mornings and evenings. In particular, trees located on the south, east, and west sides of a power plant can affect power generation depending on the time of day. At power plants adjacent to forests or slopes, the combination of terrain height and tree height can create shadows that are longer than anticipated. If power generation varies significantly with the seasons, it is necessary to check changes in solar altitude together with the surrounding environment.

In managing shading, it is important to link power generation data with on-site conditions. If power output is low only in the morning, check the east side; if it is low only in the evening, check the west side; if the decline is particularly noticeable in winter, check the south side and surrounding elevation differences. For on-site inspections, if possible carry them out during the time periods when the drop in output occurs, as this makes it easier to identify the cause. Even if there appears to be no problem during the daytime, significant shading can occur in the morning and evening.

When performing weeding or branch trimming, prioritize locations that have the greatest impact on power generation. Rather than treating everything the same, focus on the extent of shadows on the panels, areas that block inspection walkways, and zones that impede ventilation around equipment. After the work, confirm that the shading has actually been resolved and document it with photographs to assist future decisions. Because shading problems tend to recur, you need not only the record that work was done but also the ability to predict when shading will reappear.

Shadows cast by surrounding structures should not be overlooked. Fences, signs, utility poles, surveillance equipment, and adjacent facilities can create shadows depending on their placement. When refurbishing a power plant or carrying out additional construction, it is important to check in advance whether new structures will cast shadows. In managing efforts to increase power generation, it is important not only to reduce existing shading but also to design and operate in ways that do not introduce new shading.

Review 4: Isolating Equipment Shutdowns, Output Curtailment, and Connection Failures

The causes of low power generation are not limited to issues on the panel surface or shading. Even if the panels receive sufficient sunlight, power output will decrease if there are problems in the electrical path for extracting power or in the power conversion equipment. Isolating electrical factors—such as equipment shutdowns, output curtailment, poor connections, cable damage, loose terminals, or the activation of protection functions—is essential for increasing power generation.

First, I want to check the equipment stoppage history and the alarm history. For days with low power generation, look at which equipment was stopped during which time periods. Even a short stoppage can have a large impact on power generation if it occurs during periods of strong solar irradiance. Even stoppages that don’t stand out in the monthly totals should have their causes investigated promptly if they recur on the same equipment. Whether the stoppage appears only on specific equipment or simultaneously across multiple pieces of equipment changes the scope of possible causes.

If output curtailment occurs, power generation can plateau even on sunny days. If the upper part of the generation curve appears flat, check whether curtailment is occurring. However, a flat curve does not necessarily indicate output curtailment. Similar shapes can result from equipment capacity limitations, temperature increases, shading, soiling, or measurement abnormalities. Cross-check with operational data and alarm histories, and isolate each cause one by one.

Connection failures are a cause that is easily overlooked on site. Even when there are no obvious visual abnormalities, poor contact at connectors or terminals, damaged cables, moisture ingress, or animal damage can lead to reduced power generation. If you see trends such as only certain strings producing low output, anomalies occurring more frequently after rain, or instability during periods of high temperature, consider an electrical inspection. It is important for on-site personnel to clarify the extent and conditions of the anomalies and refer them for specialist examination.

High temperatures should also be taken into account. Although solar power generation is greater when solar irradiance is strong, output can decrease if panel temperature or the temperature around equipment rises. If the amount of power generated on a clear summer day does not reach expectations, check for temperature increases, inadequate airflow, grass or obstructions around equipment, and the overall ventilation environment. In particular, if there is grass or objects around the power conversion equipment that make heat dissipation difficult, it can lead to protective operation or decreased efficiency.

When reviewing equipment and connection points, prioritize safety above all. Because checking electrical equipment can involve tasks that require specialized knowledge, on-site staff should not be forced to make judgments beyond their expertise; instead, they should organize data, photos, time of occurrence, scope of the anomaly, and work history, and hand these over to the appropriate personnel. To increase power generation, it is not enough to find the cause quickly — you also need a system to resolve it safely and reliably.

Review 5: Improve terrain, drainage, and inspection routes to prevent recurrence

The causes of reduced power generation are not necessarily limited to the panels or the equipment themselves. Terrain, drainage, soil or sediment movement, inspection walkways, and changes in the surrounding environment can indirectly lower power output. For example, in areas where water tends to accumulate, weeds grow more easily and moisture can place stress on connections and around the racking. In locations where sediment flows in, the underside of panels is more likely to become dirty and inspection pathways can deteriorate. These factors may be difficult to detect in the short term but can lead to long-term generation losses.

Poor drainage is an issue that requires particular attention in site management. Areas where puddles remain after rain, where mud persists, where sediment accumulates, or where pathways have settled reduce the efficiency of inspections and weeding. On sites that are difficult to work in, detection of abnormalities is delayed and the frequency of mowing and cleaning decreases. As a result, shadows and dirt increase, leading to reduced power generation. To increase power generation, it is important not only to maintain generation equipment but also to keep a work-friendly site environment.

Changes in terrain also need to be checked. On slopes and graded land, topsoil can be washed away by rainwater and the ground around mounting structures can be eroded. Significant changes in the ground can lead to mounting-frame tilt, inter-row shading, exposed cables, and uneven pathways. Even slight changes in panel angle or height can affect shading and drainage in some locations. During regular inspections, it is important to record the condition of the ground as well as the panels and equipment.

Revising inspection routes is also related to improving power generation. Locations that are difficult to inspect tend to delay the detection of abnormalities. If grass has overgrown, making paths impassable; the ground is so muddy that you cannot get close; equipment numbers are hard to identify; or the location of an abnormality is difficult to share, on-site responses take longer. To increase power generation, when an abnormality is found you need to be able to immediately pinpoint its location and ensure that all relevant parties can confirm the same position.

When reviewing site conditions, records with location information are useful. If you can manage on a map where water accumulates, which pathways are prone to deterioration, in front of which rows weeds tend to grow, and around which pieces of equipment abnormalities are likely to occur, the prioritization of countermeasures becomes clear. By recording on-site conditions that cannot be determined from power generation data alone with location information and photos, it becomes easier to prevent recurrence of the causes.

Improvements to terrain and drainage do not necessarily translate into increased power output immediately the way cleaning or weeding might. However, in the long term they provide the foundation for reducing generation losses. At sites where dirt repeatedly accumulates in the same spot, weeds grow over the same area, abnormalities tend to occur after rain, or inspections are difficult and responses are delayed, a review is needed not only of surface measures but also of terrain, drainage, and access routes. To raise power output consistently, it is essential to adopt the idea of creating sites where problems are unlikely to occur.

Management Cycle to Sustain the Effects of Improvements

Reassessing measures to increase power output is not something you do once and then finish. A solar power plant is an outdoor facility, and weather, seasons, the surrounding environment, and equipment condition are constantly changing. Even if you clean, dirt will reaccumulate; even if you remove weeds, they will grow back; trees grow; and drainage routes change because of sediment. Equipment also becomes more prone to faults as it ages. Therefore, improving power output should not be treated as a one-off task but considered as an ongoing management cycle.

The important elements of the management cycle are understanding the current situation, forming hypotheses about causes, implementing countermeasures, verifying effects, and updating records. First, check the power generation data to identify where declines are occurring. Next, hypothesize causes based on time of day, by equipment unit, and onsite conditions. Then carry out countermeasures such as cleaning, weeding, inspections, repairs, and drainage checks. After measures are taken, confirm how power generation has changed and record the results. By repeating this cycle, power generation improvement becomes a task that does not rely solely on the experience of responsible personnel.

The quality of records is also important. If you record the work date, scope of work, before-and-after photos, changes in power generation, locations of anomalies, and conditions prone to recurrence, the next inspection can be carried out more efficiently. For example, if grass grows in the same spot at the same time each year, you can plan weed control in advance. If puddles form in the same spot after rain, you can raise the priority of drainage measures. By taking action before power output declines, you can minimize losses.

When managing multiple power plants, it is also important to standardize management criteria. If judgments by staff vary from site to site, differences will arise in the timing of anomaly detection and countermeasures. Standardizing the frequency of checking power output, the criteria for judging anomalies, how to take on-site photos, how to record inspection results, and how to compare results after measures are taken will stabilize management quality. Efforts to increase power generation lead not only to improvements at individual sites but also to operational improvements across the organization.

When improving power generation, it's also important not to try to solve all problems at once. On site there are many challenges such as dirt, shading, equipment, drainage, and access and movement routes. If everything is treated with the same priority, the workload can become large and highly effective measures may be postponed. It's easier to make progress by first tackling issues that have a large impact on power generation and are easy to check, and then expanding to causes that are likely to recur and to long-term risks.

Moreover, the effects of improvements are reflected not only in the numbers but also in the ease of on-site management. Changes such as inspection points becoming easier to identify, abnormal locations being easier to share, workflows being streamlined, and power generation data being linked with on-site conditions help prevent the next decline in power generation. Efforts to increase power generation are also efforts to improve the accuracy of daily management.

Summary

The main causes to check first when trying to increase power generation can be broadly divided into overlooked data, dirt on panel surfaces, shading, abnormalities in equipment or connections, and site conditions including terrain and drainage. When you feel power generation is low, rather than immediately considering major renovations, it is important to sequentially isolate where generation losses are occurring. If you break down power generation data by time of day and by equipment unit, it becomes easier to determine whether the issue is an overall weather impact or a problem with a specific piece of equipment.

Dirt and deposits are direct factors that block solar radiation. In particular, streaked dirt along the lower edge of panels, bird droppings, fallen leaves, and dust can affect power generation. Shadows from weeds, trees, and surrounding structures can also reduce generation depending on the time of day and season. Although these issues may seem apparent when observed on-site, in practice it is difficult to judge the magnitude and priority of their impact without correlating them with power generation data.

Equipment shutdowns, output curtailment, and connection faults can prevent power from being drawn off even when conditions for power generation are met. Check alarm histories and shutdown histories to see whether drops in generation coincide with the timestamps. If only specific equipment is showing a decline, suspect abnormalities at the connections or at the string level. Electrical checks should prioritize safety, and it is important to organize the necessary information and pass it on to professional inspection.

Reviewing terrain, drainage, and inspection access routes helps prevent recurrence of power generation declines. Puddles, mud, sediment buildup, overgrown vegetation, and locations that are difficult to inspect can cause long-term generation losses. Organizing the site environment provides the foundation for sustaining the effectiveness of cleaning, weeding, and repairs. To steadily increase power generation, you need a management perspective that includes not only equipment but also the land and access routes.

In practical work to improve power generation output, it is essential to accurately record on-site conditions and link them to power generation data. If you record, together with location information, where shadows occur, where dirt tends to accumulate, where water pools, and which equipment is prone to anomalies, it becomes easier to explain the priority of countermeasures. When stakeholders can accurately share the same locations, the workflow from inspection, weeding, and cleaning through repairs and reinspection also becomes smoother.

Using LRTK can also be effective when you want to strengthen efforts to increase power generation through on-site records and location information. LRTK, as an iPhone-mounted GNSS high-precision positioning device, is useful in situations where you want to streamline recording inspection locations within a power plant, locations where shadows occur, places with poor drainage, equipment layouts, and on-site photographs. To reduce wasted power generation, it is important to correctly identify causes and establish a management system that can consistently check the same locations. By using LRTK to retain on-site information together with high-precision positioning, it becomes easier to carry out practical improvements to the power generation of solar power plants.