5 Maintenance Tips to Reduce Operating Costs of Solar Power Plants

Maintenance of a solar power plant is not simply a matter of increasing the number of inspections. There are many things to check, such as a decline in power output, equipment failures, weeds and poor drainage, deterioration of cables and mounting structures, and abnormalities around power conditioners. On the other hand, each trip to the site incurs labor costs and travel time, and if you respond without narrowing down the scope of work, maintenance costs can easily escalate.

Reducing maintenance costs does not mean skipping necessary inspections or safety checks. Inspections and record-keeping required by laws, safety regulations, certification conditions, contracts, and manufacturers' maintenance requirements must be followed. On top of that, it is important to assess the risks for each power plant, set priorities, and reduce duplicate work and rework.

This article explains five measures for practitioners seeking information on solar power plant maintenance to achieve stable operation while keeping maintenance costs down. It organizes points that are easy to review in daily operations, from inspection planning, how to interpret power generation data, improving the efficiency of on-site work, weed control and drainage measures, to record management.

Table of Contents

• To reduce maintenance costs, prioritize inspections instead of cutting them

• Use power generation data to enable early detection of anomalies

• Consolidate on-site work to reduce wasted travel and redundant checks

• Plan and manage weeds, drainage, and soiling to reduce emergency interventions

• Keep records to prevent maintenance decisions from being dependent on individual personnel

• Maintenance of solar power plants keeps costs down through continuous improvement

To Reduce Maintenance Costs, Don’t Cut Inspections—Set Priorities

When looking to reduce maintenance costs for a solar power plant, the first thing that often comes to mind is cutting the number of inspections. However, simply reducing inspections can lead to decreased power output and missed minor abnormalities, which may result in major repairs or downtime. What matters for lowering maintenance costs is not stopping inspections but deciding what to prioritize during them.

Solar power plants require different maintenance depending on site conditions and the surrounding environment, even with similar installed capacities. In mountainous areas, attention must be paid to fallen leaves, sediment inflow, animal intrusion, and deterioration caused by humidity. On converted farmland and developed sites, it is necessary to check for weeds, drainage, ground subsidence, and slope failures. In locations close to the sea, facilities are more susceptible to salt damage and strong winds, so inspecting the condition of metal components, connections, and fastenings is important. At plants near residential areas or roads, attention must also be paid to the risk of contact with third parties, fencing, signage, and debris scattering into the surrounding area.

Although risks differ for each power plant, applying the same inspection items, the same frequency, and the same work time to all plants leads to both excessive work and insufficient work at the same time. To reduce maintenance costs, it is important first to organize the characteristics of each plant and clarify the priority inspection items. If a plant has experienced shading from weeds in the past, focus on the timing of mowing and the extent of the shading. If a plant has had poor drainage, prioritize checking drainage channels and slopes after heavy rain. At plants with frequent power conditioner shutdown histories, check ventilation, temperature conditions, error histories, connection points, and surrounding foreign objects and dirt.

When creating an inspection plan, rather than viewing the entire plant uniformly, it becomes easier to manage if you assign priorities by equipment. By separating targets such as solar modules, mounting structures, cables, junction boxes, collection equipment, power conditioners, monitoring equipment, fences, drainage facilities, walkways, and surrounding vegetation, you can distinguish items that should be checked every time from those that only need to be checked at regular intervals. Give higher priority to locations where abnormalities are likely to directly cause a shutdown of power generation, locations that affect the safety of workers or third parties, and locations that have had past faults.

On the other hand, when adjusting inspection intervals, it is necessary to do so without falling below laws, safety regulations, contracts, manufacturer specifications, insurance conditions, and similar requirements. Even for items whose condition is unlikely to change significantly over a short period, checks related to compliance with safety and technical standards cannot be omitted. In maintenance aimed at reducing upkeep costs, rather than indiscriminately reducing the total number of inspections, retain the necessary inspections and eliminate duplicated checks and tasks with little purpose.

Also, it is important not to add too many inspection items. If the inspection checklist is overly detailed, field personnel will be busy filling it out and may miss the abnormalities they should actually be checking. What matters is to reliably record information that can be used for decision-making. For example, rather than only noting whether a module is damaged, record which row and which area has dirt or shading, whether a racking looseness is localized or widespread, and whether poor drainage is temporary or persistent. If such information is retained, changes can be compared at the next inspection, reducing unnecessary rechecks and rework.

Maintenance costs vary depending on the number of on-site visits, travel distance, number of personnel, number of inspection items, and frequency of emergency responses. An operation that inspects everything in detail every time may seem reassuring, but it is not efficient if it does not match the risk profile of the power plant. Conversely, if inspections are reduced too much, there is a risk of overlooking decreases in power output or equipment failures. To reduce maintenance costs, it is necessary to design operations that allocate time to the right places based on each power plant’s risk.

Using power generation data to enable early detection of anomalies

To reduce maintenance costs at solar power plants, it is essential to make a habit of checking generation data before visiting the site. If you carry out an on-site inspection without first looking at changes in power output, you will end up walking over a wide area without knowing where the abnormalities are. As a result, work time becomes longer and oversights are more likely. By reviewing generation data in advance and narrowing down sections or equipment that may be abnormal, the locations that need to be checked on-site become clear.

Power output varies with weather and seasons. Therefore, simply noting that it is lower than yesterday or lower than last month does not allow for an accurate assessment. What is important in operation and maintenance is to compare equipment within the same plant, compare with the same period in the past, and examine trends while taking solar irradiation and weather conditions into account. For example, if only some systems within the same site show lower output, that system may be affected by factors such as shading, soiling, poor connections, or equipment shutdowns. If overall generation is low, check factors that affect the entire plant, such as weather, snowfall, widespread soiling, failures of monitoring equipment, or output curtailment.

When analyzing generation data, checking not only daily totals but also changes by time of day helps isolate anomalies. If generation is low only in the morning, shadows from the east may be involved; if it is low only in the evening, shadows from the west may be a factor. A sudden drop around midday can suggest equipment shutdown, a rise in temperature, communication problems, or grid-side impacts. If decreases occur at the same time of day each season, shadows from nearby trees or structures caused by changes in solar elevation may be affecting output. Knowing these trends in advance allows you to more efficiently check shadow direction, grass growth, and equipment condition on site.

Checking power generation data not only helps detect anomalies early but also reduces unnecessary emergency dispatches. When generation output falls, if you cannot determine whether the cause is a temporary weather-related issue or an equipment fault, you will go to the site as a precaution. However, by comparing weather conditions in the surrounding area and the behavior of multiple systems within the plant, if the fluctuation appears temporary you can decide to align on-site response with the next scheduled inspection. Of course, anomalies that affect safety or cause equipment shutdowns require prompt action. Not treating every change with the same level of urgency helps suppress maintenance costs.

On the other hand, it is also important not to determine the cause based solely on generation data. A decline in power generation can be caused by multiple overlapping factors. Dirt, shading, weeds, equipment shutdowns, communication failures, temperature increases, and aging degradation may all be involved at the same time. Data serve as material to guide on-site inspections, and final judgment requires confirmation of the actual on-site condition. When you find a drop in power generation, organize which areas are affected, since when, during which time periods, and to what extent the decline has occurred, and translate those findings into items to check on site.

What matters when using power generation data is not only looking when an anomaly occurs, but understanding the normal operating condition. If you don't know the usual generation patterns, you will find it hard to detect abnormal changes. By routinely checking power output, stop history, error logs, and communication status and understanding their normal ranges, you can more easily catch small changes early. Early detection allows you to plan and incorporate mowing, cleaning, basic inspections, and component replacements, reducing the number of emergency responses.

In maintenance aimed at reducing operating costs, it is important not to treat on-site work and data verification separately. Use data to narrow down candidate anomalies, confirm the cause on-site, and then use data again after the work to check whether trends in power output and shutdown history have changed. Creating this workflow makes the effects of the work easier to see. When the effects are visible, it becomes easier to review future inspection content and work frequency, moving maintenance management away from relying solely on experience and intuition.

Consolidate on-site work to reduce unnecessary travel and checks

One aspect of maintaining a solar power plant that is easy to overlook is the travel time and preparation time required to get to the site. If inspections, mowing, cleaning, minor repairs, photography, and equipment checks are carried out on separate days, each occasion incurs travel, entry preparation, safety checks, and post-work reporting. Even if the tasks themselves take only a short time, they become a significant burden when considered overall. To reduce maintenance costs, it is important to consolidate on-site tasks as much as possible and increase the outcomes achieved in a single visit.

Preparing before the visit is crucial for making on-site work efficient. Review power generation data and past inspection records, and categorize locations into places that must be checked on this visit, places to check if time allows, and places that can wait until the next visit. Organizing in advance the spots you want to compare with previous photos, equipment that has shown anomalies in the past, rows prone to weed growth, areas with poor drainage, and entrances where fence damage tends to occur will reduce time spent hesitating on site. An approach that decides the inspection scope only after arriving on site tends to lead to missed checks and duplicated work.

Deciding the work route in advance is also important. Solar power plants cover a wide area, and walking the same spots multiple times takes time. If you predefine the order of progression from the entrance to the power conditioner, junction boxes, module rows, drainage channels, the fence perimeter, and the areas to be mowed, even a small team can carry out checks efficiently. Standardizing the positions and orientations for photographs also makes it easier to compare them during the next inspection. Walking in a different order and taking photos from different angles each time makes it harder to determine changes and increases the time needed for checks.

When consolidating on-site work, be mindful of combining inspections with light tasks. For example, during an on-site inspection you can remove grass blocking walkways, clear leaves accumulated in drainage channels, check signage that is coming off, and photograph areas where images were insufficient; completing such short tasks at the same time can reduce the need for return visits. However, work involving electrical equipment, work at height, checks involving switches or terminals, or tasks requiring specialist judgment must be carried out only after confirming the qualifications and authority of the personnel. You must avoid omitting safety procedures to reduce maintenance costs.

In improving on-site work efficiency, insufficient preparation of items to bring also causes significant losses. If necessary keys, drawings, inspection checklists, recording devices, measuring instruments, protective equipment, cleaning tools, and minor repair supplies are lacking, items that cannot be verified will remain and a revisit will be required. Especially when visiting multiple power plants, prior confirmation is essential because keys, entry requirements, communication status, parking locations, and work-related precautions differ for each plant. The approach of assuming things can be handled once on site tends to lead to increased maintenance costs.

Even when requesting maintenance from an external contractor, ambiguity in the scope of work leads to increased costs. You need to decide in advance how far regular inspections extend and where additional work begins, what photos should be taken, what information should be included in reports, and whether to report abnormalities on the spot or afterward. If the request remains vague, necessary checks may be omitted or, conversely, unnecessary work may be included. To reduce maintenance costs, it is important not simply to lower unit prices but to clarify the content of the requested work.

Consolidating on-site work is not merely about efficiency. Because you can assess the plant’s condition broadly at once, it becomes easier to understand the relationships between anomalies. For example, if a section showing reduced power output also reveals shadows from weeds, poor drainage, and sagging cables at the same time, that becomes an opportunity to review the management approach for the entire section rather than treating them as separate issues. When work is fragmented, it becomes harder to notice such connections. To keep maintenance costs down while maintaining management quality, it is effective to clarify the purpose of each visit and to plan a combination of inspections, record-keeping, and light tasks.

Manage Weeds, Drainage, and Dirt Proactively to Reduce Emergency Responses

One of the factors that tends to drive up maintenance costs at solar power plants is reactive responses to weeds, drainage issues, and soiling. These may seem minor at first glance, but if left unaddressed they can lead to reduced power generation, deterioration of access paths, physical contact with equipment, pest and animal intrusion, sediment inflow, and degradation around the mounting structures. Weeds in particular grow rapidly, and missing the optimal timing increases the workload. To keep maintenance costs down, it's important to manage proactively with planned measures tailored to the season and site, rather than waiting to respond after problems have grown.

In weed management, it's important not only how often you mow but also which areas you prioritize. Trying to keep all weeds short at all times increases the workload. On the other hand, weeds that cast shadows on the front of modules, weeds that come into contact with cables or junction boxes, weeds that block work pathways, and weeds around fences that can create entry points should be managed as a priority. By separating locations that have a large impact on power generation from those that affect safety and maintenance operations, you can more easily narrow down the necessary tasks.

The timing of mowing also affects maintenance costs. If you wait until the grass has overgrown, the work takes longer and the cut grass is heavier to handle. Furthermore, if shadows appear on the modules, power generation losses may already have occurred. Based on past inspection records and photos, identify when and where grass tends to grow and schedule work early. Rather than mowing the same number of times at the same time every year, adjust according to the climate, site conditions, and the previous year’s growth to help avoid both excessive work and being too late.

Drainage management is also important for keeping maintenance costs down. At solar power plants, runoff can become a problem on developed land, slopes, and low-lying areas. When sediment and fallen leaves accumulate in drainage channels, rainwater can flow in unexpected directions, which can lead to muddy access paths, slope failures, and scouring around racking foundations. An operational approach that only responds urgently after heavy rain tends to increase the scope of repairs. During regular inspections, it is important to check for clogged drains, sediment buildup, the location of puddles, and ground erosion, and to address issues while they are still minor.

Soiling does not always yield high benefits from cleaning. Contamination on module surfaces varies in extent and impact depending on the cause—bird droppings, soil dust, pollen, fallen leaves, yellow sand, or dust from nearby work. Some soiling is easily washed away by rain, while other deposits remain in places. The important thing is not to immediately perform a full clean when you find soiling, but to judge based on the effect on power output, the extent of the soiling, the likelihood of recurrence, and the safety of the work. If localized soiling is conspicuous and corresponds to a power drop in specific rows or strings, it is worth prioritizing response. On the other hand, for widespread light soiling, it may be appropriate to consider the timing of cleaning according to weather and season.

A common factor in managing weeds, drainage, and soiling is making judgments by combining on-site photographs and power generation data. Photographs alone make it difficult to assess the impact on generation, and generation data alone cannot definitively identify on-site causes. If photos showing overgrown vegetation coincide with a drop in output in the same section, the priority for response increases. If photos of poor drainage and recorded on-site changes after heavy rain are available, it becomes easier to schedule preventive work before the next rainy season. Comparing the extent of soiling with changes in output makes it easier to explain the need for cleaning.

To reduce emergency responses, it is important to incorporate seasonal factors into the annual maintenance plan. From spring to summer there is weed growth; during the rainy season and typhoon season there are issues with drainage and sediment inflow; in autumn there are falling leaves; and in winter some areas are affected by snow accumulation and freezing. Although the periods of emphasis vary by region and site, problems that tend to occur every year can be included in the plan in advance. While it is difficult to eliminate emergency responses entirely, bringing forward predictable tasks can reduce sudden deployments and major repairs.

Keep records to prevent maintenance decisions from being dependent on individuals

In the maintenance of solar power plants, on-site personnel’s experience is a major asset. However, operations that rely solely on experience make it difficult to control maintenance costs. This is because decision criteria change whenever the person in charge changes, past anomaly locations can become unknown, and the same checks may be repeated multiple times. To reduce maintenance costs, it is important to keep records that allow anyone to understand the situation consistently and to avoid making decision-making dependent on individual staff.

What matters in records is not only documenting that an inspection was carried out, but also preserving information that can be used for subsequent decision-making. The inspection date, weather, personnel, scope of checks, and the presence or absence of abnormalities may not be sufficient. If you record where an abnormality is, how severe it is, whether it has changed compared with the previous inspection, whether it is likely to affect power generation, whether it was dealt with immediately, and whether it can wait until the next inspection, it becomes easier to decide the next course of action. Simply writing "no abnormalities" does not show what was checked or how it was checked, making it difficult to explain later.

Photographic records are particularly effective. At solar power plants there are many items that change over time, such as weed growth, the condition of drainage channels, module soiling, the ground around mounting structures, and fence deformation. Taking photos from the same position, orientation, and field of view each time makes it easier to compare changes. If the way photos are taken differs each time, it becomes difficult to tell whether weeds have grown or the shooting angle has simply changed. Fixing the shooting position and leaving location-identifying information in the photo filename or record field improves the efficiency of report preparation and subsequent inspections.

Keeping records of anomaly responses is also important. For example, if there is a decrease in power output and an on-site inspection suggests that shadows from grass are one of the causes, and the power output trend improves after mowing, recording that sequence of events will make it easier to judge when the same symptoms appear next time. Conversely, if power output does not improve after mowing, you should suspect another cause. By linking the work performed with the results and recording them in this way, you can reduce ineffective work and concentrate on the necessary tasks.

If records are not organized, interactions with external contractors lead to more wasted effort. If you request work while the location of an abnormality is unclear, time will be spent searching on site. If past response histories are not shared, the same explanations will have to be repeated multiple times. If report formats differ each time, it becomes difficult to compare multiple power plants. To keep maintenance costs down, it is important to standardize record formats as much as possible and ensure that the power plant name, section, equipment number, photo location, details of the abnormality, and response status can be easily tracked.

In records management, it is also necessary to take care not to increase the on-site burden by making things too detailed. If there are too many input items, recording takes more time and the quality of on-site checks can decline. What matters is prioritizing the items that will be used for later decisions. Knowing the location of an anomaly, its condition, photos, urgency, whether a response is required, and the items to check next time is highly useful in practice. Conversely, adding items that are not used is unlikely to lead to improvements in maintenance management. Records are not created for their own sake; they exist to speed up the next inspection or repair decision.

If you manage multiple solar power plants, it is also effective to arrange records so they can be compared side-by-side. Being able to compare which plants require the most weed control, which have the most equipment downtime, and which times of year are prone to poor drainage makes it easier to review annual plans and budget allocations. A problem that seems small when looking at an individual plant can, if the same trend appears across multiple facilities, become an opportunity to improve management methods themselves. By recording and accumulating personal experience, you increase the information available to make decisions that reduce maintenance costs.

Solar power plant maintenance keeps upkeep costs down through continuous improvement.

Maintenance aimed at minimizing a solar power plant's upkeep costs does not end with the creation of a single plan. The condition of the plant gradually changes with the seasons, weather, surrounding environment, equipment aging, and management practices. The inspection frequency and scope of work you initially set may not still be appropriate several years later. To maintain stable operation while keeping upkeep costs down, it is important to regularly review the maintenance plan based on inspection results, power generation data, on-site photos, and repair history.

The basic principle of review is to verify the effectiveness of the work. Check whether power generation trends improved after mowing, whether the downward trend changed after cleaning, whether puddles or sediment inflow decreased after maintaining drainage channels, and whether the number of stoppages decreased after equipment inspections. Continue tasks that are effective, and review the frequency or methods of tasks that are less effective. By repeating this, you will move closer to maintenance that suits the power plant.

When aiming to keep maintenance costs down, balancing preventive measures and reactive responses is also important. You cannot prevent all failures and abnormalities in advance, but by identifying problems that are likely to occur, you can reduce emergency responses. Areas where weeds tend to grow, places where drainage tends to clog, periods when shading is likely to occur, and equipment with a history of frequent shutdowns can be prioritized for focused management. Responding while issues are still small makes it easier to avoid major repairs or power generation outages.

Also, reducing maintenance costs is not the same as lowering quality. If necessary inspections are skipped and abnormalities are overlooked, short-term costs may decrease but long-term losses can increase. What matters is reducing unnecessary travel, duplicate checks, ineffective tasks, vague requests, and rework caused by insufficient records. While retaining the tasks necessary to protect the power plant’s safety and power generation performance, reviewing tasks that lack sufficient decision-making information or are performed merely out of habit will lead to practical reductions in maintenance costs.

Maintenance of solar power plants requires both on-site inspection skills and the ability to analyze data. Power generation data alone cannot reveal things like shadows from grass, poor drainage, fence damage, or changes in the ground. Conversely, site photos alone can make it difficult to judge the impact on power output or the timing of when an anomaly occurred. By detecting changes in the data, confirming causes on site, and creating a flow to record and apply findings for the next time, the accuracy of operation and maintenance is improved.

If you are going to review maintenance costs for solar power plants, it is best to start by organizing the current maintenance activities. Check what is inspected during routine checks, how frequently generation data is reviewed, whether on-site work is consolidated, whether weed control and drainage management are planned, and whether records are kept in a form that can be used for future decision-making. From there, it is practical to set priorities for each plant and review overlaps and gaps in tasks.

Maintenance of solar power plants is not only about protecting power generation; it also concerns site safety, equipment longevity, and the efficiency of management operations. To reduce maintenance costs, the mindset should not be about cutting inspections, but about quickly gathering the necessary information and taking appropriate action in the right places. By linking and managing generation data, on-site checks, photographic records, and work histories, you can reduce unnecessary dispatches and rework while moving toward stable plant operation.

If you want to make condition monitoring and maintenance decisions for solar power plants more efficient, it is important to establish a management system that combines on-site inspections with data utilization. By implementing a system that allows centralized review of inspection records, power generation data, photos, drawings, and repair histories, it becomes easier to compare issues across plants and to leverage that information for future inspections and repair decisions.