Solar Power Plant Prices and 6 Things to Note About Mowing Costs

When checking the price of a solar power plant, many practitioners focus on equipment capacity, power purchase conditions, generation performance, land conditions, maintenance contracts, repair history, and so on. However, mowing costs, which continue to have an effect during on-site operation, tend to be underestimated at the purchase or quote-comparison stage. Mowing may at first glance seem like a simple maintenance task, but it affects power generation, equipment degradation, relations with neighbors, fire risk, inspection efficiency, and future repair costs.

Especially when considering used solar power plants, even if the price looks low on the surface, if the land requires a lot of work for mowing or weed-control measures, long-term financial returns may worsen more than anticipated. Conversely, a plant that seems expensive when judged only by price can be operationally more stable if it has a layout that makes mowing easy, maintenance-friendly access paths, ground where weeds are unlikely to grow, and a maintenance system with records.

In this article, for practitioners responsible for evaluating the prices of solar power plants, we organize six points to watch when reviewing grass-cutting costs. Without dealing with specific prices, we explain, from the perspectives of estimate verification, on-site inspection, contract review, and long-term operation, what is easy to overlook and can lead to incorrect price assessments.

Table of Contents

• When evaluating the price of a solar power plant, consider grass-cutting costs separately

• Note 1: The frequency of grass cutting varies greatly depending on the solar plant's site conditions

• Note 2: Weeds affect not only power generation but also safety

• Note 3: Check the scope of work and the scope of responsibility listed in the estimate

• Note 4: Do not judge grass-cutting costs based only on the first year

• Note 5: Consider the balance between weed-control measures and grass cutting

• Note 6: On-site checks and record-keeping can help reduce future cost fluctuations

• Visibility of operation and maintenance is important when assessing the price of a solar power plant

When looking at the price of a solar power plant, consider grass-cutting costs separately

When evaluating the price of a solar power plant, it is important to separate the initial costs required at purchase or construction from the ongoing operation and maintenance costs that continue to occur after operation begins. Mowing costs fall into the latter category, so if you only look at the initial price they are easy to omit from your assessment. However, a power plant is equipment that is operated for a long period, and mowing is not a task that is finished once performed. It recurs depending on the season and land conditions, and it is a task in which the quality of management can vary.

One reason people tend to underestimate mowing costs is that it is not part of the power generation equipment itself. Solar panels, racking, power conditioners, cables, and transformer and substation equipment are perceived as equipment directly linked to a plant’s performance and failure risk. By contrast, mowing is often treated as part of site maintenance and may be bundled into maintenance fees on estimates. For that reason, when comparing prices it is easy for it to be unclear how much mowing is included, how frequently it will be performed, and what area is covered.

In solar power plants, grass growth can cast shadows under the panels. Even partial shading can lead to reduced power generation and increased strain on equipment. Also, when weeds become dense around equipment, it becomes more difficult to detect abnormalities during inspections. Signs you want to discover early—such as exposed cables, corrosion of racking, poor drainage, and traces of small animal intrusion—can be hidden by grass. Mowing is not merely for maintaining appearance; it is a basic task to make it easier to assess the condition of the plant.

When judging price, the important thing is not to view grass-cutting costs as "the cheaper the better." Even if grass-cutting costs appear low, additional charges may arise later if the number of service visits is small, the coverage area is limited, post-work inspections are inadequate, post-weeding cleanup is not included, or emergency responses are treated separately. Conversely, even if a fixed maintenance fee is set, if it includes a work plan tailored to site conditions, record photos, work reports, and measures to prevent recurrence, the plant can be considered easier to manage in the long term.

When evaluating the price of a solar power plant, you should consider not only equipment value, power sales revenue, and land conditions, but also routine maintenance such as grass cutting. In particular, when considering the purchase of a plant or the handover of a project, checking past grass-cutting history, the current state of weeds, surrounding vegetation, access to the site, and whether work vehicles can enter will make it easier to understand future management burdens.

Note 1: Mowing frequency varies greatly depending on the conditions of the power plant

When considering grass-cutting costs, the first thing you should check is the required grass-cutting frequency. Grass cutting for solar power plants cannot be judged by a uniform number of times nationwide. Even with the same installed capacity, the way weeds grow can vary greatly depending on region, climate, topography, soil type, surrounding environment, sunlight exposure, and drainage conditions. If you do not sufficiently confirm the grass-cutting frequency at the price-comparison stage, the management burden may become heavier than expected.

For example, in locations with ample sunlight, where rainwater collects easily and the soil is fertile, weeds tend to grow more readily. If there is farmland, forest, vacant lots, waterways, etc. nearby, seeds are more likely to be carried in, and even if cut they may regrow quickly. Also, if the power plant site contains many slopes and level differences, work efficiency is lower than on flat ground. Because not only the rate at which grass grows but also the difficulty of cutting it affect costs, you cannot compare based solely on simple area.

When considering the price of a solar power plant, you need to check what assumptions have been made about the frequency of grass cutting. Even if grass cutting is included in a maintenance contract, the timing may be fixed and not include additional actions based on actual on-site growth conditions. Conversely, if the contract provides for checking grass conditions during regular inspections and adjusting the timing of work as needed, it is easier to prevent drops in power generation and disputes with neighbors.

One point to bear in mind is that past mowing records do not necessarily guarantee the current condition. Even if there were few weeds immediately after site preparation or the start of operations, vegetation can change after a few years. Weed-control measures can deteriorate, seeds can be introduced from surrounding areas, or drainage paths can change, any of which can make weeds grow more easily than before. For used power plants, it is important to verify not only the maintenance history listed in sales documents but also recent on-site photos and seasonal conditions.

Also, the frequency of mowing is related to the design of the power plant. If the lower edge of the panels is close to the ground, even slight grass growth can easily cause shading. When aisles are narrow or racking spacing is tight, workers and machinery have difficulty getting in, and mowing takes more time. If there are many locations that tend to require manual work, such as along fences, around connection boxes, at cable entry points, and around drainage ditches, the workload increases further.

Even if a solar power plant looks inexpensive, if the land requires frequent mowing and has poor operational efficiency, the long-term maintenance burden will be heavy. Before purchasing, check not only how many times per year mowing is expected, but also why that frequency will suffice, whether power output has ever dropped due to grass in the past, and whether post-work photos or reports are retained; doing so makes it easier to judge whether the price is reasonable.

Note 2: Weeds affect not only power generation but also safety

When considering mowing costs, judging solely by the impact on power generation is short-sighted. It is true that when weeds grow and cast shadows on panels, power output decreases. However, the problem of weeds is not limited to that. It also affects power plant safety, ease of inspection, failure prevention, and the surrounding environment. Those responsible for evaluating the price of a solar power plant must view mowing not only as a task to maintain generation but also as a risk management activity.

First, when weeds become dense around equipment, it becomes harder to notice abnormalities in electrical equipment. Cable sagging, damage to cable insulation, settlement at the base of mounting frames, loose bolts, poor drainage, and animal digging are items you want to detect early during on-site patrols. If the grass is overgrown, it takes longer to check these conditions and the accuracy of inspections decreases. Power plants that are difficult to inspect are more likely to experience delayed detection of abnormalities, which can result in higher repair costs and an increased risk of outages.

Next, dry grass is related to fire risk. If a power plant has a lot of dead grass remaining, the risk increases during dry periods and strong winds. Even if there are no abnormalities in the electrical equipment itself, one cannot completely rule out the possibility that dry grass will catch and spread fire due to external factors or embers from nearby areas. Caution is also necessary when mowed grass is left lying after cutting. Management is not just about cutting; it is important to check the condition after mowing.

Also, weeds can affect relations with neighboring properties. If grass grows beyond the site boundary, sightlines around fences worsen, the vegetation becomes a habitat for pests and small animals, or the site appears poorly maintained from nearby roads or adjacent land, these issues can create a negative impression of the power plant operator. Since a solar power plant is a facility operated within a community for a long time, maintaining good relations with neighbors is also an important management task. If mowing costs are cut too much and appearance management becomes inadequate, the burden of dealing with issues later may increase.

Even in terms of power generation, the impact of weeds is not straightforward. They can not only cast shadows over parts of the panels, but also worsen ventilation and cause heat to become trapped around equipment. Airflow beneath the panels and around equipment affects generation efficiency and the condition of the machinery. Of course, the mere presence of weeds does not necessarily cause major problems, but it should be assumed that poorly maintained power plants are more likely to accumulate multiple small losses and risks.

When judging the price of a solar power plant, it is important not to narrowly regard mowing costs as merely "expenses to slightly protect power generation." Mowing is a fundamental aspect of maintenance that supports power generation, equipment preservation, safety, relations with neighbors, and inspection efficiency. Even if simulated revenues from electricity sales look good, inadequate on-site vegetation management can lead to extra effort during actual operation. It is important to check not only for a low price but also whether the plant can be kept in a safe, maintainable condition.

Note 3: Confirm the scope of work and the scope of responsibility in the estimate

One aspect of mowing costs that is particularly easy to overlook is the scope of work and the scope of responsibility stated in the estimate. In maintenance estimates and management contracts for solar power plants, mowing may appear to be included, but what is covered is not necessarily sufficient. Whether the work covers the entire site, only around the panels, only inside the fence, or extends to the road frontage outside the fence and the boundary with neighboring land can greatly affect the actual quality of management.

The first thing to check is the scope of the grass-cutting. Within the power plant there are multiple locations where grass cutting is likely to be required: under panels, between mounting racks, walkways, around electrical equipment, along fences, drainage channels, slopes, access roads, and so on. Even if the estimate simply states “grass cutting,” in practice it may only cover the easily worked flat areas, with detailed work on slopes or around equipment treated separately. If you sign a contract while the scope of work is unclear, additional work may be needed later, making unexpected costs and adjustments more likely to occur.

Next, confirming the mowing method is also important. Work inside the power plant must be carried out so as not to damage equipment. Around cables, junction boxes, mounting racks, panels, piping, signage, fences, and similar areas, there are situations that require manual work as well as mechanical operations. Prioritizing work efficiency alone creates risks such as equipment damage from flying stones or mower blades, scratches to cable sheathing, and fence damage. In the quotation, it's reassuring to confirm the work method, how areas around equipment will be handled, the response in case of damage, and the workers' experience.

Additionally, it is necessary to confirm how the cut grass will be handled. Whether the grass will simply be mowed and left on site, gathered into a defined area, removed from the site, or allowed to return to nature will affect the post-work condition. If large amounts of cut grass remain, it can increase the risk of fire when dry, clog drainage channels, and interfere with inspections. Of course, it is not always necessary to remove everything, but it is important to ensure that it will be handled appropriately according to the conditions of the power plant.

Regarding the scope of responsibility, confirm how to handle damage to equipment during work, rework if any uncut areas remain after the work, how to deal with grass encroaching on neighboring properties, additional work in emergencies, and how to handle cases where work cannot be carried out as scheduled due to bad weather. Mowing is an outdoor task and is affected by weather and growth conditions. Therefore, it may not be possible to carry it out on the scheduled date, or the grass may grow more than expected. If, in such cases, who makes the decisions and how to respond are unclear, the quality of management will vary.

When comparing prices for solar power plants, the lower the maintenance fee looks, the more you need to carefully check the details of grass-cutting. It's important not just to confirm whether the cost is included, but to see how much is covered, by what methods, how frequently, and whose responsibility it is. If you can verify work scope diagrams, post-work photos, report formats, and past performance before signing the contract, it will be easier to judge the reasonableness of the grass-cutting costs.

Note 4: Don't judge mowing costs based solely on the first year

When considering the price of a solar power plant, it is risky to judge based only on the first year's operation and maintenance costs. Mowing costs fluctuate with year-to-year weather, changes in vegetation, equipment condition, and the surrounding environment. Even if the site is neatly maintained in the first year and the management burden appears small, the mowing burden can increase after a few years as weeds proliferate, weed-control measures deteriorate, or drainage problems progress.

In newly established or newly developed power plants, the surface may appear to have few weeds. This is because the ground is leveled during development, and immediately after construction the grass has not yet filled in.

However, vegetation stabilizes over time due to seeds remaining in the soil and seeds carried in from the surrounding area. As a result, even power plants that initially required few mowing operations may, after several years, come to require regular maintenance.

In used solar power plants, the future mowing burden varies depending on past maintenance. In plants that have been properly maintained over a long period, pathways and areas around equipment are easier to inspect, and there may be consistent patterns in how the grass grows. On the other hand, in plants with insufficient maintenance, deep-rooted weeds may have spread, fence lines and slopes may have been neglected, and drainage channels may be prone to clogging. In such conditions, a one-off mowing may not be enough to improve the situation, and ongoing measures may be necessary.

To avoid judging based only on the first year, you need to consider mowing over the entire remaining operating life of the power plant. Mowing is not as conspicuous an expense as equipment replacement or major overhauls, but because it continues for a long time it gradually affects the financials. Even if the purchase price looks reasonable, a plant with heavy annual maintenance burdens may fail to achieve the expected returns. Conversely, a plant designed for easy mowing and with an effective management system has lower day‑to‑day operational burdens and makes it easier to forecast finances.

Also, mowing costs are affected by labor shortages and changes in working conditions. Outdoor work involves heat, slopes, insects, flying debris, the risk of equipment damage, and is not a simple task. If the travel distance to the site is long or there are only a limited number of contractors who can do the work in the area, it may become difficult to arrange in the future. When evaluating the price of a solar power plant, you need to consider not only the assumption that the current maintenance contract will continue, but also whether the plant can be managed at the time of contract renewal or when changing contractors.

If past grass-cutting records, work reports, on-site photos, complaint history, and emergency response records are available, it becomes easier to predict long-term management burdens. In particular, having seasonal photos allows you to check how the grass grows and how shadows form. At the price assessment stage, it is important to include maintenance records that cover grass-cutting, as well as power sales records and the equipment ledger, among the items to be reviewed.

Point 5: Consider the balance between weed-control measures and mowing

When aiming to reduce mowing costs, attention is often focused on weed-prevention measures. There are various approaches for each power plant, such as weed-control sheets, crushed stone, paving, groundcover plants, herbicides, and regular trimming. However, implementing weed-prevention measures does not simply eliminate mowing costs. When assessing the price of a solar power plant, it is important to consider the balance between initial measures and ongoing maintenance.

There are advantages and disadvantages to each weed-prevention measure. For example, weed-control sheets can be expected to provide a certain degree of weed suppression, but their durability varies depending on installation quality, fastening method, ground conditions, drainage, ultraviolet exposure, wind, and animal damage. If tearing or lifting occurs, weeds can grow through those areas. When laying crushed stone, poor ground or drainage conditions can lead to settlement or a recurrence of weeds. Measures that are closer to paving can improve manageability, but drainage and the scope of construction need to be considered carefully.

When using herbicides, you must take into account the surrounding environment, neighboring properties, drainage routes, applicable laws and local rules, and the safety of workers. Herbicides can be one means of reducing the frequency of mowing, but they cannot be used in the same way at every power plant. If there are agricultural fields or waterways nearby, extra caution is required in how they are applied. In managing solar power plants, it is necessary to consider not only short-term efficiency but also relationships with the surrounding area and long-term land use.

When assessing weed-control measures, it's important not just to confirm whether they have been installed. You should check how well they are currently functioning, whether there are any damaged areas, whether weeds are encroaching from the edges, whether the areas around racking bases and along fences are being maintained, and whether drainage is being impeded. Even if sales materials state that "weed-control measures are in place," in practice the work may be only partial or deterioration may have progressed since installation.

Also, weed-control measures can make mowing work more difficult. If sheet fastening pins or edges are exposed, they can interfere with brush cutter operations. In areas with crushed stone, be careful of flying stones. In narrow spaces between frames or around equipment, work may not be manageable by machinery alone. Weed-control measures are a means to reduce mowing, but if design or construction is inadequate, they may actually increase repairs and manual labor.

When assessing the price of a solar power plant, it is important not to simply evaluate whether weed-control measures are present, but to consider them in combination with mowing. Leaving the entire plant completely unmaintained is not realistic. Rather, you should identify areas where grass tends to grow, places prone to creating shadows, routes used for inspections, and locations visible from neighboring properties, and check whether the design focuses management efforts on those spots. If weed-control measures and mowing plans are coordinated, it becomes easier to forecast maintenance.

Point 6: Reduce future cost fluctuations through on-site verification and record-keeping

The final point to emphasize regarding mowing costs is on-site inspection and documentation. To correctly assess the price of a solar power plant, documents alone are not enough. Drawings, generation performance records, maintenance contracts, and photos can provide some level of verification, but when it comes to grass cutting there are many factors that are difficult to understand without seeing the site. In particular, the width of access paths, unevenness of the ground, slope of embankments, condition along fences, clogged drains, intrusion of grass from surrounding areas, and access routes for service vehicles are all worth checking on-site.

During on-site inspections, it is important not only to check whether the grass has grown, but to consider why it is in that condition. Even if the grass is short immediately after maintenance, signs such as roots remaining, grass concentrated at the edges, only areas around equipment left uncut, slopes not being tended, or vigorous growth only in poorly drained spots may indicate a future maintenance burden. Conversely, even if some grass remains, if it has little impact on shading or inspections, the work area is clearly defined, and records are kept, you may be able to conclude that the management policy is well organized.

How records are kept is also important. If photos taken before and after the work, photo locations, dates of photography, work area, workers, methods used, treatment of grass clippings, whether any equipment was damaged, and notes for the next time are retained, it becomes easier to verify the quality of the grass cutting. Without records, even if you can tell whether the work was performed, you cannot tell which areas were managed and to what extent. In situations such as power plant handovers or sales, the presence or absence of such records affects the credibility of the management status.

When comparing prices of solar power plants, if the photos provided by the seller or management company are limited, pay attention to when the photos were taken. Photos from periods with little grass do not show conditions during the time when the grass grows the most. Ideally, seasonal photos or before-and-after mowing comparisons make judging easier. If you can inspect the site in person, check the distance between the bottom edge of the panels and the ground, the accessibility between the mounting racks, the fence perimeter, the access road, and the neighboring property boundaries, and get a concrete sense of how easy it will be to mow.

Keeping records also helps reduce future cost fluctuations. If you know where grass tends to grow, when shadows are likely to occur, and which areas are difficult to work in, you can more easily plan future work. Rather than simply mowing the entire area the same way each time, identifying priority areas for management can reduce waste while maintaining work quality. In power plant operations, it is effective to manage by combining location information and photos instead of relying solely on experience and intuition.

In power plants where on-site inspections and record-keeping are insufficient, mowing costs become difficult to estimate. Even if a site appears problem-free at purchase, once operations begin you may find areas that are hard to mow, receive complaints from neighboring properties, have grass left around equipment affect generation, or be unable to verify the post-work condition. Checking on-site management records at the price-evaluation stage and, if necessary, establishing your own record-keeping system will contribute to stable long-term operation.

Visibility of Operation and Maintenance Is Crucial When Valuing Solar Power Plants

When evaluating the price of a solar power plant, grass-cutting costs may seem like a minor line item. However, in reality they are important maintenance costs that affect power generation, safety, inspection efficiency, relations with neighbors, and repair risks. Even for a low-priced plant, if conditions such as high mowing frequency, a large work area, many slopes, narrow access paths, degraded weed-control measures, and a lack of records coincide, the long-term burden can become significant.

When checking mowing costs, it is important not simply to see whether they are included in the maintenance contract, but to look at what area will be covered, how often, by what method, and under what scope of responsibility. You should also consider not just the first year but the entire remaining operational life of the power plant. Weed growth patterns change from year to year, and weed-control measures deteriorate over time. Do not judge based only on the clean photos taken at the time of purchase; it is important to check seasonal conditions and past work history.

In practice, by putting in place a system for on-site inspections and recordkeeping, it becomes easier to reduce uncertainty around mowing costs. If you record before-and-after photos, the photo locations, the work area, any uncut patches, places where shadows occur, and abnormalities around equipment, you can use that information for future work planning and for verifying estimates. When managing multiple power plants, you can compare grass growth and workload at each site, making it easier to set priorities for maintenance.

When evaluating the price of a solar power plant, it is important to consider not only the value of the equipment itself but also how easy it is to operate. Grass-cutting costs are a representative example of such items. By accurately measuring site conditions, recording photos and location information, and keeping them as management history, the accuracy of estimate comparisons and purchase decisions is improved.

One tool that helps visualize on-site management is LRTK, a GNSS high-precision positioning device that can be attached to and used with an iPhone. If you can record locations requiring grass mowing, areas prone to missed cuts, spots along fences and slopes, drains, and areas requiring attention around equipment with high-precision positional information, it becomes easier to share the details of on-site inspections later. To correctly assess the price of a solar power plant and stabilize maintenance, including grass mowing costs, it is important not to leave the site condition vague but to document it with location data and photos. By utilizing LRTK, you can more easily and consistently manage everything from on-site inspections and mowing plans to post-work checks and future handovers.