8 Pitfalls When Comparing Prices of Solar Power Plants

Table of Contents

• Price comparisons for solar power plants can vary even when conditions appear identical

• Pitfall 1: Comparing prices based only on installed capacity

• Pitfall 2: Not checking the details of power generation performance

• Pitfall 3: Downplaying the feed-in conditions and the remaining contract period

• Pitfall 4: Not including maintenance and fixed costs in comparisons

• Pitfall 5: Overlooking equipment degradation and future repairs

• Pitfall 6: Deferring consideration of land conditions and property rights

• Pitfall 7: Assessing site risks solely from documents

• Pitfall 8: Failing to check discrepancies between documents, drawings, and on-site information

• A practical approach to turning price comparisons into purchase decisions

• Summary: Price comparisons should be backed by evidence verifiable on-site

Price comparisons for solar power plants can vary even under seemingly identical conditions

When considering the purchase or acquisition of a solar power plant, many practitioners compare prices by lining up multiple projects. Because project documents list installed capacity, location, power purchase terms, start of operation, generation performance, and so on, they may at first appear comparable side by side. However, a solar power plant is not simply equipment; it is a business asset that integrates land, generation equipment, power purchase terms, generation performance, operation and maintenance, contractual relationships, and the local environment. Therefore, judging something as expensive or cheap based solely on price can lead to misreading the actual situation.

Even power plants that appear to have similar installed capacity can have very different business values depending on whether their actual power generation is stable or whether they have frequent histories of generation decline or stoppages. Even if the power purchase conditions are similar, differences in remaining term, equipment degradation, planned repairs, output curtailment, management costs, land contracts, access roads, or drainage conditions can make the actual burden after purchase completely different. Even when documents make the conditions look good, visiting the site may reveal overgrown vegetation, shading from surrounding trees, clogged drainage channels, corrosion of mounting frames, cable damage, or unclear boundaries.

Those responsible for searching for "solar power plant price" are not simply looking for ways to find properties cheaper than the market. What matters is whether the quoted price is reasonable, why it may be low, whether a high price can be explained, and how to present the rationale in internal approval processes. Price comparison is an entry point to the purchase decision, not the final judgment. The purpose of comparison is not to decide whether a price is high or low, but to break down the value and risks contained in that price.

This article summarizes eight pitfalls that are easy to overlook when comparing the prices of solar power plants. Instead of specific monetary amounts, it focuses on the perspectives that practitioners should verify when comparing projects, making purchase decisions, negotiating prices, and explaining matters internally. Use this as a foundation for making decisions that reflect the actual condition of the power plant, rather than being misled by superficial prices.

Pitfall 1: Comparing prices based solely on equipment capacity

The most common pitfall when comparing prices of solar power plants is judging solely by installed capacity. Installed capacity is an easy-to-understand indicator of a plant’s size and is useful as an entry point when comparing multiple projects. However, installed capacity merely indicates the size of the installed generation equipment and does not guarantee how much electricity is actually being produced.

Even with the same installed capacity, power generation can vary greatly depending on solar irradiance conditions, installation angle, orientation, surrounding shading, panel soiling, vegetation overgrowth, the condition of power conversion equipment, the integrity of cables and connection equipment, and the quality of operation and maintenance. Even projects that appear to have large installed capacity cannot be said to offer business value commensurate with their price if their generation performance has not been strong. Conversely, projects that may seem unimpressive based on installed capacity alone can be easier to consider for long-term operation if their generation performance is stable, they have few outage records, and they are well maintained.

If you compare only by installed capacity, you may overlook the reasons a project appears inexpensive. Even a power plant that looks cheap on price may actually have significant shading, a year-by-year decline in generation, frequent outages of power conversion equipment, or require time-consuming vegetation management. While it may look cost-effective per unit of capacity, when you consider actual generation performance and repair risks, it may not be advantageous in practice.

In price comparisons, you should check the installed capacity and then assess how much of that capacity is actually being utilized on site. Review monthly and annual generation records, inspection reports, shutdown history, and cleaning and grass-cutting records to confirm there is no inconsistency between capacity and actual performance. Installed capacity is the entry point for comparison, but the central factor in a purchase decision should be whether it is actually generating power reliably.

Pitfall 2: Failing to Check the Details of Power Generation Records

When comparing prices of solar power plants, failing to check the details of their generation performance is a major pitfall. If project documents show annual generation and power sales results, it may at first seem that there is enough information to make a judgment. However, annual totals alone do not provide a sufficient understanding of the plant’s condition or on-site risks. In practice, you need to verify monthly and yearly trends and the reasons for any anomalies.

Even if annual power generation appears stable, monthly figures can show significant drops during specific periods. There is always a reason for fluctuations in generation—for example, weeds growing in summer that cast shadows on panels, surrounding trees or terrain casting longer shadows in winter, the effects of leaf fall or snow cover, or stoppages due to equipment shutdowns or inspections. If the same seasonal decline is observed every year, you should suspect site-specific factors as well as the weather.

Trends over multiple years are also important. Even if a single year’s power generation performance looks good, that year may simply have had favorable weather. If output has been gradually declining over several years, factors such as panel soiling, equipment deterioration, growth of surrounding trees, insufficient vegetation management, degradation of cables and connections, or malfunctions in power conversion equipment may be involved. If output suddenly drops from a certain point in time, equipment failure or unrepaired damage following a disaster may also be the cause.

When checking the details of power generation performance, we also look at the difference from the generation simulation. If the planned assumptions and the actual results are continuously diverging, it is necessary to identify the reasons. We clarify whether the simulation was optimistic, whether on-site shading or output control were not sufficiently anticipated, or whether inadequate management is having an impact. By interpreting not only the power generation figures but also the context behind those numbers, it becomes easier to judge the reasonableness of the price.

Pitfall 3: Taking the feed-in tariff terms and remaining contract period lightly

A factor that is often overlooked when comparing prices is differences in the power sale conditions and the remaining term. A solar power plant is a business that generates revenue by selling the electricity it produces. Therefore, the power sale conditions and the remaining term have a large impact on the price. However, if you take comfort in only the conditions shown in the documents or downplay differences in the remaining term, your post‑purchase profit-and-loss assessment may be distorted.

When checking the terms for selling electricity, organize the contract details, the start date of operation, certification-related information, the procedures required for succession, interconnection conditions, and whether output control is present. Even if projects appear the same on paper, if there are uncertainties about name changes or succession procedures, additional actions may be required after acquisition. You should also confirm that the location, installed capacity, name on the contract, and scope of management are consistent across documents.

The remaining operating period is also important. Power plants with a long remaining period have many future operating opportunities left, but accordingly you need to anticipate equipment degradation and future repairs. For power plants with a short remaining period, a major repair can more easily weigh heavily on their finances. A short remaining period is not necessarily bad, but you need to confirm whether the plant can continue to generate electricity reliably throughout that period.

Projects with favorable feed-in conditions tend to command higher prices, but judging them by conditions alone is risky. No matter how good the feed-in terms are, if generation output has declined, revenue will not increase. Conversely, a project that looks unremarkable based only on its terms may still be capable of solid operation if its generation record is stable and the equipment and land pose low risk. When comparing prices, it is important to evaluate feed-in conditions, the remaining term, generation performance, and equipment condition together.

Pitfall 4: Not including maintenance and fixed costs in comparisons

In price comparisons for solar power plants, people sometimes focus only on the purchase price and do not include maintenance and fixed costs in the comparison. This is a major pitfall. A power plant is not finished when purchased; it maintains its value through long-term inspections, generation monitoring, mowing, cleaning, insurance, administrative procedures, land management, and emergency response. Even if the purchase price is low, high fixed costs can result in a significantly greater real burden.

Maintenance and management include regular inspections, checking electrical equipment, monitoring power generation, mowing, weed control, cleaning, managing drainage channels, repairing fences and gates, managing surrounding trees, and on-site response during abnormalities. These vary greatly depending on the power plant’s location and the condition of its equipment. Management ease differs between a plant on flat, easily accessible land and one located in forested or sloped terrain, even with the same installed capacity.

Even if a project has had low maintenance costs in the past, it is dangerous to simply take that as a positive indicator. The low costs may be due only to insufficiently performed necessary inspections, grass cutting, drainage management, and repairs. If you switch to an appropriate management system after purchase, fixed costs may increase more than expected. Conversely, even if certain fixed costs are incurred, if they result in stable power generation performance and good equipment condition, those costs can be regarded as necessary management expenses.

Insurance, taxes, and administrative procedures also need to be accounted for as fixed costs. Once you own a power plant, ongoing tasks such as contract management, document organization, insurance verification, accounting, and confirming ownership and management scope will continually arise. If you compare prices without allowing for these, the apparent financial results can look better than the reality. When comparing prices, it is important to separate the purchase price from the fixed operating costs and judge based on the total burden over the entire operating period.

Pitfall 5: Overlooking Equipment Deterioration and Future Repairs

When comparing prices of solar power plants, it is common to overlook equipment degradation and future repairs. Even if a plant appears to be generating electricity without problems now, solar panels, power conversion equipment, mounting structures, foundations, cables, connection equipment, monitoring systems, fences, and drainage facilities all deteriorate gradually. If repairs become concentrated after purchase, the actual burden increases even if the purchase price was low.

For solar panels, check for dirt, cracks, discoloration, loose fastenings, and the effects of shading. For power conversion equipment, check the installation year, downtime history, replacement history, and repair history. For cables and connection equipment, check for damage to the sheath/insulation, broken protective components, deterioration at connection points, and contact with vegetation. For mounting structures and foundations, check for corrosion, tilting, loose fastenings, and scour or settlement around the foundation.

Inspection reports and repair histories are important documents for anticipating future repairs. They show what kinds of defects occurred in the past and how they were addressed. The mere fact that failures occurred is not necessarily a problem. If the cause was identified, appropriate repairs were made, and measures to prevent recurrence have been put in place, it becomes easier to assess the state of maintenance. The problem is when noted issues remain unaddressed or when the details of repairs are ambiguous.

In lower-priced listings, the low cost may stem from unaddressed repairs or equipment that is nearing its replacement time. In higher-priced listings, the value may come from good equipment condition, clear repair histories, and an easier ability to forecast future repairs. When comparing prices, you need to check not only current power generation but also which equipment is likely to require repairs during the remaining operational period.

Pitfall 6: Putting land conditions and property rights on the back burner

Focusing too much on comparing power generation equipment and power sales conditions while postponing consideration of land conditions and rights is a major pitfall. A solar power plant is installed on land and is a business asset that operates in the same location over a long period. If stable use of the land cannot be secured, concerns about long-term operation will remain even if the equipment is in good condition.

First, what you should check is the form of land use. Confirm whether the land is owned or leased, whether the land-use contract period is sufficient, and what the renewal and termination conditions are. For leased land, it is important to ensure that land-use rights are sufficiently secured for the period of electricity sales and the expected operation period. If there are multiple landowners or the contract is divided into multiple agreements, you also need to consider the future burden of coordination.

Boundaries and the scope of use are also important. Check that the contractual boundary, the boundary shown on drawings, the area enclosed by fences, and the area actually being managed all match. Also confirm that fences, panels, mounting structures, drainage channels, maintenance access routes, and cable routes are contained within the site. If you purchase with the boundaries unclear, you may later need to coordinate with neighbors or carry out additional surveys.

Access roads and entry routes must not be overlooked. Verify not only that they can be used for routine inspections, but also that work vehicles can enter for tasks such as grass cutting, cleaning, equipment replacement, and disaster recovery. Conditions such as narrow access routes, unclear right-of-way, muddiness in wet weather, or lack of vehicle turning space can affect maintenance costs and recovery operations.

Problems related to land cannot be replaced as easily as equipment. In lower-priced projects, uncertainties about land conditions may be behind the low price. In higher-priced projects, land conditions may have been sorted out, with boundaries, road access, and drainage stabilized, and that may be included as part of the value. When comparing prices, it is important to confirm the land not merely as a site for installation but as the foundation that supports the value of the power plant.

Pitfall 7: Relying solely on documents to assess on-site risks

It's important to review documents when comparing prices, but judging on-site risks based on documents alone is dangerous. A solar power plant is an outdoor installation and is affected by drainage, shading, vegetation, natural disasters, topography, road access, and the surrounding environment. These factors may not be adequately understood from the project summary or power generation performance alone.

Drainage is particularly important. Check where rainwater flows in and where it drains out, whether drainage channels are prone to clogging, and whether there are places where water tends to accumulate. Poor drainage can lead to scouring around foundations, weakening of the ground, impacts on cables and electrical equipment, and deterioration of maintenance access routes. Even if there appear to be no problems on paper, on site there may be sediment buildup and traces of water flow.

Shadows and vegetation risks also need to be checked on site. Shadows from nearby trees and terrain change with the time of day and season. Even if shadows are not visible during an on-site inspection, they may affect power generation in winter or at dawn and dusk. Conditions such as vegetation casting shadows under panels, growing densely around wiring, or covering areas around fences are also items that are difficult to assess without seeing them on site.

Recoverability during disasters is also part of on-site risk. If heavy rain, strong winds, snowfall, fallen trees, or sediment inflow occur, we check whether the site can be accessed, whether service vehicles can reach it, and whether damaged areas can be easily identified. If recovery is delayed, the power generation outage period will be longer and revenue from electricity sales will also be affected.

Documents are the starting point for on-site verification and not the final decision. For low-priced deals, on-site risks may not be adequately reflected in the documents. For high-priced deals, verify whether a low on-site risk is the basis for the price. When comparing prices, always cross-check the documents against the site.

Pitfall 8: Not checking for discrepancies between documents, drawings, and on-site information

The final pitfall is failing to verify discrepancies between documentation, drawings, and on-site information. Even if you have the project summary, power generation records, power sale terms, land contracts, inspection reports, drawings, and site photos, they may not match the current on-site conditions. This is especially true for secondhand solar power plants, where repairs or modifications carried out during operation, changes in the natural environment, or a change of management company can leave the documentation outdated.

What I want to check first is whether the basic information recorded in multiple documents is consistent. I look to see whether equipment capacity, location, land area, operation start date, owner, scope of management, and equipment configuration differ between documents. Even differences that appear minor in notation can become problematic in contracts, handovers, and management planning.

Verifying the drawings against the site is also important. Check that the panel layout, mounting structures, power conversion equipment, connection equipment, fences, gates, drainage channels, access paths, and boundary lines shown on the drawings match the actual site. If there are discrepancies between the site and the drawings, you need to confirm when and why the changes were made and whether the related documents have been updated. If the drawings remain outdated, you cannot accurately identify repair candidates or items to be managed.

We also check the quality of inspection reports and site photographs. Even if photos exist, if it is not clear where they were taken, it becomes difficult to deal with them later. Damaged areas, locations of drainage failures, causes of shadows, the extent of vegetation growth, and checkpoints near boundaries should ideally be recorded together with their locations.

Projects where the documentation and on-site information do not match carry high uncertainty. A low price may stem not from low risk but from insufficient information or inconsistent documentation. When comparing prices, it is important not only to consider the attractiveness of the conditions but also to confirm that the documents supporting those conditions match the on-site situation.

Practical approach to connecting price comparisons to purchase decisions

To turn price comparisons of solar power plants into purchase decisions, you must first align the comparison criteria. Check the same aspects—installed capacity, generation performance, power purchase terms, remaining term, land conditions, operation and maintenance costs, repair risks, and consistency of documentation. If you compare prices alone without aligning the conditions, you are likely to overlook the risks of cheaper projects and the value of more expensive ones.

Next, break down the reasons for low prices and high prices. For lower-priced projects, check whether there are underlying factors such as decreased power generation performance, equipment degradation, a short remaining term, uncertain land conditions, management burdens, or insufficient documentation. For higher-priced projects, verify whether the price is justified by factors such as stable power generation performance, good equipment condition, clarified land conditions, a clear management structure, and consistency between the documentation and the site.

It is also important to distinguish between risks that can be mitigated and those that are difficult to mitigate. Insufficient grass cutting, inadequate cleaning, minor equipment repairs, and poor document organization can often be improved through appropriate measures. On the other hand, strong shadows, poor road access, unclear boundaries, restrictions in land contracts, drainage problems caused by the terrain, and severe deterioration of major equipment may not be easily remedied. When making a purchase decision, it is necessary to check not only the price but also the feasibility of addressing these risks.

In internal briefings, it is important to present the rationale, not just the conclusion of a price comparison. Rather than focusing on which project is cheaper, organize why it is cheaper, which risks have been confirmed, what costs are anticipated, and what on-site checks were carried out. Price comparison is not a task of lining up numbers; it is a task of visualizing the actual condition of the power plant.

Summary: When comparing prices, check the evidence that can be verified on site

The pitfalls when comparing the prices of solar power plants are judging by installed capacity alone, not checking the details of generation performance, taking the power sale terms and remaining period lightly, not including operation and maintenance costs and fixed costs in comparisons, overlooking equipment degradation and future repairs, postponing consideration of land conditions and property rights, judging on-site risks based only on documents, and failing to check discrepancies among documents, drawings, and on-site information.

There may be reasons why a cheap project is inexpensive. A decline in power generation, equipment deterioration, heavy fixed costs, uncertain land conditions, or insufficient documentation may be behind it. There are also reasons why a project is expensive. If generation performance is stable, equipment is in good condition, land and management systems are in order, and the documentation is consistent with the site, it can be said to be a project that is easier to consider in the long term.

What matters for practitioners is not to judge price levels by intuition. They must correlate and organize power generation data, terms of power sales, inspection reports, repair histories, land contracts, drawings, and on-site inspection results so that they can explain the reasons behind a price. Especially for used solar power plants, it is essential to reconcile past operational history with current on-site conditions.

During on-site surveys, it is effective not only to take photographs but also to record verification points with accurate location information. If you record, with location data, boundary-adjacent equipment, drainage channels, trees that cause shadows, areas of vegetation overgrowth, cable damage, fence damage, equipment deterioration, and candidate repair locations, they become easier to use as a basis for price comparisons.

If you want to compare the prices of solar power plants more reliably, using LRTK (an iPhone-mounted GNSS high-precision positioning device) is also effective. If you can record the locations of equipment and inspection points within the plant together with high-precision positional information, it becomes easier to share among stakeholders the discrepancies between drawings and the site, drainage and shading risks, areas of equipment degradation, and points to watch near boundaries. When comparing the prices of solar power plants, it is important to make judgments not only based on desk figures but also by building up evidence that can be verified on site.