8 Factors to Check About the Price of a Solar Power Plant Before Purchasing

Table of Contents

• Do not judge the price of a solar power plant solely by the purchase price

• Element 1: Confirm the assumptions for power generation and revenue from electricity sales

• Element 2: Confirm land conditions and site preparation risks

• Element 3: Confirm equipment configuration and degradation condition

• Element 4: Confirm the conditions for grid interconnection and output control

• Element 5: Confirm maintenance management and costs after commissioning

• Element 6: Confirm contract terms and rights/ownership relationships

• Element 7: Confirm disaster risks and insurance terms

• Element 8: Confirm future equipment replacement and exit strategy

• On-site inspection is essential to determine the price of a solar power plant

Do not judge the price of a solar power plant solely by the purchase price

The first thing a practitioner tasked with researching the price of a solar power plant should be careful about is not to judge it as expensive or cheap based solely on the quoted purchase price. A solar power plant is a business asset that combines land, generation equipment, grid connection rights, power sales contracts, maintenance arrangements, future repair liabilities, and other elements. Therefore, even projects that appear to have similar output capacities can differ greatly in actual value.

When considering a purchase, people especially tend to focus only on headline yields and projected revenues. However, the price of a power plant needs to be assessed by including the certainty of its power output, the condition of the equipment, the usability of the land, disaster risks, contractual constraints, maintenance costs, and future replacement costs. If unexpected repairs, land development, neighbor relations, grass cutting, drainage measures, or equipment replacement become necessary after purchase, a project that looked cheap at the time of purchase can end up being more expensive overall.

When deciding whether to purchase a solar power plant, it is important to break down and verify not just "how much it costs" but "what is included in that price," "what level of risk you are taking on at that price," and "how much management burden will arise after purchase." This applies equally to new projects and used ones. Even a completed plant with an operating record is not necessarily safe. Even if generation appears stable, there are cases where the measurement period is short, the impact of output control is not sufficiently reflected, equipment degradation has progressed, or there are problems with land drainage.

Also, once a solar power plant is purchased, it is an asset that is difficult to relocate or to change its conditions significantly. Land conditions or contractual terms overlooked at the time of purchase will continue to affect operations throughout the operating period. Precisely for that reason, before purchase you should not view the price as a single number; instead, you need to break it down into multiple elements, check them, and assess the reasonableness of the price.

This article organizes eight factors to review before buying a solar power plant price: energy production, land conditions, equipment condition, grid connection conditions, maintenance costs, contractual terms, disaster risks, and future renewal and exit strategies. To make it easy for practitioners to use in internal review, investment decisions, on-site inspections, and questions with sellers, we explain from the perspective of where to look to assess the reasonableness of the price rather than presenting mere concepts.

Element 1: Confirm the assumptions for power generation and electricity sales revenue

When evaluating the price of a solar power plant, the first factors to check are the assumptions about power generation and revenue from electricity sales. The value of a solar power plant depends greatly on how much electricity it can stably generate in the future. Even if installed capacity is large, profitability will decline if actual generation is low. Conversely, for plants with similar installed capacity, those with good solar irradiation, minimal shading impact, and controlled system losses make it easier to evaluate whether the price is reasonable.

Before purchasing, you should verify the basis used to calculate the stated annual power generation. The reliability varies depending on whether it is a simulation estimate or measured data, and if it is measured data, how many years of data are included. Revenue forecasts based solely on short-term performance are susceptible to weather-related bias. If the baseline is a period that happened to have unusually strong solar irradiation, the future average generation may be overestimated.

When looking at power generation, it is important to check monthly trends as well as the annual total. If there is an extremely large difference in generation between summer and winter, it may be affected by snow, shading, tilt, orientation, or surrounding terrain. If generation dips only in certain months, you need to check for causes such as faults, curtailment, measurement anomalies, shading from vegetation, snow, or dirt. Problems that are not visible in annual values may become clear in monthly or daily data.

Also, when checking power generation and electricity sales revenue, the electricity selling price and the remaining years on the contract are important. Even with the same generation, profitability differs depending on the sales conditions. If the remaining sales period at the time of purchase is short, the way you consider investment payback also changes. Whether you can consider options after the sales period ends—self-consumption, direct/bilateral transactions, or contract renewal—also affects future value.

When making assumptions about power generation, you also need to verify the expected equipment losses. In solar power generation, panel temperature rise, wiring losses, conversion losses, shading, soiling, and degradation over time reduce the electricity that can be produced from the theoretical irradiance. If you look at the price without checking how these losses are accounted for in the pre-purchase documentation, your revenue forecasts may be overly optimistic.

For used power plants, historical performance data is extremely important. However, you should not unconditionally trust past results; you need to check the accuracy of the measuring instruments, whether there are data gaps, how outage periods are treated, whether output control was applied, and the history of equipment replacements. Even documents that make generation look good may have excluded outage days, adjusted anomalous values, or insufficiently explained the impacts of curtailment.

When reviewing the price of a solar power plant before purchase, you should place more emphasis on how reproducible the generation figures are than on the figures themselves. Only when solar irradiance conditions, equipment conditions, operational conditions, and the reliability of the data are all in place can you assess profitability relative to the price. Projects whose basis for the projected generation is unclear should be verified carefully, even if the apparent price is attractive.

Element 2 Confirm land conditions and development risks

The price of a solar power plant varies greatly not only with the equipment but also with land conditions. A solar power plant is a land-based project, and the shape of the land, slope, ground conditions, drainage, road access, and surrounding environment affect maintenance and management during the operation period. If you do not sufficiently check the land conditions before purchase, additional burdens such as site development, drainage work, slope repairs, vegetation control, and access road improvements may arise after purchase.

First, you should check the shape and slope of the land. Flat, regularly shaped land makes it easier to secure equipment layout and maintenance routes, and also makes inspections and weeding easier. On the other hand, sloped or irregular land requires attention to adjusting the mounting frame heights, protecting slopes, planning drainage, and access for work vehicles. Even if it looks fine at first glance, walking the site can reveal level differences, muddy spots, rainwater flow paths, and sediment buildup.

Next, ground conditions and drainage are important. At solar power plants, if rainwater does not drain properly, the areas around the mounting foundations can be eroded, on-site access paths can become muddy, and sediment can accumulate under the panels. In particular, on sites developed from forest, valley terrain, land lower than the surrounding area, or land that used to be rice paddies or wetlands, drainage conditions need to be checked carefully. Even if drainage channels are in place, if they are prone to clogging with fallen leaves or sediment, maintenance effort increases.

Access road conditions are also important when evaluating the price. Check whether inspection and construction vehicles can safely access the power plant, whether equipment can be replaced in emergencies, and whether it is necessary to pass through neighboring private roads or shared roads. If the access route is narrow, has a steep gradient, becomes slippery in wet weather, or is difficult to pass in winter, these conditions will affect maintenance costs and response times. If delivery is difficult when replacing large equipment, future repair costs may increase.

Do not overlook the property boundaries. At solar power plants, fences, drainage channels, mounting racks, electrical equipment, and access routes may be located near the boundary. Purchasing with unclear boundaries can leave risks of disputes with neighboring land or of having to relocate equipment. It is important to check for the presence of boundary markers, whether the plans match the site, any encroachments, and the impact of trees from neighboring properties.

The surrounding environment also affects the price of a power plant. If there are tall trees or buildings nearby, shadows can occur depending on the season and time of day. Photos taken at the time of purchase alone may not be sufficient to judge the impact of shading. In winter the sun's altitude is lower, so objects that appear to pose no problem in summer can cast large shadows in winter. Also, if there are development plans in the surrounding area, you should consider that future shading, drainage, and access conditions may change.

Even for a power plant where site development has been completed, it is necessary to verify the quality of the earthworks. If there are cracks in slope faces, settlement in drainage channels, soil runoff around fences, or ruts and subsidence on internal access roads, the risks for operation and maintenance increase. Even projects that appear cheap can carry a significantly heavier actual acquisition burden if land repairs or drainage improvements become necessary.

When looking at the price of a solar power plant before purchasing, you should evaluate the land not merely as an installation site but as the foundation that supports long-term operation. A plant with good land conditions will positively affect not only the stability of power generation but also ease of maintenance and future repair risks. Conversely, for a plant with questionable land conditions, it is important to carry out sufficient investigations and risk assessments at the time of purchase.

Element 3 Confirm equipment configuration and degradation status

When assessing the price of a solar power plant, checking the equipment configuration and the degree of degradation is essential. A solar power plant is composed of many components, including photovoltaic modules, mounting structures, foundations, junction boxes, power conversion equipment, collector equipment, monitoring systems, wiring, and communication equipment. If any one of these has a problem, it can lead to reduced or halted power generation and increased repair costs.

First, check the specifications and installation year of the major equipment. Even if equipment capacity is the same, the value of a power plant varies depending on the performance of the components used, installation methods, and design philosophy. By checking the output of the solar modules, the capacity of the power converters, the configuration of the DC and AC sides, the approach to oversizing, the number of circuits, and the placement of protective devices, it becomes easier to determine whether the plant’s design is appropriate.

For used power plants, checking for age-related degradation is especially important. Photovoltaic (PV) modules can be used for a long time, but their output gradually declines. Verify how much generation is being maintained relative to the elapsed years since installation, and whether warranty documents and inspection records are consistent with actual performance. Also, there are degradations that can be confirmed on site, such as surface soiling, cracked glass, frame deformation, backsheet discoloration, and deterioration of connection components.

Power conversion equipment and electrical installations are directly linked to the stable operation of a solar power plant. It is important to check records of abnormal shutdowns, replacement history, alarm logs, the condition of cooling components, the installation environment, dirt or corrosion inside control panels, loose wiring, and signs of overheating at terminals. In particular, in environments with high temperature and humidity, salt damage, snowfall, dust, or intrusion by insects or small animals, equipment deterioration can accelerate.

The condition of the mounting structure and foundation also affects whether the price is reasonable. Check for corrosion or deformation of the mounting structure, loose bolts, and any settlement or tilting of the foundation. If the mounting structure tilts, it affects not only appearance but also resistance to wind loads, the angle of the panels, drainage, and ease of cleaning. In locations with poor ground conditions, partial settlement may also occur.

Wiring conditions should not be overlooked. If cables are in contact with the ground, protective conduits are damaged, fastenings have come loose, or connectors are positioned where they are easily exposed to water, the risk of insulation failure and malfunction increases. In solar power plants, wiring and fastening components are subjected to stresses from sunlight, rain, wind, snow, and mowing operations. Performing a visual inspection and electrical checks before purchase can reduce future problems.

It is also necessary to confirm the presence of monitoring equipment and its operational status. At power plants where monitoring is not being conducted properly, detection of abnormal shutdowns or reduced power generation is delayed. Check whether monitoring data can be acquired, whether historical records can be reviewed, whether communications are stable, and whether alarm notification procedures are in place. If a drop in power generation is discovered late, it can lead to lost opportunities to sell electricity.

The purpose of confirming equipment configuration and the state of deterioration is not simply to check for the presence or absence of failures. It is to understand the equipment’s residual value at the time of purchase and the future repair burden, and to determine whether the offered price is reasonable. Power plants whose equipment is in good condition and whose inspection records are well organized have lower post-purchase uncertainty. By contrast, power plants with unclear equipment histories or with noticeable on-site deterioration require a price revision or additional investigation.

Element 4: Confirm the conditions for grid interconnection and output control

When checking the price of a solar power plant before purchase, you must always verify the grid connection and output control conditions. Because a solar power plant earns revenue by sending the electricity it generates to the grid, connection and control conditions directly affect the project’s value. Even if the facility can generate power normally, if grid-side constraints limit the amount of electricity that can be sold, revenues will be lower than expected.

First, you should check the contents of the interconnection agreement. Confirm the interconnection capacity, point of interconnection, connection equipment, protective devices, operating conditions, the contract holder, and whether succession/transfer procedures are possible. When purchasing a power plant, it is important not only that the land and equipment are transferred, but also that the rights and procedures related to interconnection are properly handed over. If changing the registered name or transferring rights takes time, it can affect the start of operations and the revenue from electricity sales after purchase.

Conditions for output curtailment are also important. Depending on the region and grid conditions, it may not always be possible to sell all the power you generate. If output curtailment could occur, check past curtailment records, future outlooks, the conditions of the control targets, and the status of remote-control compatibility. If the impact of output curtailment is not reflected in the projected revenues, actual returns may fall short after purchase.

When assessing the impact of output curtailment, simply checking whether curtailment occurs is not sufficient. It is important to verify with actual performance data which seasons and times of day are more likely to experience curtailment and how much it affects annual power generation. In some regions, curtailment tends to occur during periods of high generation and low demand, such as sunny spring and autumn days. If you cannot sell power during the periods when generation is at its best, the impact on revenue cannot be ignored.

Also, attention is required for generation curtailment caused by voltage rise on the grid side. Depending on the grid conditions around the power plant, an excessive rise in voltage can cause the power conversion equipment to reduce output or shut down. Such phenomena may be attributable to grid conditions rather than equipment faults. Before purchasing, check past shutdown history, alarm history, generation curves, and time-of-day output variations to look for signs of grid constraints.

The maintenance and management burden of interconnection equipment also affects the price. Inspections and replacements may be required for cubicles, transformer equipment, protective relays, meters, communication equipment, and so on. If these facilities are aging, you need to anticipate future replacement costs. Even if the equipment appears to be in good condition at the time of purchase, if statutory inspections or equipment replacements are imminent, the actual burden will increase.

Furthermore, it is advisable to check whether there is room for expansion or refurbishment. When considering future equipment upgrades or operational changes, grid capacity and contractual terms can become constraints. At the time of purchase, people tend to focus only on current revenues, but in the long term grid conditions will determine a plant’s operational flexibility. Especially when planning for use after the end of the power sales period, the value of the grid connection becomes an important factor in decision-making.

The price of a solar power plant is determined not only by its generation capacity but also by its ability to sell electricity. Even if the generation equipment is excellent, strict grid conditions will reduce the project’s value. Before purchase, it is important to check the grid connection agreement, output control, voltage suppression, interconnection equipment, and transfer procedures, and to understand to what extent you will have to accept constraints relative to the price.

Element 5 Verify maintenance management and post-commissioning costs

When looking at the price of a solar power plant before purchase, you must always check the maintenance and management costs that will occur after purchase. Even if the purchase price looks attractive, high management costs after commissioning will reduce the overall profitability of the project. A solar power plant is not equipment you can install once and then leave alone; it requires long-term inspections, cleaning, grass cutting, equipment replacement, monitoring, and emergency response.

In maintenance management, the first thing to check is the current management structure. Confirm who performs the inspections, how often inspections are carried out, whether inspection records are kept, and whether procedures for responding to abnormalities are established. Power plants with well-organized management records make it easier to understand past problems and repair histories and to assess post-purchase risks. Conversely, for power plants with inadequate management records, it is necessary to carefully verify the condition of the equipment through on-site surveys.

Mowing and vegetation management are also major factors. At solar power plants, overgrown grass can cast shadows on panels, become entangled in wiring, and impede inspection work. The frequency of mowing varies depending on the region, land conditions, and surrounding environment. Especially in areas where grass grows rapidly in summer, neglecting management can lead to reduced power generation and equipment damage. On sloped or irregularly shaped land, the difficulty of mowing work also increases.

Also check the need for panel cleaning. Rain can wash away some dirt, but accumulation of bird droppings, pollen, dust, fallen leaves, volcanic ash, and post-snow grime can affect energy output. If cleaning is necessary, worker safety, securing water, work flow and access, slope, and panel layout will influence the cost. Before purchasing, it is advisable to confirm whether cleaning has been performed in the past and whether dirt is affecting energy output.

Regular inspections and checks of electrical equipment are also important. The necessary inspection items vary depending on the size of the power plant and the equipment configuration. Insulation condition, grounding, loose terminals, protective devices, overheating, unusual noises, communication status, monitoring data, etc. should be checked, and any abnormalities must be addressed promptly. If inspections are carried out only formally, there is a risk of overlooking signs of impending failures.

Emergency response arrangements also affect price assessment. If events such as shutdowns of power conversion equipment, communication outages, typhoon damage, snow-related damage, lightning strikes, or animal damage occur, losses will vary depending on how quickly an on-site inspection can be carried out. If the power plant is in a remote location, response times and travel expenses may increase. Before purchase, confirm the power plant’s location and the distance to maintenance bases, the scope of emergency response, and the process for ordering parts.

Care must also be taken regarding the terms of the maintenance contract. If the tasks that are included in the contract and those that are not are not clearly defined, unexpected costs may arise after purchase. Confirm to what extent regular inspections, grass cutting, monitoring, on-site emergency response, minor repairs, report preparation, cleaning, snow removal, and post-disaster inspections are covered. Even if a contract appears to include maintenance, there may actually be many additional charges.

To correctly assess the price of a solar power plant, you need to factor in not only the payment at purchase but also the management burden during the operating period. Properly maintained plants are easier to assess in terms of generation stability and equipment lifespan. Conversely, plants with unclear maintenance histories and uncertain on-site conditions may require additional effort and costs after purchase. When evaluating the price, it is important to treat maintenance costs as part of the revenue plan.

Element 6 Confirm contract terms and rights

When purchasing a solar power plant, it is crucial to verify not only the equipment and land but also the contractual terms and rights. The price of a plant involves various rights and obligations, including power purchase agreements, land use rights, grid interconnection rights, maintenance contracts, lease agreements, permits and approvals, warranties, and handover documentation. If you purchase without checking the contractual terms, you may encounter problems such as being unable to generate revenue after acquisition, increased cost burdens, or an inability to transfer rights.

First, what you should check is the land rights. Whether the project involves ownership of the land or leasing the land changes the value and risks of the power plant. In the case of ownership, confirm the boundaries, land classification, encumbrances (security interests), rights of way, and the relationship with neighboring land. In the case of a lease, confirm the contract term, renewal conditions, rent, obligations to restore the site to its original condition, whether consent for transfer is required, and mid-term termination clauses. If the land-use period is shorter than the power sales period, a significant risk to business continuity arises.

Next, confirm the succession of rights related to the power purchase agreement and project certification. If the purchase requires a change of name or transfer of rights, you need to understand the procedure flow, required documents, the timeframe until approval, and whether any conditions will change. If there are discrepancies in the name on documents, equipment information, location, capacity, or operation start date, the transfer procedures may take longer.

The transfer of maintenance and monitoring contracts should also be checked. Whether existing contracts can be taken over as-is or need to be replaced with new agreements will affect post-purchase operational burden. Existing contracts may include cancellation restrictions, automatic renewal, or additional fees. It is important to review the contract terms and confirm they align with actual operations.

The remaining term of equipment warranties and construction warranties also affects the price. Even if a warranty is still in effect, confirm whether the warranty will continue after transfer of ownership, what the warranty covers, and whether there are any exclusions or limitations. Even if there is a warranty certificate, it can be difficult to actually use if required inspections have not been performed, construction records are not kept, or documents necessary for warranty procedures are missing.

Under the contract terms, the allocation of responsibilities is also important. Confirm who will be responsible for burdens related to fixed assets, land management, maintenance of drainage channels, road repairs, dealings with neighbors, removal and restoration to original condition, and disaster response. If the buyer assumes many obligations after purchase, this should be reflected in the price valuation.

It is also important to have the drawings and documents related to the power plant in order. Projects that include single-line wiring diagrams, layout drawings, equipment specifications, inspection records, maintenance reports, power generation records, contracts, permits and approvals, warranties, construction photos, and the like are easier to manage after purchase. For projects lacking documentation, on-site verification and re-surveys will be necessary, increasing the management burden.

The price of a solar power plant is also affected by the contractual stability. Even if the equipment appears to be in good condition, if land-use rights are unstable, succession procedures are unclear, warranties cannot be transferred, or contractual obligations are heavy, the price should be viewed cautiously. Before purchase, it is important to spend as much time checking contractual matters as you do technical aspects.

Element 7 Confirm disaster risks and insurance conditions

When determining the price of a solar power plant before purchase, checking disaster risks and insurance terms is essential. Because solar power plants are installed outdoors for long periods, they are exposed to typhoons, heavy rain, landslides, floods, snowfall, lightning strikes, strong winds, flying debris, earthquakes, and other hazards. If you purchase without adequately accounting for disaster risks, unexpected repair costs and power generation stoppages may occur, significantly reducing profitability.

The first thing to check is the natural conditions at the power plant location. Confirm the surrounding topography, elevation, distance to rivers, presence of slopes, drainage routes, and any history of past flooding or sediment runoff. Not only hazard information but on-site verification is important. Even if a location appears low-risk on maps, it may actually be a landform that easily collects rainwater or a place where sediment can readily flow in from upstream.

Heavy rain and drainage risks have a significant impact on the operation and maintenance of solar power plants. If drainage channels are insufficient, side ditches have poor slopes, slopes are unprotected, or on-site roads act as watercourses, sediment runoff and scouring are likely to occur during heavy rainfall. Before purchase, it is ideal to be able to check site conditions after rain. Appearance in fine weather alone can make it difficult to judge drainage problems or muddiness.

Risks from strong winds and typhoons are also important. Check whether the mounting structures and foundations are properly designed for wind loads, whether there have been any past incidents of panels being blown away or rack deformation, and whether there are any nearby structures or trees that could generate flying debris. In coastal areas or terrain that tends to channel winds, wind-induced loads on equipment can be higher. If rack bolts are loose or there are foundation defects, the risk of damage during strong winds increases further.

In snowy regions, it is necessary to check snow loads, snow shedding, snow removal, and winter access. Snow can not only reduce power output but also impose loads on the racking and panels. If panels are installed at angles or in configurations where snow does not slide off easily, they may remain covered for long periods. Also, at power plants that cannot be accessed during winter, response to abnormalities may be delayed.

It is also necessary to check the risks of lightning strikes and electrical hazards. If lightning causes equipment failures, communication outages, or monitoring stoppages, losses will occur not only from repairs but also from power generation downtime. Verifying lightning protection measures, grounding conditions, past failure records, and insurance response performance makes it easier to grasp the magnitude of the risk.

Insurance terms are the basis for determining how much disaster risk can be covered financially. Check whether you are insured, what is covered, what the deductible terms are, whether business interruption losses are included, and whether there are limits to coverage for each type of disaster. Do not be reassured simply by being told that you have insurance; you need to confirm in the policy what kinds of incidents are actually covered.

Also, for power plants that have had insurance claims in the past, verify the extent of the damage, the repair work carried out, and the measures implemented to prevent recurrence. Even if repairs have been completed, if underlying drainage failures or ground stability issues remain, similar damage may recur. A history of disasters is not necessarily a problem in itself, but it is important that the causes and countermeasures are clearly identified.

The price of a solar power plant should be evaluated after accounting for disaster risk. A plant located on a disaster-resilient site, with appropriate design, adequate drainage, sufficient insurance, and a clear response system will have greater stability for long-term operation. Conversely, a plant that carries high risk but lacks adequate countermeasures or insurance may have burdens that cannot be judged from the purchase price alone.

Element 8 Confirm future equipment upgrades and exit strategy

When reviewing the price of a solar power plant before purchase, you should check not only current revenue but also future equipment renewals and exit strategies. A solar power plant is an asset intended for long-term operation, and even if there are no problems at the time of purchase, equipment replacement or refurbishment will be required during the operating period. If you purchase without anticipating future burdens, your revenue plan may be disrupted later.

First, check the timing of major equipment replacements. While solar photovoltaic modules are used for long periods, inverters, monitoring devices, communications equipment, protection devices, switchgear, and components related to air conditioning and ventilation may need to be replaced during that time. Confirm the elapsed years since installation, failure history, availability of replacement parts, and continuity of maintenance support, and determine when and which equipment is likely to incur replacement burdens.

Updating conversion equipment is particularly important. It is equipment directly connected to the power plant's overall electricity sales, and if it fails it can lead to a shutdown of power generation or a reduction in output. If the system is configured with multiple units, it may be possible to limit the outage to a partial shutdown, but the larger the capacity of the equipment that stops, the greater the impact on revenue. Before purchasing, check past replacement history, outage history, availability of spare parts, and the ease of repair response.

Updates to monitoring equipment and communication environments are also often overlooked. If communication methods and equipment become outdated, data acquisition and anomaly notifications can be hampered. At power plants where monitoring is not possible, detection of abnormal shutdowns may be delayed, potentially resulting in lost generation opportunities. If monitoring systems will need to be updated in the future, the associated effort and cost should also be anticipated.

The plan for utilizing a plant after the feed-in tariff period ends is also a major factor when considering price. Whether you make an investment decision based solely on revenues during the feed-in contract period or plan to continue using the site as a power plant after that period ends changes the way it should be evaluated. Plants that can consider options after the period—such as self-consumption, bilateral transactions, or continued operation through equipment replacement—are more likely to have future value. On the other hand, when the land-use term is short, equipment replacement is difficult, or grid conditions impose constraints, exit strategies are limited.

It is also necessary to confirm the conditions for removal and site restoration. In the case of land leasing, removal of equipment and site restoration may be required at the end of the contract. Confirm the items to be removed, the scope of removal, disposal of waste materials, the treatment of foundations, and matters to be negotiated with the landowner. If future removal liabilities are significant, you must factor that risk into the purchase at the time of acquisition.

If there is a possibility of selling in the future, it is also important to keep the facility in a condition that makes it easy for third parties to assess. If inspection records, generation data, repair history, contract documents, drawings, and on-site photos are well organized, it will be easier to explain at the time of a future sale. Conversely, a power plant with insufficient documentation and unclear on-site conditions may receive a lower valuation at the time of sale.

Additionally, it is important to pay some attention to future regulatory changes and shifts in operating conditions. The regulatory and market environment surrounding solar power plants is subject to change. Although you cannot predict everything, you can evaluate long-term flexibility by checking whether you are relying too heavily on fixed assumptions at present and whether you can consider multiple possible uses.

The price of a solar power plant varies not only with its current condition but also with what burdens and options will arise in the future. By anticipating equipment replacement, the end of the power purchase period, decommissioning, and resale at the time of purchase, you will be less likely to be swayed by superficial prices. The longer you plan to operate it, the more important it is to include exit strategies in price evaluations.

On-site inspection is essential to accurately assess the price of a solar power plant.

When checking the price of a solar power plant before purchasing, it is important not to judge based only on document review but to carry out an on-site inspection. Power generation, feed-in tariff conditions, contract documents, equipment specifications, maintenance records, and so on can be checked on paper, but many aspects—such as land slope, drainage, vegetation condition, equipment deterioration, fence damage, condition of access paths, surrounding shadows, and the relationship with neighboring properties—are difficult to understand without seeing the site.

Especially with solar power plants, the drawings do not always match the actual site. Equipment layouts may have been changed, wiring routes may differ from those shown on the plans, drainage channels may have been added later, or the conditions near the boundaries may be unclear. By inspecting the site before purchase, you can identify risks that are not apparent from the numbers in the documents alone.

During on-site inspections, we walk the entire power plant to check the terrain, mounting structures, foundations, wiring, electrical equipment, fences, drainage channels, access paths, and the surrounding environment. It is better to assess not only conditions in fine weather but, where possible, also conditions after rainfall and seasonal changes, as these allow for judgments that more closely reflect reality. In snow-prone areas, winter conditions are important, and in regions where vegetation grows densely, summer vegetation conditions are also important.

It is also important to record the results of on-site inspections together with photographs and location information. If you accurately document where deterioration exists, the extent to which vegetation casts shade, which drainage channels are clogged, and which mounting frames show tilting, this will help in negotiations with the seller, internal explanations, and the creation of maintenance plans. By keeping records tied to specific locations rather than as mere impressions, the basis for price negotiations and purchase decisions becomes clear.

To assess the price of a solar power plant, it is necessary to comprehensively check eight elements. By separately reviewing the assumptions for power generation and electricity sales revenue, land conditions and site development risks, equipment configuration and deterioration state, grid interconnection and output control, maintenance management and post-commissioning costs, contract terms and rights relationships, disaster risk and insurance conditions, and future equipment replacement and exit strategy, it becomes easier to determine whether the presented price is reasonable.

What matters in pre-purchase checks is being able to explain why a price is low or high. In low-priced deals there may be reasons related to land conditions, equipment condition, contract terms, or future liabilities. Even for high-priced deals, if there are grounds—such as stable power generation performance, good land conditions, well-documented maintenance records, or a low risk of future renewals—you may be able to justify the price.

A solar power plant is not an asset you simply buy and forget; it is an asset that must be managed over the long term. Therefore, the accuracy of pre-purchase surveys has a major impact on subsequent profitability and operational burden. For practitioners, it is important to do more than just look at the listed price in the documentation: accurately assess on-site conditions and visualize the risks for each plant as key inputs to decision-making.

To conduct on-site inspections efficiently, a system that can keep records with location information is useful. For example, if you can record high-precision location information and photos of mounting racks within the power plant, drainage channels, fences, slopes, electrical equipment, areas where shadows occur, and locations requiring repairs, the accuracy of pre-purchase surveys will improve. It also makes it easier to share exact locations later when confirming internally or consulting with maintenance companies, contractors, or sellers.

To improve the efficiency of such on-site surveys, utilizing LRTK (an iPhone-mounted GNSS high-precision positioning device) is also an option. If you record inspection points within the plant together with high-precision location information and organize the on-site conditions in an easy-to-understand way, it can help create the basis for determining the price of a solar power plant before purchase. In addition to verifying power generation and contract terms, accurately documenting the condition of the land and equipment makes it easier to grasp pre-purchase risks and to explain them within the company.