Solar Panel and Inverter Defects in Turkey: Warranty Claims for Foreign Energy Investors – 2026 Updated Guide

Solar panels or inverters defective in Turkey? Learn how foreign energy investors can pursue warranty claims, EPC contractor liability, equipment replacement, performance loss and compensation claims under the 2026 Turkish legal framework.

Solar power investments are typically structured around long-term assumptions concerning module output, inverter efficiency, degradation, plant availability and electricity generation. When solar panels or inverters fail prematurely, repeatedly malfunction or perform materially below contractual specifications, the economic consequences can continue for years and significantly reduce the value of the investment.

For foreign investors developing or acquiring solar power plants in Turkey, defective equipment can create several overlapping claims. Depending on the contractual structure, responsibility may lie with the EPC contractor, module manufacturer, inverter manufacturer, supplier, distributor, operation and maintenance contractor, or more than one party.

The critical legal questions are therefore not simply whether equipment has failed, but who assumed responsibility for that equipment, what warranties were given, whether contractual notification requirements were satisfied, whether the defect caused measurable generation loss and whether compensation can be claimed in addition to repair or replacement.

In 2026, these disputes must be assessed against Turkey’s general contractual and defective-work framework, electricity market requirements, the project’s EPC and supply agreements, manufacturer warranties and the technical requirements applicable to the facility. Turkey’s renewable generation framework also continues to operate through licensed and unlicensed generation regimes, with EMRA maintaining specific regulations and connection documentation for unlicensed electricity generation.

What Are the Most Common Solar Panel Defects?

Photovoltaic modules are expected to remain operational for many years, but several technical problems can substantially reduce their output or useful life.

Potential defects include excessive degradation, microcracks, delamination, hot spots, defective junction boxes, moisture ingress, potential-induced degradation, defective bypass diodes, cell damage and manufacturing inconsistencies. Installation problems may create similar symptoms even where the module itself was correctly manufactured.

This distinction is legally important.

If modules were inherently defective when supplied, the manufacturer or supplier may bear responsibility under the applicable contractual framework. If damage resulted from improper transportation, storage, mounting, cabling or installation, responsibility may instead fall on the EPC contractor or another project participant.

A technical root-cause investigation should therefore normally precede any substantial warranty claim.

What Are the Most Common Solar Inverter Defects?

Inverters are central to the commercial operation of photovoltaic plants because they convert electricity produced by solar modules into electricity suitable for delivery to the project’s electrical system and grid.

Repeated inverter shutdowns can therefore cause substantial generation losses even where the photovoltaic modules themselves are performing correctly.

Common problems may include power-electronics failures, overheating, defective cooling systems, communication failures, control-board defects, insulation faults, MPPT problems, firmware errors, component deterioration and recurring shutdown events.

An inverter may also technically remain operational while operating below the efficiency guaranteed in the supply or EPC documentation.

For investors, the relevant question is therefore not limited to complete equipment failure. Persistent efficiency losses and abnormal downtime can also become legally significant where contractual performance standards are breached.

Who Is Responsible for Defective Solar Equipment?

Responsibility depends heavily on the contractual structure.

Under a full-wrap EPC arrangement, the project owner may have a direct contractual claim against the EPC contractor even where the underlying technical defect originates from equipment supplied by a manufacturer. The EPC contractor may then pursue the manufacturer under its own supply agreement.

Other projects use split contractual structures under which the owner contracts directly with module or inverter suppliers.

Investors should therefore examine the EPC agreement, equipment supply agreements, manufacturer warranties, warranty assignments, operation and maintenance agreement and any direct agreements before pursuing a claim.

A common mistake is contacting the manufacturer immediately without first determining whether the EPC contract requires claims to be pursued through the EPC contractor.

EPC Contractor Liability for Solar Panel and Inverter Defects

Where the EPC contractor assumed responsibility for engineering, procurement, installation, testing and commissioning, defective modules or inverters may constitute a breach of EPC obligations.

The EPC contractor may have guaranteed that equipment would be new, free from defects, compliant with technical specifications and suitable for the intended purpose. Separate performance guarantees may also apply to plant capacity, availability or performance ratio.

A defective inverter that repeatedly shuts down may therefore create both a warranty claim and a broader plant-performance claim.

Similarly, modules experiencing abnormal degradation may cause the facility to fail guaranteed performance tests even where the individual modules continue producing electricity.

The EPC agreement must be examined to determine whether the investor can require repair, replacement, reperformance, compensation or performance liquidated damages.

Manufacturer Warranties for Solar Panels

Solar module warranties commonly contain separate concepts of product warranty and performance warranty.

A product warranty generally concerns manufacturing or material defects. A performance warranty typically addresses the module’s ability to maintain a specified percentage of original output over an agreed period.

This distinction can become extremely important.

A module may have no obvious physical defect but may degrade faster than the guaranteed degradation curve. Conversely, a physically defective module may require replacement regardless of whether the overall plant still meets its annual generation target.

Foreign investors should review the exact warranty rather than relying on marketing statements concerning a module’s expected operational life.

Inverter Warranty Claims

Inverter warranties can contain particularly detailed exclusions and procedural requirements.

The warranty may regulate replacement units, repair procedures, shipping expenses, labor costs, diagnostic requirements, firmware obligations and circumstances in which warranty coverage becomes invalid.

Repeated inverter failures should be documented individually.

Investors should preserve fault codes, SCADA information, maintenance reports, manufacturer communications, photographs, replaced components and downtime records. If the same failure repeatedly occurs across multiple units, the evidence may support an argument that the problem is systemic rather than an isolated equipment malfunction.

Defective Work Rights Under Turkish Law

Solar equipment disputes may also engage the defective-work provisions of the Turkish Code of Obligations, depending on the contractual relationship and circumstances.

The statutory framework governing contracts for work requires the contractor to deliver the agreed work and establishes important rights where the completed work contains defects. Depending on the nature and seriousness of the defect and the applicable statutory requirements, the owner may potentially seek repair, a reduction of the price, withdrawal from the contract in appropriate circumstances, and compensation where the requirements for damages are satisfied.

These statutory remedies must be analyzed together with the negotiated EPC agreement.

Large energy contracts commonly contain extensive warranty procedures, liability limitations, notice requirements and dispute-resolution mechanisms. Contractual rights and mandatory provisions of Turkish law must therefore be considered together rather than in isolation.

Defect Notification Is Critical

One of the most important practical issues is notification.

When a defect becomes apparent, the investor should review the applicable contractual and statutory notification requirements immediately. Informal discussions with an EPC contractor or manufacturer should not automatically be assumed to preserve every legal right.

The notice should normally identify the affected equipment, describe the defect, record when it was discovered, refer to relevant contractual warranties and reserve the investor’s rights concerning repair, replacement, generation loss and other damages.

Hidden defects require particular attention because they may become apparent only after prolonged operation.

An investor that delays notification can create unnecessary arguments about acceptance, waiver, causation or expiry of warranty rights.

Can Foreign Investors Demand Replacement Rather Than Repair?

Potentially, depending on the applicable contract, warranty and seriousness of the defect.

Manufacturers often reserve the right to choose between repair and replacement. EPC agreements may provide different rights where equipment failure prevents the plant from achieving contractual performance standards.

The investor should consider whether repeated repairs provide an adequate long-term solution.

If an inverter has repeatedly failed despite attempted repairs, or if a particular series of modules demonstrates systemic deterioration, replacing the affected equipment may become technically and economically preferable.

Whether the investor can legally compel replacement depends on the contractual language and applicable law.

Can Investors Claim Lost Electricity Generation?

Potentially, but this is frequently the most disputed part of a solar equipment claim.

Replacing a defective inverter may resolve the physical problem, but it does not automatically compensate the owner for electricity that could not be generated during months of abnormal downtime.

The investor must establish causation and quantify the loss.

For solar projects, relevant evidence may include irradiation measurements, SCADA data, historical generation, inverter availability, module performance, comparable unaffected strings or inverters, plant performance ratio and electricity price data.

The calculation should isolate losses caused by defective equipment from losses caused by weather, grid curtailment, planned maintenance or other events.

Performance Guarantees and Liquidated Damages

An EPC contract may provide a more efficient route to compensation through performance guarantees and liquidated damages.

For example, the contractor may guarantee minimum plant availability or performance ratio. If inverter failures or module defects cause the facility to fall below that threshold, the owner may become entitled to predetermined performance liquidated damages.

The contract should be reviewed carefully to determine whether these damages are the exclusive remedy or whether additional claims remain available.

Liability caps are equally important. A theoretically strong compensation claim can have limited commercial value where contractual recovery is subject to a low aggregate cap.

Can the Manufacturer and EPC Contractor Both Be Liable?

Potentially, although the legal basis of each claim may differ.

The owner may have contractual rights against the EPC contractor while the manufacturer has provided a separate direct warranty. In other cases, manufacturer warranties may have been assigned to the project company after completion.

The investor should avoid double recovery but may need to preserve claims against several parties until technical responsibility is established.

This is particularly important where the EPC contractor alleges a manufacturing defect while the manufacturer argues that the failure resulted from incorrect installation or operating conditions.

Evidence Preservation Before Equipment Replacement

Defective equipment should not simply be removed and discarded.

Before substantial replacement work begins, the investor should consider whether the equipment may become evidence in future arbitration or litigation.

Independent inspection, photographs, serial numbers, laboratory testing, SCADA records and failure reports should be preserved. Where appropriate, the other party should be formally invited to participate in an inspection.

Failure to preserve evidence may allow the contractor or manufacturer to argue that the actual cause of failure can no longer be independently determined.

2026 Regulatory Issues for Solar and Storage-Integrated Projects

Equipment disputes can also interact with current grid requirements, particularly where the solar project incorporates electricity storage.

TEIAS published revised final grid connection and compliance criteria for electricity storage facilities on February 27, 2026, replacing the criteria previously published in December 2024.

TEIAS subsequently published updated technical criteria and testing procedures concerning the participation of electricity storage units and facilities in ancillary services on July 3, 2026, replacing the previous version.

For storage-integrated solar projects, investors should therefore determine whether an apparent equipment-performance problem results from defective hardware, control-system integration, inverter configuration, battery interaction or compliance with updated technical requirements.

The distinction can materially affect who is responsible.

2026 Renewable Energy Market Considerations

Foreign investors should also consider the regulatory and revenue environment when quantifying equipment-related losses.

EMRA confirmed the final list of licensed facilities participating in the renewable energy support mechanism for 2026 through its decision dated December 30, 2025.

For unlicensed renewable generation, capacity allocation and connection conditions remain particularly important. TEIAS published assessment results in May 2026 for relevant transmission-level unlicensed solar and wind applications submitted between December 1, 2025 and April 30, 2026 following EMRA Board Decision No. 14353 dated February 26, 2026.

These regulatory developments do not themselves determine warranty liability, but they illustrate why equipment claims should be assessed within the project’s complete regulatory and revenue structure.

Warranty Claims When Buying an Existing Solar Plant

Equipment warranties should be a major component of legal due diligence when a foreign investor acquires an operational solar plant.

The buyer should identify module and inverter manufacturers, model numbers, installation dates, warranty periods, historical failure rates, previous replacements, degradation data, outstanding warranty claims and whether warranties can legally be transferred to the buyer or remain with the project company.

Historical SCADA information should also be compared with the seller’s representations concerning plant performance.

A project may appear financially attractive while carrying significant hidden equipment liabilities that will become apparent only after acquisition.

The share purchase agreement should therefore include appropriate representations and warranties concerning equipment condition, unresolved defects, existing warranty claims and disclosure of historical failures.

What If the Manufacturer Becomes Insolvent?

Long manufacturer warranties have limited practical value if the manufacturer no longer exists or cannot satisfy claims.

Foreign investors should therefore evaluate warranty counterparty risk during procurement.

Where manufacturer recovery is uncertain, the EPC contractor’s continuing contractual liability, performance security, parent company guarantees, warranty bonds or other security mechanisms may become particularly valuable.

This issue should also be reviewed when acquiring older operating plants.

Arbitration and Litigation for Solar Equipment Disputes

Large renewable energy contracts frequently provide for arbitration, while other disputes may be subject to Turkish courts.

The dispute-resolution clause should be reviewed before formal proceedings begin. Contracts may also require mandatory negotiation, expert determination or another preliminary procedure.

Technical expertise is particularly important in solar disputes because legal liability often depends on engineering evidence.

An independent expert may need to determine whether the defect originated in manufacturing, design, transportation, installation, commissioning, operation or maintenance.

Frequently Asked Questions

1. Can a foreign investor claim compensation for defective solar panels in Turkey?

Potentially, yes. Depending on the contractual structure, claims may exist against the EPC contractor, supplier, manufacturer or another responsible party. The warranty terms, cause of the defect and applicable Turkish law must be examined.

2. Can an investor claim if solar panels degrade faster than promised?

Potentially. If the modules fail to satisfy an enforceable performance warranty or contractual degradation guarantee, the investor may have warranty or contractual remedies.

3. Who is responsible when an inverter repeatedly fails?

Responsibility depends on the cause. A manufacturing defect may create manufacturer or supplier liability, while installation, engineering or commissioning errors may support claims against the EPC contractor.

4. Can the investor demand replacement instead of repeated repairs?

Possibly. The answer depends on the warranty terms, EPC agreement, applicable law and whether repair provides an adequate remedy for the particular defect.

5. Can lost electricity revenue be claimed after inverter failure?

Potentially. The investor must establish the legal basis for compensation, prove that the equipment defect caused the generation loss and quantify the recoverable damage with appropriate technical and financial evidence.

6. Does EPC final acceptance eliminate warranty claims?

Not necessarily. Contractual warranties may continue after acceptance, and hidden defects can raise separate issues under Turkish law. Notice and limitation requirements should be reviewed immediately.

7. What evidence should be preserved for a solar equipment warranty claim?

Important evidence includes SCADA records, serial numbers, photographs, inspection reports, fault codes, maintenance records, manufacturer correspondence, performance test results, irradiation data and historical generation information.

8. Can a buyer pursue warranty claims after acquiring an existing solar plant?

Potentially. The buyer should determine whether the project company already owns the relevant rights or whether warranties and claims must be assigned. This should be verified during acquisition due diligence.

9. What should a foreign investor do immediately after discovering widespread panel or inverter defects?

The investor should preserve technical evidence, review warranty and notice deadlines, obtain an independent root-cause assessment, issue appropriate contractual notices and calculate generation losses before substantial repairs destroy relevant evidence.

Legal Support for Solar Panel and Inverter Warranty Claims in Turkey

Solar panel and inverter defects can create substantial long-term losses through equipment replacement costs, reduced generation, prolonged downtime and failure to achieve contractual performance guarantees. A successful claim requires early coordination between legal counsel and independent technical experts.

Fırat Fesih Kaya Law Office provides legal assistance to foreign energy investors, international companies, solar project developers, lenders and power plant owners in solar panel and inverter warranty disputes, EPC contractor liability claims, equipment defects, performance guarantee disputes, lost generation claims, renewable energy acquisitions, arbitration and litigation in Turkey.

If your solar power plant has experienced abnormal module degradation, repeated inverter failures, unexpected equipment downtime or performance below contractual guarantees, you may contact our office for a project-specific legal assessment. Early legal action can help preserve warranty rights, secure technical evidence and improve the possibility of recovering repair costs, replacement costs and compensable project losses from responsible parties.

Phone: +90 312 434 22 22
Mobile Phone: +90 532 769 22 22
Email: info@firatfesihkaya.av.tr
Address: Mevlana Boulevard No: 221, Yildirim Tower No: 148, 06520 Balgat, Cankaya, Ankara, Turkey