

In the energy sector, the terms EPC (Engineering, Procurement, and Construction) and Turnkey contracts are often used interchangeably, but they represent distinct legal and commercial concepts. An EPC contract involves a contractor who is responsible for all aspects of design, procurement of equipment and materials, and construction of the project. The EPC contractor assumes the duty to deliver a functioning facility that meets pre-agreed performance criteria. In contrast, a Turnkey contract not only includes all these responsibilities but also adds an additional layer: the obligation to deliver a fully operational and legally commissioned project that the client can “turn the key” and start using immediately without further input. Legally, the key distinction lies in functional readiness and risk allocation. In EPC contracts, the owner is more involved during the construction process, retains certain risks, and often engages in progress approvals and milestone certifications. In Turnkey contracts, the contractor bears more comprehensive risks and must handle all interfaces, from land acquisition to permitting and grid connection. The legal implications of these structural differences are profound, particularly when it comes to liability for delays, defects, or incomplete handover. In Turkey, while many projects claim to be EPC, in practice they function more like Turnkey contracts, leading to disputes when responsibilities are misunderstood or poorly defined. Recognizing the core differences between these contract models is essential for determining the correct legal strategy when conflicts arise, especially in high-value infrastructure such as wind farms, solar plants, or combined-cycle power stations.
An EPC agreement is fundamentally a design-and-build contract, under which the contractor is obliged to deliver a project that conforms to the technical specifications, performance metrics, and completion timelines stipulated by the employer. The legal anatomy of a typical EPC contract in Turkey includes several core elements: (1) the scope of works, defining the boundaries of design and construction; (2) risk allocation, outlining which party bears responsibility for regulatory delays, third-party interference, or force majeure events; and (3) performance obligations, such as guaranteed output levels or system efficiency benchmarks. Turkish EPC agreements often incorporate liquidated damages provisions for delay or underperformance, which are enforceable under Article 179 of the Turkish Code of Obligations, provided they do not violate public order or good faith. Another critical component is completion testing, whereby the employer is entitled to conduct performance verification before accepting the project. The testing regime must be unambiguous and enforceable—many disputes in Turkish energy infrastructure have stemmed from ambiguous acceptance criteria or insufficient commissioning documentation. Moreover, EPC contracts frequently contain warranty clauses covering both defects liability (typically 1–2 years) and performance warranties (sometimes 5–10 years for major equipment). Dispute resolution mechanisms, usually arbitration or Istanbul-based commercial courts, are also enshrined in these agreements. These legal features are not merely academic—they directly affect the success of claims and defenses when a dispute arises, especially in multi-party setups involving subcontractors, lenders, and regulatory authorities.
Turnkey contracts represent a legally distinct delivery model in which the contractor bears complete responsibility for the project’s readiness for use, including legal, technical, and operational compliance. Under Turkish legal practice, Turnkey contracts are often interpreted as broad-scope construction contracts under Article 470 and following of the Turkish Code of Obligations, with additional emphasis on functional delivery and commissioning obligations. In energy projects, a Turnkey agreement typically includes tasks such as land permitting, grid connection, environmental approvals, and final acceptance by EMRA (EPDK). The legal expectation is that the employer should be able to “turn the key” and start operations immediately—hence any failure to meet these criteria often constitutes material breach. One distinguishing legal aspect is that force majeure defenses and variation orders are far more limited in Turnkey contracts, placing stricter risk on the contractor. In addition, Turkish case law recognizes that Turnkey contractors owe a duty of proactive compliance—that is, the obligation to anticipate and resolve legal, regulatory, and technical hurdles, rather than merely respond to employer instructions. This is particularly important in renewable energy projects where timelines for incentive eligibility (such as YEKDEM feed-in tariffs) are rigid. If the project is not completed in time due to contractor failure, the employer may lose the right to preferential tariffs, triggering substantial damages. Therefore, Turnkey contracts require stricter legal review at the drafting stage and demand higher scrutiny during execution, especially regarding handover protocols, penalty structures, and acceptance certificates.
Disputes in EPC contracts typically arise from delays, cost overruns, defective work, scope ambiguities, or regulatory non-compliance. One of the most common issues is the failure to meet completion deadlines, often due to external factors such as delayed permit approvals, supply chain disruptions, or force majeure events. Under Turkish law, Article 117 and following of the Turkish Code of Obligations governs contractual default, and allows the non-breaching party to claim damages or terminate the contract if delay becomes substantial and unjustified. Another frequent dispute involves variation orders, where the employer claims certain work falls within the original scope, while the contractor insists it is an extra-cost item. If the contract lacks a clearly defined variation clause or does not document scope evolution, courts often resort to expert evaluation to determine the technical classification and value of the disputed work. Defective performance—where the facility does not meet agreed specifications or performance guarantees—is another major ground for legal action. In such cases, the employer may demand rectification, price reduction, or contractual penalties, depending on the nature of the breach. Under Turkish practice, project-specific court-appointed expert panels are frequently used to assess technical deviations, evaluate causality, and quantify losses. Another area of conflict includes early termination, especially when the employer invokes breach and the contractor alleges wrongful repudiation. Turkish courts typically favor parties who demonstrate procedural compliance (e.g., formal notices, cure periods, documented correspondence), so proactive legal management during contract administration is critical. Lastly, disputes related to liquidated damages enforcement—where the employer seeks pre-agreed compensation for delay or underperformance—are increasingly subject to judicial review, especially to test whether the amount is penal in nature or reasonably pre-estimated. These conflicts underscore the importance of well-drafted contract terms and meticulous project documentation.
Turnkey contracts, by their very nature, concentrate both responsibility and liability in the hands of the contractor. Consequently, the legal claims arising from such agreements are typically more substantial and involve full-scope failure scenarios. The most common claim by employers is for non-readiness of the facility, i.e., the contractor fails to deliver an operational, licensed, and grid-connected asset. This failure often results in lost revenue, missed incentive opportunities (such as YEKDEM feed-in tariffs), and reputational harm. In such cases, the employer may seek compensation for loss of profit, contractual penalties, and even rescission of the contract. Turnkey contractors, in contrast, often file counterclaims for unpaid variations, cost escalations, or force majeure delays. However, courts and arbitral tribunals in Turkey and internationally tend to scrutinize such defenses more strictly in Turnkey models, since the contractor accepted a one-point obligation: a fully operational facility by a specific date. Another frequent claim is related to non-conformity with regulatory standards, such as failure to obtain EPDK commissioning approval or grid synchronization certificates. In these cases, the employer may be entitled to reject delivery, invoke bank guarantees, and trigger step-in rights if provided under the contract. From the contractor’s side, payment disputes also emerge—especially in milestone-based payment models where the employer may withhold progress payments citing incomplete documentation or failed testing. It’s worth noting that in Turnkey projects involving foreign contractors, international arbitration (e.g., under ICC or UNCITRAL rules) often governs the dispute resolution process. Therefore, proper drafting of Turnkey contract clauses—including handover protocols, certificate issuance procedures, and governing law provisions—is not just contractual housekeeping but a vital risk management function.
In legal terms, one of the most consequential differences between EPC and Turnkey contracts is the extent and structure of liability. In EPC contracts, liability is typically fragmented—the employer retains responsibility for certain elements (e.g., land acquisition, permitting, utility interfaces), while the EPC contractor handles engineering, procurement, and construction. Therefore, concurrent liability situations are common, and Turkish courts often allocate damages proportionally, relying on expert evaluations and fault analysis under Article 51 of the Turkish Code of Obligations. In contrast, Turnkey contractors accept integrated liability—they are responsible for delivering a fully operational asset, regardless of intermediate failures by subcontractors or third parties. This includes liability for regulatory delays, logistics breakdowns, design errors, and equipment non-conformity. As such, Turnkey providers must carry extensive insurance, negotiate robust subcontractor back-to-back terms, and perform exhaustive risk assessments. If a Turnkey contractor fails, the employer may hold them liable for both direct losses and indirect damages (such as delay in production start-up or grid penalty costs). However, in practice, Turkish courts are cautious with awarding indirect damages unless they are foreseeable and specifically covered under the contract. Another legal distinction is that EPC contractors may claim relief under force majeure or variation orders, but Turnkey contractors face greater difficulty invoking such clauses unless explicitly detailed. In case law, Turkish courts have consistently enforced performance guarantees, especially in Turnkey disputes where the contractor’s failure led to regulatory or commercial project losses. Therefore, the legal burden on Turnkey contractors is considerably higher and must be reflected in pricing, legal defenses, and internal risk management policies.
Performance guarantees in energy infrastructure contracts—whether EPC or Turnkey—serve as critical legal tools to ensure that the constructed facility meets specified operational benchmarks such as power output, fuel efficiency, environmental compliance, and grid integration. These guarantees are typically backed by bank guarantees, insurance bonds, or retention payments and provide the employer with a mechanism to recover damages in the event of underperformance or non-compliance. Under Turkish law, performance guarantees are enforceable under the Turkish Commercial Code (TCC) and the Code of Obligations, provided they are clearly linked to contractual obligations and not excessive in scope. In EPC agreements, performance tests are staged—typically including a pre-commissioning test, a guarantee performance test, and a final acceptance test. Failure to meet performance parameters often entitles the employer to liquidated damages, usually calculated on a per-day or per-MW basis. In Turnkey contracts, performance guarantees carry even greater weight, as the contractor is solely responsible for delivering a functioning asset, and must remedy deficiencies at their own cost or compensate the employer accordingly. Turkish courts recognize the binding nature of such guarantees, especially when third-party certifications or independent engineers validate the non-performance. Furthermore, international EPC and Turnkey contracts in Turkey often include step-in rights, where the employer can take over the project and use remaining funds or guarantees to complete it—especially when performance guarantees have been triggered. One common enforcement mechanism is the drawdown of unconditional bank guarantees, which can be executed without a court order, although contractors often challenge these actions through injunction applications. Thus, while performance guarantees offer employers a layer of protection, their drafting must be precise, their triggering events well-defined, and their duration clearly stated—especially in light of Turkish procedural rules and banking regulations.
Termination clauses represent some of the most litigated elements in EPC and Turnkey contracts, especially when project delays, regulatory bottlenecks, or performance failures arise. These clauses generally fall into two categories: termination for cause and termination for convenience. Termination for cause typically allows one party—usually the employer—to cancel the contract if the contractor fails to meet critical obligations, such as achieving substantial completion by a long-stop date, delivering a compliant facility, or addressing default notices within a cure period. Under Turkish law, such terminations are governed by Articles 473–478 of the Turkish Code of Obligations, and the non-breaching party may also seek damages for unfinished work or restitution for advance payments. In contrast, termination for convenience allows a party to end the contract without alleging breach, subject to notice and compensation obligations. This is more common in public sector projects or PPP schemes governed by Turkish administrative law, where strategic or political factors may justify withdrawal. Disputes frequently arise when a party disputes whether the termination was valid, particularly when the clause language is ambiguous or does not define “material breach” or “long-stop date.” Additionally, dispute resolution clauses play a vital role in energy project claims. Many EPC contracts stipulate arbitration—usually under ICC, LCIA, or ISTAC rules—whereas local projects may default to Istanbul commercial courts. Arbitration allows for confidentiality, industry-specific expertise, and international enforcement, but also carries higher costs and longer timelines. Increasingly, contracts include multi-tiered dispute resolution clauses, beginning with negotiation or mediation, followed by adjudication or expert determination, and only then arbitration or litigation. Proper structuring of termination and dispute resolution provisions is essential, especially in cross-border projects, as these clauses often determine the forum, timing, and outcome of legal claims.
In multinational energy projects, particularly those involving foreign EPC or Turnkey contractors, the selection of governing law and jurisdiction becomes a critical strategic consideration. While many Turkey-based energy projects opt for Turkish law as the governing framework, others—especially those financed by international lenders or involving foreign investors—choose English law, Swiss law, or the UNIDROIT Principles due to their commercial familiarity and predictability. Under Turkish private international law (Law No. 5718), parties are allowed to select foreign law to govern their contractual relations, provided it does not conflict with Turkish public order. For example, an EPC contract governed by English law may include dispute resolution before London Court of International Arbitration (LCIA), while a Turnkey agreement may provide for ICC arbitration seated in Geneva. However, such choices have procedural consequences: Turkish courts may decline jurisdiction or limit interim measures if they find that the parties have agreed to arbitrate. Similarly, enforcement of foreign arbitral awards is regulated under the New York Convention, which Turkey ratified in 1991. Therefore, legal actions—such as interim injunctions, payment disputes, or guarantee enforcement—may be subject to dual systems: the substantive contract law and the procedural forum law. This duality often complicates project execution and claim strategies, especially where domestic regulators (e.g., EMRA, EIA authorities) are involved. Accordingly, parties must ensure consistency between governing law, jurisdiction, and contract administration practices. Failure to align these elements can result in jurisdictional deadlocks, conflicting interpretations, and unenforceable judgments—outcomes that are particularly costly in billion-euro energy infrastructure.
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