Chapter VI: Commissioning and Closeout

Chapter VI turns to commissioning and project closeout, the final phase where systematic startup sequencing, performance testing, and operator readiness determine whether the plant actually runs as designed, and where your documentation, punch lists, final acceptance, and lessons-learned processes determine whether the project ends cleanly or leaves a trail of unresolved obligations that follow both parties for years.

Where Everything Converges

Commissioning is the phase where design intent meets physical reality. Every engineering decision made in the front-end, every construction activity performed in the field, every equipment specification written by a vendor, comes together at startup. If the project has been well-executed up to this point, commissioning is demanding but manageable. If it has not, commissioning is where the accumulated deficiencies surface, all at once, under time pressure.

This is also where the stakes are highest. The contractor is demobilizing, the owner is eager to begin commercial operations, lenders and offtakers are watching the schedule, and the pressure to declare success and move on is intense. That pressure is exactly what makes commissioning dangerous. Shortcuts taken here do not disappear. They get buried under operating procedures and maintenance schedules, and they resurface months or years later, sometimes with serious consequences.

The lesson from decades of project experience is straightforward: all the hard work in design and construction can be undone by a poorly executed commissioning program. The phase deserves the same rigor and discipline applied to every phase that preceded it.

A Different Skillset

One of the most persistent and underappreciated risks in commissioning is the assumption that construction expertise translates directly into commissioning capability. It does not. Construction is about sequencing physical work, managing crews, and driving progress against a schedule. It is about bringing materials and equipment together and building.  Commissioning is about systematic verification, analytical troubleshooting, and an intimate understanding of how integrated systems behave under load. I have come across extremely knowledgeable and experienced construction managers who genuinely don’t know how a power plant works, and vice versa.  Very few individuals are genuinely skilled at both. Fewer still are available at the right time.

This distinction matters because owners frequently make the mistake of treating commissioning as the tail end of construction rather than the beginning of operations. The result is a commissioning team assembled from whoever is left on the project, rather than specialists brought in for the purpose. A competent commissioning team, whether built in-house or outsourced to a specialist firm, must be assembled deliberately and early, well before mechanical completion.

The decision to outsource commissioning is not an admission of weakness. For owners who do not commission plants regularly, it is often the most prudent choice. The cost of a competent commissioning firm is modest compared to the cost of a delayed commercial operations date or a startup failure caused by inadequate expertise.

Cold Commissioning: Verification Before Energization

Cold commissioning, sometimes called pre-commissioning, covers all verification activities conducted before systems are energized or brought into service. It is the foundation on which everything else rests. Its purpose is to confirm that what was designed, specified, and constructed is actually installed correctly, wired correctly, and configured correctly, before any power flows or any fuel is introduced.

The discipline required here is painstaking and unglamorous. Loop checks verify that every instrument signal traces correctly from the field device to the control system. Input/output verification confirms that each signal is correctly mapped and functional. Protection system testing confirms that safety interlocks will activate at the correct setpoints and in the correct sequence. Alarm and trip levels are set, documented, and tested against design intent.

There is no shortcut through this work. Every tag that is not checked is a potential startup failure waiting to happen. The following anecdotes are drawn from personal experience on actual projects and are offered not as cautionary tales in the abstract, but as examples of what happens when cold commissioning is compressed or treated as a formality.

On the first major plant I worked on early in my career, labeling of electrical switchgear had not been completed before commissioning activities began. A construction electrician came into contact with a live busbar that was already under commissioning. The shock was at 6.6 kV. He survived. The label that should have been there was not. This was not a complex failure, it was a sequencing failure, one that cold commissioning protocols are specifically designed to prevent. An energization plan and a completed labeling verification checklist would have stopped it.

On a separate project, two signal wires on the generator excitation system had not been properly loop-checked before hot commissioning began. When the generator reached approximately fifty percent load, it tripped. The troubleshooting process that followed consumed days and involved systematically eliminating control logic, protection settings, and mechanical causes before the wiring discrepancy was finally identified. The root cause was two wires. The cost was measured in schedule, resources, and credibility. A thorough I/O loop check during cold commissioning would have found it in minutes.

These two examples share a common thread: neither failure was complex, and neither required specialized knowledge to prevent. Both required only the disciplined execution of a standard cold commissioning protocol. When that discipline is absent, the consequences are unpredictable in severity but predictable in their likelihood.

Hot Commissioning: Energization and Startup

Hot commissioning begins when systems are energized and equipment is brought into service for the first time. This is the phase that most people picture when they think of commissioning, the moment when a plant begins to resemble an operating facility. It is also the phase where the quality of cold commissioning work becomes immediately apparent.

A credible hot commissioning program includes a detailed energization sequence, first-of-type equipment start procedures, vendor and OEM representative coordination, operability testing across operating modes and ranges, and early reliability runs that stress systems under controlled conditions before commercial obligations begin.

OEM representative availability deserves particular attention. Complex rotating equipment, generators, turbines, compressors, heat exchangers with sophisticated controls, virtually all of it requires factory representatives on-site for first start. These individuals are not interchangeable with general commissioning engineers. Their availability is often constrained, their scheduling lead times are long, and their presence is contractually required by most equipment warranties. Owners who treat OEM coordination as a last-minute logistics matter routinely find themselves paying for idle commissioning crews while waiting for a vendor representative who is booked on another continent or doesn’t have the proper visa to enter into the country that your project is in.

One of the more instructive examples of hot commissioning failure involves not a complex system but a simple timer. On a project where identical gas turbine units were built across two phases, with different commissioning teams executing each phase, a forced cooling start timer was inadvertently set to an incorrect value on the Phase I units. The setting was wrong, it was not caught during commissioning verification, and it was not identified during initial operations. Some years after commercial operations date, the incorrect timer setting contributed to a significant operational event. The Phase II units, commissioned by a different team, did not have the same error. The lesson is not complicated: identical equipment demands identical, independently verified commissioning procedures.

The Commissioning Plan

A commissioning plan is not a schedule. It is a structured document that defines what will be verified, in what sequence, by whom, to what acceptance criteria, and with what documentation. Owners should require the EPC contractor to submit a commissioning plan well before mechanical completion, review it with their own commissioning team or independent advisor, hold the contractor accountable for executing against it, and verify that the paperwork is being filled with individual signatures when an activity in the plan is completed.

A credible commissioning plan must address, at minimum, the following:

• Construction handover documentation and sign-off procedures
• Instrument and I/O loop check protocols and completion records
• Protection system testing procedures and setpoint documentation
• Alarm and trip level setting and independent verification
• Equipment energization sequence and first-start procedures
• Operability testing across all design operating modes
• Reliability testing to demonstrate stable sustained operation
• Performance testing against contractual guarantees

This list is not exhaustive. Plant type, fuel system, regulatory requirements, and offtake obligations will add to it. The point is that commissioning plans submitted as thin documents with vague milestones and no acceptance criteria are not commissioning plans. They are schedule placeholders. Owners who accept them as sufficient should expect to manage the consequences of that acceptance.

Document Control and Turnover

By the time a facility reaches commissioning, the volume of project documentation is substantial. Design drawings, construction redlines, QA/QC inspection records, material certifications, equipment data sheets, factory acceptance test reports, OEM operation and maintenance manuals, calibration records, and regulatory permits have accumulated across years of project execution. The commissioning phase is when all of this documentation must be organized, validated, and prepared for transfer to the permanent owner’s record system.

This work is not glamorous and it is frequently underestimated. It is also contractually significant. The EPC contractor’s obligation to deliver a complete and accurate document package, including redlined as-built drawings reflecting actual field conditions, updated O&M manuals, and final QA/QC records, is a real obligation that real contractors routinely deprioritize once their attention turns to demobilization. Owners who do not actively manage this deliverable often find themselves, at final completion, holding a partial document set and a contractor who has moved on.

The practical guidance here is simple: do not wait until final completion to chase documents. Establish document turnover milestones during execution. Require preliminary as-built submissions before substantial completion. Audit the document package against the contract deliverable list before releasing retainage. Incomplete documentation is leverage, and it is leverage that disappears the moment final payment is made.

The Punch List

A punch list is a formal record of incomplete or deficient items identified during commissioning and inspections. It is not a snagging sheet. Managed well, it is one of the most effective tools available for maintaining contractual clarity in the final stages of a project. Managed poorly, it becomes either a pressure release valve that lets deficiencies accumulate indefinitely or a dispute trigger that delays commercial operations.

A well-structured punch list uses a priority classification system. The following is representative of standard practice, though specific project contracts may define these differently:

• P1: Items that must be resolved before the facility can operate or before the next operational sequence can begin. These are safety-critical or operationally blocking items with no acceptable workaround.
• P2: Items required to be completed as a condition of substantial completion or commercial operations date. These are not immediately blocking but represent contractual obligations that must be satisfied before milestone payments are released.
• P3: Items required for final completion. These are typically cosmetic, administrative, or low-consequence deficiencies that do not affect facility operations.

The boundary between these categories is often contested. Owners and contractors frequently disagree on whether a given item is P1 or P2, or whether it belongs on the punch list at all versus being covered by a separate warranty claim. The commissioning plan should define classification criteria in advance, and the owner’s commissioning team should actively participate in punch list reviews rather than accepting the contractor’s classifications without challenge.

One underappreciated area of punch list contention is the pre-commissioning boundary. Items that surface during cold commissioning, such as incorrect wiring, missing labels, or misconfigured instruments, technically originate from construction, not commissioning. Who owns them, how they are classified, and what schedule relief, if any, they entitle the contractor to are questions the contract should answer. If the contract is silent, the answer will be negotiated under pressure, which is never the best time to negotiate.

Milestone Definitions: COD, Substantial Completion, and Final Completion

Few areas of an EPC contract generate more end-of-project friction than imprecise milestone definitions. Commercial operations date, substantial completion, mechanical completion, and final completion each carry contractual consequences, and each is subject to interpretive dispute if the contract language is vague.

For practical purposes, commercial operations date and substantial completion typically signify that the facility is capable of reliable commercial operation, that key commissioning activities have been completed and documented, that all P1 and P2 items are closed, and that only low-priority items remain outstanding. The exact criteria should be defined in the contract, not left to judgment at the time of declaration.

Final completion is the point at which the project is formally closed and fully turned over to the operations and maintenance team. All punch list items are resolved, all document deliverables have been accepted, and all contractual obligations other than warranty have been discharged.

Warranty period activation is a milestone consequence that owners frequently handle carelessly. COD or substantial completion typically starts the clock on equipment and system warranties. Owners who are unclear about which milestone triggers which warranty, or who allow commissioning to extend informally beyond milestone dates without formal documentation, risk inadvertently reducing the warranty coverage available to them. This is worth a deliberate review with legal counsel before the first startup.

Owner Readiness: Operations Staff and Training

Commissioning is not something the EPC contractor does to a facility while the owner waits. It is a phase that requires active owner participation, and the most critical form of that participation is the presence and engagement of the operations team that will run the plant after commercial operations date.

Operations staff who are present during commissioning acquire something that no training program can replicate: direct experience with how their specific facility behaved at first start, what anomalies were observed and resolved, what workarounds were accepted and why, and where the systems are sensitive. This institutional knowledge is irreplaceable. When it is absent because the O&M team was not brought on-site until after COD, the consequences typically appear in the first operating year as avoidable incidents, diagnostic delays, and repeated troubleshooting of issues that were already understood and resolved during commissioning.

Operator training is frequently a contractual deliverable that receives less attention than it deserves because it competes with schedule pressure in the final weeks before COD. Owners should resist the temptation to accept abbreviated or deferred training in exchange for schedule gains. The contractual obligation is there for a reason. Enforce it.

Retainage, Final Payment, and the Loss of Leverage

The financial mechanics of project closeout create a dynamic that every owner should understand clearly: contractor motivation is directly correlated with outstanding payment. As long as significant retainage remains withheld, the contractor has financial incentive to close punch list items, deliver documents, and resolve disputes. Once final payment is made, that incentive disappears.

This is not a cynical observation. It is a structural reality of how EPC contracts work. And it is human nature. The practical implication is that owners should treat final retainage release as a carefully managed event, not a formality that follows COD by some number of days. Before releasing the final dollar, confirm that the document package is complete and accepted, that all P2 and P3 punch list items are closed or formally carried forward with agreed remedies, that warranty obligations are clearly documented and the warranty clock is running, and that any open claims or disputes have been addressed or preserved.

Owners who release final retainage early, under commercial pressure or as a gesture of goodwill, frequently regret it. The warranty period is meaningful only if the contractor remains motivated to honor it. Retainage is the mechanism that creates that motivation. Use it accordingly.

Closing Reflection

This series began with the observation that the gap between development thinking and construction thinking is one of the most consequential and least discussed risks in energy project delivery. Six chapters later, the argument has traced that gap across the full arc of an EPC project: from the moment an owner first considers an RFP, through contract structure and risk allocation, into the daily reality of construction management and dispute resolution, and finally to the startup phase where everything that preceded it is either validated or exposed.

Commissioning is a fitting place to end, not because it is the most dramatic phase, but because it is the most honest one. A plant being commissioned does not care about the elegance of the contract structure or the sophistication of the schedule logic. It responds to the quality of the work that was actually done. Wires are either correctly landed or they are not. Valve timers are either correctly set or they are not. The O&M team either knows the facility or it does not.

The hidden costs in an EPC contract are not confined to change orders and liquidated damages. They accumulate in every phase where rigor is substituted by assumption, where expertise is substituted by availability, and where the pressure to declare progress overrides the discipline to verify it. Commissioning is simply the phase where the bill arrives.

The practitioners who manage these projects well are not necessarily the ones with the most sophisticated contracts or the most aggressive commercial positions. They are the ones who understand that an EPC project is a system, that every phase affects every subsequent phase, and that the decisions made at development, procurement, and construction each carry forward into how a plant starts up and how it runs for the decades that follow.

That understanding, more than any single clause or checklist, is what distinguishes a well-delivered energy project from one that simply reaches commercial operations date.

I hope this series has been useful. Comments, questions, and pushback are welcome.