How can a data-centre owner assess risk between construction, first power and commissioning?

TLDR: For owner-side project and commissioning leads on a data-centre build whose power date has moved: treat building completion, first power, integrated systems testing and operational readiness as four milestones, each with its own owners, evidence and open assumptions. Re-forecast from first power onwards and compare recovery options against all four before accepting a revised handover date.

Owner teams on data-centre builds will recognise the month when the contractor reports the halls close to complete and the permanent power date moves back by several weeks. The quickest response is to slide every later milestone by the same amount. Uptime Institute's Chris Brown has described what tends to follow when construction and equipment delays push a programme: "the commissioning just gets reduced in scope to meet that same schedule" (Uptime Institute Journal, May 2016).

Our view is that schedule risk on a data centre concentrates after construction, at the points where one team's finish becomes another team's start. A moved power date therefore calls for a fresh forecast and a side-by-side comparison of options, done at the next schedule update and before anyone signs up to a new date.

How should an owner assess risk between construction, first power and commissioning?

Assess it at the three handoffs between those milestones rather than against a single completion date. Building completion means the construction works are finished. First power means the permanent supply is energised. Integrated systems testing (IST) proves that power, cooling and controls work together under simulated load and failure. Operational readiness means a trained team can run the facility under approved procedures and the owner can accept it for service.

Each milestone depends on the one before it, and each has a different owner. A schedule that reports construction progress well can still look healthy while the later three milestones quietly compress, because the people responsible for them often sit outside the main contractor's reporting line. Reviewing the handoffs makes that compression visible while there is still time to choose a response.

Why does the risk sit after construction rather than during it?

The work after construction is long, sequential and hard to compress safely. One common industry framing, set out by the equipment-rental supplier Aggreko, splits commissioning of critical power and cooling plant into five levels: factory acceptance testing, site acceptance testing, pre-functional checks through initial energisation, individual system testing and, finally, integrated system testing at full load across power, cooling and IT infrastructure, including staged equipment failures and utility problems (Aggreko commissioning whitepaper, April 2020). Uptime Institute uses the same Level 5 label for integrated system testing. Numbering and content vary between owners, so check the scheme in your own specification.

Integrated testing is where the facility is proved as a whole. Uptime Institute describes Level 5 as installing load banks that simulate IT equipment so power and cooling are fully tested, with systems operated together in every specified maintenance and failure scenario. Its reviewers also warn that cutting utility power, watching the generator start and load-banking only the generator is not commissioning (Uptime Institute Journal).

Operational readiness then depends on people as much as plant. ASHRAE Guideline 0-2019 frames commissioning as verifying that the facility meets the Owner's Project Requirements from predesign through occupancy and operation, and it includes requirements for training operations and maintenance staff (ASHRAE Guideline 0-2019 scope). Uptime's reviewers describe owners releasing contractors and vendors before handover so the operations team arrives "cold" to a stack of manuals, which is a readiness risk no construction progress report will show.

Why is first power the dependency an owner controls least?

First power is set outside the project, by the body that connects the site, through a regulated process that is under strain. The IEA estimates that around 20% of planned data-centre projects worldwide could be at risk of delay unless grid risks are addressed, and that waits for transformers and cables have doubled in three years (IEA, Energy and AI, April 2025). None of this tells an owner when their own connection will arrive, but it does mean the power date can move, and the review needs a method for when it does. The rules differ by market.

How is the connection queue changing in Great Britain?

In Great Britain, data-centre demand has swollen the connection queue, and Ofgem is tightening the rules for keeping a place in it. Contracted demand offers rose from 41GW to 125GW between November 2024 and June 2025, at least 80GW of it from data centres (Ofgem, 29 July 2026). Ofgem has consulted on a commitment fee and progress milestones that data-centre developers would need to meet to hold their queue position, and a decision is awaited (Ofgem consultation page).

GB dates can move earlier as well as later: Ofgem says wider connections reform has brought around 7.8GW of projects forward by an average of six years. Your distribution network operator or transmission owner gives the date, with NESO coordinating connections to the transmission system, so ask them for the connection offer milestones in writing.

How is large-load interconnection changing in the United States?

In the United States, federal regulators are reworking how large loads such as data centres connect to the grid, which leaves interconnection timelines in flux. On 23 October 2025 the Department of Energy directed FERC to begin rulemaking to accelerate the interconnection of large loads, including data centres (DOE, 23 October 2025).

In June 2026 FERC opened proceedings on large and co-located loads for two grid operators, NYISO and MISO (FERC order, Docket EL26-69-000; Docket EL26-70-000). Your serving utility gives the date, within whatever grid-operator process applies to your region, so ask it how these proceedings could affect the conditions or timing of your service.

What should the interface review show for each milestone?

Each milestone needs four things written down: what must be true before it, who is accountable, what proves it, and which assumptions are still open. The two tables below are a starting template. Adapt the rows to your specification, phasing and contract, and keep one set per hall or phase where energisation is staged.

The first table sets out what each milestone needs and who answers for it.

The second table sets out what proves each milestone and the assumption most worth testing.

Other assumptions are worth the same test: which open snags would block commissioning, whether commissioning access was assumed before completion, whether capacity arrives in stages, whether temporary power is available, how long IST takes per hall, and whether tenant or customer acceptance needs extra testing.

The assumptions column carries the most weight. A milestone can show green while resting on an assumption nobody has confirmed, and the interface review exists to turn each assumption into either evidence or a named action.

What should happen when the power date moves?

Treat the change as a new input to the forecast, then work forward through every milestone before any revised handover date is agreed.

1. Confirm what has changed. Get the revised date in writing from the network operator or utility and establish whether it covers energisation or full contracted capacity, whether capacity arrives in stages and which conditions remain open on the owner's side.
2. Update the dependency in the schedule logic. Link every power-dependent activity to the first power milestone so the change flows through to everything that depends on it. The US Government Accountability Office calls this horizontal traceability: a schedule that accounts for the interdependence of activities and the handoffs between them (GAO Schedule Assessment Guide, GAO-16-89G).
3. Agree which tests depend on permanent power. Ask the commissioning authority to mark, test by test, which need the permanent supply and switchgear in service and which could start earlier on generator or temporary supply under the specification and safety case. That split sets how much of the work after first power can move into the wait.
4. Re-forecast all four milestones. Forecast building completion, first power, IST and operational readiness separately, and note which paths now drive each one. A delay to first power can turn an IST activity that had float into the driver of handover.
5. Build and compare recovery options. Develop resequencing options with the contractor, commissioning authority, vendors and operations team who would deliver them, compare each against all four milestones as in the next section, and send one or two to detailed engineering, safety and acceptance review before any new handover date is agreed.

How do you compare recovery options when first power moves?

Compare them by where each one moves the risk, because two options can show the same handover date while leaving very different exposure in IST and operational readiness. The option types below are common starting points, not recommendations for any particular project.

Each option also needs sign-off from the people who carry its risk. The commissioning authority confirms any change to test timing or scope, the owner's electrical engineer confirms temporary power arrangements, the network operator or utility confirms staged capacity, and the operator confirms readiness work.

A worked example with illustrative numbers

Take a hypothetical hall where the plan needs eight weeks after first power: two weeks of equipment-level testing, four weeks of IST and two weeks of operational acceptance, so handover falls in week 8 after energisation. The power date then moves back by five weeks. These figures are assumptions for illustration, not a project result.

• Shift everything: 5 + 8 = 13 weeks from the original first power date to handover.
• Test equipment on temporary power during the wait: if the commissioning authority accepts those results without retest, the path after first power falls to 4 + 2 = 6 weeks, and handover moves to 5 + 6 = week 11.
• Compress IST from four weeks to two: 2 + 2 + 2 = 6 weeks after first power, so handover also lands in week 11.

Both recovery options show week 11, which is exactly why the date alone cannot separate them. The first moves risk into the temporary power interface and the chance of retests. The second removes test coverage from the milestone that proves the facility works. An owner comparing the options against all four milestones, and against forecast durations rather than planned ones, would send the first to detailed engineering review and ask hard questions about the second.

Where does a forecast help, and where does judgement take over?

A forecast helps once the question becomes "which option holds up best across every milestone?", because that comparison needs a consistent basis. With nPlan Insights Pro, we forecast every activity in the schedule drawing on more than 780,000 past project schedules, show the paths most likely to drive each key milestone through Driving Paths, test mitigation scenarios side by side with Mitigation Strategies, the Insights Pro scenario tester, and use Schedule Optimisation, included in Insights Pro, to look for resequencing options that recover time. Any option the comparison favours still goes to your commissioning authority and engineering review.

Late-stage testing is one place such a forecast can find risk. On an 11-storey hospital extension in Boston, our forecast showed testing and balancing activities at 100% criticality, so any delay to them would directly delay the end milestone, and delays could come from leaks in ductwork, dampers or valves that only show up during testing and need rework. The recommendation was to resequence that work earlier or keep specialist resources on standby, and our published case study with the contractor Suffolk reports that Suffolk adopted it and avoided 20 days of delay, put at $1.25m in delay cost.

On a data centre, the current plan and each recovery option can be forecast the same way, showing whether an option that protects handover leaves IST as the most likely source of delay, the same early-warning idea behind our data-centre work.

Judgement stays with the people accountable for each milestone. Owners, planners, network operators or utilities and commissioning specialists still confirm connection availability, validate the schedule dependencies, approve test sequences and decide whether an option meets engineering, safety and acceptance requirements.

Some questions sit outside what a forecast of your schedule can answer:

• Grid timing: we do not predict when a network operator or utility will connect your site; that sits with them and the regulatory process.
• Missing logic: if the schedule does not yet model power and commissioning activities in enough detail, the first job is to add that logic with your planners.
• Schedule quality: if the concern is whether the schedule is well built and maintained, schedule-health tools address that question directly, as we explain in Schedule Analytics vs nPlan.

What should an owner ask for before accepting a revised handover date?

Ask for three things at the next schedule update, before any new date is agreed:

• both interface tables, with every open assumption either evidenced or assigned to a named person;
• the written basis for the new power date, including whether it is energisation or full capacity and any staging;
• a side-by-side comparison of at least two feasible recovery options against building completion, first power, IST and operational readiness, using forecast durations.

With those in hand, the decision in front of the owner becomes which option deserves detailed engineering review.

Frequently asked questions

Is a finished data-centre building ready to operate?

No. After building completion the facility still needs permanent power, integrated systems testing and a trained operations team before the owner can accept it for service. Each of those is a separate milestone with its own owner, so each needs its own forecast.

What is integrated systems testing in a data centre?

Integrated systems testing, often labelled Level 5 commissioning, proves that power, cooling and controls work together under simulated IT load. Uptime Institute describes it as using load banks and operating the systems together in every specified maintenance and failure scenario. It normally follows first power, so a late power date pushes directly into it.

Which commissioning tests can run on temporary power?

The commissioning authority decides test by test under the specification and safety case. Equipment-level tests are often the candidates for an earlier start on generator or temporary supply with load banks. Integrated systems testing exercises power, cooling and controls together, including the response to utility problems, which is why the interface review lists permanent power among its prerequisites.

What evidence should an owner ask for when the power date changes?

Ask for the revised date and its conditions in writing, including whether it covers energisation or full contracted capacity. Then ask for an updated schedule with every power-dependent activity linked to that date, and a comparison of at least two recovery options against every milestone.

Can nPlan predict when a data centre will get its grid connection?

No. The connection date is set by the network operator or utility and the regulatory process. nPlan Insights Pro forecasts the project schedule around that date, shows which paths are most likely to drive each milestone and lets teams compare recovery options once the power assumption changes.

Sources

1. Uptime Institute Journal: Avoid failure and delay on capital projects, lessons from Tier Certification (May 2016)
2. Aggreko: Loadbank and commissioning for data centres, vendor whitepaper (April 2020)
3. ASHRAE: titles, purposes and scopes, Guideline 0-2019 The Commissioning Process
4. IEA: Energy and AI, executive summary (April 2025)
5. Ofgem: Ofgem acts to free up grid capacity by tackling speculative data centre projects (29 July 2026)
6. Ofgem: Proposed data centre connection reforms, consultation page
7. US Department of Energy: Secretary Wright directs FERC on large-load interconnection (23 October 2025)
8. FERC: Order instituting proceeding, New York Independent System Operator, Docket EL26-69-000 (18 June 2026)
9. FERC: Order instituting proceeding, Midcontinent Independent System Operator, Docket EL26-70-000 (June 2026)
10. US Government Accountability Office: Schedule Assessment Guide, GAO-16-89G (December 2015)
11. nPlan: How Suffolk used AI risk management and forecasting to construct a new extension for a major Boston hospital (published case study and its downloadable PDF)
12. nPlan: Insights Pro
13. nPlan: From AI-driven forecasting to rapid decision making, why we built Driving Paths
14. nPlan: Schedule Analytics vs nPlan
15. nPlan: Data Centers