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Commissioning & Energisation

Bringing the site to life in a controlled sequence - dead testing, first energisation with the network operator, functional and protection testing, grid compliance and performance testing, then the reliability run and handover to operations.

Last updated 2026-09-06

Typical duration

Typically 4-10 weeks from first energisation to takeover on a scheme of a few tens of megawatts, though outage availability, witnessing dates and the length of the reliability run drive it more than the testing itself.

What is Commissioning & Energisation?

Commissioning is where a collection of installed equipment becomes an operating power station. It runs in a deliberate order: everything is proved dead first, then the auxiliary and control systems are brought up, then the high voltage plant is energised from the network under the operator's control, then the conversion plant, and only then is the direct current side closed onto the batteries. From that point the site is worked progressively harder - charging and discharging at increasing power, exercising the control systems, checking behaviour against the design - until it can demonstrate that it does what was promised, when asked, without intervention.

The network operator is a participant, not an audience. Energisation happens on its terms and to its programme, often within a booked outage, with its people present and its inspections satisfied beforehand. Grid compliance testing follows, demonstrating that the site behaves as the connection requires: that it responds correctly to the conditions the network can present, that its protection operates as declared, that its metering reads correctly and that it disconnects when it should. Failing those tests is expensive not because the retest is costly, but because the next available witnessing slot may be weeks away and the revenue clock is already running.

The last part of commissioning is documentation, and it is genuinely the product. A battery site spends its life unmanned and controlled remotely, so what the operator inherits is a control system, a communications link, an alarm route and a folder of evidence. Test records, verified settings, as-built drawings, operating and maintenance manuals, spares, training and the emergency plan all have to be complete and coherent, because the person diagnosing a fault in three years will have none of the context the commissioning team has now. The reliability run at the end - a period of operating the site as it will be operated commercially - is the final proof that all of it hangs together.

Compare the methods at a glance

Method comparison graphic coming soon

When and why is Commissioning & Energisation used?

Commissioning starts as soon as sections of the installation are complete enough to be tested and finishes when the operator takes the site over, and its sequence is fixed by safety rather than convenience: nothing is energised until it has been proved dead and correct, nothing is loaded until it has been proved to protect itself, and nothing is handed over until it has been proved to run. The reason so much of the effort concentrates here is that a battery site has very few moving parts and enormous dependence on control - the plant does nothing useful unless the software, the settings, the metering and the communications all agree with each other and with the network operator. Commercially, this is the stage everything else has been building towards, because the connection date, the contracted capacity and the start of revenue all hinge on completing the operator's tests and the client's performance tests to programme. It is also the stage where earlier shortcuts surface: an unverified setting, a mismapped control point, an undersized auxiliary supply or an incomplete test record turns into days of investigation exactly when there is no float left. Teams that commission smoothly are almost always teams that recorded properly during installation.

Types of Commissioning & Energisation

Explore each method in depth - benefits, limitations, plant and quality control on its own page.

Pre-commissioning and dead testing

Inspection and testing of the whole installation while it is safely de-energised - insulation, continuity, earthing, protection injection, interlocks and functional wiring checks. It is the least visible part of commissioning and the part that determines whether the rest goes well.

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Energisation and functional commissioning

Bringing the plant into service in stages, from auxiliary supplies through to the batteries, and proving that each system does what it is meant to under real conditions. Carried out under strict safety rules with the network operator involved at the connection point.

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Grid compliance testing

Demonstrating to the network operator that the site behaves as the connection agreement requires - protection operation, response behaviour, metering accuracy and disconnection. Usually witnessed, and usually the item that fixes the date everything else works towards.

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Performance testing and reliability run

Proving the commercial promises: available capacity, round-trip efficiency, response times and availability, followed by a period of operating the site as it will be operated in service. This is what the client and the funders actually buy.

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Best suited for

  • Schemes with a fixed connection date and contracted capacity to demonstrate
  • Projects carrying performance and availability obligations to a client or funder
  • Unmanned sites operated remotely, where control and communications must be proved before takeover
  • Any connection where the network operator witnesses and formally accepts the compliance tests

Commissioning & Energisation: step by step

  1. 1

    Step 1: Assemble the evidence and review readiness

    Before any energisation is discussed, the installation is reviewed as a whole. Test records from the installation stages are collated and checked for completeness, not just for existence. Settings schedules, approved drawings, manufacturer procedures and the commissioning programme are confirmed as the current revisions. Outstanding work is listed honestly and assessed for whether it prevents energisation or merely needs finishing. The safety rules for the site are put in place: who is the appointed authorised person, how permits are issued, how isolations are proved and locked, and what the boundaries are between the parts of the site that will be live and the parts still under construction. Readiness is a formal decision with a name against it, because from here onwards the consequences of being wrong change entirely.

  2. 2

    Step 2: Complete dead testing and put the safety regime in place

    Any remaining dead testing is completed and the whole system is confirmed correct while it is still de-energised. Physical checks accompany it - covers fitted, barriers in place, temporary works and tooling removed, cable trenches reinstated, access and escape routes clear, labelling complete and matching the drawings. The permit system goes live and the site is divided clearly between energised and non-energised areas, with signage and physical demarcation so that people working elsewhere on the platform know exactly where the boundary is. Everyone on site is briefed on what is about to change. On a project that has run for months as an ordinary construction site, this cultural shift is the single most important thing the commissioning team does.

  3. 3

    Step 3: Bring up auxiliary supplies and control systems

    The auxiliary supplies that feed cooling, controls, lighting, small power, communications and security are energised first, since almost everything else depends on them. The control and monitoring systems are brought up and their communications proved: the link off site, the interfaces with the network operator where required, and the routing of alarms to whoever will act on them. Every control point and every alarm point is checked against the plant it is supposed to represent, which is tedious and always finds errors. Where the site is expected to operate unmanned, this is also where the security, camera and access systems are proved, because they are part of how the operator will run the site rather than an afterthought bolted on at the end.

  4. 4

    Step 4: Energise the high voltage plant with the network operator

    First energisation happens under the network operator's control, at the time and in the manner agreed, usually within a booked outage and with its inspections already satisfied. The switching sequence is written, checked and briefed in advance, with clear responsibility for every operation and clear communication between the site and the operator's control. Plant is energised progressively rather than all at once, with inspections between steps - thermal surveys, checks for unusual noise, vibration or smell, and verification that protection and metering are reading what they should. Nothing about this step is improvised. If a check is not satisfied, the sequence stops, and the discipline to stop is what separates an uneventful energisation from an incident report.

  5. 5

    Step 5: Bring the conversion plant and battery systems into service

    With the high voltage system live, the conversion plant is energised and its controls proved, and then the direct current side is closed onto the battery enclosures following the manufacturer's procedure. The battery management systems come online and report cell and module condition, temperatures and state of charge, and any unit that does not report cleanly is investigated before it is loaded. Cooling systems are proved under real conditions rather than on paper. First charging and discharging is done at low power and built up, with the plant watched closely and the data reviewed between steps. This is the point where the design assumptions meet the actual equipment, and where problems are cheapest to find because the energy involved is still small.

  6. 6

    Step 6: Prove protection, control and safety interfaces

    The protection and control systems are functionally tested with the plant live, confirming that trips operate, that isolation happens where it should, that alarms are raised and transmitted, and that the sequences the control system executes match the design. The interfaces with the fire and safety systems are proved end to end - detection causing the intended shutdown and isolation, and the intended signal leaving the site. Emergency shutdown facilities are tested. Settings that were verified against the schedule during installation are confirmed in service. Testing follows an agreed procedure with the plant in a defined state, witnessed and recorded, because a protection system that has been proved on paper and never operated is an assumption rather than a safety measure.

  7. 7

    Step 7: Carry out grid compliance and performance testing

    The site then demonstrates that it does what was promised. The network operator's compliance tests confirm that the plant behaves as the connection requires, that it responds correctly to the conditions the network can present, that metering is accurate and that it disconnects when it should - typically witnessed and formally recorded. The client's performance tests run alongside or after: available capacity, round-trip efficiency, response times and the behaviour of the plant across its operating range, measured with calibrated instrumentation to an agreed procedure so the results are defensible. Data is reviewed against the design targets and the contract, and shortfalls are diagnosed properly rather than explained away, because the same numbers will be measured again by whoever operates the site.

  8. 8

    Step 8: Complete the reliability run and hand over to operations

    The site is finally run as it will be run commercially for an agreed period, responding to real instructions and real conditions, to prove that everything holds together over time rather than for the length of a test. Faults and alarms during this period are logged, diagnosed and closed with evidence. In parallel the handover pack is completed: as-built drawings updated to reflect what is actually installed, verified settings, all test results, operating and maintenance manuals, spares, warranties, the emergency response plan and the training the operator's staff need. Snags are closed with evidence rather than assertion. Takeover is a formal event, and the discipline applied to the documentation at this point determines how well the site runs for the next twenty years, long after everyone who built it has gone.

Plant & equipment

  • Calibrated insulation, continuity and earth test equipment with current certificates
  • Primary and secondary injection test sets for protection testing
  • Power quality analysers and data loggers for compliance and performance measurement
  • Thermal imaging cameras for inspection during and after energisation
  • Communications and control system test tools, including the manufacturer's configuration equipment
  • Permit, isolation, lock-off and portable earthing equipment for the site safety rules
  • Arc-rated protective equipment and the rest of the personal protective equipment the assessment requires
  • Temporary supplies, site radios and a defined means of communication with the network operator

Quality control & testing

  • Every test carried out with calibrated instruments and recorded with traceable serial numbers
  • Protection settings verified in service against the approved schedule and signed off
  • Every control and alarm point checked against the plant it represents, one by one
  • Switching sequences written, checked and briefed before any energisation step
  • Compliance and performance results measured to an agreed procedure and reviewed against the design targets
  • Snags closed with evidence rather than assertion, and retested where the evidence requires it
  • As-built drawings updated to reflect the plant as installed, not as originally designed
  • Complete handover pack issued and accepted before takeover, including manuals, spares and training records

Safety watchpoints

  • The site is live - all work under the site safety rules, with permits issued by an appointed authorised person
  • The direct current side cannot be switched off like a supply, and is treated as energised unless the manufacturer's procedure proves otherwise
  • Arc flash risk during switching and testing, with protective equipment and exclusion set by the assessment
  • Switching operations at the connection point carried out under the network operator's control
  • Clear physical and procedural separation between energised areas and any construction still in progress
  • Emergency and rescue arrangements in place and rehearsed before energisation, including recovery from high voltage areas
  • Battery-specific hazards - gas, heat and stored energy - covered by the site emergency plan and understood by everyone present
  • Fatigue management during out-of-hours testing and outage work, when errors are most likely and least forgiving

Common defects to hunt

  • Protection settings applied but never verified in service, so the plant does not protect itself as declared
  • Control and alarm points mismapped, so commands and alarms refer to the wrong unit
  • Auxiliary supplies undersized or unstable, causing nuisance trips that take weeks to trace
  • Communications links unproven off site, leaving an unmanned site with alarms that reach nobody
  • Compliance testing failed because a design assumption was never checked with the network operator
  • Performance shortfalls discovered only at the reliability run, when there is no programme left to fix them
  • Incomplete or inconsistent documentation delaying takeover long after the plant works
  • Snags recorded as closed without evidence, reappearing as operational faults within months

How long does Commissioning & Energisation take?

Typical duration: Typically 4-10 weeks from first energisation to takeover on a scheme of a few tens of megawatts, though outage availability, witnessing dates and the length of the reliability run drive it more than the testing itself..

Related processes

Previous in sequence

04 - Fire Safety & Separation

Handover complete - the journey ends here.