A BESS SCADA specification is the document that tells the controls supplier exactly what the site SCADA, the controller interfaces, the data and the tests must deliver on a battery storage site. Writing it properly before the controls package is let is the cheapest way for an EPC contractor to avoid late surprises over who owns the plant controller, which protocols are used, what the point lists contain and what evidence proves it all works.
Our earlier article on BESS SCADA in Great Britain explains what the control system has to do. This one is about writing it down so it gets delivered.
Why the BESS SCADA specification decides the programme
Seven batteries came online in Q1 2026, adding 397 MW and 744 MWh and taking the GB fleet to 7.2 GW and 11.8 GWh, according to Modo Energy. More sites means more interfaces between battery OEMs, inverter suppliers, optimisers and network operators, and the controls are usually the last thing finished before energisation. A gap in the specification becomes a variation at exactly the point when the programme has no float left.
Settle the scope split first
| System | Usually supplied by | What the specification must decide |
|---|---|---|
| Battery management system (BMS) | Battery OEM | Data exposed to SCADA, register map version |
| Power conversion system (PCS) | Inverter OEM | Control modes, setpoint interface, fault codes |
| Power plant controller or EMS | OEM, integrator or controls supplier | Who owns it, who tunes it, who proves compliance |
| Site SCADA, HMI and historian | Controls supplier | Screens, alarms, data retention, remote access |
| Optimiser or trader interface | Route-to-market provider | Setpoint handshake, fallback on loss of signal |
| Fire detection, HVAC, auxiliaries | Various | Which signals SCADA monitors and alarms |
The row that causes most arguments is the power plant controller. If the specification does not say who owns it, three parties will each assume someone else does.
What the BESS SCADA specification must contain
- Architecture drawing showing every controller, network, firewall and external connection, with ownership marked.
- Protocol per interface, such as Modbus TCP or IEC 61850, with the register map or data model version the supplier must work to.
- Point list templates with tag naming, units, scaling, update rates and which points are logged.
- Alarm philosophy: priorities, who responds, and which alarms go to the remote operations centre out of hours.
- Historian and reporting: resolution, retention and the reports the asset owner, optimiser and network operator need.
- Grid compliance data: the signals needed to demonstrate performance against the Grid Code and the connection agreement.
- Cyber security: zones and conduits, remote access method and patching responsibilities, using the ISA/IEC 62443 series as the reference.
- Time synchronisation across every device, so event sequences can be reconstructed after a trip.
Fire safety information and the emergency response plan
The National Fire Chiefs Council's grid scale energy storage planning guidance, approved in December 2025, expects operators to run a comprehensive risk management process and develop a battery safety management plan and emergency response plan with the local fire and rescue service. SCADA is where much of the live information those plans rely on is seen, so the specification should state which detection, suppression and ventilation signals are monitored, how they are alarmed and how they are presented to an attending crew or remote operator.
Testing: write the evidence into the specification
- FAT with simulated devices. Test SCADA and controller logic against emulated BMS, PCS and meter interfaces before anything ships. IEC 62381 is a useful structure for FAT, SAT and integration tests.
- Interface tests with each OEM. Prove register maps against the actual firmware version on site, not the datasheet.
- SAT and integration tests with the optimiser link, network operator signals and communications loss scenarios.
- Compliance testing with the network operator; our guide to G99 and battery storage controls covers what that involves at distribution level.
Decoding BESS: What is Battery Energy Storage Systems | Moxa
Moxa
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Watch on YouTubeInterfaces that cause most of the trouble
Four come up again and again. OEM register maps that change between firmware releases. The setpoint handshake with the optimiser, especially what the site does when that signal stops. State-of-energy reporting that differs between the BMS and what the optimiser expects. And communications loss behaviour that nobody tested until a router failed. Each one is cheap to specify and expensive to discover during commissioning. The fix is the same every time: name the owner, freeze the version, state the expected behaviour in the specification and test it at FAT with an emulated device before the real one is energised. For frequency response sites, our article on Dynamic Containment battery controls explains why response timing adds another layer.
Where Wartens fits
Wartens engineers site SCADA, monitoring dashboards and controller logic for grid-scale and commercial battery storage in Great Britain, working for storage developers and EPC contractors. We can write or review the BESS SCADA specification, then deliver the package. See our battery storage SCADA and controls service.
Next step
Send us your draft specification or single-line diagram through the contact page. We will mark up the gaps and return a written scope and price for the controls package.
