E-HAZOP of a large BESS plant

Context:
For a large-scale Battery Energy Storage System (BESS) in Belgium, an in-depth analysis of electrical risks was required. The project includes high-voltage components (150 kV to 33 kV) and complex interactions between battery modules, transformers and control systems. The challenge: maximum safety and reliability during design, construction and operation.

Approach:
An E-HAZOP was carried out: a structured risk analysis specifically for electrical installations. This method combines three sub-studies:

• SAFAN (Safety Analysis): assessment of the layout and physical risks such as electrocution, fire and explosion.
• SYSOP (System Security & Operability Analysis): analysis of system design, protection and operational reliability.
• OPTAN (Operator Task Analysis): evaluation of operator actions in normal and emergency situations to minimise human error.

The study was carried out by a multidisciplinary team and proceeded in several phases: from concept to “frozen design”. All risks were assessed semi-quantitatively using a risk matrix, including inherent, current and residual risk.

Result:
The analysis revealed several critical points and led to concrete improvements, such as:

• Modification of the layout to limit the risk of electrocution during maintenance work (e.g. additional physical separations and clear access control).
• Addition of fire detection and extinguishing systems in battery containers to mitigate the risk of thermal runaway.
• Optimisation of protection logic in high-voltage switchgear to prevent unwanted trips and black-outs.
• Improved operator procedures and emergency instructions to avoid human error during switching operations.
• These measures provide a robust safety foundation and increase the reliability of the energy supply.

Added value:
This approach is unique in Belgium for BESS projects. By integrating the E-HAZOP into the design process at an early stage, costly redesigns were avoided and a solid safety framework was created. The project shows how specialised risk analysis contributes to:

Compliance with legal and internal safety standards.
Operational reliability of critical energy infrastructure.
Protection of people and the environment in a complex high-voltage environment.