Health and safety in grid scale electrical energy storage systems

This stage relates to the design, manufacture and certification of equipment, site appraisal and performance estimation. Effective assessment of potential risks is central to management of health and safety at the outset of a project.

When considering the BESS context, hazards should be considered for all stages of the system lifecycle which are applicable to the organisation (either directly or indirectly). All system components should be designed, manufactured, and tested in accordance with relevant safety standards. The integration of BESS components should also be considered when performing a risk assessment, in particular any incompatibilities between components which may present a risk to H&S.

There should be a full consideration of risks including, but not limited to, accidental or intentional damage and natural phenomena and security. Risk assessments should include both risks to the project and from the project. The planning process should assess the following risks and describe how the credible worst case has been mitigated.

Due to the potential hazards to the surroundings of any BESS, careful considerations must be made as to its location to determine the risks that the storage proposes. With lithium-based technologies, thermal runaway is a key failure mode which can lead to hazards to the nearby environment.

There should be a full consideration of site/ project risks including, but not limited to, accidental or intentional damage and natural phenomena such as fire, weather (including snow and ice and access during severe weather), flooding, land subsidence, flora, and fauna (including birds and mammals), and security.

Co-locating energy storage with energy generation is becoming increasingly common. Energy storage could be co-located with solar panels, wind turbines, hydroelectric generators, hydrogen production facilities, storage or different battery technologies. Where there is the potential for co-location, additional risk assessments need to be undertaken for the combination of technologies at a given site and the potential propagation of hazards.

Where multiple generation, storage or industrial facilities are located in close proximity (but not necessarily co-located in such a way as to pose a direct risk to one another), consideration should also be given to the local capacity to deal with multiple concurrent issues and the implications for emergency response.

This stage relates to the preparation and execution of the physical movement of equipment/assets between locations. The preparation and transport of BESS equipment can pose various logistical challenges and safety risks and as such should be considered in the context of health and safety. The preparation and transport of BESS equipment must have the same level of protection as it would once installed.

BESS developers should consider access requirements for equipment transportation, which may include heavy or oversized vehicles requiring wider or stronger access routes than will be needed during normal site operation. This should extend not just to the site itself, but to surrounding roads and routes from nearby trunk roads that equipment will be transported on. Where oversize loads (e.g. transformers) are being transported consider whether special signage or escort vehicles may be required.

This stage covers the physical installation, training, and connection of assets at their intended location and connection to their respective interfaces. It also covers inspection, testing and training for operators and handover of the system from installer to operator and the post-handover tuning/ bedding-in period. Project management and governance is particularly important here, as correct mitigation of risk will ensure robust health and safety measures are in place at this stage. Recommendations include health and safety training to all relevant staff, as well as due diligence on potential contractors, and ownership of hazards across the project.

During the installation and commissioning phase it is possible that safeguards planned for the final site configuration, such as fire detection and suppression systems, will not yet be in place. Developers should consider how hazards may arise or evolve during this stage, and whether temporary mitigations such as portable fire detection/firefighting equipment are required.

Commissioning consists of a series of steps to demonstrate, measure and record component and system performance. Commissioning processes include sets of tests, checklists, specifications, standards and procedures to validate performance and identify and correct problems before a system becomes operational. The guidance sets out a helpful overview of the range of activities which could be expected to be undertaken during commissioning, many of which have implications for system safety.

This stage relates to usage, inspection, testing and upkeep of the system and may include periodic verification of system safety by a third party e.g., manufacturer or regulator.

Safe operation will be supported by a range of operational and safe working practices. The plant should only be operated by skilled personnel and output should be maintained within operational limits. Site access should be limited to authorised personnel, site safety rules should be in place and policies and processes adopted to maintain site cybersecurity.

Bringing together the various safety plans, features and monitoring systems discussed across previous sections, safe operation will include continuous monitoring of equipment across the site (batteries, inverters, transformers etc) to detect abnormal operation or indications of emergent faults and monitoring of CCTV to ensure site security. Escalation plans should be in place to respond to potential hazards, including out of hours support.

There should be an asset management strategy in place which details appropriate equipment inspection, preventative and reactive maintenance requirements and the methods through which equipment defects are assessed. This may include multiple inspections or maintenance and testing intervals throughout the year to ensure all parts of the system are in working order and system settings (e.g., electrical protection) are correct.

During the life of a BESS there may be the need to make unplanned changes to its design or operational arrangements. In these cases, many of the principles discussed earlier in the document around risk assessment around any redesign, installation, commissioning, operation and maintenance apply.

This stage relates to the preparation and execution of permanent shutdown and disconnection of the system and its components, the removal from the installation site, restoration of the land, re-use and recycling or disposal in accordance with waste equipment regulations.

The decommissioning of a BESS site presents similar health and safety risks to its commissioning, due to changes in the site’s operation and potential removal of safeguards.

The Waste Batteries and Accumulators Regulations 2009 require that “industrial batteries” – a definition that applies to BESS li-ion cells – must be sent for recycling by an approved operator. Distributors of industrial batteries are also obliged to take back waste cells free of charge when requested by the end user. BESS developers should consult with proposed battery suppliers at an early stage to establish their processes for take-back and recycling, and to ensure as far as possible that these schemes (or equivalents) will be available at the predicted end of site life.

Developers should also be aware of the Waste Electrical and Electronic Equipment Regulations 2013, which imposes broad obligations on the recycling of electronic products. While the core equipment of a BESS site may not meet this definition, many items installed on site will – examples may include computers and display equipment, monitoring, control and communication instruments and lighting equipment.