Understanding the New British Standards for Battery Energy Storage Systems [2024]

The UK is at the forefront of the global transition to a low-carbon economy, with Battery Energy Storage Systems (BESS) playing a pivotal role. Driven by the increasing integration of renewable energy sources, the electrification of transport, and the need for grid stability, the demand for batteries has surged. Lithium-ion batteries, while dominant, are not the sole focus, with chemistries like sodium-ion gaining traction.

The UK government has recognized the strategic importance of batteries, as evidenced by initiatives such as the Faraday Institution and the Battery Industrialisation Centre. These institutions, alongside industry leaders, are working to develop the battery ecosystem, from supply chain to recycling. The Autumn Statement 2023 further emphasised the government’s commitment to supporting the battery industry, aligning with the Critical Minerals Strategy to secure supplies of essential materials like lithium, nickel, cobalt, and graphite.

However, the rapid growth of the BESS sector necessitates robust regulation and safety standards. PAS-63100:2024 is a crucial step in this direction, addressing critical aspects such as fire safety, electrical installation, and location restrictions.

Safety remains a paramount concern. The potential hazards associated with batteries, including thermal runaway, electric shock, and the release of explosive gases, necessitate stringent safety provisions. Aligned with the National Fire Chiefs Council and the Safety Executive, the industry is focused on developing robust suppression systems and functional safety measures.

As the UK seeks to enhance its energy independence and reduce reliance on fossil fuels, BESS will be instrumental. By fostering a thriving battery manufacturing supply chain and supporting research and development, the UK can position itself as a global leader in this critical technology.

What is PAS-63100?

PAS-63100:2024 is a comprehensive standard designed to mitigate the fire risks associated with battery energy storage systems (BESS) in domestic dwellings. Recognizing the increasing popularity of home battery installations, this standard establishes crucial guidelines for the safe and secure placement, installation, and maintenance of these systems. By addressing factors such as battery location, battery chemistry, electrical safety, ventilation, and fire protection measures, PAS-63100:2024 aims to protect homeowners and their properties from potential hazards while facilitating the widespread adoption of sustainable energy solutions.

What does PAS-63100-2024 apply to?

PAS 63100-2024 specifically addresses the installation requirements for battery energy storage systems (BESS) in terms of safety and fire protection.

However, the standard does not cover:

• Battery systems operating at voltages exceeding low voltage limits

• Small batteries incorporated into other products (e.g., alarms, UPS systems)

• Domestic dwellings larger than 200 square metres

• Battery transportation or second-life batteries

• Alternative energy storage systems

• BESS in high-risk residential buildings

• BESS connected before a distributor’s cut-out or a consumer’s meter

Safe Battery Placement

It is important to note that for any indoor BESS installations, appropriate fire resisting separations from indoor locations. This includes walls, ceilings, and floors with a fire performance rating of at least REI 30.

PAS-63100-2024 imposes strict regulations on the placement of battery energy storage systems (BESS) to ensure safety. Certain areas within a dwelling are categorically unsuitable for battery installation.

The following locations are strictly prohibited:

Unsuitable locations:

• Rooms in which persons are intended to sleep.

• Routes used as a means of escape that are not defined as protected escape routes, including landings, staircases and corridors.

• Corridors, shafts, stairs or lobbies of protected escape routes.

• Firefighting lobbies, shafts or staircases.

• Storage cupboards, enclosures or spaces opening into rooms in which persons are intended to sleep.

• Outdoors (ground-mounted or wall-mounted in a suitable enclosure) within 1 m of:

  1. escape routes;

  2. doors;

  3. windows; or

  4. ventilation ports.

• Voids, roof spaces or lofts.

• Within 2 m of stored flammable materials and fuel storage tanks or cylinders.

• Cellars or basements that have no access to the outside of the building.

Storage Capacity Restrictions

PAS-63100-2024 imposes specific limitations on the total energy capacity of battery storage systems (BESS) within a dwelling. These restrictions are designed to mitigate fire risks and ensure the safety of occupants.

Key Capacity Limits:

• Per Compartment Limit: The maximum energy storage capacity within a single compartment is restricted to 20kWh.

• Dwelling Capacity Limits: The overall battery capacity for a dwelling varies depending on its structure:

  • 80kWh: Permitted for external, detached garages, or fire-rated garages.

  • 40kWh: Maximum capacity for all other dwelling types.

It's crucial to understand that these limits are in place to safeguard homeowners. Exceeding these capacities can pose significant risks.

Electrical Installation Guidelines

Safe and efficient operation of a battery energy storage system (BESS) hinges on correct electrical installation. To prevent electrical hazards and ensure longevity, strict adherence to guidelines is essential. PAS-63100-2024 specifically addresses this, with provisions designed to protect against electrical arcs caused by those without proper electrical training.

DC Arc Prevention: Cable & Fuse Safety

Proper cable selection, installation, and maintenance are paramount in preventing electrical accidents. Using cables with appropriate current-carrying capacity, proper insulation, and protection from physical damage is crucial. Incorrectly installed or damaged cables can lead to overheating, short circuits, and fire hazards.

PAS-63100-2024 states that cable connections should be impossible to remove without the use of a tool OR without removing a cover secured by the use of a tool.

Additionally, it is stated that fuses for DC circuits must meet at least one of the following criteria:

• Accessible only by the use of a tool; or

• Arranged such that fuses are only capable of being removed after opening an appropriately sized isolator for on-load isolation.

System Controls and Monitoring

PAS 63100-2024 mandates robust system controls and monitoring to ensure the safe operation of battery energy storage systems (BESS).

System Control Requirements

• Compliance with Standards: System controls must adhere to the specifications outlined in BS EN IEC 62933-5-2, which establishes technical requirements for battery management systems.

• Battery Management and Monitoring System (BMMS): A dedicated BMMS is essential for overseeing battery performance and identifying potential issues.

Failure Mode Detection and Response

The standard requires manufacturers to implement monitoring systems capable of detecting various failure modes. When abnormalities are detected, the system must initiate appropriate actions.

• Audible Warnings: For indoor installations, a clear and prominent audible warning must be activated in case of persistent dangerous conditions.

• Remote Monitoring: Outdoor systems can utilise remote monitoring via an app to alert users of potential issues.

Fire Safety and Ventilation

PAS 63100-2024 places significant emphasis on fire safety and adequate ventilation for battery energy storage systems (BESS).

Fire Safety

• Smoke Detection: Recommended in locations where the battery is installed, but required for installations in infrequently visited locations. These detectors should be linked to the main fire alarm system. This further extends to Power Conversion Equipment (PCE) such as Solar Inverters.

• Fire Suppression: While not explicitly mandated, the standard acknowledges the potential need for fire suppression systems in cases of persistent dangerous conditions.

• Compartmentalization: The standard indirectly promotes compartmentalization of the battery system through restrictions on location and capacity, which can help to contain a fire if it occurs.

Ventilation

Proper ventilation helps to dissipate heat and prevent the build-up of flammable gases. It's essential to consult local building regulations and fire safety guidelines for specific ventilation requirements.

PAS 63100-2024 states that indoor locations for battery energy storage systems (BESS) must have fresh air ventilation to outdoors. The edges of the ventilation must be at least 1 metre from the edges of:

• Doors

• Windows

• Ventilation ports for other locations

Furthermore, any ventilation for the location must not compromise the fire resistance of the enclosure.

Conclusion

PAS 63100-2024 represents a significant advancement in ensuring the safe and efficient operation of battery energy storage systems (BESS) in the UK. By establishing clear guidelines for installation, maintenance, and safety, the standard plays a crucial role in protecting homeowners and the environment. Atlantic Renewables is committed to adhering to these regulations, offering compliant solar & battery installations that prioritise safety and performance.

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