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Battery energy storage systems (BESS)

Battery energy storage systems (BESS) for homes or small commercial buildings are a serious safety risk if incorrectly installed. Any business installing a BESS must make sure that their workers are safe.

Battery energy storage systems (BESS) for homes or small commercial buildings are a serious safety risk if incorrectly installed, potentially leading to:

  • electric shock
  • fire
  • flash burns
  • explosion
  • exposure to hazardous chemicals.

Any business installing a BESS must ensure the safety of their workers. The BESS must be safely installed and commissioned. In addition you will need to pass on information to your customer so they can continue to keep it safe and be able to safely shut it down.

You must have the appropriate safe systems of work, and the appropriate technical expertise, training and competence for installing this technology.

BESS types

Use the appropriate technology to suit your customer's battery energy storage system requirements. There are three main types:

  • a pre-packaged battery module (enclosed factory connected batteries)
  • a pre-packaged system (enclosed factory connected batteries with other components such as a charger control or inverter)
  • a custom-made battery bank (individual batteries installed with other components and interconnected).

Your decision to use a specific BESS type will likely be influenced by factors such as price, available space and ease of installation and operation and maintenance.

Select the right battery technology for your application

A range of battery technologies are available in Australia. This could include, but not be limited to, the following technology types:

  • lead-acid (advanced, flooded-cell and sealed)
  • lithium (ion and polymer)
  • nickel-based (metal hydrides and cadmium)
  • flow (zinc bromine and vanadium redox)
  • hybrid ion.

Different battery technologies and chemistries have different performance capabilities, and different requirements for installation, operation and maintenance.

You will need to be aware of the chosen technology's hazards and know how to safely handle (including transporting), install and operate the system. Hazards can result from overheating, over-charging or emissions from hazardous chemicals.

Design the system for the intended application

Several factors influence the overall design of the BESS, including your customer's required energy storage capacity, their budget and the battery technology and type. You should also consider the system's intended lifespan.

When designing a battery system, take into consideration your knowledge and experience, applicable standards, industry guidelines for best practice and the manufacturer's recommendations. You should also think about:

  • the physical size required for the installation
  • necessary building modifications, which may need local council approval
  • the type of electrical switching and protection devices, cable sizes, inverter size and the overall reliability and compatibility of the various electrical components in the system
  • compatibility with an existing solar PV system or local electricity grid
  • whether the system will export electricity to the local grid to maximise tariff returns
  • a suitable emergency plan that the customer can manage.

Control the electrical and chemical hazards

Electric shock

Battery cells have the potential to deliver a severe electrical shock when interconnected as battery banks, reaching hazardous voltage levels. There will also be 240 volt rated parts or other components present on the energy regulators, inverters etc, that have hazardous voltages.

Arc flash

A battery has sufficient energy to cause an arc flash if it short circuits, or if a fault occurs. An arc flash can have temperatures above 12,000°C, capable of melting metal or causing fires and explosions. Generally, higher battery energy storage capacities have a higher risk of arc flash.

Fire and explosion

Most lead-acid batteries generate hydrogen and oxygen gases when charging. Other battery types also emit flammable gases and need adequate ventilation to avoid an explosion or fire.

Lithium-ion batteries do not produce any exhaust gases during normal operation, but they can produce flammable gases if there is a fault.

Fire and explosions can also result from excessive temperatures (either under normal operating conditions or due to an overload), component failure, short circuit or loose connections.

Hazardous chemicals

Battery casings can degrade, or be damaged from a variety of impacts. They can also rupture as a result of excessive temperatures generated from a change in chemical reaction from over-charging. If a battery casing is ruptured, the fluid or gel (electrolyte) inside can leak, resulting in toxic fumes, burns, corrosion or explosions.

Suitability of the install location

When considering the location of the BESS components in a domestic installation, the designer/installer should conduct a risk assessment to address the risks of the battery technology being used in that location. At a minimum, AS/NZS 3000 (the wiring rules) and the supplier (the manufacturer/importer) instructions for installation should be followed. All BESS installations should restrict access by untrained people, children, pets or vermin.

Note: Information on location of BESS will be subject to further review once the Australian standard on BESS installations is finalised.

Before you install a BESS, think about:

  • any building codes applicable to batteries (national and local) and changes to floor loadings
  • whether the location complies with the manufacturer's recommendations to protect the system from weather and extreme heat, light and temperature, which may reduce performance or the life span of the system
  • how any electrolyte spills will be captured to avoid exposure to hazardous chemicals and damage to equipment or the environment
  • using the correct fire-rated walls to avoid the spread of fire, should it occur
  • allowing suitable access to the area during installation and maintenance work
  • ways to achieve adequate ventilation
  • protecting it from being hit by vehicles or other objects in the yard.

Installing the BESS

To install a system, you will need to use safe work practices and comply with legislation, the wiring rules and other relevant standards.

Ensure your workers are competent to install BESS, and they follow the manufacturer's guideline and instructions.

Other safety concerns during installation include:

  • insulating live parts to prevent electric shock, including battery terminals, and other electrical connections
  • knowing how to test, commission or de-commission the system as required
  • ensuring there is sufficient clearance between items to prevent overheating
  • ensuring shutdown switches are easily accessible
  • placing signage and warnings to clearly identify equipment and shut-down procedures and the battery chemical being used (so it can be identified by emergency workers)
  • being aware of the hazardous chemicals in batteries and taking precautions, including having the appropriate safety data sheets nearby.

Best Practice Guide for battery storage equipment – electrical safety requirements

Industry associations involved in renewable energy have developed a best practice guide for battery storage equipment.

This guide will assist in providing a minimum level of electrical safety for lithium based battery storage equipment.

Products that are covered in this guide include battery storage equipment with a rated capacity of equal to or greater than 1kWh and up to and including 200kWh of energy storage capacity when measured at 0.1C.

The guide includes suggested safety requirements for:

  • battery modules (BM) - one or more cells linked together for use in other equipment
  • pre-assembled battery systems (BS) - a complete package for connection to a DC bus or DC input of power conversion equipment (PCE)
  • pre-assembled integrated battery energy storage systems (BESS) - a complete package that has AC output for connection to the electrical installation.

The guide includes details of what should be supplied with the equipment including:

  • declaration of compliance or certification
  • technical datasheets and safety data sheets
  • installation, operating and maintenance instructions.

The guide does not cover electrical installation requirements for batteries. Installation of battery storage equipment referred to in the guide should still follow appropriate safety standards. Installation safety practices should include undertaking a suitable risk assessment and adherence to the manufacturer's instructions, industry accepted guides, the Wiring Rules AS/NZS 3000 and the proposed battery system installation standard, when published.

View the Best Practice Guide.

Test and commission the system and explain the maintenance requirements

The BESS must be tested and commissioned in accordance with the manufacturer's instructions and relevant standards.

They will need to:

  • know how to safely operate, maintain and shutdown the system in an emergency
  • understand various safety warnings and lights, specific to the BESS
  • know which safety data sheets are required and where they should be located
  • know what maintenance is required, when it should be scheduled and who should do it.

Useful information

Energy storage safety: Responsible installation, use and disposal of domestic and small commercial battery systems, CSIRO

Battery storage safety, Clean Energy Council

National Electrical and Communications Association (NECA)

Master Electricians Australia

Australian Standards references

Australian Standards

Reference standards:

Note: specific Australian standards and code of practices for battery storage system installations for small scale are currently under development to supplement the requirements in AS/NZS 3000 Electrical installations (known as the Australian/New Zealand Wiring Rules). In the interim, existing standards with related content may be used for reference as appropriate to help mitigate the risks associated with these installations.

AS 1319 Safety signs for the occupational environment
AS 1530.4 Methods for fire tests on building materials, components and structures - Fire-resistance test of elements of construction
AS 3011.2 Electrical installations - Secondary batteries installed in buildings - Sealed cells
AS/NZS 4509.1 Stand Alone Power Systems - Installation
AS 4086.2 Secondary batteries for use with stand-alone power systems - Installation and maintenance
AS/NZS 3000 Electrical installations (known as the Australian/New Zealand Wiring Rules)
AS/NZS 5033 Installation and safety requirements for photovoltaic (PV) arrays
AS/NZS 4777.1 Grid connection of energy systems via inverters – Installation requirements
AS/NZS 4777.2 Grid connection of energy systems via inverters – Inverter requirements
AS 62040.1.1 Uninterruptible power systems (UPS) - General and safety requirements for UPS used in operator access areas
AS 62040.1.2 Uninterruptible power systems (UPS) - General and safety requirements for UPS used in restricted access locations
AS/NZS 60529 Degrees of Protection Provided by Enclosures (IP Code)
AS/NZS 60898.2 Circuit-breakers for overcurrent protection for household and similar installations - Circuit-breakers for a.c. and d.c. operation.
AS/NZS 60947.3 Low-voltage switchgear and control gear - Switches, disconnectors, switch-disconnectors and fuse-combination units
AS/NZS 60950.1 Information technology equipment - Safety - General requirements
IEC 62109-1 Ed. 1.0 (English 2010) Safety of power converters for use in photovoltaic power systems - Part 1: General requirements
IEC 62109-2 Ed. 1.0 (Bilingual 2011) Safety of power converters for use in photovoltaic power systems - Part 2: Particular requirements for inverters