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Battery energy storage systems (BESS)

Battery energy storage systems (BESS) are using renewable energy to power more homes and businesses than ever before. If installed incorrectly or not safely commissioned, they pose serious safety risks. A BESS must be installed by a properly licenced electrician.

What are battery energy storage systems?

Battery energy storage systems (BESS) are the technologies we simply know as batteries that are big enough to power your business. Power from renewables, like solar and wind, are stored in a BESS for later use. They come in different shapes and sizes, suit different applications and settings, and use different technologies and chemicals to do their job.

They play an important role in green energy supplies and make renewable energy more reliable. Sometimes they are connected to the main power grid to supply unused or excess power for others.

There are three main types of BESS:

  • 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).

What are the risks of battery energy storage systems?

They are a serious safety risk if not correctly installed or commissioned. They can cause:

Electric shock

Battery cells can 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 on the energy regulators and inverters that have hazardous voltages.

Fire and explosion

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

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.

Flash burns

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, and cause arc flash injuries. Generally, higher battery energy storage capacities have a higher risk of arc flash.

Exposure to hazardous chemicals

Battery casings can degrade or be damaged from a variety of impacts. They can also rupture because 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.

How do I manage the risks?

Workers and management can work together to reduce the risks of battery energy storage systems.

For workers

As a worker, you must:

  • use safe systems of work
  • only do work you are licenced and competent for
  • take care of your own health and safety as well as the health and safety of others
  • cooperate with management to meet health and safety requirements and reduce risks.

For businesses

You have legal responsibilities as outlined in the Electrical Safety Act 2002 and Work Health and Safety Act 2011 (WHS Act) for the health and safety of every worker and visitor.

By following the four-step risk management process below you should meet your responsibilities under these laws. Where the WHS Act and the Electrical Safety Act both apply the Electrical Safety Act takes priority.

You can also use the practical advice in the Electrical safety code of practice 2021 - Managing electrical risks in the workplace.

Four steps to manage risk

The first step is to identify the hazards. They can result from the actions of people working with the battery system or the battery system itself, including its installation and location.

Ask yourself:

  • Has the right battery technology been chosen for the application?
  • Is it installed according to the manufacturer’s instructions, industry standards and guidelines, and building codes?
  • Could the system overheat or over-charge?
  • How would an accidental chemical spill be managed and contained?
  • Are workers trained to safely handle, use and maintain the battery system?

Talk to your workers and ask:

  • Are you aware of any potential hazards?
  • How can we improve our safety and our processes?
  • Do you know how to report a hazard?

Regularly review your own records, and consider:

  • What do your workers’ compensation claims, recorded incidents, sick leave and worker complaints tell you about past incidents and hazards?
  • What can you do to prevent the same things happening again?

Identifying hazards should be an ongoing activity and something organised at least once a year, or whenever there is a change in equipment, facilities or work practices.

Next, assess the level of risk posed by each hazard. The risk level is determined by:

  • how serious the potential harm is
  • how likely it is to happen.

You can use this risk assessment template (DOCX, 0.02 MB) to guide you and record your assessments.

The law requires you to eliminate the risks if practical, or to minimise them as much as possible.

You must work through the hierarchy of controls to choose the control that most effectively eliminates or minimises the risks. This may involve a single control measure or combination of two or more different controls.

Find the hierarchy of controls in How to manage work health and safety risks code of practice 2021 (PDF, 0.65 MB) or use the Electrical safety code of practice 2021 - Managing electrical risks in the workplace.

Additional ways to control the risks associated with battery energy storage systems are as follows.

A. Choose the right battery technology for the application

A range of battery technologies are available in Australia, including:

  • 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. Choose a battery technology that suits the application and know how to safely handle (including transporting), install and operate the system.

B. Design the battery system to suit the application

Required energy storage capacity, budget, battery technology, type and intended lifespan will all influence the design of the battery energy storage system, as will 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.

Source components that are suited to Australia’s climate and only buy from businesses that have product expertise, aftersales service, warranty, replacement components and ready access to spare parts.

C. Find the right location for the installation

A battery energy storage system is a fixed installation, so it’s important to assess the risks of the technology being used in that location.

This includes complying with any requirements specific to the choice of location according to:

  • AS/NZS 3000 (the wiring rules)
  • AS/NZS5139 Electrical installations – Safety of battery systems for use with conversion equipment
  • supplier (the manufacturer/importer) instructions.

It’s also important to consider:

  • any building codes that apply 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 lifespan 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.

All locations and installations should restrict access by untrained people, children, pets or vermin.

D. Safely install the battery system

Ensure safe work practices are followed, and compliance with the manufacturer’s guidelines and instructions, legislation, the wiring rules and other relevant standards are achieved during installation.

You should also:

  • insulate live parts to prevent electric shock, including battery terminals and other electrical connections
  • know how to test, commission or de-commission the system, as required
  • ensure there is sufficient clearance between items to prevent overheating
  • ensure shutdown switches are easily accessible
  • place 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)
  • be aware of the hazardous chemicals in batteries and taking precautions, including having the appropriate safety data sheets nearby.

E. Correctly test and commission the system and explain the maintenance requirements

Test and commission the system according to the manufacturer’s instructions and relevant standards.

Explain the maintenance requirements to the system’s owner, to maximise its life and performance. 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 system
  • know which safety data sheets are required and where they should be located
  • know where to locate the serial number to help traceability should a recall occur
  • know what maintenance is required, when it should be scheduled, and who should do it
  • visit the Electrical Safety Queensland website for more information on BESS.

F. For lithium-based battery storage equipment, also follow the best practice guide

Use the Best Practice Guide: Battery Storage Equipment – Electrical Safety Requirements for minimum levels of electrical safety for lithium-based battery storage equipment. Products 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, AS/NZS 3000 (the wiring rules) and AS/NZS5139 Electrical installations – Safety of battery systems for use with conversion equipment.

You should regularly review your control measures. Don’t wait for something to go wrong. If necessary, change or adjust your approach. The aim is to maintain a work environment that is without risks to health and safety.

Work health and safety laws require you to review controls:

  • when you become aware a control measure is not working effectively
  • before a change that might introduce a new risk
  • when you find a new hazard or risk
  • after a near-miss
  • when your workers tell you that a review is needed
  • after a health and safety representative requests a review.

Standards and compliance

Other relevant standards include:

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 AC and DC 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