Department of Energy and Water Supply

Battery energy storage

Battery storage systems store electricity, such as from a solar system or the electricity grid, for use at another time.

Battery systems can vary in size:

  • small systems (1 kilowatt hour (kWh) to 12kWh) for households or small to medium businesses
  • large systems (up to and over 200kWh) for business; and
  • grid-scale systems (up to and over 1 megawatt hour) operated by electricity generators and network providers.

Small battery systems can be installed with a new solar system or connected to an existing system.  Note that some modification or replacement of parts may be necessary.

Different battery types

Battery technology has developed rapidly in recent years and this is expected to continue.

It's important to understand the type of battery storage systems available. Each have different installation and maintenance requirements, as well as different safety precautions.

Lithium-ion batteries

Most home battery storage systems coming onto the market use lithium-ion (or Li-ion) technology. They have a long life and can store a lot of energy for their physical size. Mobile phones and laptops typically use lithium-ion batteries. Characteristics of lithium-ion batteries:

  • a life span of 5 to 15 years
  • greater  power storage and release than lead acid batteries of a similar size and weight
  • faster charging times
  • up to 98% efficient (i.e. only 2% of electrical charge is lost during use)
  • susceptible to fire risk and therefore requires careful safety management.

Lead acid batteries

The most common and well known battery type has been around for decades. They work similarly to your car battery and have been used to provide back-up power in black outs and in remote areas. Some characteristics:

  • a life span of between 3 and 15 years (depending on how they're used)
  • cheaper than other battery technologies
  • using more than 50% of the overall charge can affect life span and ability to hold charge
  • about 85% efficient (i.e. about 15% of charge is lost during use)
  • about 80% of components are recyclable
  • safe and reliable, with well-established safety standards
  • battery compartment or room requires very good ventilation to prevent gas build-up.

Comparing lithium-ion and lead acid batteries

Technology

Suitable application
(energy - kWh or power - kW) 1

Lifetime (years)

Cycle life 
(number of charge – discharge cycles)

Depth of discharge

Round trip efficiency

Operating temperature

Lithium iron phosphate

Both

5-10

3000-6000

50-90%

89%

0 to 45 degrees

Lithium cobalt oxide

Both

5-7

800-1200

50%

97%

-10 to 45 degrees

Lithium manganese oxide

Both

10-30

5000-10000

90%

75-95%

-10 to 45 degrees

Lead acid

Energy

3-15

2000-3000

50%

85%

-10 to 40 degrees

1 A battery suitable to supply energy is one which can store electricity for use over time. A battery suitable to supply power is one which can produce a high instantaneous output of electricity. 
Adapted from CSIRO: Energy Storage Safety, Responsible installation, use and disposal of domestic and small commercial systems (2015). 

Flow batteries

These store energy in liquid electrolyte solutions that flow through the battery. They tend to be used in commercial and large-scale applications, and are more environmentally friendly than other batteries. Flow batteries have a life span of more than 20 years (approximately 10,000 charging cycles) and are about 80 per cent efficient. However, flow batteries are a complex technology and there is no recycling process or plant currently available in Australia.

Salt water batteries (sodium-ion analogue batteries)

These store energy using salt water-based chemistry. They are comparatively affordable, very safe and the most environmentally-friendly batteries on the market. Salt water batteries are 100 per cent efficient, but they tend to have a shorter life span (10 years), and are quite big and heavy. As with flow batteries, there is no recycling process or plant in Australia.

Battery costs

The price of batteries can vary greatly depending on the brand, type and size of the battery, and how advanced the technology is. Prices are expected to reduce as new products and manufacturers enter the Australian and Queensland markets.

It's important to understand the whole-of-system cost. For example, some advertised prices do not show the other components and installation charges you may have to pay. The whole-of-system costs can include:

  • the battery
  • the inverter: to convert DC to AC power for use in the home
  • a battery management system: this is an electronic system that manages the safe operation of your battery by telling it when to charge and when to power your home. Some battery management systems come with an app that shows you what your battery is doing at any given time.
  • installation: such as the installer's labour and any siting or battery casing requirements
  • wiring or retrofitting: for example to a solar system, or for use as a battery back-up system.
  • ongoing maintenance
  • end of life recycling and/or disposal.

As with any significant purchase, it's a good idea to shop around and get a better understanding of the different types of batteries, what they can do, and how much they cost to install. Ensure you compare like for like and not just cost alone.

Also consider the safety and performance of the battery. Cheaper batteries that have not been manufactured properly or tested to ensure they meet minimum safety or performance requirements may not be a bargain if they don't last or cause a safety hazard.

For more information, read about installing battery energy storage.

Battery safety

Batteries can be dangerous if they are not installed, used and looked after properly. It's therefore important to deal only with qualified and accredited battery designers and installers. The Clean Energy Council publishes consumer information about battery storage and safety (including an excellent customer checklist) that sets out the things you need to know about safely installing and maintaining a battery energy storage system.

In 2015 the Clean Energy Council commissioned the CSIRO to undertake a comprehensive safety performance study for different battery types. The report provides detailed advice on best practice for battery installations, maintenance and disposal.

Last updated:
13 September 2016
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