How Safe Are Solar Battery Storage Systems?

The solar battery revolution will soon start really getting into gear in Australia. According to a survey carried out in 2017, safety is among the major concerns of Australians considering purchasing energy storage – and this includes environmental safety issues when a battery system reaches the end of its service life.

For those of you wishing to dive into the technical nitty-gritty of these issues, this report (PDF) by the Clean Energy Council contains everything you’d ever need to know about home battery storage system safety.

For everyone else, here’s an overview:

Solar battery storage, regardless of whether it’s lithium ion, lead acid, flow or aqueous hybrid ion, is perfectly safe if it is installed by an accredited electrician and properly maintained.

However, the inherent safety behind battery storage does vary between competing technologies. Even within each technology, quality in this regard will vary between manufacturers and how the system is installed.

Lead acid batteries are generally safe, and easily recyclable. By “generally safe”, it needs to be kept in mind that lead acid batteries emit an explosive combination of hydrogen and oxygen gases towards the final stage of charging, so adequate ventilation is very important.

While it sounds a little off-putting, it’s just a case of avoiding a potentially dangerous situation by observing appropriate care and maintenance when working with lead-acid energy storage. The danger level is really not much different to that associated with petrol powered cars and gas used in the home.

Lithium ion batteries pose a fire hazard if not installed properly, or if you use inferior quality batteries. This is due to the chemistry behind lithium-ion batteries making them more prone to ‘thermal runaway’  if they are damaged or if they overheat.

Thermal runaway is a phenomenon whereby where an increase in temperature fuels a further boost in temperature, which can very rapidly lead to a battery venting with flame or even exploding.

Because ‘lithium ion’ is an umbrella term that describes a wide variety of lithium chemistries (such as lithium iron phosphate, lithium cobalt oxide, lithium manganese oxide and lithium nickel manganese cobalt oxide), it’s important to note that some types of lithium ion batteries are much safer than others. Lithium Iron Phosphate (LiFePO4) is considered the safest in terms of thermal runaway risk and is the most durable lithium battery chemistry.

Aside from the type of lithium-ion chemistry, safety will also depend on what else is built into the battery storage system. For example, Tesla’s Powerwall battery also boasts a special safety feature that seals off any thermally unstable cells if they pose a thermal runaway risk, which is why they’re rated for both outdoor and indoor installations.

Lithium ion batteries are very difficult to dispose of/recycle, making them hazardous from an environmental perspective.

Flow batteries are much more environmentally friendly, and have a very low fire risk due to the chemistry of the solutions they contain, such as zinc-bromide electrolyte, which is essentially a fire retardant. They’re also very easy to recycle.

Salt water batteries are non-toxic, non-flammable, and non-explosive. Their chemistry is inherently safe and not capable of thermal runaway. This form of energy storage is also entirely touch-safe, and environmentally friendly to recycle.

One other important safety issue regardless of chemistry or solar battery type relates to the primary purpose of the product – to store energy, and a lot of it; i.e there is a potential electrocution hazard.

In short? Don’t skimp on solar energy storage system quality or installation costs. Get the job done right, and your home solar battery storage system will operate safely and have a long service life.

National standards are currently being developed by Standards Australia to ensure solar battery manufacturers provide safe home energy storage products in Australia and that they are installed correctly. Additionally, the Clean Energy Council has introduced installation guidelines for home battery systems. The CEC’s Battery Installation Guidelines for Accredited Installers became mandatory as of the beginning of November 2017.

>> Next: What kind of payback periods can you expect for a hybrid solar system? >>

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