New draft standards for installing home battery systems could stifle the home energy storage market.
While Standards Australia’s draft voluntary standard seems to be less restrictive than details leaked some months ago, industry experts say it limits battery installations to external locations or non-habitable storage rooms. And it includes “onerous” fire safety requirements.
For instance, there are no known incidents of home batteries exploding (but the standard is silent on storage of electric vehicles, whose batteries have been known on rare occasions to explode into flames).
Alternative Technology Association energy analyst Andrew Reddaway said the standards meant that fewer households would be in a position to install battery technology.
- See our story Should we ban lithium batteries from our homes
“The development of the draft standard has not been without controversy,” Standards Australia said in a media statement on Tuesday.
“Earlier in 2017, concerns were raised in the media that the draft standard would seek to ban lithium-ion batteries in homes. Since then, experts from industry and government together with community interests have continued to work together to prepare the consultation draft.”
The draft standard classifies batteries based on hazards, rather than chemistries, using the following risk classifications:
- Electrical hazard – all battery types
- Energy hazard – all battery types
- Fire hazard level 1 [self-sustaining] – lithium based
- Fire hazard level 2 [non self-sustaining] – lead acid and nickel alkaline based
- Chemical hazard – lead acid, flow batteries and nickel alkaline based
- Toxic gas hazard – lithium based, flow and hybrid ion
- Explosive gas hazard – lead acid, nickel alkaline based, some lithium batteries, some flow batteries
- Mechanical hazard – all types
To mitigate the risks around energy and electrical hazards, a number of measures are prescribed, including the use of battery management systems.
What’s likely to be contentious are the requirements around the other risks.
The draft proposal is that no battery that poses a fire risk, chemical hazard, toxic gas hazard or explosive gas hazard be installed in any habitable room. Also, in either a dedicated indoor space or external space, such as a garage or verandah, battery systems will need to be in an enclosure that meets strict fire rating requirements.
“The draft standard currently includes provisions to minimise the risk of self-sustaining fires,” Standards Australia said.
“In considering the fire hazards associated with some of these systems, the draft contains provisions that exclude certain battery systems from being installed inside domestic homes.
“They may be installed externally and adjoining to domestic homes provided certain fire related safety measures are met.”
Onerous fire-proofing rules
Mr Reddaway said the fire-proofing required for battery enclosures seemed “onerous”.
Someone installing a Tesla Powerwall, for example, on the exterior of their home would need to have fire-proof material rated for 60 minutes of burning between the unit and the wall, then extending two metres above the unit and 600mm either side.
It is also uncertain whether it would need a further degree of added enclosure in front of the battery unit.
“It is also unclear, if it is a fully-manufactured product and has its own enclosure, whether that is enough,” Mr Reddaway said.
Further, any battery system that involves a potential gas hazard will need to have ventilation to the exterior of the building for the enclosure, preferably natural ventilation in case of failure of mechanical ventilation systems.
There are also proposed rules about how close enclosures or ventilation outlets can be to adjacent properties.
“In arriving at this consultation draft, it is clear that different views exist amongst stakeholders as to whether the draft provisions are set appropriately and whether the benefits of emergent technology are appropriately balanced with community safety expectations,” Standards Australia said.
“Given the level of interest in the introduction of battery storage in homes, public comment on the draft is sought in particular on Clauses 4.5.3 and Table 3.1 of the draft.”
- Read the AS/NZS 5139 Electrical Installations – Safety of battery systems for use with power conversion equipment draft standard and lodge comments here