?Kill the viability?: big batteries to lose out from electricity grid rule change

Tesla, Snowy Hydro and other big suppliers of storage capacity on Australia's main electricity grid warn proposed rule changes amount to a tax on their operations that will deter investors and slow the decarbonisation of the industry.

The Australian Energy Market Commission (AEMC) will release its final decision this Thursday on new rules for integrating batteries, pumped hydro and other forms of storage.

The AEMC's draft decision, released in July, angered many firms because it proposed charging storage providers for drawing power, ignoring a recommendation by the Australian Electricity Market Operator (AEMO) that they be exempt.

Battery maker Tesla, which has supplied some of the largest storage to the National Electricity Market, said in a submission that the charges would "kill the commercial viability of all grid storage projects, causing inefficient investment in alternative network", with consumers paying higher costs.

Snowy Hydro, which is building the giant Snowy 2 pumped storage project and already operates a smaller one, said in its submission the proposed changes if implemented would jeopardise investment.

"This is a major policy change, amounting to a tax on infrastructure critical to achieving a renewable future," Snowy Hydro said.

AEMO itself argued it was important storage providers were not "disincentivised from connecting to the transmission network, as they generally provide a net benefit to the power system by charging at periods of low demand".