The inquiries target the owners of WA's growing battery fleet — Synergy and French firm Neoen — and come amid mounting scrutiny from the Australian Energy Market Operator as well. Large-scale battery capacity in WA's main grid has surged from negligible levels to about 1400MW in recent years, with batteries now meeting more than 20 per cent of peak demand and sometimes supplying over a third of power. More notably, batteries set the price in the grid more than 90 per cent of the time.
Mr Edwell said batteries had become an instrumental part of the power system, capable of storing renewable energy when surplus and supplying it when scarce, delivering benefits to consumers. But he signalled those benefits were not guaranteed. 'We have been actively undertaking enquiries on these matters, as we always do when we see unusual behaviours or unexpected outcomes in the wholesale electricity market,' he said. 'Where we suspect non-compliance with the Electricity System and Market Rules, we will investigate and take compliance action. These batteries are an important part of the energy transition, but only if we maintain a well-functioning market.'
In one reported episode, coordinated charging by all of Synergy's batteries shortly after midnight propelled spot prices from $120 to more than $350 per megawatt hour. One market player, not authorised to speak publicly, said the incident was one of many in which Synergy's batteries seemed to be driving prices materially higher. While prices in WA's short-term market account for only about 10 per cent of electricity traded — most is done via direct contracts — experts say they are a vital indicator of underlying supply-demand tightness. Observers also note that prices are highest in winter, when wind and solar output are at seasonal lows.