On Wednesday, the offer price on the National Electricity Market for a megawatt of electricity from Queensland reached $9999.90, which was the first time the permitted maximum price level had been reached.

While the price hikes have an immediate impact on retail prices, they affect the average price of electricity charged by generators in their forward contracts to retailers.

From April 1, the Australian Competition and Consumer Commission allowed generators to lift their maximum prices from $5000 a MW/h to $10,000 MW/h, responding to industry arguments that returns were not sufficient to justify new capital investment.