Origin Energy’s giant Eraring coal power plant cannot close in 2027 without risking blackouts in NSW, the Australian Energy Market Operator has advised, warning that equipment needed to keep the grid secure will not be installed in time.

The threat to power supply from shutting down Eraring is not because of a lack of electricity to replace the 2880-megawatt generator – the country’s biggest – but because of a lack of system strength services for the power grid, according to the market operator.