Wholesale power prices fell in most states

But prices fell in Victoria and South Australia, and substantially declined in Tasmania due to more hydro power and a fixed electricity interconnector, the Australian Energy Market Operator's latest quarterly market report found.

Overall, quarterly emissions from the east coast's National Electricity Market were at their lowest on record while the output from renewable energy was at its highest ever level.

Renewables powered more than 20 per cent of the NEM's supply, with levels of hydro generation at its highest since 2013.

This was largely fuelled by an increase in Tasmanian hydro, which was partially transferred into Victoria while also reducing local wholesale electricity prices.

Wind output exceeded gas powered generation for the first time, the data shows.

Despite reduced demand for gas, wholesale prices were higher compared to the same quarter last year.

The latest quarter also saw record amounts of large-scale solar contributing to the NEM, outnumbering the total amount the system had at the start of the year.

Wholesale electricity prices slightly increased in Western Australia as average demand remained stable, although small-scale solar saw the region's demand drop to its lower point in September.

Fuelled by an increasing uptake of small-scale solar, demand for electricity in SA reached its ever level during the quarter, a record which was again broken last month.

However, AEMO spent $7.4 million over the quarter ensuring SA's system was operating securely, up slightly from the previous period.

Black coal-fired generation dropped to its lowest levels since the end of 2016, largely driven by outages at NSW power stations and lower output caused by periods of lower spot electricity prices in Qld.

The price of Australia's thermal coal from Newcastle rose 15 per cent compared to the previous quarter, its highest cost since early 2011.

Demand from Asian power stations and a depreciating Australian dollar compared to the US dollar is keeping coal prices high, the report says.

Australian Associated Press