One of Australia’s biggest and worst performing wind farms back on line after near two month outage

One of the biggest but worst performing wind farms in Australia is back on line after a seven week outage caused by a transmission failure at its substation.

The 420 megawatt (MW) MacArthur wind farm near Warrnambool in south western Victoria was once the biggest wind project in the country, and the southern hemisphere, but it has delivered poor returns in terms of output since starting full operations in early 2013.

Over the last three years it has delivered an average capacity factor of less than 20 per cent, according to data provided by Rystad Energy, less than half the best performing wind farm in the main grid, which happens to be the much smaller 31 MW Kiata wind farm to the north.

Macarthur was predicted to produce at a 35 per cent capacity factor when the project was first announced by AGL Energy in 2010, which would have equated to around 1,200 gigawatt hours a year. But it has never reached that figure and in recent years it has failed to produce more than 800 gigawatt hours a year.

It’s never been clear exactly why the wind farm has failed to deliver on expectations, with some speculation about lower than expected wind speeds, and others pointing to the layout of the turbines. It is located on flat grazing land.

The chart above, from Rystad, identifies Macarthur as having the fourth lowest capacity factor in the three years from the start of 2021 to the end of 2023. Most of the wind farms around it on that table were ramping up capacity after completing construction and connections.

The Macarthur wind farms uses 140 Vestas turbines, each sized at 3 MW and with a hub height of 85 metres. Newer turbines are at least twice the capacity and at least twice the height. But it’s not always size that counts – Kiata is consistently the best performing wind farm in the country with a turbine size of 3.45 MW.

The latest problem at Macarthur occurred in early June because of a transformer failure, said a spokesman for operator AGL. It did not return to service until late last week. The project is operated by AGL but is now owned by Palisade, Atmos and Dexus.