Wind out-powers hydro for five hours on Tasmania grid, allowing utility to cash in

Windy conditions in south-eastern Australia last week led to an interesting energy generation mix for Tasmania, where the island state’s well established hydro power resource regularly supplies 100 per cent of demand.

According to a LinkedIn post from Hydro Tasmania’s executive general manager of commercial, Vedran Kovac, from midnight to 5am on Friday May 25 there was more wind energy on the Tasmanian grid than hydropower.

As the chart below shows, for that period Tasmania was powered 35 per cent by wind compared to 28 per cent by hydro. The remaining 37 per cent of energy was imported from the mainland via the Basslink undersea cable.

As Kovac explains here, just as Tasmania’s comparatively small wind resource was firing on all cylinders, so too were the wind farms in Victoria.

“There was so much wind energy pouring into the National Electricity Market (NEM), that Hydro Tasmania was paid to import the excess energy. That’s right, they paid us to take electricity.

“By the evening, things had changed. The sun had set, and across the country, people arrived home and switched appliances on, driving up electricity demand in the NEM.

“With this change in conditions, wholesale prices on the NEM went up, creating another opportunity for Tasmania. The hydro power we’d saved by importing when we were being paid to do so, we could now export into the NEM for $300/MWh.”

Kovac says the “windy story” illustrates how Tasmania – “a small island at the bottom of the country” – can benefit from Australia’s energy market transition.

It also, he says, makes a good case for Marinus – the second undersea cable proposed to link Tassie’s grid to the mainland – and the Battery of the Nation concept, where Tasmania’s existing hydropower, boosted by new capacity and added pumped hydro, can be used to “soak up” excess renewables for use later on the mainland.

“They are revenue-generating investments that will set Tasmania up for decades to come, delivering benefits for Tasmanians and for Australians,” Kovac says.