Basslink cable damaged during maintenance, out until mid-April

The under-sea cable linking Tasmania’s electricity market to that of the Australian mainland has been accidentally damaged during maintenance work, taking it out of action until mid-April.

The operator of the cable, Basslink, said on Wednesday it had been undertaking “planned maintenance works” of the 289km Basslink Interconnector when a third-party contractor damaged a piece of equipment at a transition station in Victoria.

“Given the damaged equipment is unique, it will require appropriate expertise and equipment from overseas for repair before the interconnector can recommence operations,” Basslink said in a statement.

“Based on current information, its anticipated return to service date is 14 April 2018.”

The outage comes as federal government-backed studies investigate the business case for a second interconnector across the Bass Strait, to complement – and back up – the existing cable.

It also follows a push for Australia’s island state to become the “battery of the nation,” by expanding its hydro power capacity and developing “significant” pumped hydro resources to store and dispatch renewable energy – feasibility studies into which have also been backed by ARENA.

Meanwhile, the recently re-elected Tasmania Liberal government has also flagged the possibility that the state will cut ties with the National Electricity Market, while continuing to export and import power over its sub-sea cable.

Tasmanian Premier, Will Hodgman, said the measure would be taken to ensure the mostly hydro-powered state was not exposed to future market fluctuations caused by power stations closures or system failures on the mainland.

“With Tasmania charging toward 100 per cent energy self-sufficiency … now is the time to take back our competitive advantage and break away from inflated mainland prices, and to drive down the cost of living of Tasmanians,” Hodgman said in February.

Tasmania, meanwhile, has been doing just fine coping on its own since the outage, has managed to deliver 24 hours of 100 per cent renewable electricity supply, and stopped using gas, as the chart in the tweet below illustrates.

According to electrical engineer and energy analyst at Advisian, Bruce Miller, this is not surprising. As he explained at the Wind Industry Forum in Melbourne earlier this month, “the frequency control of Tasmania, when it’s not connected to the mainland, is actually better than the mainland.”

When it is connected, he noted, “what you see is that Tasmania is actually providing a little bit of frequency control to the mainland, which is just the opposite to what was intended.”

But things didn’t run as smoothly as all that the last time the Basslink cable suffered an outage, over the summer of 2015/16. At that time, the state was plunged into an energy crisis when the outage coincided with damn levels at record low levels and other grid problems caused by bushfires.

To remedy this, the state was forced to restart its mothballed gas-fired generator, import new parts from the Middle East and also bring in 200MW of diesel gen-sets to ensure there was enough power.