Drought forces Tasmania to fire up its biggest gas plant for first time in five years

Tasmania has been forced to fire up its biggest gas fired power generator for the first time in five years as an extended dry period puts pressure on the state’s hydro resources.

The Tamar Valley gas generator is rated at 207 megawatts, and is the only “combined cycle” gas plant in the state. When gas power is needed, which is very rarely and not at all in 2020 and 2021, it fired up some “open cycle” peaking plants.

“Tamar Valley Power Station is one option we have for managing extended dry conditions,” Vedran Kovac, Hydro Tasmania’s head of commercial, told Renew Economy in an emailed statement.

“We started running the Combined Cycle Gas Turbine (CCGT) on 6 June as a pre-emptive measure to maintain water storages after what has been a very dry year. The last time we used the CCGT was in 2019.”

The Tamar Valley CCGT was mothballed in 2014, and was to be decommissioned and sold. But the state’s energy crisis in late 2015, caused by the failure of the Bass Link sub-sea cable and the depletion of its hydro resources, saw it brought back into service. The last time it operated was also in a drought.

The last few weeks have seen it operating on occasions at full capacity, mostly in the evenings where it either relieves the pressure on Tasmania hydro resources, or replaces imports from Victoria.

Some energy market observers have suggested that the gas plant was brought back on line because of weak wind conditions. But Kovac said that is not the case.

“The extended dry conditions have been the primary consideration behind the decision the start the CCGT,” he said.

“The low wind conditions seen over Autumn result in less overall energy in the Tasmanian system, but were not a strong driver in our decision making.”