More than one hundred years ago, Australia’s island state carved out a pioneering project—churning their water into electricity. Now, Tasmania is preparing to store and export its renewable energy in bulk via Marinus Link, delivering it across the strait and into the mainland grid, writes Rosie Bensley.
TasNetworks’ proposed Marinus Link—a 1,500MW undersea interconnector traversing the Bass Strait—is lauded as a major step in Australia’s emissions reduction strategy.
Three hundred-and-forty-kilometres of undersea cable will link the Burnie area in Tasmania to the LaTrobe Valley in Victoria, and then onwards to the mainland utility grid. The project, comprising two 750MW cables, is expected to cost $3.5 billion.
Tasmania’s hydroelectric reserves are set to become Australia’s “national battery” in the ambitious plan to double the state’s clean energy output.
Marinus Link has already passed major hurdles, winning the support of the Tasmanian Chamber of Commerce and Industry, the State Government and the Australian Energy Market Operator (AEMO).
The project is now in the design and approvals phase, carrying out underwater surveying to refine the route, but questions still remain on who is footing the bill and if the project is worth the investment.
The case for Marinus Link
Tasmania is positioning itself as a key player in Australia’s transition to renewables with their “Battery of the Nation Project”, enabled by Marinus Link.
“It can be windy in Victoria and not windy in Tassie and vice versa or in South Australia. So really what you want is a network that can move energy, and transmission moves energy really efficiently from where it’s being generated to where customers use it,” Marinus Link CEO Bess Clarke told Parliament in September.
The project boasts a suite of pumped hydro stations to reliably provide energy when wind and solar may not be viable, and export this energy to the mainland through the cross-strait link.
On top of its contribution to Australia’s transition to renewables, the project will help secure the lowest possible power prices, says TasNetworks CEO Seán McGoldrick.
“In Tasmania, that all relies on having more interconnection, via Marinus. This is the biggest opportunity in Tasmanian history since hydro-industrialisation itself,” he said.
The state already runs on nearly 100 per cent clean hydropower, and Tasmania’s climate and existing infrastructure make it the obvious and cost-effective choice for energy storage, according to TasNetworks.
The capital cost of hydro energy systems in Tasmania is 30 per cent lower than in mainland Australia, and wind turbines have a 25 per cent higher energy output, according to a Marinus project report.
Energy company Nexsphere has also flagged the strait for a multi-billion-dollar wind farm, with the capacity to export renewable electricity through Marinus Link to Victoria.
The fall of Basslink
As Marinus jumps through the approval hoops, the financial failure of Tasmania’s existing undersea cable Basslink is ongoing.
The Singaporean owners of the existing Basslink cable went into voluntary administration in November, unable to pay the $70 million arbitration owed to the Tasmanian Government and HydroTasmania after a major outage in 2015.
The cable connecting Tasmania to the mainland electricity grid took six months to be repaired and coincided with record low water levels in Tassie’s hydroelectric dams.
The crisis forced the state to import 80 diesel generators and fire up the Tamar Power Station to keep Tasmania running.
While Basslink is still operational, in June the Federal Government promised to fast track approvals for the Marinus project.
Marinus Link will not follow the same route as Basslink, instead providing a more direct and reliable connection through the Bass Strait. However, both cables still run into the same problems: transmission lines are expensive to construct and maintain, and can be disrupted and damaged by a number of natural causes.
The project’s price tag has also drawn criticism from Dr Bruce Mountain, who says the proposed cable and energy storage project will not be able to compete with battery storage technologies in Victoria.
Snowy 2.0?
Dr Mountain’s report from the Victoria Energy Policy Centre found the cost of battery storage was decreasing and, by the time Marinus Link is constructed in 2028, it will be cheaper to store energy in Victoria than import it from Tasmania.
Victoria has already invested in large-scale battery projects, namely the 300MW Victorian Big Battery Project. The report compares Marinus Link to Snowy 2.0, labelling it a design that “will be stranded from the outset”.
Marinus Link CEO Bess Clark says the project has already factored in falling battery prices, and according to their modelling, the undersea cable will still be profitable.
“Marinus Link provides access to long duration, intraday and seasonal shifting of energy that the NEM will need, and it does that at a lower cost than batteries can,” Clark told Parliament.
There are also concerns Tasmanians will be left footing the bill for a project designed to solve energy problems on the mainland.
Tasmanian Energy Minister Guy Barnett has assured Tasmanians they would only pay their “fair share” for the national infrastructure, but is yet to provide figures.
Full steam ahead
With support from AEMO, Marinus Link has been labelled as fully actionable.
Modelling from AEMO has suggested that brown coal and two-thirds of black coal-fired power stations could be retired by 2032, meaning renewable generation, storage and transmission projects remain a strong priority.
Marinus Link CEO Bess Clark says AEMO’s report shows Marinus Link is essential for Australia’s clean energy future.
“The report confirms that we will need all available energy firming technology, including deep long duration pumped hydro storage and further interconnection, to support the rapid transition underway,” Clark said.
For more information on Marinus Link, click here.
