A major expansion of the undersea interconnector between the Tasmanian and Victorian grids could unlock thousands of megawatts of new clean energy capacity in the National Electricity Market, while keeping prices low and improving reliability, a new report on the ‘Battery of the Nation’ proposal has argued.

The white paper for the Battery of the Nation project, published by chief proponent Hydro Tasmania, has set out the challenges to the integration of higher penetrations of renewables into the electricity grid and the role Tasmanian pumped hydro could play in solving these challenges.

The Battery of the Nation project proposes to draw upon the more than 2,500MW of new pumped hydro opportunities that have been identified by Hydro Tasmania to act as energy storage for the NEM.

Hydro Tasmania, which is owned by the Tasmanian government, believes that the construction of an additional interconnector between Tasmania and Victoria would facilitate a rapid expansion of a crucial renewable energy generation, providing an additional source of power and avoid repeat of the load shedding events that hit Victoria last summer, leaving up to 100,000 customers without power.

“Victoria will need to access significant energy storage to ensure they can meet their renewable energy targets while keeping the power system reliable,” Hydro Tasmania CEO Steve Davy said.

“Tasmania has idle capacity waiting to be unlocked by market signals and delivered through the additional interconnection required by Battery of the Nation.”

Hydro Tasmania has used the white paper to make the case for a major expansion of the undersea network transmission links between Tasmania and the Australian mainland, as a first step that will unlock further investment in pumped-hydro energy storage.

Hydro Tasmania pointed to two options for the Marinus Link that are currently under consideration, adding either 600MW or 1,200MW of additional interconnector capacity, on top of the existing 500MW Basslink connector.

“With change already underway, we need proactive support for interconnection through TasNetwork’s Marinus Link project to get the electricity to where it’s needed, along with the timely development of investment incentives to ensure supply is available when it’s needed,” Davy said.

Hydro Tasmania sees the Battery of the Nation project as supporting the increased adoption of renewable across the National Electricity Market, particularly Victoria, which has just officially legislated a 50 per cent renewables by 2030 target.

Key to tapping into Tasmania’s large supply of stored energy will be an expansion of the capacity of interconnections between Tasmania and the mainland, including the completion of the proposed Marinus Link.

“Further interconnection between Victoria and Tasmania will help manage the energy transition over coming decades, enabling practical solutions that are complementary to Victoria’s renewable energy, as well as supporting the rest of the National Electricity Market,” Davy added.

The white paper examined two potential scenarios for how the Battery of the Nation project may be able to assist Victoria to maintain a reliable and affordable electricity supply following the retirement of the 1,480MW Yallourn power station. Hydro Tasmania believes it is well placed to provide additional supply as Victoria’s fleet of brown coal power station reach retirement.

With a large number of hydroelectric generators and good wind availability, Tasmania sources almost all of its power from renewable sources. The Hydro Tasmania white paper has encouraged early investment in new network infrastructure that would allow the State to supply the Australian mainland with zero-emissions power, especially in a scenario with the unexpectedly early retirement of coal generators.

Hydro Tasmania found that under normal circumstances, the retirement of Yallourn power station would create an opportunity for up to 3,450MW in replacement generation, predominantly from financially viable wind and solar projects.

But the report also found that if the Tasmanian-Victorian interconnector was boosted by 1,200MW via the Marinus Link, a significantly increased total of 5150MW of wind and solar projects could be financially viable, spread across both Tasmania and Victoria, along with 600MW/24-hours of pumped hydro battery storage.

“Because of the diversity of demand, wind resources and the utilisation of rich hydropower resources and storage, both Victoria and Tasmania can develop new renewable energy assets whilst remaining commercially viable and reducing power prices,” the report said.

Hydro Tasmania has already identified three high potential sites for pumped hydro energy storage that would utilise the company’s existing hydro infrastructure at Lake Cethana, Lake Rowallan and a third site at Tribute that would link Lake Plimsoll and Lake Murchison.

The white paper was prepared by Hydro Tasmania and was supported by $300,000 in funding from the Australian Renewable Energy Agency (ARENA). ARENA has agreed to provide up to $5 million of funding to assist further studies for the Battery of the Nation project.