Synergy proposes massive 2GW wind-solar-battery hub for WA’s wheatbelt region

W.A. state-owned utility Synergy is proposing its largest venture into wind and solar yet, with a 2,000 megawatt (MW) project pitched for a site near Enneabba that will combine renewable generation and storage technologies.

The project, known as Tathra, could include up to 1,000 MW of wind capacity from 140 turbines, and 500 MW of solar capacity spread over five different locations, and a 500 MW battery, with the storage still be decided.

The Tathra project may acalm fears over whether Synergy will have enough capacity once its last three coal power units close over the coming four years. 

Synergy has four wind projects in development or under construction, including the Tathra proposal, but its biggest wind project to date is the expanded Warradarge wind farm, which is right next to the Tathra project, where work is underway not to lift capacity to 283 MW in 2027.

The company’s experience with grid-scale solar is the 47 MW, two stage Greenough River project. Most of its recent efforts have been focused on battery storage.

Synergy is currently commissioning one of the country’s biggest battery projects, the 500 MW, 2,000 MWh facility at Collie, adding to the two big batteries it has built at the site of its Kwinana gas generator (and former coal plant) that total 300 MW and more than 1,100 MWh.

The Collie battery – located just up the road from Neoen’s even bigger 560 MW, 2,240 MWh battery at Collie – is expected to be operational by the end of this year, and will take Synergy’s total big battery capacity to more than 800 MW (and nearly 3,200 MWh).

The Tathra renewable energy hub is the latest proposal to zero-in on the state’s new 330 kilovolt (kV) transmission spine. 

The Western Power-owned transmission line upgrade is still under development and will link Perth to the Three Springs substation in the Wheatbelt region.

If the Tathra project goes ahead, the hub will be the 24th renewable energy proposal sited on or directly next to that transmission line.

For Synergy, adding generation significant new forward capacity to a portfolio of just 11 solely-owned and jointly-developed projects may calm fears of what it plans to do once its last coal power plants shut over the next four years. 

Synergy’s current renewable energy portfolio of proposed through to operating projects totals just 577.6 MW, according to data from RenewMap.

Last week, the company wrote off the value of its entire remaining coal fleet. Impairment costs of $521.8 million, of which more than $500 million was for decommissioning alone, added to a $778.5 million loss for the last financial year.

The surging cost of coal and gas are a big factor behind both the loss, and the need to shut the aging coal power stations: the 240 MW Collie A unit will close in 2027 and the Muja 7 and 8 (both 227 MW) in late 2029.

The utility’s coal units have been progressively shut down over the past decade, starting in 2015 with the closure of the Kwinana coal fired generation.

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