Mining city Broken Hill to host one of world’s biggest renewable micro-grids

Source: Giles Parkinson · RENEW ECONOMY · | August 12, 2020

Renew Economy

The iconic mining city of Broken Hill in the far west of New South Wales is set to host one of the world’s largest renewable mini-grids, powered almost entirely by solar, wind and grid scale storage.

The proposal comes from the transmission company Transgrid, which says it is seizing on the opportunity to replace the city’s ageing back-up diesel generators with “21st century technology”.

The main thrust of this will be investment in storage facilities to support the existing wind and solar resources in the region – principally the 200MW Silverton wind farm (pictured above) and the 52MW Broken Hill solar farm, both owned by the renewables investment fund PARF, part owned by AGL.

The interesting, and possibly surprising part of the Transgrid proposal is its choice of storage options. It considered a range of big battery proposals – ranging from 73MW with four hours of storage to 50MW and 90 minutes storage supported by demand response (including one big battery proposal from AGL).

But Transgrid has chosen as its preferred option a huge 150-200MW compressed-air storage facility with 1,550MWh of storage proposed by Canadian company Hydrostor. It will be the world’s biggest compress air energy storage facility.

Transgrid appears to have done this because it prefers “synchronous generation” rather than grid-forming battery inverters – which are relatively new, although recently proven in several smaller off-grid applications and with the Dalrymple battery in South Australia.

The only other such project of note in Australia is a 5MW installation with two hours of storage proposed by Hydrostor for an old zinc mine in South Australia.

Hydrostor has a big blue blob on the map of Australia near Broken Hill that identifies a “near term” development opportunity that could now come true. Like the AGL battery study, its project was one of 14 storage proposals for NSW that received funding by the NSW government for feasibility studies.

Hydrostor describes Compressed Air Energy Storage (CAES) as similar to pumped hydro, delivering long duration storage by using a proprietary thermal management system and the use of purpose-built hard-rock air-storage caverns. Presumably, the mining town of Broken Hill provides plenty of options for such caverns. The air is then released to spin a turbine.