Snowy Hydro power struggle at Tumut over interstate transmission line limits and underused electricity capacity

Snowy Hydro chief executive Paul Broad told ​The Daily Advertiser that the Tumut station has for years had the ability to produce more power than its transmission lines can carry.

“Since the upgrade of Tumut 3 the capacity of the station has been increased to 1800 megawatts - 300MW more than the original 1500MW rating,” he said. 

“Due to transmission constraints in NSW there are times where the Snowy Scheme cannot get all of its available capacity, including the additional 300MW from Tumut 3, into the market.”

Snowy Hydro has called for an upgrade that would allow its hydroelectricity generation to supply an additional 1000MW of power and help offset the closure of coal-fired Liddell power station’s closure in 2022. 

“Transmission upgrades would integrate future renewable energy sources into the shared network and unlock up to 1000MW of existing capacity from the Snowy Scheme,” Mr Broad said.

“Upgrades to NSW transmission lines would allow energy from both the Tumut side and the Murray side of the Snowy Scheme to flow north into Sydney at the same time.

“Upgrading NSW’s transmission lines to ensure all available capacity can reach the energy market will help put downward pressure on energy prices and improve the reliability of the system.”

TransGrid is the organisation responsible for managing and operating the high voltage electricity transmission network in NSW.

TransGrid’s annual planning report has proposed a “reinforcement of Southern NSW Network in response to Snowy 2.0” as one of its “proposed major developments”.

Earlier this month, Riverina Highlands RFS was concerned that bushfires in the Snowy Valleys area presented a risk of having to shut down the main interstate power connection between NSW and Victoria.

The RFS said at the time that shutting down the line would have endangered power supplies across the Riverina and both states. 

Mr Broad said new power lines would spread the risk.

“Bushfires can of course impact transmission infrastructure and are always a strong focus of mitigation activities,” he said.

“Additional lines between Victoria and NSW and from Southern NSW to Sydney via diversified routes will greatly reduce the impact of bushfires on the transmission system.”

Snowy Hydro has contracted almost 900MW of new wind and solar capacity to built by 2020.

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