Rain is good news for dam levels

24 November 2021

By Ian Brooksbank, Acting CEO Hydro Tasmania 



One of the wettest springs in recent memory may have been ruining our weekends, but it’s been good news for Hydro Tasmania’s energy storages, which are currently sitting at 52.8 per cent, the highest levels since 2013.  


Healthy storage levels are good news for us and for the state, but we cannot assume this will always be the case. For many of our employees, 2016 is never far from our minds.  


That year, we faced an unprecedented combination of unusual events: the driest spring on record and a six month interconnector outage. Our people worked hard through this time to keep the lights on and we are proud of that response. 


But if such unforeseen events can happen once, they can happen again. This is why the state is far better prepared now than in 2016, primarily through the introduction of the Tasmanian Energy Security Risk Response Framework.  


The framework requires Hydro Tasmania to hold a minimum level of energy in storage at all times. Called the High Reliability Level, this is based on having enough water to protect Tasmania if the extraordinary circumstances of 2016 were ever repeated. 


On top of that, there is the Prudent Storage Level which creates an additional buffer. Together, both the High Reliability Level and the Prudent Storage Level mean that in an unrealistic scenario of having no rain or interconnection, Tasmania would have 9 months’ of hydro energy still available before storages are depleted. 


The required High Reliability Level and the Prudent Storage Level change through the course of each year, and our current storage level of 52.3 per cent is well above both.  


Another significant change since 2016 is the commissioning of the Cattle Hill and Granville Harbour windfarms. Wind generation now contributes 15 per cent of the state’s total energy needs. Put simply, Hydro Tasmania is no longer the only generator in town.  


But if 2016 taught us anything, it is the importance of having the five units at the Tamar Valley Power Station as a backup if required. This will not change, but the station is not expected to run for energy security or commercial reasons in the foreseeable future. 


Any discussion of energy storages has to include climate change. Hydro Tasmania has been investing in understanding the impacts of climate change on our systems for more than 15 years and we continue to do so. This enhances our ability to plan for the future. 


Looking ahead, the development of more wind generation and the construction of Marinus Link will further improve our energy security, and mean that Tasmania can assist the rest of Australia with its clean energy transition.  


And as this transition continues, Tasmanians can be confident that our energy security position is strong.


This article was originally printed in the Mercury on Tuesday 23 November 2021

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