Ms O’CONNOR – Minister, as you’re aware, both Tasmanian and Commonwealth government have prepared National Climate Risk Assessments and State Climate Risk Assessments. Tasmania is identified in the National Climate Risk Assessment as the state most prone to significant adverse impacts.
We have talked at the table here about what dry years Hydro has had. The modelling shows that the West Coast and the central plateau of Tasmania continue to dry over the course of the century. Are you able to give a sort of a broad picture of what Hydro Tasmania has done in terms of modelling of the climate impacts on its operation and what risks it’s identified.
Mr DUIGAN – Obviously Hydro’s business is predicated on understanding the weather and I know they have long-term modelling. I don’t have a level of detail with me here today I can provide to you. But again, I would make the point that Hydro will be here next week, and they will be able to provide those answers
Ms O’CONNOR – Have you seen the modelling of the climate impacts?
Mr DUIGAN – Yes, I have.
Ms O’CONNOR – What did they tell you?
Mr DUIGAN – It points to a gradual reduction, particularly on the West Coast over, I’m going to say I have seen a 50-year climate model?
Ms O’CONNOR – You might have seen something a bit longer because the climate futures work goes out to 2100 from memory.
Mr DUIGAN – Yes, I’m relying on my memory.
Ms O’CONNOR – Hydro Tasmania would have access to science that gives them a reasonably believable picture of the future.
Mr DUIGAN – What I would say and what I think is well accepted is a higher level of variability. In terms of dry years, wet years they would say that they’re modelling shows that above other certain outcomes.
Ms O’CONNOR – The long-term trends in the climate projections are of a drying of the West Coast.
Mr DUIGAN – Certainly, I think it’s hard to argue that we’re seeing anything other than that at the moment, and whether this is a cycle or whatever, I don’t know.
Ms O’CONNOR – And have you seen any assessments of the impacts of climate on the energy GBE’s infrastructure? I mean, you’d have seen pictures of power lines down, sort of flooding –
Mr DUIGAN – Yes, and certainly the last two years, last year more starkly, the August weather event where we had that sort of unusual circumstance of having a big wet and a blow and then having another one and then having another one in a compressed timeframe of the week, which really does test your infrastructure, because-
CHAIR – Tests your trees, too, if they fall over the infrastructure.
Mr DUIGAN – Tests your trees, yes, because the ground gets wet and then they have another blow and all of that sort of stuff. There is a great level of awareness – that was a storm that cost $20 million – it gets your attention and building reliance and resilience into our power delivery system is a work in progress.
Ms O’CONNOR – What’s the evidence of that, where you’re seeing investments being made in infrastructure to ruggedise them? Is there any actual work on the ground happening in that way?
Mr DUIGAN – Absolutely. An example that comes to my mind is if you think about some of those areas that have single long feeders like the Derwent Valley or the Peninsula or places like that, and you’re in highly vegetated corridors where- when a branch comes across the line, the power goes out, the system trips, needs to be reset, all of that – putting insulated lines. There is a new product where the the lines themselves are insulated, so when something falls or if they touch, it doesn’t trip the system.
And so, that builds a great deal of resiliency. It’s obviously more expensive, and again, like all things, there is this balance about how much do you spend to beef up the infrastructure and what are the cost implications for customers when your stated objective is to keep power prices as low as you can. There is a tension there. But TasNetworks certainly spends a lot of time and a lot of money going around clearing trees – not always to everyone’s satisfaction – to try and keep the network as resilient as it can be.
We haven’t seen those massive transmission impacts we saw in New South Wales not so long ago-
Ms O’CONNOR – But you’d have to plan for them, wouldn’t you?
Mr DUIGAN – I am not across the details of what that plan looks like and sure there would have been thought given to it. I won’t make anything up here on the spot, noting that TasNetworks will be here and able to speak to that next week. But we all need to understand that an event like that has serious implications.
Ms O’CONNOR – So you’re confident as minister that Hydro for example, but also TasNetworks, in their planning are aware of climate risk and making preparations for what science tells us is coming?
Mr DUIGAN – Certainly Hydro. As I say, it is a business predicated on understanding the weather. It is absolutely reliant on rain as its fuel. There is good reason for it to know and understand the weather and I know they do long-term projections. There is modelling; there is a range of inputs. So, yes.
And again, as I made the point to the Chair, Project Marinus is as much about giving us the ability to manage those storages and manage that energy security in a more certain way and places higher value on those storage elements.
Ms O’CONNOR – Can I ask, because we did ask the Treasurer yesterday and he referred us to you: Has there been hydrological modelling done by Hydro Tasmania on the impacts of Marinus Link? Financial modelling was done; was there hydrological modelling also done?
CHAIR – He actually referred that to Hydro Tasmania, with the minister there.
Mr DUIGAN – Yes. For the whole-of-state business case anyone –
Ms O’CONNOR – It’s about the physical viability of the project.
Mr DUIGAN – Sure, yes. It lets us export when we’re running – when we’re spilling in the dams and all those sorts of things. Do you know if there’s hydrological modelling?
Ms PINTO – My observation would be – I am making reference to advice from Hydro – that when undertaking – and the partners that they work with are the Bureau of Meteorology, CSIRO, and also the University of Tasmania. They dynamically – again I’m making reference to advice from Hydro. When they undertake modelling, they take into account what will occur over a shorter period, like a two-week, a three-month, and then a longer range –
Ms O’CONNOR – That’s not of much use in a climate context.
Ms PINTO – In undertaking that modelling, they consider what dynamics will change in the market. In doing that, they would consider in undertaking their modelling the impact of Marinus being available and the quantum of that in addition to Basslink and the scenarios that are associated with that. Through the sustainable yield figures they have, that will be considered as a part of that modelling. Those sustainable yields will consider climate impacts as well.
Ms O’CONNOR – Final question, just on this line of questioning, Chair. It’s not really clear to me from your answer, through you, minister, that Hydro Tasmania has done sort of a comprehensive hydrological modelling of the impact on the system.
Mr DUIGAN – I have got some lines here in regard to that. Scientific studies undertaken for Basslink, which presumably is the base case for –
Ms O’CONNOR – That was nearly 30 years ago. The science would be very different now.
Mr DUIGAN – Indeed. 20 years ago, 25 years ago. Anyway – showed only limited operational impacts across the system with changes mainly at Gordon and Poatina, so the big storages. Long-standing mitigation measures such as environmental flow rules and re‑regulated pond have been in place since June 2025 and are regularly reviewed. Existing safeguards will apply with the additional interconnection through Marinus Link. Hydro Tasmania manages water storage is prudently and in accordance with the energy security risk framework.
For members who are unfamiliar with the energy risk framework, it’s a really interesting piece of work. You would have been in the thick of it in 2016-17, whenever it was, when we had the Basslink outages and the million litres of diesel a day and all those sorts of things. Since that, there have been great learnings about managing our storages and putting in very clear protocols for what to do in the event of certain things happening. If you enter into what’s known as the prudent storage level – and we got close to that in late July, probably early August before it started to rain. We were getting close to the prudent storage level, and that triggers certain things. Then if you go through the prudent storage level, you enter what’s known as the higher-reliability level. That basically means there’s enough energy and storage to survive a six-month outage on Basslink and basically zero inflows. Then –
Ms O’CONNOR – Then you fire up the gas, don’t you?
CHAIR – That gas would be fired up before then, I reckon.
Ms O’CONNOR – That’s right.
Mr DUIGAN – We run the gas in the last two years.
Ms O’CONNOR – Can I get some information from you? Is it possible? About the gas costs to the state over the couple of years?
Mr DUIGAN – Again, Hydro will be very tooled up.
CHAIR – So we will take that on notice – the cost of gas to generate energy for the state. Is that what you’re agreeing to? I’m just being clear what you’re agreeing to.
Mr DUIGAN – Again, I know that Hydro will just come to the table with that sort of information next week if you’re content to wait from –
Ms O’CONNOR – I just thought you might be across something like that.
Mr DUIGAN – It reflects on Hydro’s profit, absolutely. It’s expensive.
Ms O’CONNOR – Yeah, it’s a dirty fossil fuel.
Mr DUIGAN – Yep, but the lights stayed on, and I think a lot of people in their homes would be surprised to hear that the last two years are the driest two years on record for Hydro Tasmania because there weren’t any problems –
CHAIR – Depends where the rain falls.
Ms O’CONNOR – Any disruption.
Mr DUIGAN – Any disruption. As minister, I’m always happy to err on the side of caution. If there is advice that it might be a good idea to think about getting some gas if it doesn’t rain, then we will get some gas.
