When it rains, it pours: Managing a complex energy network that depends on the weather

26 September 2024



This article was written by Vedran Kovac, Executive GM of Commercial at Hydro Tasmania

 

We keep a very close eye on the weather here at Hydro Tasmania. As Australia’s largest generator of renewable energy, rain = energy = profit. And because we return 90 per cent of our profits to the State Government, it also means better healthcare, housing, and education for Tasmanians. 

 

So, it’s incumbent upon us to make the most of whatever the weather throws at us. 

 

This year alone, it’s thrown us drought, fire, floods and even lightning strikes. Coordinating generation across our network of 30 power stations and 54 major dams has been an intricate dance. Fortunately, we have some of the world’s best people working on the system. 

 

The year of wild weather kicked off in February with fire in the Upper Derwent region. The blaze encircled Lake Echo Power Station and damaged the headworks. Thanks to comprehensive bushfire preparation, including backburning, the flames licked the edges of the power station but went no further and we avoided extensive damage. 

 

We were able to bring it back online with some nifty engineering and kept the water flowing down the Derwent. 

 

 

Lake Echo Power Station and surrounds.

 

While the fire presented significant immediate danger, the drought has been a slow burn that dealt us the biggest challenge of the year. 

 

The 2023-24 financial year was the driest in 90 years. Not great for a company that relies on the rain. We increased energy imports over Basslink and fired up our Tamar Valley Gas Power Station as pre-emptive measures to save water. 

 

We coordinated power station upgrades and maintenance, shuffling the schedule and prioritising resources so we kept sufficient generating capacity online without drawing too much water from dams that were already getting low. 

 

It’s not just power generation we need to think about. We’re also juggling potential impacts on threatened species, water for irrigators and flows for recreational users. To add to the complexity, our Tamar Valley Power Station was struck by lightning, damaging the smaller open cycle gas units. 

 

As a business leader, I was incredibly proud of the professionalism, skill, and collaboration right across the organisation. We identified potential problems and took mitigation action early. We were conservative in our modelling, and we planned for the worst-case scenarios. 

 

Lake Barrington spilling over Devils Gate Dam, in Tasmania's North-West

 

The results speak for themselves. Despite the complex and difficult circumstances, we kept the lights on and maintained water storages well above the high reliability level set by the Energy Security Framework. We still returned a healthy profit over the 2023/24 financial year and will deliver dividends back to Tasmanians. 

 

Just a couple of months into the new financial year, and we’re faced with an entirely different set of circumstances. In late August, we were hit with flooding, heavy rains, and strong winds.

 

Our field staff were out in force, working in very difficult conditions to keep power stations operational, clear roads and assist emergency services. As always, the safety of our staff and local communities were the top priorities.

 

After many months of disappointing inflows, we received several weeks’ worth in just a few days. But many of our systems are ‘run of river’ meaning they fill quickly during heavy rain and eventually flow out to sea. By the first week of September, many of our dams were ‘on spill’, with water flowing over the top of the dam wall through specially designed spillways. 

 

Once again, the expertise of our generation controllers came to the fore. They operate our power stations, choosing which to run so we can in respond swiftly to fluctuations in supply and demand.

 

The silver lining of the storms has been a significant increase in our water storages. We need to make the most of this weather because we don’t know what the future brings. We’ve shut down the gas power station – for now.  

 

If the last 12 months have taught us anything it’s to plan for the worst and expect everything to change. 

 

I want to send an enormous thanks to the many people across Hydro Tasmania and Entura who played their part: the maintenance assistants, electricians, technicians, controllers, engineers, analysts, planners, environmental scientists, co-ordinators, communicators and many more. Hats off to all of you. 

 

This article, written by Vedran Kovac, Executive GM of Commercial at Hydro Tasmania, first appeared in our Industry Newsletter. Sign up to receive the latest news straight to your inbox by clicking here! 

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