Reimagining the Tarraleah hydropower scheme

Client: Hydro Tasmania
Location: Tarraleah, Tasmania, Australia
Date: May 2018 – ongoing

Exploring the potential redevelopment of an ageing hydropower scheme to better meet the needs of the future electricity market

Background

Tasmania’s iconic Tarraleah hydropower scheme was constructed in the late 1930s in the Central Highlands and is one of Hydro Tasmania’s oldest hydropower schemes. Located in the headwaters of the Derwent and Nive catchments, it is an important asset, regulating flows to the Derwent system of dams and hydropower stations as well as water supply to Hobart. 

With the support of the Australian Renewable Energy Agency (ARENA), a feasibility study assessed options for reimagining the Tarraleah scheme to deliver more renewable power with more flexibility in the future.   

This project forms part of Hydro Tasmania’s Battery of the Nation initiative to support the transition of the Australian electricity market to more wind and solar generation, which will require dispatchable renewables such as hydropower to smooth supply and provide vital grid support services. 

The feasibility study was completed in 2021 and followed a pre-feasibility study conducted in 2017–18, also co-funded by ARENA. 

In April 2022, the federal government announced a funding commitment of up to $65 million for the Tarraleah hydropower scheme, which will bring the exciting vision for its future one step closer.  
 
Together with investment from Hydro Tasmania, this represents a ~$123 million investment, with work progressing on assessing the commercial viability of scheme redevelopment and enabling a staged program of upgrade works that provide flexibility for the scheme's future. 

Solution

Entura was involved in the feasibility stages of the project and is continuing to play a key role in Hydro Tasmania’s integrated owner’s team, developing an appropriate technical solution for a potential future scheme redevelopment. We are contributing our expertise to help develop a sound understanding of project risks, costs, future revenue, operational flexibility, schedule and possible procurement methods. We are also contributing to the efforts to build broad stakeholder support.  

In parallel, Entura is delivering detailed designs for components of an upgrade works program, including a new water intake and connecting tunnel at Lake King William to meet up with a future new water conveyance. 

Outcome

As part of the project team, Entura is helping to develop a general arrangement solution for a reimagined Tarraleah that can be constructed with minimal operational impacts on the existing scheme, minimises environmental impacts, best manages surface and underground geotechnical risks, and has manageable project risk. 

A number of Entura specialists are fulfilling important leadership roles in the project. As well as providing detailed designs to support the upgrade works program, Entura will play a key role in work currently underway to assess the commercial viability of redevelopment and reach a Final Investment Decision (FID).