This report provides information regarding Hydro Tasmania’s Battery of the Nation (BotN) strategic initiative to investigate and map out future development opportunities for Tasmania to make a bigger contribution to a future National Electricity Market (NEM).
Report extract
The purpose of Hydro Tasmania’s Battery of the Nation (BotN) strategic initiative is to investigate and map out future development opportunities for Tasmania to make a bigger contribution to a future National Electricity Market (NEM). Gordon Power Station in south-western Tasmania must maintain a minimum environmental flow release of 10 m3/s from December to May (summer-autumn) and 20 m3/s from June to November (winter-spring). This flow is mandatory under Hydro Tasmania’s water license to ensure minimal impact on the ecology of the Gordon River.
When the station is not required for generation, environmental flows must still be maintained by running one of the station’s large 144 MW units in a very low load range of 15-30 MW. This mode of operation historically occurs for around 30% of the time in summer-autumn and 50% of the time in winter-spring.
This means of providing the environmental flow is inefficient due to the poor efficiency of large Francis type hydro turbines in this low load range. A new smaller generator, sized appropriately for these flows, would be much more efficient and produce approximately double the energy output for the same flow.