General GNX News, page-435

Hi jezyh et al,

This ARENA presentation (Dec 2018) says fixed speed turbines have been selected for Kidston.

7. What factors should be considered in choosing between fixed speed vs. variable speed turbines and what are the relative advantages between the two alternatives?

- 2 x 125MW fixed-speed reversible turbines have been selected for K2-Hydro. This was selected due to the lower cost (compared to variable speed), greater operational simplicity and the ability to provide ‘real inertia’ (rather than ‘synthetic inertia’) into the grid.

- A variable speed turbine can offer greater operational flexibility, with the ability to ramp up and down during both the generation and pumping cycle. Variable speed turbines also have faster response times from both a cold-start and from the transition between generation and pumping mode. Therefore, variable speed turbines have a higher purchase cost compared to fixed-speed turbines.

https://arena.gov.au/assets/2017/02/kidston-pumped-storage-hydro-project.pdf

Has this decision been overtaken by later developments?

Not being difficult, just curious, To my batty pro-battery thinking, a small-big battery at Kidston could absorb variable current and discharge smoothly to one or both turbines as desired, saving the cost and complexity of variable speed turbines.

Ash