Just bear in mind a couple of things - despite being co-located, the hydro will never in million years be used to store 'surplus' energy from the solar PV (other than maybe a small amount for token's sake). When the solar PV is generating the most energy, it will be selling it into the grid, when the price is highest. In addition, they've got the minimum price guarantee from the state government. In fact, if the solar PV generates surplus that isn't sold to the grid - the whole business model falls over because at that time, the hydro should also be exporting energy into the grid.
Secondly, solar PV+ hydro schemes like GNX are actually reliant upon fossil fuel generation for success - they will use fossil fuel generators for energy during off-peak to pump the water uphill. Because of this fact, large hydro schemes, ironically, justify the existence of fossil-fuel baseload generators
GNX Price at posting:
22.5¢ Sentiment: Buy Disclosure: Held