The financial model for solar or wind power stations such as Kidston Stage 1 is typically to arrange long-term power purchase agreements prior to construction in order to gain financing from risk-averse banks.
Where dispatchable power storage (battery or PHES) is included, the economic model is dramatically different - revenue will be obtained by selling power during periods of shortage when prices are high, rather than being backed by long-term PPAs. This may make such projects less palatable to the same risk-averse banks, so there will be some challenges for GENEX management to get funding, and it may well involve multiple sources of funds (e.g. debt and equity), but may also include a PPA covering part of the Stage 2 solar if not required to re-charge the Pumped Hydro.
The following report on the feasibility study for the proposed Cultana PHES project in SA. Section 5 discusses the financial and market considerations around the Cultana PHES, and are thus directly relevant to Kidston Stage 2 (although Kidston Stage 2 obviously has the additional consideration of a large solar power plant as well).
