Page - 202 - in Book of Full Papers - Symposium Hydro Engineering

Fig. 2 NEM generation mix, 2020, 2030, 2050 [3] While moving towards a low carbon future, the challenge is the energy ‘trilemma’ of security, equity (accessibility and affordability) and environmental sustainability. These three factors need to be in balance to ensure a secure power sector that meets the present and future needs of energy consumers while moving towards a lower carbon future. 2.1. THE NEED FOR LARGE-SCALE STORAGE The rapid growth of renewable energy generation has been driven by two concurrent factors: the falling levelised cost of the energy produced by wind and solar, and the retirement of a number of coal-fired power stations. The recently released Finkel Review [3] notes that by 2035, approximately 68 per cent of the current fleet of Australian coal-generating plants will have reached 50 years of age. Renewables cannot, on their own, meet the fluctuations in demand that occur throughout the day without some regulation as to when power reaches the grid. Power needs to be dispatchable, which means that energy can be provided upon request. If the sun is not shining or the wind is not blowing, renewable 202