In the quest for a sustainable energy future, researchers from the Australian National University, led by Timothy Weber, have presented a compelling case for replacing fossil gas with low-cost, abundant long-duration pumped hydro energy storage in electricity systems. Their work challenges the notion that fossil gas is a necessary enabler for variable solar and wind generation beyond 2050.
The research, published in the journal Applied Energy, highlights that balancing solar and wind generation with pumped hydro energy storage can eliminate the need for fossil gas without incurring additional costs. The study critiques existing long-term electricity system plans that often rely on fossil gas due to outdated modeling methods. These methods either heavily constrain storage cycling behavior or lose track of the state-of-charge, failing to consider the potential of low-cost, long-duration off-river pumped hydro.
The researchers developed a new electricity system model that rapidly evaluates millions of near-optimal solutions. They found that a temporal aggregation method based on ‘segmentation’ closely resembles full-series optimization, capturing long-duration storage behavior (48- and 160-hour durations) and identifying near-optimal 100% renewable electricity solutions. The study emphasizes the importance of modeling pumped hydro sites with a low energy volume cost (