Optimal design of micro pumped-storage plants in the heart of a city

Growth in renewable energy generation leads to an urgent need of expanding energy storage capacity. While large pumped hydro storage remains the most established and prevalent energy storage method, there is potential for evaluating its applicability on a micro scale in urban areas. This study develops a multi-objective optimisation model in Python to assess the feasibility of micro pumped-storage (MPS) for high-rise buildings up to 300 m in height, considering different future energy market conditions. The findings indicate that increasing electricity tariff values lead to improved solutions from both environmental and financial perspectives across all building heights. However, for buildings 50 m or less, the MPS is currently considered economically unviable. In a world first, this study examines the techno-economic viability of MPS systems as a function of building height and different water storage types, including modular tanks, multilayer green roofs, blue roofs, and nearby streams. The MPS system using modular tanks and nearby streams boasts the shortest payback period (4.8 years) and Net Present Value of A$ 600 k over the MPS lifetime. The study provides insights into feasible flow rates and storage sizes. The findings are valuable for designers, helping them decide if MPS is feasible based on the building's height and features.