The SMARTWATER project generated some investigation tools to assess the feasibility of the rehabilitation of end-of-life quarries and mines into medium-sized Pump Hydro Energy Storage (PHES) units. The project implemented a holistic approach encompassing legal, environmental, economic, hydraulic, electro-mechanical, and geological aspects. The reservoir capacity and hydraulic head of most of the sites under consideration are around a few hundreds of thousand cubic meters and a few dozen meters respectively. Economic feasibility included assessment of the cost reduction opportunities offered by such site configurations (widespread in Wallonia region) and the exploration of innovative multi-service (DSO and TSO) exploitation strategies in the context of an increasing intermittent production.

Finally, the project has developed a demonstration plant, in Froyennes (Belgium), implementing a first-of-its-kind PHES micro facility integrated into an autonomous network comprising photovoltaic production sources and micro wind turbines. Interestingly, this micro-PHES runs with a single centrifugal pump for both pumping and generating phases. Variable speed regulation allows the pump to constantly operate at the maximum hydraulic efficiency in order to deal with load variations.

Principal potential case type exploitable in Wallonia: a) coal mine, b) slate quarry, c) open-air quarry

Upper reservoir of the demonstrator micro PHES plant