The exploitation of an increasing share of electricity from renewable sources is leading to the exit from the market of fossil-fueled thermoelectric plants, starting from the oldest ones. Furthermore, due to the fluctuations introduced into the grid by non-programmable renewable energy sources, the grid operator requires even more flexible balancing resources, which only some kinds of conventional plants are able to provide.

In this context, the Pumped Hydropower and other storage technologies such as batteries and flywheels could provide valuable resources. In this seminar different flavors of the matter are portrayed with reference to some recent results of the Italian Public Energy System Research and other international experiences (UniPD - DII, RSE and UPM).

A hybrid pumped hydropower dynamic model with batteries, flywheel and refined controllers to supply flexibility services will be presented. The effectiveness of different configurations, from the pumped system alone to the integrated system, is evaluated, also in terms of wear and aging (loss of useful life), for the case study of the potential Seawater Pumped hydro in Foxi Murdegu (Sardinia-Italy).

To make this type of innovative storage systems economically feasible and viable, new rules are needed in the frame of the ancillary services market: the current evolution in Italy will be illustrated with reference to the ongoing pilot projects.