Abstract
Energy Storage Systems (ESSs) will play a crucial role in the future energy scenario since they can provide different services such as decoupling the energy production from its usage. If ESSs are coupled with a variable Renewable Energy Source (RES), they can also enable the possibility of achieving a self-sufficient energy consumption on-site, as the case of a small-scale Local Energy Community (LEC) working completely off-grid and avoid the carbon emissions related to the energy withdrawn from the national grid. Different ESSs technologies are currently available, and these technologies store energy in different forms. The choice of the ESSs technology and its rated capacity are highly dependent on their compatibility with the technical requirements of the end-use application. This work aims at identifying, through a model-based technical point of view, using Calliope, an open-source modelling framework, the ESSs configurations to meet a LEC demand with fully decarbonised electricity by analysing hydrogen or Li-ion battery storage solutions coupled with a 220-kW small-scale hydropower plant in the centre of Italy, which shows a highly variable output power profile throughout the year. Results show that for a small-scale LEC annual electricity demand with only a generation source from the hydropower plant, the hydrogen solution could be successfully adopted with 137 kW electrolyser, 41 kW fuel cell, and 5247 kgH2 of hydrogen storage, whereas the battery must have 280 MWh capacity. Although the battery has higher round-trip efficiency, it requires huge economical investment, because of the significant Energy-to-Power ratio (i.e. over 1400) of the specific storage application, for which indeed decoupling the energy and power aspects has an enormous benefit.