Modelling Methodologies to Design and Control Renewables and Hydrogen-Based Telecom Towers Power Supply Systems

Proton exchange membrane fuel cell (PEMFCS) and electrolyser (PEMELS) systems, together with a hydrogen storage tank (HST), are suitable to be integrated with renewable microgrids to cover intermittency and fully exploit the excess of electrical energy. Such an integration perfectly fits telecom tower power supply needs, both in off-grid and grid-connected sites. In this framework, a model-based tool enabling both optimal sizing and proper year-through energy management of both the above applications is proposed. Respectively, the islanded optimisation is performed considering two economic indices, i.e., simple payback (SPB) and levelised cost of energy (LCOE), together with two strategies of hydrogen tank management, charge sustaining and depleting, and also accounting for the impact of grid extension distance. On the other hand, the grid connection is addressed through the dynamic programming method, while downsizing PEMELS and HST sizes to improve techno-economic effectiveness, thanks to grid contribution towards renewables curtailment issues mitigation. For both the above introduced HST management strategies, a reduction of more than 70% of the nominal PEMELS power and 90% of the HST size, which will in turn lead to SPB and LCOE being reduced by 80% and 60% in comparison to the islanded case, respectively, is achieved. Furthermore, the charge depleting strategy, relying on possible hydrogen purchase, interestingly provides an SPB and LCOE of 9% and 7% lower than the charge sustaining one.