In this paper hydrogen generation from large size renewable power plants such as the ITAIPU hydraulic plant (14 GW power) in South America is investigated using an original thermo-economic approach developed by the Authors. The choice of Itaipu plant is related to the international agreement between “Parque Technologico de Itaipu” (PTI), Asuncion, Paraguay and “Sistemi Intelligenti Integrati” (SIIT) district based in Genoa, Italy.In this analysis, only the hydraulic energy related to water which is not normally used by the plant named “spilled water”, and the particular electricity load profile during the different periods of the year (and of the day), are taken into account. In this way, the hydrogen generation does not affect the standard electricity production and consumption in Paraguay and Brazil, and it may be a very useful way to recover the otherwise lost hydraulic energy.The analysed system consists of the hydrogen generation plant based on classical water electrolysers fed with “spilled water electricity”, the H2 storage system and H2 utilization sections. Since the spilled water power referred to H2 generation is in the “hundreds MW range” the definition of the optimal size of the plant, related capital costs, and optimal management is the key point of the problem. Therefore, different aspects of the problem have been carefully investigated such as: (i) atmospheric vs. pressurized electrolysers utilization; (ii) time dependent available hydraulic energy profile; (iii) time dependent H2 generation and storage plant optimum plant size and management; (iv) H2 consumption profile for differentapplications.The results of a preliminary investigation based on available data at PTI and the use of the original thermo-economic method are presented and discussed. It is worthy to note that the results for this particular H2 application also represent a general value, since the method is applicable for different size, primary energy, location plants, and different utilization of H2.
