The Gorona del Viento project was characterized in this article, concerning its implementation, as well as several years of exploitation in an isolated location, namely on the El Hierro island. The hybrid system includes a wind farm and a pumped storage power plant, which acts as an energy storage, and all are equipped with a control system. The planned strategy assumed a configuration based on 100% wind energy supply. However, the system does not guarantee the anticipated effectiveness. The problems with the lack of energy self-sufficiency are partly the result of changes in the project made already during construction, in particular because of the mismatch of the water reservoir's capacity and the wind turbines' energy production efficiency. This results in the necessity to limit the wind farm capacity to ensure grid stability and hence requires supplementation of energy from the diesel generator. The author compared the object to analogical ones which employ different technological solutions and presented potential suggestions as to improve the existing state and achieve the reliability of the system's operation.Reference [7] assessed the isolated electricity network and goals proposed in the Canary Islands energy plan (PECAN), taking into account the average cost and risk associated with different alternatives to electricity generation. In order to increase efficiency (even by 30%), authors additionally suggest the use of natural gas. Current and future (until 2050) action plan in this area was presented in Reference [8]. Reference [9], on the other hand, presented the program of introducing RES in the Azores from 2007 to 2018. The smallest of the archipelago islands, Corvo, is planned to be powered exclusively from RES [4,9]. Reference [10] concerned the Greek islands of Crete, Kythnos, Ikaria, and Agios Efstrations. An interesting solution was applied on Ikaria (thermal, PV (photovoltaic), wind, and hydro with storage in two locations). The island of Agios Efstrations is planned to achieve 100% energy self-sufficiency only from RES. In Reference [11], the importance of assessing the technical and economic feasibility of isolated wind energy systems is emphasized.Because of the instability of the RES (the availability of their potential depends on many factors), a reserve conventional source and a storage are often introduced into the system [4].Reference [12] proposed a novel method of optimizing the efficiency of battery energy storage systems. Four optimal objective functions have been taken into account, such as minimum energy storage capacity, minimum load dump, the maximum lowest deflection frequency, and minimum disruption duration indicator.An overview of possible solutions for electricity storage is presented in References [13-18] including pumped hydro storage, flywheel, superconducting magnetic energy storage (SMES), supercapacitors, battery energy storage system (BESS), pumped heat electrical storage (PHES), and compressed air energy storage (CAES), whereas in References [13,14,[16][17][18], the ...