There is a global effort to integrate renewable energy sources (RES) into the energy balance, setting out to develop a more sustainable future. The dependence of RES on natural phenomena and their low reliability can be mitigated by hybrid renewable energy systems (HRES). In this paper, an evaluation of an under-study HRES in Leros, Greece, is carried out in order to examine the economic viability of the project and its contribution to sustainability. Two scenarios are being examined, according

more »

... to the eligible grant. In the first case, the project receives a 40% State subsidy in contrast to the second, which receives a 60% funding from the Innovation Fund 2020 (IF). The main difference, between these two scenarios, is the size of the loan taken, whereas in the IF scenario it is 20% less than the first one. Several results can be obtained by this study, as follows: i) in both cases, the project is considered profitable for water and energy selling prices, 91.7% and 67% lower than the current ones respectively. ii) in the case of IF scenario, the same internal rate of return (IRR) index is achieved, with 0.15 €/m 3 less compared to the price in the case of State subsidy.