Among the issues that are most relevant in the study of climate changes (CC), the effects on hydropower play a double role. On one hand, hydropower plants will be affected by a change in water availability. On the other hand, as the present major source of renewable energy, it is useful to support and increase the production in order to reduce the human induced CC.C The aim of the activity presented in the article is the impact evaluation of expected CC on future reservoir control, in order to assess the variations in hydropower production and to identify the possible changes in water management. This activity is part of ACQWA project, a EU FP7 large scale integration project whose aim is the use of advanced modelling techniques to quantify the influence of CC on the major determinants of river discharge and analyse their impact on society and economy. The present activity has been focused on the development of a model of the management of a complex hydropower system network as a function of climate conditions and power prices. The methodology has been applied to a case study, the hydropower plants in Valle d’Aosta Region in Italy. A conceptual scheme of the network of plants and reservoirs has been developed and its optimal management has been computed by means of a simple optimisation tool, using energy prices and inflows as the main drivers of the system. The expected variations in reservoir management and power production has been quantified through a comparison between optimisation results of present and future years, considering different climatic scenarios and electricity prices guesses. Results show a statistically significant decrease in overall hydropower production; they give indications of variations in monthly production and a shift in the peaks timing of future yearly production; moreover, results show an increase in water deficits and, as a consequence, in possible water conflicts.