Theoretical settings of photovoltaic-hydro energy system for sustainable energy production

Since the main problem of continuous energy supply from photovoltaic (PV) power plant is intermittence and inability to provide continuous energy supply, this paper proposes its hybridization with hydro energy, or with pump storage hydroelectric (PSH) as a possible solution. This creates a new type of sustainable hybrid power plant which can work continuously, using solar energy as primary energy source and water for energy storage. The characteristics of the solution as an open thermodynamic system are presented, as well as the basic theoretical settings for its application, i.e. key relationships between power and collector field area of PV power plant and working volume of upper storage. The paper introduces hydrological and hydro-energetic indicators for the hybrid plant description, "artificial rainfall", as the relationship between the water pumped into the upper water storage of the PSH (artificial water inflow) and collector field area of the PV power plant, as well as hydroenergy potential. The proposed hybrid electric power plant does not emit greenhouse gases, produce waste or significantly exploit water resources while the risks to humans and the environment are far smaller than when using conventional technology. This solution is flexible for implementation and can be applied in various climates, hydrological and physical conditions. It is especially productive in cases of joint use of solar and hydro energy where they naturally complement each other as natural energy sources in the annual working cycle. (C) 2012 Elsevier Ltd. All rights reserved.