Artificial Water Inflow Created by Solar Energy for Continuous Green Energy Production

Abstract

This paper presents the artificial water inflow created by the photovoltaic (PV) or solar thermal (ST) generator which pumps it into the upper water/energy storage of pump storage hydroelectric (PSH) for continuous green energy production. Formulas have been derived for the calculation of artificial water inflow created by the PV and ST generator, as well as the general formula for calculating the artificial water inflow created by solar energy and formulas for calculating the corresponding energy, all in order to assess the site location suitability for solar hydro system applications. In order to verify the obtained formulas, two sites were observed at typical climate areas, i.e. Mediterranean (Vis, 1575 kWh/m2y) and Continental (Osijek, 1262 kWh/m2y) climate of Croatia, and as expected, the PV generator provides more stable time series in both climates than the ST generator that creates high energy dissipation and therefore less reliable energy production, particularly in the areas with Continental climate. Compatibility analysis of natural and artificial water inflows, with the use of a small water reservoir, showed that the PV-PSH system can ensure a continuous supply of energy throughout the whole year, while winter energy shortages in the ST-PSH system can be solved by using a larger reservoir. The obtained results show that the integrated solar-hydro system is efficient and desirable in terms of achieving goals related to the increase of green energy production.