A dimensionless index evaluating the time complementarity between solar and hydraulic energies

Abstract

The power plants based on renewable sources face various acceptance difficulties mainly due to high initial costs and low overall efficiencies. A way to improve performance of these systems is to utilize more than one type of source of energy chosen to provide some degree of complementarity. An interesting, albeit improbable, combination is obtained using hydroelectric and photovoltaic energy, taking advantage of the complementarity between these two types of sources coupled to reservoir and/or battery storage. This paper discusses energy complementarity in time and proposes a numerical dimensionless index, evaluating this energy complementarity between two types of energy sources, in the same or in different locations, or between two sources of the same type in different locations. In the end, the results of the application of this index to the solar and water availabilities over the state of Rio Grande do Sul, in southern Brazil, is presented in the form of maps. r

Complementarity Maps of Wind and Solar Energy Resources for Rio Grande do Sul, Brazil

“…According to Beluco et al [1], the index i a was created to account for the difference between maximum and minimum energy availability of the sources in the complementarity evaluation. One energy source cannot be considered for complementarity purposes if it has no available energy during the period of interest.…”

“…Beluco et al [1] explain that Time-related complementarity is used to evaluate the time interval between the minimum availability of the two energy sources. If this interval is exactly half the period, the index will equal to one.…”

“…However, if two or more energy sources exist in the same region, and in significant quantities, this might well justify their complementary use in a hybrid power system. Referring to energy sources, Beluco et al [1] defined the term complementarity as the capacity of two (or more) energy sources to present a complementary availability between them. This complementarity may take place in time, in space or both, and it may occur between similar or different types of energy sources.…”

“…The present work uses an approach similar to that of Beluco et al [1], but estimating complementarity between solar and wind energy, instead of solar and hydro. Based on existing data of solar radiation and wind speed, complementarity indices between these two energy sources were calculated and represented in the form of maps for the state of Rio Grande do Sul, in southern Brazil.…”

Editorial Special Issue on “Energetic Complementarity”

“…The paper of Pianezzola, Krenzingerand Canales makes a fairly complete assessment of the complementarity between wind and solar energy along the territory of the State of Rio Grande do Sul, the southernmost State of Brazil, making small adjustments in the concept of complementarity presented by Beluco et al [2]. The paper of Bagatini, Benevit, Beluco and Risso compares the wind and solar resources as well as the water resource, also for the State of Rio Grande do Sul, evaluating only the complementarity in time.…”