Water footprint of the Sobradinho hydropower plant, Northeastern Brazil

Nayara Paula Andrade Vieira,Silvio Bueno Pereira,Eduardo De Oliveira Bueno,Carlos Rogério De Mello

doi:10.4136/ambi-agua.2134

Nayara Paula Andrade Vieira, Silvio Bueno Pereira + Show 2 more

Open Access

https://doi.org/10.4136/ambi-agua.2134

Copy DOI

Abstract

Hydroelectricity is responsible for the greatest fraction of the electric energy generated in Brazil. The water footprint of hydropower plants (WFP) is an important indicator of the sustainable and efficient use of water resources. In this context, WFP of the Sobradinho Hydropower Plant was determined for the period from 2003 to 2012, taking into account the reservoir’s historical variation for the flooded area. To accomplish this, monthly series of electric energy production, flooded area, evaporation and evapotranspiration rates were used. Average gross and net evaporation were 2,031 and 1,577 mm year-1, respectively. The average power generation of this facility in the analyzed period was 462 MW, and the flooded area of its reservoir presented an average value of 3,054 km². Based on the monthly data, the gross and net water footprints were, respectively, 417 and 325 m³ GJ-1. Based on these results, it can be concluded that the changes in the reservoir’s area exert direct and important influence on the WFP estimates of the Sobradinho hydropower plant. The WFP estimates in this study were different from other studies that adopted a constant value of 4,214 km² for this reservoir’s area, which is taken based on the normal water level of the plant operation.

Highlights

Hydroelectric power plants (HPPs) have accounted for up to 65% of electric energy production in Brazil
Mekonnen and Hoekstra (2011) classified WFP as: i) green water footprint (“green water”), which refers to the volume of rainwater consumed during the production process, being more relevant to agricultural and forestry products; ii) gray water footprint (“gray water”), that indicates the level of freshwater pollution associated with the production process; and iii) blue water footprint (“blue water”), that is related to the consumption of surface or underground freshwater
The objective of this study was to refine the water footprint characterization of the Sobradinho HPP using the historical variations of the flooded area of the reservoir, instead of the average value which has been considered in other studies

Summary

Introduction

Hydroelectric power plants (HPPs) have accounted for up to 65% of electric energy production in Brazil. The volume of water in the reservoirs lost by evaporation results in loss of electric energy generation in cascade hydropower plants, in addition to the negative impacts on the allocation of water resources. According to Hoekstra et al (2011), water footprint (WFP) is an indicator of the efficiency of the use of water resources, as it can quantify the total water consumption of a production chain. Mekonnen and Hoekstra (2011) classified WFP as: i) green water footprint (“green water”), which refers to the volume of rainwater consumed during the production process, being more relevant to agricultural and forestry products; ii) gray water footprint (“gray water”), that indicates the level of freshwater pollution associated with the production process; and iii) blue water footprint (“blue water”), that is related to the consumption of surface or underground freshwater. The WFP of HPPs is included in the last category

Objectives

Methods

Results

Conclusion