Applying an Exponentially Weighted Moving Average control chart using flow history and assured energy levels to small hydroelectric power plants

Bruna Tayla Cabral De Vasconcellos,Geraldo Lúcio Tiago Filho,Benedito Donizeti Bonatto,Oswaldo Honorato De Souza Junior

doi:10.1590/2318-0331.252020190159

Bruna Tayla Cabral De Vasconcellos, Geraldo Lúcio Tiago Filho + Show 2 more

Open Access

https://doi.org/10.1590/2318-0331.252020190159

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Journal: RBRH	Publication Date: Jan 1, 2020
Citations: 1	License type: CC BY 4.0

Affiliation: Federal University of Itajubá

Abstract

ABSTRACT Small hydroelectric power plants make up 6 GW of installed capacity in Brazil. However, electricity generation at the plants has been below their expected Assured Energy Levels (AELs) recently. This paper analyzes the flow history of 24 plants using exponential moving average control charts in an attempt to verify whether climate change or land use and occupation could have changed the average annual flow available in the basin over time. The graphs showed neither a decreasing or increasing trend in average flows, but rather showed a recurring number of out-of-control points, which proves the sensitivity of assured energy to hydrological variations and the need to evaluate the use of daily average flow rates for calculating and analyzing the energy generated by small power plants.

Highlights

Brazil is a country in which 65% of the electricity matrix is composed of hydroelectric power plants (Agência Nacional de Energia Elétrica, 2018)
It is estimated that 23% of the small power plants in operation in Brazil were built more than 30 years ago (Agência Nacional de Energia Elétrica, 2018)
This study uses an Exponentially Weighted Moving Average chart (EWMA) to perform an analysis on the flow history of 24 small power plants that did not consistently generate electricity in accordance with their respective Assured Energy Levels (AELs), in order to identify if there were changes in the available flow, and to determine whether the current debate on the methodology for calculating AELs should be directed to the method itself or to the changes in the hydrological cycle

Summary

Introduction

Brazil is a country in which 65% of the electricity matrix is composed of hydroelectric power plants (Agência Nacional de Energia Elétrica, 2018). Applying an Exponentially Weighted Moving Average control chart using flow history and assured energy levels to small hydroelectric power plants

Results

Conclusion