Hydropower Operation and Fish Conservation: Challenges of a Changing Energy Matrix

Brazil’s electricity matrix has long been dominated by hydropower. Recently, however, the rapid expansion of intermittent renewable sources, solar and wind, has reshaped the national energy landscape. In 2024, these sources accounted for 91.13% of the country’s electricity expansion, now representing around 25% of total installed capacity. This transition has altered the role of hydropower, which increasingly operates as a balancing resource to compensate for the variability of solar and wind generation, leading to significant intraday variations in turbine discharge, especially during periods of low solar generation and high system load. Such altered flow regimes can affect aquatic ecosystems, especially fish populations. This study evaluates whether the increasing share of solar and wind…