Alternative Uses of Hydroelectric Power Plants in a Decarbonized Energy Scenario

Drastic reduction of greenhouse gases emissions depends, among other factors, on a quick and efficient integration of renewable sources in the energy generation pool. In this context, hydropower nowadays represents the biggest share of the world renewable energy generation. However, in the case of European Union, many hydropower plants are about to reach their end-of-life stage and environmental regulations on the recovery of natural water flows require these plants to be dismantled. In the controversial scenario where the need to recover natural waterflows and the loss of a key source of green energy clash with each other, the objective of this work is to provide an exhaustive review of the different auxiliary services that hydropower plants can provide in the current and especially future decarbonized electricity paradigm. To this end, services such as participation in secondary and tertiary regulation markets, power purchase agreements, local energy communities, reduction of curtailments, renewable energy storage or contribution to physical inertia to the grid are analyzed and final conclusions are drawn.