About Hydropower in Europe

General Importance & Advantages

Hydropower is Europe’s oldest and most reliable renewable energy source. In 2024, it accounted for nearly 30% of the EU’s renewable electricity generation, and around 13% of the total power mix.
Its greatest strength lies in its flexibility. Plants with reservoirs can store energy and release it when demand is high. They can ramp up or down within minutes. They can even restart a grid after a blackout. Few other technologies offer this range of services.
As Europe increases its share of wind and solar, the need for grid balancing grows. Hydropower is well suited to meet that need as it works alongside variable renewables, providing stability.

General Importance & Advantages

Photo: Electric Power of Serbia / „Elektroprivreda Srbije”

Key figures

30%

hydropower’s share of EU renewable electricity generation

13%

hydropower’s share of the EU’s total electricity mix

47.5%

renewable energy’s share of EU electricity consumption in 2024

263 GW

total hydropower installed capacity in the EU (2025)

614 TWh

annual electricity generated by EU hydropower plants (2025)*

* source: International Hydropower Association, Hydropower in Europe.

Current Challenges

Hydropower of course also has its trade-offs.

River ecosystems can be affected, with fish migration routes that can be blocked and natural flow patterns altered. Hydropeaking (sudden flow changes caused by rapid ramping) affects more than 800 km of European rivers. On top of that, around 28% of planned hydropower projects are located in protected areas. And even small plants that generate limited electricity can still cause significant disruption to biodiversity.

Social tensions are hence growing. Communities downstream experience abrupt water level changes that affect fishing, irrigation and recreation. Decision-making is often perceived as opaque and local voices are not always heard. Therefore, trust in operators remains low in some regions, even when plants are legally compliant with environmental regulations.

Operators also face competing policy demands. The Water Framework Directive requires good ecological status while the Renewable Energy Directive pushes for more flexibility and renewables integration. Navigating these requirements is therefore a growing challenge.

SE-Hydro is designed to address these tensions: by developing solutions that work for the grid, for rivers, and for the people who live alongside them.

Hydropower plant and technologies

There are three main types of hydropower plants onshore: run-of-river, storage and pumped storage. These technologies can often overlap. For example, storage projects can often involve an element of pumping to supplement the water that flows into the reservoir naturally, and run-of-river projects may provide some storage capability.

A facility that channels flowing water from a river through a canal or penstock to spin a turbine. Typically a run-of-river project will have little or no storage facility. Run-of-river provides a continuous supply of electricity (base load), with some flexibility of operation for daily fluctuations in demand through water flow that is regulated by the facility.

Most of SE-Hydro’s pilots are RoR plants and represent a diversity of run-of-river configurations found across Europe (Louros in Greece, Mizoen in France, Fratel in Portugal).

Typically a large system that uses a dam to store water in a reservoir. Electricity is produced by releasing water from the reservoir through a turbine, which activates a generator. Storage hydropower provides base load as well as the ability to be shut down and started up at short notice according the demands of the system (peak load). It can offer enough storage capacity to operate independently of the hydrological inflow for many weeks or even months. This typology is represented in SE-Hydro by the Limske HPP cascade in Serbia (EPS), where four reservoirs on the Uvac and Lim rivers allow generation to be coordinated with flood protection, agriculture and tourism needs across the basin.

Provides peak-load supply, harnessing water which is cycled between a lower and upper reservoir by pumps which use surplus energy from the system at times of low demand. When electricity demand is high, water is released back to the lower reservoir through turbines to produce electricity. None of the current SE-Hydro pilots operates as pumped storage.