A Hydropower Renaissance?

For decades, hydropower plants were mainly built and operated as a cost-efficient source of clean electricity. But despite more than a century of development, there is still scope for expanding generation from hydropower. Today, in line with Europe’s energy and climate goals, the role of hydropower looks set to gradually evolve into support for a future power system based on a mix of low-carbon technologies, including hydro.

Hydropower provides around 50% of the total renewable electricity generation in Europe today, representing approximately 200 GW of installed capacity. Moreover, there is still significant hydropower potential to be optimized and further developed in Europe (in energy over 650 TWh a year). Hydropower offers very high efficiency rates (between 85% and 95%) and, cumulatively, it supplies almost 18% of total electricity consumption in the EU-28, Norway, Switzerland, and Turkey. It also represents the only large-scale storage technology available, offering a host of benefits for the electricity system and beyond.

Hydropower: Backbone of a Reliable Renewable Electricity System

By providing the necessary flexibility and storage capacity to ensure stability of the electric grid, hydropower supports the integration of increasing amounts of variable renewables like wind and solar.

Hydropower plants with reservoirs such as storage hydro or pumped storage power plants reduce dependency on the variability of the natural inflow and enable adjustments of power generation to variability in demand. They have very quick ramp possibilities and are able to start up and shut down in a few minutes. Due to their responsive and flexible nature, they have the ability to respond to short-term changes in the power system.

Pumped storage power plants, for example, can ramp up and down by more than 40% of the nominal output per minute. The Grand’Maison power station in France can ramp up as much as 1,800 MW in only 3 minutes. Meanwhile, German transmission system operators’ predicted maximum power ramps within 15 minutes range from –2 to +3 GW in 2020 and from –6 to +7 GW in 2050. Thus, storage combined with rapid ramping makes hydropower very flexible.

European hydropower plants provide a combined storage capacity of more than 220 TWh— equivalent to nearly 25 days of average European consumption. The storage capabilities of many hydropower plants make them an appropriate instrument for optimizing the use of variable renewable energy sources (RES) over shorter and longer periods. As a matter of fact, pump storage plants are the only form of electricity storage that is available on a large scale.

Hydropower also provides a number of ancillary services that are needed to ensure transmission system stability and security of supply. Moreover, during power system restoration, such as in the case of an extreme event such as a blackout, auxiliary loads of conventional thermal and nuclear power plants need an external power source, which can be provided quickly by hydropower.

A Role in Climate Change Mitigation and Adaptation

Hydropower contributes to climate change mitigation, as it has one of the lowest carbon footprints. How well Europe can adapt to a changing climate depends also on our ability to react to extreme weather events. Hydropower plants with storage capacity help us avoid flood disaster and provide water in dry seasons. Thus, hydropower can deliver on a broad spectrum of services, including irrigation, water supply, flood control, and recreation, all while being a key tool for water management.

Major Challenges But Great Potential

Europe’s electricity landscape is undergoing profound changes, linked to the aim of a more renewable and low-carbon energy sector. The EU has set ambitious goals to cut its greenhouse gas emissions by 80% below 1990 levels by 2050. The 2030 climate and energy framework sets a number of targets for 2030, including, among others, a 27% EU-wide target for RES energy consumption and an EU target of 40% GHG reduction compared to 1990 levels. In order to reach these targets, more variable renewables like wind and solar power are introduced into the system. As a consequence, power systems will not only have to follow varying electricity demand throughout the day but also adjust to an increasingly variable power intake.

Ensuring system stability and a continuous flow of electricity by balancing fluctuations in frequency and voltage will be the challenge of the future. Although details of the future electricity mix are unknown, wind and solar are likely to make up 50% of RES power generation in Europe by 2020.

Hydropower’s flexibility and storage capabilities make it a valuable instrument for dealing with the challenges of the European power system. However, to ensure cost-efficient decarbonization and security of supply, competition between different kinds of technologies is desired. Therefore, leading up to 2050, the key is to transition to a power system based on a mix of low-carbon, flexible, and reliable technologies.

More findings on the challenges of the power sector in Europe (including environmental challenges and market framework) and the corresponding policy measures required can be found in the EURELECTRIC report “Hydropower—Supporting a Power System in Transition” ( as well as in the “Macro-Economic Study on Hydropower” (, presented by a group of companies and associations representing the hydropower sector in Europe.

Hans ten Berge is secretary-general of EURELECTRIC (, the taking clomid at 44 sector association representing the common interests of the electricity industry at a pan-European level.


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