Carina Belusa – ReHydro

News articlesOktober 13, 2025Oktober 13, 2025byCarina Belusa

Initial studies for retrofitting with pumped storage

The Ain River hydropower chain is one of France’s most strategically important systems for energy production and water resource management. It stretches approximately 60 km along the Ain River and includes six main installations. Among them are the Saut-Mortier reservoir and Vouglans dam.

Even before ReHydro, EDF has been working to modernize this hydropower system and enhance its flexibility. The focus is on transforming the Saut-Mortier reservoir into a pumped-storage hydropower facility capable of storing and releasing energy on demand. Additionally, the 40 km stretch of the downstream river is included in the impact assessment.

Now, the project team has begun the first phase of studies to support this transformation. Retrofitting the site with variable-speed reversible generating and pumping units will allow for better use of water, improved response to grid needs, and reduced environmental impacts, including lower hydropeaking intensity, better temperature regulation, and more controlled algae growth through managed water releases.

To support this work, EDF has been improving and testing detailed 1D and 3D models of the reservoir system. These models simulate how temperature and water flow interact under different operational scenarios. By consolidating them into a fully 3D digital twin, we now have a more accurate representation of spatial thermal processes and vertical stratification.

With the groundwork done, the follow-up goal is to qualify the “environmental sensitivity” of each reservoir, which describes their response to changes in weather, flow, and temperature. To support this, a semi-automated simulation tool has been created to test large sets of operational scenarios and connect multiple reservoirs within the system. The first flow-temperature scenario series for the entire reservoir chain is already in development.

These early studies lay the foundation for a smarter, more climate-resilient hydropower network. By linking ecological knowledge with flexible infrastructure, the Ain River system is becoming a model for modern river basin management under changing climate conditions.

You can read more about EDF’s long-term work on the Ain River in the publicly available paper “Initial studies for retrofitting pumped storage”.

News articlesSeptember 25, 2025September 25, 2025byCarina Belusa

Development of a new tool to assess hydropower’s environmental pressure

Hydropower plays a key role in Europe’s renewable energy future, but it also puts pressure on rivers and freshwater ecosystems. To help hydropower operators and decision-makers better understand these impacts, ReHydro is developing a practical tool that assesses environmental pressures across the entire life cycle of a hydropower project.

This new approach doesn’t replace ecological assessments, but complements them by integrating insights from multiple fields: environmental sciences, ecology, and life cycle analysis (LCA). The goal is to offer a more complete picture of a new project or refurbishment measures affect biodiversity, both locally and globally.

The tool is designed to be used for support in the early stages of planning, when decisions about design and operation are still flexible. It uses publicly available and/or easily accessible data to help compare options and guide eco-conscious choices. Local indicators, such as habitat changes, species pressures, or water quality, will be considered to see which best reflect ecological impact, even when data is limited.

Ultimately, the aim is to create a biodiversity footprint index that supports sustainable decision-making. For a more in-depth look at the first stage of the work done, the deliverable is publicly available here in our knowledge hub.

News articlesSeptember 24, 2025September 25, 2025byCarina Belusa

Mapping habitat conditions in Brattlandsdalsåa and Roalkvamsåa.

In late August, researchers from SINTEF headed into the stunning surroundings of Brattlandsdalsåa and Roalkvamsåa to assess their current habitat conditions. These rivers are part of Røldal-Suldal power system and currently receive only local runoff, as the main water flow is diverted for hydropower production. Together with our partners at Lyse, NINA, Intoto and INRAE, we are working to understand how much water is needed to support healthy habitat conditions and boost spawning opportunities for the local population of large trout. By investigating the local habitat conditions and comparing them with the trout’s known habitat preferences, we gain a quick and effective understanding of current conditions, and a clear idea of what changes could help improve them. This research is part of ReHydro’s broader goal: showing how sustainable hydropower refurbishment can also mean better outcomes for biodiversity.

We’re exploring two different approaches to restore flow in these rivers. In Roalkvamsåa, we’re looking at the option of releasing environmental flow from a small hydropower plant. While this may slightly reduce the total power production, the potential environmental gains are significant and could make the loss more than worth it. Meanwhile, in Brattlandsdalsåa, we’re evaluating the possibility of pumping water from the downstream lake Suldalsvatn back into the river to secure flow in key spawning areas in the most downstream part of the river.

In our efforts, we’re combining high-tech tools with tried-and-true field methods. We’re testing a simplistic habitat assessment method developed by our partner INRAE (France’s National Research Institute for Agriculture, Food and Environment), and using both remote sensing technologies and traditional hydraulic-habitat survey techniques.

News articlesSeptember 24, 2025September 25, 2025byCarina Belusa

Designing new turbines and a safer journey for the European eel

ReHydro’s main objective is to make hydropower more sustainable by retrofitting existing power plants with new technology. Part of that sustainability is the protection of biodiversity: one of our tasks is solely dedicated to the protection of the European eel. Once thriving in our rivers, this migratory species is now critically endangered. The eels begin their life cycle in the ocean, then make their way towards European freshwater rivers where they spend most of their lives before returning to the sea to spawn. Aside from predators, parasites and overfishing, hydropower facilities pose a risk to their health and survival as their journey often leads them through hydropower turbines.

To make their migration safer, ReHydro is working on the design of eel-friendly turbines that can significantly reduce eel mortality in large hydropower plants. These specially designed turbines will be optimized for a wide range of operating conditions and will retrofit existing Kaplan and bulb machines, starting with 15-meter head Kaplan turbines at our Belver demonstration site in Portugal.

A strategy has already been defined, supported by a detailed literature review conducted by our partners at GE Vernova with the support of EDP, EDF, CNR, and NINA, that pinpointed the laws and parameters most critical to eel survival. Based on our review, turbine design will be optimized to reduce collisions and mortality while not sacrificing its performances. A key part of this will involve model eels, designed to represent the average sizes of wild eels. These models will pass through model scaled turbine on GEV platform, with cameras recording their journey. A post-processing software will be adapted to detect any collisions with runner blade edges, and collect data on the turbine’s performance in relation to the model eels’ “survival”. Model testing at Belver will begin in spring 2026.

Once the design meets its safety targets at Belver, testing will expand to 20-25-meter head Kaplan and bulb turbines on-site at Bollène and Golfech in France.

Header image by the Freshwater and Marine Image Bank at the University of Washington.

News articlesJuli 16, 2025Juli 16, 2025byCarina Belusa

Second Consortium Meeting in Stavanger

From May 3^rd to 5^th, representatives from each ReHydro partner travelled to Stavanger, Norway, for our second Consortium Meeting. About 70 people attended the three days dedicated to our collaboration, knowledge sharing, and the progress of our efforts towards sustainable hydropower refurbishment. With our partner Lyse hosting us, this meeting offered a special highlight beyond presentations and roundtable discussions: An excursion to the beautiful Norwegian nature and the Røldal-Suldal hydropower system nestled within it

Our agenda was reasonably full. Across a total of seven work packages plus dissemination, exploitation, and communication, and our five main demonstration sites, partners shared insights into the progress they had made so far, as well as the challenges they had overcome and opportunities that lie ahead. From technological developments to societal impacts and environmental considerations, our discussions reflected the broad range of topics covered within ReHydro, and our collective ambition to drive it forward. With at least one representative from each partner present, we could use the opportunity to directly ask for input and ideas.

Our highlight was undoubtedly the excursion to the village of Nesflaten. For one day, we swapped microphones and power points for hiking boots and rain jackets as we ventured into the Norwegian mountains to visit the (former) control center of Røldal-Suldal Kraftverkenen. It consists of a total of 17 reservoirs and nine separate hydropower plants, producing an impressive 3,300 GWh annually. We got to enjoy a guided tour through different parts of the system, such as one of its reservoirs, and learned more about it: How it works, expansion plans for the future, and the positive impacts it has on the area- the latter of which we witnessed first-hand.

Reflecting on these three days, we can clearly say that the value of meetings like these really lies in the personal interactions, collaborations, and the opportunity to see the places we usually only talk about in person. We look forward to continuing this journey together, and to our next opportunity to meet, exchange ideas, and advance sustainable hydropower refurbishment.

News articlesApril 25, 2025Mai 21, 2025byCarina Belusa

Installation of Monitoring Systems in Valeira

As part of our project, our partner Voith designed and installed a cavitation monitoring system at our demonstration site Valeira in Portugal. The new system contributes to improved real-time monitoring and operational efficiency.

Two cavitation sensors per unit were installed to measure and monitor cavitation conditions in real time. The system also features a data acquisition system which processes and records data from the sensors, ensuring efficient storage and analysis of information. Additionally, it acquires five additional analogue signals from each unit: active power, speed, gate opening, blade opening and net head. Finally, the system includes a dedicated monitoring PC for data collection and analysis, meaning all monitoring can be done locally. The cavitation status results are stored in the Cloud, where they are available and visualized for remote access and analysis.

In the gallery below, you can see the monitoring cabinet and PC, sensors and coupler boxes at Valeira Power Plant.

News articlesApril 23, 2025Mai 5, 2025byCarina Belusa

Virtual Powerplants for Monitoring and Control – A digital twin for Røldal-Suldal Kraftverkene

The launch of a real-time Virtual Powerplant for our demonstration site Røldal-Suldal Kraftverkene in Norway powered by live data marks a key milestone on ReHydro’s digitalization journey. The system consists of two digital twins that operate in parallel. One is mirroring the power plant in real time, providing additional output such as total plant efficiency, flow, and head loss. The other twin operates on manual inputs to create “what if” scenarios so personnel working on the power plant can train and be prepared for potential emergency situations without a real emergency being present. Later in the project, two or three additional twins might be added for environmental analysis and predictions.

What distinguishes this setup from others is that, due to certain practicalities at Røldal-Suldal, the communication between the physical power plant and its twins is handled via Azure database instead of direct industrial Input/Output. Azure collects and stores data from a large array of datapoints in all plants within the Røldal-Suldal system, which results in an extremely detailed overview of current situations. The drawback to this wide-spread data network is that it introduces a slight latency, however, no more than 15-60 seconds. While this is a challenge, it will give us valuable experience and insights into working with databases like Azure rather than industrial standards like Profibus and its advantages and disadvantages.

One major aspect in favour of Azure that we are benefitting from is that it enables more virtualisation. The entire system can be installed anywhere, preferably on a server in the Cloud, but also on personal PCs. When active control output is not needed, these aspects are very interesting for monitoring, analysis and everyday operation of one or several plants.

News articlesApril 15, 2025Mai 21, 2025byCarina Belusa

External Modernisation Survey and Workshop offer Insights into Hydropower Plant Operators’ Needs

For the past months, our partners working on the business side of ReHydro have conducted a survey aimed at hydropower professionals across Europe, focusing on hydropower modernisation within the European hydropower fleet, to better understand the key drivers behind modernisation efforts and to identify the main barriers faced by the sector.

The survey was rolled out in three phases: Phase one focused on internal surveying among the ReHydro project partners, phase two gathered data from a number of select hydropower operators, and phase three opened the survey up to the public and any relevant hydropower plant personnel that would help us close any remaining gaps in knowledge.

All three phases have been completed within the first quarter of 2025. On April 11^th, a workshop was held with many of the survey’s participants to discuss and finalise conclusions. Viewing the results within specific contexts was also made possible through the direct dialogue with participants.

We were able to obtain responses from companies representing 121 GW, about half of the European hydropower fleet, gathering information from 34 individual companies of all sizes. These utilities are geographically representative of all of Europe, which provides us with solid data to align our research focus with the needs of the hydropower sector.

The survey led us to three key conclusions:

About a quarter of the European hydropower fleet was partially modernised within the past ten years.
The main trigger of hydropower modernisation is to make sure assets keep producing electricity, for example, by reducing planned and unplanned downtimes.
Uncertainties are the main challenges the sector faces when planning modernisation projects (see graph below).

Going forward, the data we collected will help us align our actions within ReHydro with the needs of the hydropower sector. The workshop held together with the participants also fostered connection and provided contextual insights into the challenges faced by hydropower experts, making for a great first ReHydro-organised event.

News articlesFebruar 25, 2025März 17, 2025byCarina Belusa

Installation of monitoring system in Brattlandsdalsåi

Sustainable Hydropower starts with better data!

ReHydro partner Intoto just installed an online monitoring system in the river Brattlandsdalsåi, Norway- helping bridge the gap between physical rivers and digital insights.

Brattlandsdalsåi is part of Røldal-Suldal Kraftverkene (RSK), one of our demonstration sites that is owned by our partner Lyse. The monitoring system installed by Intoto provides real-time information about the water level and flow in the river.

This work is one of ReHydro’s activities to discover and develop new standards for sharing a river’s status with society and relevant stakeholders, and maximizing services without compromising or conflicting hydropower production. They will also bridge gaps between the physical and digital relationship between hydropower and rivers as sustainable shared environments and resources. This effort is part of work package 1 and will progress further in summer of 2025.

We can’t wait to share it with you!

Press ReleasesDezember 12, 2024März 17, 2025byCarina Belusa

Monitoring technology for more efficient hydropower plants

In Europe, around 11% of electricity is generated from hydropower every year, but 35% of the potential output is not utilised. As part of the ReHydro research project, Munich University of Applied Sciences is developing new methods for the early methods for the early detection of cavitation, one of the main causes of turbine damage.

Cavitation is a hydrodynamic effect in which vapour bubbles created by a drop in pressure collapse in liquids. If this happens near solid surfaces, such as turbine blades, extreme localised pressures are created that catapult out material like a volcano, leading to material damage. Up to now, cavitation can only be recognised through cost-intensive inspections, during which the turbine has to be completely emptied. If cavitation is detected, the only option left is to limit the damage by increasing the pressures or reducing the flow rate.

To avoid this, operators run the turbines at a large safety distance from critical operating areas where the pressure could drop. However, this limits the operation of the turbine and generates less electrical power than would be possible.

Detecting cavitation at an early stage with the help of AI

As part of the ReHydro project, funded by the EU, Prof. Busboom is working with Voith Hydro and Energias de Portugal (edp) to develop innovative measurement solutions and AI monitoring systems to reliably detect cavitation during operation and reduce expensive inspections. For example, they use ultrasonic sensors that detect the high frequencies generated during the cavitation process.

The technology is being implemented at the Valeira hydropower plant in Portugal and is intended to demonstrate how modern sensor technology and data analysis can optimise the efficiency of hydropower plants. This not only increases the flexibility of the plants, but also supports the stability of the electricity grids by extending the availability and service life of the hydropower plants. ReHydro thus makes a decisive contribution to the ecological and economic optimisation of the European hydropower industry.

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