Site visit: Europe's biggest solar-hydro hybrid plant

The Alqueva power plant in eastern Portugal is the largest floating solar-hydro hybrid in Europe… and a marvel of innovation.

Enlit on the Road visited Portuguese energy company EDP’s ground-breaking project, which offers a glimpse into the potential future of renewable energy. The hybrid project – which sits on Europe’s biggest artificial lake - showcases how combining different renewable sources can create an efficient energy solution.

We spoke to Pedro Miguel Oliveira, Director of EDP Generation's Innovation Department, who explained that Alqueva comprises three key components: a hydroelectric power station with a 510MW capacity, including a pumping system that acts as a significant energy reserve; a floating solar power station with 12,000 photovoltaic panels and 5MW installed capacity; and a battery storage system with a storage capacity of around 2MWh.

According to Oliveira, the hybrid combines the two renewable sources into the same injection point into the grid.

"This is efficient because we use the infrastructure that already exists: all the connection points, substations and lines. And connecting these projects into the hydropower plant, we save a lot of the costs and also reduce the impact on the environment."

Have you read?
How solar can keep its place in Europe’s sun
High stakes for hydropower’s future

A pioneering example of hybridisation

Alqueva stands out for its pioneering approach to hybridisation. It's not just about combining solar and hydro: it's about intelligent management. The project serves as a real-world testing ground for the complementarity between renewable energy production and storage technologies.

Here's how it achieves this:

• The photovoltaic plant, batteries, and hydro are integrated into an intelligent management system;
• The battery storage, with a capacity of around 2MWh, reinforces the project's innovative nature by allowing EDP to explore hydro-solar complementarity;
• The battery uses mature lithium-ion technology, a proven and widely used solution in the global electricity sector.

Innovation at every corner

EDP's commitment to innovation is evident throughout the Alqueva project, especially in the cost-effective design. 

For example, the project benefitted from the FreShER project, a European-funded initiative that aimed to significantly reduce anchoring and mooring system costs by 60%.

Meanwhile, the unusual east-west panel orientation significantly lowers wind drag on the platform, leading to fewer mooring lines and lower costs.

Sustainability prioritised

The project was built with sustainability in mind.

Said Oliveira: "Typically normal conventional PV uses land and there's some deforestation associated [with it]. In this particular project, we use an area that is basically unoccupied because it's the safety area of the dam.

Besides the fact that no additional land is needed for the project, sustainability is also prioritsed by the innovation in the pontoon’s floaters, which incorporate recycled plastic and, in a world-first, cork composite from Amorim Cork Composites and Isigenere.

By introducing the cork, EDP reduced the footprint of these floaters by 30%.

Challenges and solutions: Bird waste and robot cleaners

To keep the system clean and generating power as needed, EDP introduced robots to clean the solar panels. The panels are flat and make it easy for robots to move from one point to another and one string to the next.

Also of interest:
Accelerating the energy transition with Artificial Intelligence
Embedding circularity and sustainability for profitable business models

It's simpler, safer and reduces cleaning time by 50%, emphasised Oliveira.

Watch the full video to find out how EDP is looking ahead with the TALOS project, a European initiative focused on developing autonomous robots that can clean the platform, without human intervention.