Converting solar energy into electricity through photovoltaic technology is an increasingly cheap and efficient process. Portugal has one of the highest solar resource levels of European countries, but using it means occupying very significant geographical areas.
The opportunity lies in using the dam reservoir of hydroelectric facilities. Thanks to this the occupation of other areas of recognized utility (for agriculture, for example) can be avoided and it's possible to make use of the connection to the already installed electrical network that hydroelectric stations do not use constantly. Because there is more sunlight when there is less rain and vice versa.
Recognizing this context and this opportunity, EDP opened, in 2017, a floating solar photovoltaic power plant at the dam reservoir of Rabagão river in Montalegre and launched, in 2019, the Alqueva Floating Photovoltaic project (waiting for licensing).
A pioneering project at the European level, the floating photovoltaic solar power plant at the Rabagão river basin, in Montalegre, tests the cooperation between solar energy and hydro, as well as the environmental and economic advantages of this new technology.
With 840 solar panels occupying an area of 2500 square meters, the platform, which results from a partnership between EDP Produção, EDP Renewables and EDP Comercial, has an installed capacity of approximately 220 kWp and an estimated annual production of around 300 MWh.
The studies to move forward with this plant were initiated in 2015 and the construction, which involved 13 suppliers (mostly Portuguese) and, at the peak of the work process, 25 workers, started in June 2016.
EDP has invested 450.000 euros to move forward with the installation of this pilot unit, which will help in assessing the implications, advantages and disadvantages of the installation on floating platforms of the photovoltaic conversion panels and their exploitation together with the hydroelectric production. It is also intended to prove that this solution has clear environmental benefits in the water body, and because it reuses existing installations, avoiding the construction of new transport lines.
The Alto Rabagão reservoir was chosen because of the space and adverse climate conditions which allow it to test the technology in extreme conditions. It also has a deep valley with rocky soil and significant variations of dimensions, which provided an opportunity to test the mooring solutions.
The Alqueva Floating Photovoltaic project previews the integration of solar panels in the Alqueva Hydroelectric Power Ecosystem, a pumping hydro power plant, which is one of the largest energy storage systems in the country. The pumping system allows the use of wind and solar power, during periods of lower consumption, to pump water from the reservoir and reuse it to produce new hydroelectric power.
EDP's new floating solar project is aligned with regulatory changes in Portugal that open the door to hybridization and photovoltaic solar auctions, the combination of energy from multiple renewable energy sources with that from conventional power plants.
If this project goes forward, the new floating solar panels, with 4 MW of installed power, will allow to test not only this hybridization of the floating photovoltaic with pumping water, but also, its combination with a battery system.
The project can therefore give origin to the first Living Lab of integrated renewable energy and storage solutions to respond to the energy market of the future. A market that, according to the Roadmap for Carbon Neutrality 2050 - the Portuguese commitment to the goals of the Paris Agreement, 80% of the electricity consumption must be form renewable energy, as early as 2030.
In addition, Alqueva will also add a second platform, containing a 20-foot container (approximately 12 meters), which will have a transformer and Medium Voltage cells, in order to reduce losses. The technology used will be in Seaflex.
Floating Solar of the Alqueva in numbers:
- Installed Power: 4 MW
- Number of panels: up to 11,000
- Platform dimensions: 4 ha
- Depth of the bay: 60 m
- Water plane oscillation: 30m
- Annual energy to be produced: up to 7 GWh (equivalent to 25% of the families in the region - Portel and Moura)
- Duration of installation project: 12 months