The most powerful solar installation in the world is in the Pyrenees, it reaches 3,500 °C and is not a power plant

In the middle of summer and with the heat wave upon us, frying an egg on the hood of a car parked in the sun is a reality that gives us an idea of ​​the thermal potential of the sun. But that sensation falls far short of what happens in the heart of the French Pyrenees: there, a building embedded in the side of a mountain concentrates sunlight until it becomes a source of artificial heat so intense that it would be capable of melting steel.

The great solar oven. It is the Odeillo solar oven, in Font-Romeu-Odeillo-Via, and it is one of the two largest and most powerful installations of this type in the world along with that of Parkent, in Uzbekistan. The most striking thing about the installation is the colossal curved mirror measuring 54 meters and 48 meters wide that is integrated, composed of 9,000 facets. This design has a reason for being: it concentrates sunlight up to 10,000 times its natural intensitywhich allows you reach temperatures of between 3,300 and 3500°Caccording to data from the facility’s operating laboratoryPROMES-CNRS.

The system combines two optical elements: a field of 63 motorized flat mirrors that follow the path of the sun and constantly return its light to a large fixed parabolic reflector with a surface area of ​​1,830 square meters. All that light converges on a focal tower, that point barely 40 centimeters in diameter where it develops a thermal power of one megawatt.

The Odeillo installation. Philipendula via Wikimedia

Context. The origin of the Odeillo solar oven dates back to the 1940s, when the chemist Félix Trombe, who at that time He was director of the Meudon rare earth laboratorymanages to concentrate sunlight with a reused anti-aircraft defense mirror. In 1949 the first prototype is built in the citadel of Mont-Louis, just over 10 kilometers from Odeillo. After several increasingly powerful attempts, between 1962 and 1968 is built the current oven. Its location was chosen with complete intention: the French Cerdanya offers a high number of sunny days per year and an atmosphere of great optical purity at altitude, ideal conditions to minimize radiation losses.

In figures. Throughout the article we have broken down some of the most impressive numerical data of this solar oven, which we condense here:

• Main reflector height: 54 meters
• Parabolic mirror area: 1,925 square meters
• Rated thermal power: 1 megawatt
• Maximum temperature: 3,500 °C
• Solar concentration factor: 10,000 times normal solar radiation

Why is it important. Because this oven has been in operation since 1969 and constitutes the first serious attempt towards the large-scale exploitation of solar energy for industrial purposes, long before the today so common solar plants existed. Although pioneering, its function is more research than energy. Thus, it paved the way for one of the first solar tower plants on the planet, that of Thémis in the early 1980s.

Today it has essentially two applications: the study and manufacture of materials resistant to extreme conditions with applications such as the aeronautical industry and the development of solar fuels. A recent example: Sunfuela research project that uses heat from the solar furnace to produce alternative fuels by heating metal oxides to generate gases that are then converted into clean fuels.

Yes, but. Taking into account its figures and the fact that it is 50 years old, the Odeillo solar oven is a true engineering prodigy and the precursor of the solar energy boom that we are experiencing. Of course, it is worth remembering that it is not an electricity generation plant: it does not produce electricity significantly nor is it part of the current renewable mix.

As for its comparison with Parkent, both are the only two theoretical 1,000 kW solar ovens in the world, with similar focus temperatures. Of course, Odeillo wins in real power: although the Uzbek park has a slightly larger mirror (1,840 square meters compared to 1,830), its lower altitude (1,050 m compared to 1,600 m) reduces the available solar intensity, limiting its useful power to 700 kW compared to Odeillo’s 1,000 kW, according to SolarPACES.

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Cover | Rabatakeu