The world’s largest thermodynamic solar power station


© Xinhua / Eyevine

Ancient tales tell of how, following a long siege in 212 BC, the Consul Marcello’s legionnaires outwitted the city of Syracuse, which was allied with Carthage. For a full two years, the city walls had withstood every assault, defended by the fearsome machines of the genius Archimedes—including, according to legend, his infamous burning mirrors.
Modern CSP (Concentrated Solar Power) systems that concentrate sunlight to produce electricity and heat, descend from Archimedes’ legendary mirrors. Although CSP technologies represent only a niche in the world’s energy landscape today, they have considerable potential: by 2050, they could cover 10% of the world’s electricity demand, helping to decarbonise many industrial thermal processes that currently rely on fossil fuels. In fact, it is estimated that the sun provides the Earth with about one billion terawatt hours of radiant energy annually with very low density, with the potential of satisfying the world's energy requirements 10,000 times over. One of the world’s largest CSP power stations is located at the foot of the High Atlas in Morocco, not far from the northern edge of the Sahara Desert. The energy generated by the Noor Ouarzazate complex (510 MW) avoids the production of almost 800,000 tonnes of CO2 per year. The most spectacular section of the Ouarzazate site is undoubtedly the central tower system with its 7,400 reflective panels (called heliostats) that concentrate solar radiation onto a 250-metre-tall tower to heat a thermal carrier fluid to over 500°C. That heat is then converted into electrical energy by a traditional 150 MW steam turbine. Then, thanks to its innovative molten salt thermal accumulation system, the plant can provide power over the grid for almost eight hours, even at night.

Alessandro Braggion