The Azimuth Project

Archimede is a concentrated solar power plant named after Archimedes, located in Sicily near Archimedes’ home town, Syracuse:

It started operations on 14 July 2010. It produces 5 megawatts of electricity, enough for 4,500 families. That’s not much compared to the 1 gigawatt from a typical coal- or gas-powered plant. But it’s an interesting experiment.

It consists of about 50 parabolic trough mirrors, each 100 meters long, with a total area of around 30,000 square meters. They concentrate sunlight onto 5,400 metres of pipe. This pipe carries molten salts — potassium nitrate and sodium nitrate — at a temperature of up to 550 °C. This goes on to produce steam, which powers an electrical generator.

The news is the use of molten salt instead of oil to carry the heat. Molten salt works at higher temperatures than oils, which only go up to about 390° C. So, the system is more efficient. The higher temperature also lets you use steam turbines of the sort already common in gas-fired power plants. That could make it easier to replace conventional power plants with solar ones.

The project is being run by Enelref=“, Europe’s third-largest energy provider. It was developed with the help of ENEA, an Italian agency that deals with new technologies, energy and sustainable economic development. At the Guardian, Carlo Ombello writes:

So why hasn’t this technology come before? There are both political and technical issues behind this. Let’s start with politics. The concept dates back to 2001, when Italian nuclear physicist and Nobel prize winner Carlo Rubbia, ENEA’s President at the time, first started Research & Development on molten salt technology in Italy. Rubbia has been a preminent CSP advocate for a long time, and was forced to leave ENEA in 2005 after strong disagreements with the Italian Government and its lack of convincing R&D policies. He then moved to CIEMAT, the Spanish equivalent of ENEA. Under his guidance, Spain has now become world leader in the CSP industry. Luckily for the Italian industry, the Archimede project was not abandoned and ENEA continued its development till completion.

There are also various technical reasons that have prevented an earlier development of this new technology. Salts tend to solidify at temperatures around 220°C, which is a serious issue for the continuous operation of a plant. ENEA and Archimede Solar Energy, a private company focusing on receiver pipes, developed several patents in order to improve the pipes’ ability to absorbe heat, and the parabolic mirrors’ reflectivity, therefore maximising the heat transfer to the fluid carrier. The result of these and several other technological improvements is a top-notch world’s first power plant with a price tag of around 60 million euros. It’s a hefty price for a 5 MW power plant, even compared to other CSP plants, but there is overwhelming scope for a massive roll-out of this new technology at utility scale in sunny regions like Northern Africa, the Middle East, Australia, the US.

The last sentence may be a reference to DESERTEC.

category: energy