Rome, 2010
- Enel inaugurated the “Archimede” solar thermal power plant at Priolo Gargallo (Syracuse, Sicily). First in the world to use molten-salt technology integrated with a combined-cycle plant.

Participating in the ceremony together with the CEO and General Manager of Enel, Fulvio Conti, were, among others, the Minister for the Environment, Stefania Prestigiacomo, the President of the Province of Syracuse, Nicola Bono, and the Mayor of Priolo Gargallo, Antonello Rizza.

The Archimede plant is the first in the world to use molten salts as the heat transfer fluid and is also the first in the world to integrate a combined-cycle gas facility and a solar thermal power plant for electricity generation.

Archimede can collect and store the heat of the sun for many hours in order to use it to generate electricity at night or in overcast conditions. This allows to overcome the common limitation of this renewable source, namely that you can use it only when nature makes it available.

Solar thermodynamic technology uses a set of parabolic mirrors to concentrate the sun's rays on pipes carrying a fluid. The latter, collected in special tanks, can be used to power a steam generator. The high-temperature steam and pressure drives the turbine in the adjacent combined-cycle power plant to generate electricity when needed, reducing consumption of fossil fuels.

The special technology used in the Priolo plant was developed by Enea. The molten salts used in the system are a mixture of sodium nitrates and potassium, which can accumulate heat for prolonged periods.

The capacity of the solar plant is about 5 MW, representing an annual savings of 2,100 tonnes of oil equivalent, reducing carbon dioxide emissions by about 3,250 tonnes.

The solar thermal power plant consists of a field of about 30,000 square metres of mirrors (the parabolic collectors) that concentrate sunlight onto 5,400 metres of pipe carrying the molten salt fluid. The thermal energy harvested by the system produces high pressure steam that is channelled into the turbines of the power plant to produce electricity, reducing the consumption of fossil fuels and, as a result, enhancing the environmental performance of the combined-cycle plant.
The solar collectors (the parabolic mirrors and pipes or receivers), together with a steam generator and two heat storage tanks – one cold and one hot – make up the solar portion of the system.