We’ve reported in the past about the use of molten salt "batteries" as a means of energy storage for solar thermal farms, allowing solar power to move a step closer towards providing reliable baseload power under all weather conditions..
Late last week, the Archimedes solar farm was opened in Italy by Enel, the first in the world to use molten-salt technology as the heat transfer fluid and is also the first to integrate a combined-cycle gas facility and a solar thermal power plant for electricity generation.
The molten salts used in the system are a mixture of sodium nitrates and potassium that are heated to a temperature of 550 degrees Celsius and injected into a "hot tank", where the thermal energy is stored. The heat from the molten salt is used to produce steam directed that is then piped into turbines to generate electricity.
The capacity of the solar plant is about 5 MW, which Enel says represents an annual savings of 2,100 tonnes of oil equivalent and a reduction of carbon dioxide emissions by about 3,250 tonnes.
The Archimedes solar thermal power farm is made up of around 30,000 square metres of mirrors that concentrate sunlight onto 5,400 metres of pipe carrying the molten salt fluid.
This system enables the plant to generate electricity at any time of the day and in all weather conditions until the stored energy is depleted – which can be a number of days.
The plant is named after Archimedes, who was a Greek mathematician, physicist, engineer, inventor, and astronomer and is said to have used mirrors to set fire to the Roman ships besieging Syracuse during the Punic War of 212 BC.
