Solar advances

Sicily has just announced the opening of the world’s first concentrated solar power (CSP) facility that uses molten salt as a heat collection medium. Since molten salt is able to reach very high temperatures (over 1000 degrees Fahrenheit) and can hold more heat than the synthetic oil used in other CSP plants, the plant is able to continue to produce electricity even after the sun has gone down.

While photovoltaic solar panels work by directly producing electricity from sunlight, CSP plants use mirrors to concentrate sunlight and produce high temperatures in order to drive a turbine to generate electricity. CSP plants have been in existence for many years, but the Archimede plant is the first instance of a facility that uses molten salt as the collection medium.

Some existing CSP plants have used molten salt storage in order to extend their operation, but the collectors have relied on oil as the heat collection medium. This has necessitated two heat transfer systems (one for oil-to-molten-salt, and the other for molten-salt-to-steam) which increases the complexity and decreases the efficiency of the system.

The Archimede plant has a capacity of 5 megawatts with a field of 30,000 square meters of mirrors and more than 3 miles of heat collecting piping for the molten salt. The cost for this initial plant was around 60 million Euros.

Cost is one thing, the other being maintenance of the wide-spread unit. Huge tracts of land are required for CSP units plus, the use of salt could lead to some problems in cleaning when the salt freezes. Still, CSP could be the technology for desert or waste lands? How would it compare with biofuels used on the same land? Any comparisons?

The U.S. Senate Energy Committee meanwhile advanced a big piece of solar energy legislation recently. This bill is aimed at getting 10 million new solar systems on U.S. roofs in the next 10 years. The U.S. Department of Energy claims that combined with existing solar energy incentives, the 10 Million Solar Roofs bill could exceed its goal of 10 million new solar systems in 10 years.