SolFocus was founded in 2005 and raised already at least 100MUSD from New Enterprise Associates, Moser Baer India, David Gelbaum, Metasystem Group, NGEN Partners and Yellowstone Capital. They have a first model operating in Phoenix Arizona (near APS STAR site) with x500 concentration factor on a 1cm² multi-junction cell (17% efficiency, by Spectrolab). They have acquired a Spanish tracker company, Inspira (Open loop with auto calibration through sun sensor with accuracy up to 0.3o.), and has also an in–house mirror company (SolFocus glass works). In Dec 2007 they started to build a 200KW plant in Spain (at ISFOC). Current cost is 10USD/kw
The system concept is nice and attractive from a scientific point of view, with several advantages (efficiencies, cooling, shadowing etc.), but it looks like a complicated system to manufacture and maintain. There are rumors, that were not confirmed, that one of the resons they are currently looking for further huge investment is for solving technological problems; however, what Solfocus say is that the funding is required for marketing or establishing automated production lines.
Solfocus’ its first generation comprises of a mini-dish approach (that was developed by professors Jeff Gordon and Dany Feuerman from Ben-Gurion University), with primmary mirror that collects and focus direct sun on a secondary mirror located at the focus of the primary mirror. The second mirror reflects the concentrated light into a non-imaging optic located directly over the solar cell. A number of mini-dishes are arranged in a honeycomb arrangement.
Scalability: single point design.
For repairing: you have to replace many cells at a time; it is difficult to protect non-perimeter cells and the Structure is sensitive to loads (wind etc.)
Main risks for potential investors
- meeting cost targets reduction (currently 10USD/w, and the target for
2010 is 6-7USD/w, which by itself is not so attractive. )
- the system consists of three optical elements, that each produce
additional losses, increase the number of components and involve
additional costs and complexity.
Main advantages: - this design reflects a nice solution to the cooling problem (as the solar cell is not mounted in direct light); there are no support arms shading shadow on the mirror, decreasing power output; they have acquired their own trackers company (Inspira) and their own glass company (SolFocus Glass); have an experienced staff, and two installed prototypes.
Will they be competitive with Concetrix regarding total efficiency?? (unfortunately we have not seen any official results from Solfocus, while Concetrix reports on 23%).
