Very high fluxes for concentrating photovoltaics: Considerations from simple experiments and modeling

Among commercial photovoltaic technologies, concentrating photovoltaics (CPV) has the highest solar energy-to-electricity conversion efficiency; however, CPV electricity costs are still higher than thin film or silicon PV costs, mainly because of the additional components needed (optics, tracker) and the very high price of III–V multi-junction solar cells. To date, most commercial CPV systems operated at maximum concentrations of about 500 suns; but even at this concentration level, multi-junction cells retain a significant contribution to the total cost of the system. Further increasing the concentration ratio seems an interesting route for decreasing CPV electricity costs since the efficiency of concentrator cells theoretically increases with increasing illumination levels whilst the part of the solar cells in the total system cost decreases.