“…The modules used GaAs single -junction concentrator solar cells, achieving an effi ciency of about 28% [25] . Furthermore, a module effi ciency of 22.3% was reported, which was achieved with a Fresnel lens concentrator equipped with 12 GaAs solar cells and without applying a temperature correction [26] . Considering this concentrator would have been equipped with today ' s triplejunction solar cells instead of the single -junction cells, one could expect a module operating effi ciency of about 30%.…”