Ix. AN ASSESSMENT F THE FUTURE
Photovoltaics is still evolving and has not reached its full potential [49]. Efficiencies of flat-plate modules are expected to approach and even exceed 15% and of concentrator modules will exceed 20%. Lifetimes of over 20 years will certainly be a reality in the near future. Thirty year lifetimes are projected by the year 2000 and beyond. Space cell technologies are advancing at a rapid rate, with a record 31% AM0 efficiency of conversion for GaAs/GaSb stack for satellite applications using concentrating optics and
tandem cells with 37% efficiency for terrestrial applications [50]. Adoption of space cell technologies for large-scale electric power generation could become a reality in the decades to come.