At the outset of the U.S. National Photovoltaic Program, it was envisioned that a large-scale deployment of grid-connected systems would be essential for photovoltaics to have a significant impact on the solution of the energy problem. To achieve this large-scale deployment, the installed system cost must break even with the net monetary return in terms of deferred energy cost and/or the cost of energy sold back to the grid. However, the current module and installation costs are significantly higher than what are economically viable. Therefore, during the past several years the reduction of the installed module cost has been the major emphasis of the Program. The cost estimates for three candidate photovoltaic systems (1) flat plate, (2) linear-focus Fresnel concentrator, and (3) point-focus Fresnel concentrator showed that the installed cost of all three systems would be economically viable provided that various technology advancements are achieved and production volume increases as expected.