A fully commercial photovoltaic system at around EUR 2.8/Wp (for the installed system) was expected in the framework of this project (after 10MWp cumulated production). Achieving this low cost the market growth will be explosive not only in long term but also in the short to medium term. A real and cost-competitive mass production of photovoltaic electricity will dawn. For the short term, GaAs cells, fitting the requirements of optoelectronics industry, can be readily industrialised, because this industry has been manufacturing a huge quantity of devices similar to GaAs solar cells (basically LED's) for more than two decades. Nevertheless, if the technology succeeds and goes to the market its future at mid-term is in the tandem cells. Unlike the case of other concentrators, the product we propose here to develop has an almost tremendous efficiency-increasing potential by incorporating to it the advances of tandem cells developed today for the space technology. Such advanced cells will certainly be expensive but the high concentration level we are using, above 1000x, will allow its use in a cost-effective way. This concentration level is permitted by the small size approach that is made cost effective by using automated optoelectronics techniques of assembling. Concentrators have not been well accepted by the market so far. Besides a component of technical maturity that has not to be discarded, we think they are too big. The small size of these concentrators not only facilitates modularity but also requires it. The module size would not be greater than the one of conventional flat modules that will ease the market penetration of the new product. Although solar installation will be much cost effective in countries in the Sunbelt, the climatic conditions of Southern Europe (Spain, Italy, Greece) are highly convenient, so solar power plants would be exploited and integrated in the grid utility of these countries. Additionally, because the concentrator unit is small, this concentrator solution is not exclusively focused for big electric plants, as the other concentrator solutions are. Thus it could have an impact on rural electrification where the social benefits are dominant. More than 35PV modules have been built during this project. It has been a very good opportunity for identifying the problems to be solved once mass production for market penetration would arrive. Most of the topics involved have been properly identified and solutions for overcoming them proposed and tested. A very interesting one is related with the procedures for final assembly of the module: Accurate placement procedure for Optic system. In the Engineering process exclusively developed for the assembly of the PV module, the low tolerances allowed for the system (X,Y,Z +/-100 microns) has revealed itself as very important for the correct performance of the system. Accordingly, new inputs for the HAMLET project (already running) are also addressed from them not only for the proper electrical profiles but also for the long-term performance of the module. As a general conclusion, the cumulated experience during this project is key for the success in further efforts oriented to solve the aforementioned new opened points.