Grid-connected photovoltaic (PV) energy is one of the fastest growing and most promising renewable energy sources in the world. In fact, since 2007, it has increased over 10 times (from 10 to 100 GW of installed capacity), with 60 GW installed in the last two years alone, as can be seen in Figure 7.1 . Furthermore, PV power has reached 35% of the installed wind power capacity, although in 2007 it accounted only for 10%. Following this trend, PV energy penetration is currently around five years behind the wind energy industry. Nevertheless, grid-connected PV systems are experiencing an accelerated version of the trend experienced by wind energy during the last two decades, which offers a promising glimpse of the future ahead for the solar industry.