Grid-connected photovoltaic power system Solar energy gathered by photovoltaic solar panels, intended for delivery to a power grid, must be conditioned, or processed for use, by a grid-connected inverter. Fundamentally, an inverter changes the DC input voltage from the PV to AC voltage for the grid. This inverter sits between the solar array and the grid, draws energy from each, and may be a large stand-alone unit or may be a collection of small inverters, each physically attached to individual solar panels. See AC Module. The inverter must monitor grid voltage, waveform, and frequency. One reason for monitoring is if the grid is dead
History of photovoltaic growth History of photovoltaic growth The history of photovoltaic growth includes previous forecast and annual deployment figures by country. Most PV deployment figures in this article are provided by the European Photovoltaic Industry Association in the "Global Outlook for Photovoltaics" report, the "Observatoire des énergies renouvelables" or EurObserv'ER's "Photovoltaic Barometer" report, and the IEA-PVPS (photovoltaic power systems) "Snapshot" and "Trends" report. In 2013, worldwide deployment of solar PV amounted to almost 40 GW (39,953 MW)—an increase of about 35 percent over the previous year. Cumulated capacity increased by 38 percent to more than 139 GW. This is sufficient to generate at