A balcony power plant , often referred to as a mini solar system or plug-in solar system, is a small photovoltaic system consisting of one or two solar modules and a special inverter . The major difference from conventional large-scale PV systems is its simple plug-and-play installation. The modules are simply placed on the balcony, terrace, facade, or in the garden, and the inverter converts the generated direct current into standard household alternating current.