Electrical measuring instruments, electrical controlling instruments, electrical regulating instruments and electrical analyzing instruments, each for electrical current flow in photovoltaic installations; transformers, inverters, electrical storage batteries, electrical controllers for solar power and wind turbines; computer hardware and peripherals as well as construction parts for microprocessors; optical display panel for monitoring the data of a solar plant or an inverter; computer software for the configuration of solar plants and the communication with inverters, computer evaluation software for inverters in photovoltaic installations; data loggers for collating and transmitting data of energy equipment, namely, photovoltaic installations