Are there different kinds of efficiency?

Efficiency is generally defined as the ratio between output and input power. The output power can never exceed the input power. As a result, efficiency levels can never be higher than 1 (instead of performance, you can also calculate the ratio of energy absorbed and emitted). In solar power generation, one differentiates between cell, module and system efficiency. In commercial mass production, a cell efficiency of up to 20 percent is currently reached, depending on the technology used.

The module efficiency refers to the entire surface of a module and is therefore always slightly lower than the cell efficiency. This is due, among other things, to the non-useable gaps between the strung solar cells in the module. In addition, the inverter converts the direct current of the solar generator into alternating current with a certain efficiency. Two partial efficiencies play a role: the conversion and dynamic tracking efficiency, which reflects the precision and speed of the MPP tracking. High-end devices now reach a total efficiency of up to 99 percent.

The system efficiency refers to the complete photovoltaic system. In relation to the modules and inverter efficiency, a further drop is recorded here, which is due to transmission losses, e. g. by cable.