Module efficiency

Module efficiency is the percentage of incoming solar energy on a PV module that is converted into rated electrical output under stated test conditions. In datasheets it is usually listed beside module power, dimensions and standard test condition ratings, so it helps compare how much rated wattage fits into a given roof area. The figure should be read as a laboratory rating, not a promise of annual generation or household output: orientation, inclination, shading, temperature, dirt, inverter limits and system design all affect what the array produces in use. It is not the same as kWp, module power, an MCS performance estimate, inverter efficiency, export capacity, DNO acceptance or installation quality.