Self-sufficiency

Self-sufficiency is the proportion of a property's electricity consumption that is supplied by its own behind-the-meter solar PV generation or electrical storage rather than imported electricity. MCS MGD 003 uses the related label grid electricity independence and defines it as the percentage of electricity consumed in the property over a year that is met by behind-the-meter solar or electrical energy storage. It is different from self-consumption, which measures how much PV generation is used on site instead of exported. A self-sufficiency figure depends on total electricity demand, solar generation, when loads run, occupancy, shading, array orientation, battery usable capacity and control settings, so it does not guarantee zero import, zero export, off-grid operation, backup power, SEG payments, DNO approval, lower bills or installation quality.