Solar Self-Consumption Calculator — See How Much PV You Use On Site
Estimate how much annual solar generation is used directly by your site, how much demand is supplied by other sources and how much surplus remains for export or storage.
Self-consumption inputs
What solar self-consumption means
Solar self-consumption is the share of photovoltaic generation that is used by the site rather than exported or otherwise unused. It is different from solar self-sufficiency, which asks how much of the site's total electricity demand is supplied by solar.
Two useful percentages
The self-consumption rate is based on solar generation. Self-sufficiency is based on total site demand. A system can therefore have a high self-consumption rate while still covering only part of the site's annual electricity consumption.
Why batteries change the picture
Energy routed through storage can move solar generation from one time of day to another. The stored amount is not necessarily equal to later delivered energy because batteries and associated electronics have losses.
Self-sufficiency rate = solar energy serving site demand ÷ site demand
Worked example
With 12,000 kWh of annual PV generation and 6,500 kWh of direct solar use, the direct-use share is about 54.2%. If another 1,200 kWh enters storage and 90% is later delivered, the storage path contributes another 1,080 kWh of usable solar energy.
Frequently asked questions
Is exported solar self-consumed?
No. Exported energy leaves the site and is not counted as on-site self-consumption.
Can self-consumption exceed 100%?
No. A correctly bounded energy-flow result cannot exceed total solar generation.
Why can self-consumption be high but solar self-sufficiency low?
The site may use most of the solar it produces while still having a large amount of electricity demand outside solar-production hours.