Glossary
Export limitation
Capping how much electricity a system sends out to the grid, which is not the same as capping how much it generates.
Export limitation means restricting how much power a generating system sends out to the grid, usually by measuring what the home is using and turning generation down so the surplus stays under a set level. “Zero export” is the strictest version: nothing leaves the property.
The GB plug-in solar rules work differently. They limit the device’s total output: a plug-in microgenerator must have “a maximum rated alternating current output not exceeding 800 watts” (SI 2026/848), and 800 VA and 3.5 A under the product specification (IPS §4.1). Whatever your home isn’t using at that moment flows out to the grid.
That matters because exported power from a plug-in kit is usually unpaid: the Smart Export Guarantee needs an MCS-certified installation (gov.uk). Kits can’t store surplus in a battery under the rules. If a kit’s app lets you turn its output down, that reduces generation as well as export; it doesn’t save the surplus for later. The practical answer is to match the kit’s size to your daytime use.