G98/G99 Backup & SEG Export

UK Solar PV & Home LFP Battery Calculator

Size UK solar panels, Smart Export Guarantee (SEG) savings & LFP battery capacity for winter power cut resilience and off-peak charging.

Home Battery Size (kWh)

Essential Blackout Load (Watts)

Roof Solar Array (kWp)

Usable Reserve (90% DoD)

9.0 kWh

Blackout Autonomy (No Sun)

20.0 hrs

Est. Annual UK PV Output

3,400 kWh

Critical Difference: Grid-Tied Inverter vs EPS Islanding During a UK Power Cut

Standard G98/G99 UK solar and battery installations legally shut off automatically when a street power cut hits (anti-islanding protection so roof power cannot back-feed live voltage onto lines DNO engineers are repairing). To run fridge-freezers, broadband and combi boilers during a blackout, specify an inverter fitted with an automated Emergency Power Supply (EPS) gateway / Gateway changeover.