Grid Independence & Solar Self-Reliance Calculator for Cardiff

Self-consumption is the percentage of on-site solar generation used within your home. Grid autonomy measures what proportion of your total electricity consumption is met without drawing imported power from your supplier.

Pairing a properly sized solar system with domestic battery storage raises annual grid autonomy to 65% to 80% for typical homes in Cardiff.

Through load shifting and solar diverters: install an immersion diverter (e.g. eddi or Solar iBoost) to convert surplus solar into hot water, and schedule washing machines and dishwashers for sunny midday hours.

A standard family home in Cardiff without storage typically reaches approximately 25% to 35% grid independence, as peak daytime solar production diverges from evening cooking and lighting demand.

While achievable from May to August, year-round 100% off-grid living is impractical in Cardiff because winter solar irradiation drops to ~10% of summer peaks, requiring impractically oversized battery banks.

With retail electricity rates around 7.8p/kWh in Cardiff and export tariffs paying 5p–15p/kWh, every kilowatt-hour consumed on-site saves you the full retail import rate.