Does this mean free electricity for 6 months?

Daily average: yes — you generate more than you consume. But hour by hour: you still draw from the grid in the evening and morning. A battery captures the daytime surplus for evening use, turning the daily surplus into genuine near-zero bills.

Spring Equinox Crossover

By Home Solar Guide Team|Updated 19 March 2026|educational

Independently written | Evidence-based | Sources cited

Spring equinox crossover — Around March 20: daily solar output first exceeds consumption. 6 months of surplus begin.

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When does solar output exceed consumption?

The spring equinox crossover — the date when daily solar generation first exceeds daily household consumption: 4kW SYSTEM, SOUTHERN ENGLAND: Crossover date: ~March 15-20. Daily generation: 10-12 kWh. Average daily consumption: 8-10 kWh. From this date: daily surplus for 6 months (until September equinox). 4kW SYSTEM, SCOTLAND: Crossover date: ~March 25-30. Daily generation: 8-10 kWh. Slightly later due to lower sun angle. WHAT THIS MEANS: Before crossover: you're a net grid consumer (even with solar). After crossover: you're a net exporter (generating more than you use daily). The 6-month surplus period (March-September) generates 70-80% of your annual solar electricity. TRACKING YOUR CROSSOVER: Watch your monitoring app. The day your daily generation bar exceeds your daily consumption bar = your personal crossover date. Celebrate — it's the start of solar season. Sources: PVGIS, Ofgem, BEIS consumption patterns.