Saturday, 21 March 2026
Solar generation in Derry, Saturday, 21 March 2026
Mixed cloud over Derry. Even so, a 4kW install would generate around 9 kWh today.
4kW system
Typical 3-bed NI home (10-12 panels)
9 kWh
£3.02 of electricity
6kW system
Larger home, EV owner, or heat pump
13.5 kWh
£4.53 of electricity
Weather on the day
- Sunshine
- 6.8 h
- Cloud cover
- 92%
- Max temp
- 13.5°C
- Solar radiation
- 2.89 kWh/m²
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How we worked this out
We used daily shortwave radiation data for Derry from Open-Meteo and applied the standard PV yield model:
energy = radiation × system kWp × performance ratio.
The performance ratio is 0.78 (accounts for inverter and temperature losses, orientation and soiling).
Electricity is valued at 33.5p/kWh, the Power NI standard credit tariff.
Figures are an estimate based on observed conditions and a representative install. Actual generation varies with roof orientation, shading and hardware.