What is Solar Irradiance?
The amount of solar energy falling on a surface, measured in watts per square metre (W/m²) or kWh/m² per year.
Quick Answer
The UK receives annual solar irradiance of 900–1,200 kWh/m², compared to 1,200–1,800 kWh/m² in southern Europe. While lower, the UK's irradiance is sufficient for productive solar installations. The south coast receives the highest irradiance, while Scotland receives the least. The UK's latitude means long summer days partially compensate for cloudier conditions.
Fact-checked by John Rooney, Solar Energy Editor. Editorial policy
Solar Irradiance Explained
Solar irradiance is the power per unit area received from the sun in the form of electromagnetic radiation. It is measured in watts per square metre (W/m²) for instantaneous measurements, or kilowatt hours per square metre per year (kWh/m²/year) for annual totals. Solar irradiance determines how much electricity solar panels can generate in a given location. It varies with latitude, altitude, weather patterns, and time of year.
How Does Solar Irradiance Work in the UK?
The UK receives annual solar irradiance of 900–1,200 kWh/m², compared to 1,200–1,800 kWh/m² in southern Europe. While lower, the UK's irradiance is sufficient for productive solar installations. The south coast receives the highest irradiance, while Scotland receives the least. The UK's latitude means long summer days partially compensate for cloudier conditions.
Frequently Asked Questions
Does the UK get enough sunlight for solar panels?
Yes. The UK receives 900–1,200 kWh/m² annually, enough for a 4kWp system to generate around 3,400 kWh per year and save roughly £600 annually.
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John Rooney is the founder of Solar Info and has been covering the UK solar energy market since 2023. He researches every battery and inverter brand against manufacturer datasheets, MCS and Ofgem data, and feedback from the MCS-certified installers in our directory before publishing.