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
Ireland receives annual solar irradiance of 900–1,100 kWh/m², compared to 1,200–1,800 kWh/m² in southern Europe. While lower, Ireland's irradiance is sufficient for productive solar installations. The southeast (Wexford, Waterford, Kilkenny) receives the highest irradiance, while the northwest receives the least. Ireland'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 Ireland?
Ireland receives annual solar irradiance of 900–1,100 kWh/m², compared to 1,200–1,800 kWh/m² in southern Europe. While lower, Ireland's irradiance is sufficient for productive solar installations. The southeast (Wexford, Waterford, Kilkenny) receives the highest irradiance, while the northwest receives the least. Ireland's latitude means long summer days partially compensate for cloudier conditions.
Frequently Asked Questions
Does Ireland get enough sunlight for solar panels?
Yes. Ireland receives 900–1,100 kWh/m² annually — enough for a 4kWp system to generate 3,400–3,800 kWh per year and save €1,000+ annually.
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John Rooney is the founder of Solar Info and has been covering the Irish solar energy market since 2023. He fact-checks all content against official SEAI data and maintains relationships with SEAI-registered installers across Ireland.