Solar panels in Ireland produce between 776 and 1,081 kWh per kWp of installed capacity per year, depending on county. Wexford is the most productive county; Donegal is the least. The gap between best and worst is 39% — enough to change your payback period by roughly two years, but not enough to make solar a bad investment anywhere in Ireland. Source: PVGIS v5.3, European Commission Joint Research Centre, queried June 2026.
The Full Table: All 26 Counties Ranked by Solar Yield
The figures below are from the European Commission's PVGIS database (version 5.3), queried in June 2026 for the main town of each county. The assumptions: a south-facing roof at 35° tilt, crystalline silicon panels, and 14% total system losses — the standard residential setup in Ireland. The household coverage column compares a 4 kWp system's output against average Irish household consumption of roughly 4,200 kWh per year.
| County | Yield (kWh/kWp/year) | 4 kWp system output | % of average household use |
|---|---|---|---|
| Wexford | 1,081 | 4,324 kWh | 103% |
| Waterford | 1,047 | 4,188 kWh | 100% |
| Wicklow | 1,004 | 4,016 kWh | 96% |
| Cork | 994 | 3,976 kWh | 95% |
| Dublin | 982 | 3,928 kWh | 94% |
| Louth | 966 | 3,864 kWh | 92% |
| Kilkenny | 956 | 3,824 kWh | 91% |
| Meath | 947 | 3,788 kWh | 90% |
| Laois | 941 | 3,764 kWh | 90% |
| Carlow | 940 | 3,760 kWh | 90% |
| Kildare | 940 | 3,760 kWh | 90% |
| Offaly | 938 | 3,752 kWh | 89% |
| Westmeath | 933 | 3,732 kWh | 89% |
| Clare | 932 | 3,728 kWh | 89% |
| Roscommon | 929 | 3,716 kWh | 88% |
| Galway | 926 | 3,704 kWh | 88% |
| Limerick | 916 | 3,664 kWh | 87% |
| Tipperary | 913 | 3,652 kWh | 87% |
| Longford | 909 | 3,636 kWh | 87% |
| Monaghan | 896 | 3,584 kWh | 85% |
| Cavan | 893 | 3,572 kWh | 85% |
| Kerry | 888 | 3,552 kWh | 85% |
| Mayo | 886 | 3,544 kWh | 84% |
| Sligo | 849 | 3,396 kWh | 81% |
| Leitrim | 822 | 3,288 kWh | 78% |
| Donegal | 776 | 3,104 kWh | 74% |
Source: PVGIS v5.3 (Photovoltaic Geographical Information System), European Commission Joint Research Centre. Queried June 2026 at the main town of each county. Assumptions: south-facing, 35° tilt, crystalline silicon, 14% system loss. Yields at other locations within a county vary by a few percent; coastal and elevated sites differ most.
What the Numbers Actually Mean
The south-east is Ireland's solar belt. Wexford, Waterford and Wicklow occupy the top three places, and they are the only counties where a standard 4 kWp system generates as much electricity in a year as the average Irish household consumes. This is why Wexford is sometimes called "the sunny south-east" — on solar yield data, the nickname is earned.
Most of the country sits in a tight band. Twenty of the 26 counties fall between 880 and 1,000 kWh/kWp/year. If you live anywhere from Cork to Louth to Galway, your yield is within about 10% of the national median (roughly 930 kWh/kWp/year). The difference between, say, Kildare and Galway is 14 kWh per kWp per year — about €5 worth of electricity. County-level differences only become financially meaningful at the extremes.
The north-west pays a real but manageable penalty. Donegal, Leitrim and Sligo are the only counties below 850 kWh/kWp/year. A 4 kWp system in Donegal generates around 1,200 kWh less per year than the same system in Wexford. At current electricity prices that is a meaningful gap — it stretches the payback period by roughly two years. But a Donegal system still covers around three-quarters of an average household's annual consumption, and still pays for itself well within the 25-year panel warranty.
Why County Is Not the Biggest Factor
The numbers above assume an identical roof in every county: south-facing, 35° tilt, no shading. In practice, your roof matters more than your county:
- Orientation: An east- or west-facing roof loses 15–20% compared to south-facing — a bigger penalty than moving from Dublin to Sligo.
- Shading: A chimney shadow across the array during peak hours can cost more output than the entire Wexford-to-Donegal gap.
- Roof pitch: Most Irish roofs are pitched between 30° and 40°, which is close to optimal — but flat-roof and steep-roof installs lose a few percent.
The practical conclusion: use the table to set expectations for your county, but get a proper site assessment before deciding system size. Our guide to how many solar panels you need in Ireland walks through the sizing maths, and the do solar panels work in Ireland guide covers what affects output on a real roof.
Yield Is Only Half the Equation
What makes solar financially viable in Ireland is not the yield — it is the price of the electricity you avoid buying. Ireland has among the highest household electricity prices in Europe (Eurostat). A kilowatt-hour generated on your roof in Leitrim is worth exactly the same as one generated in Wexford: the full retail price you would otherwise have paid.
That is why payback periods across Ireland cluster in the 7–9 year range despite the 39% yield gap between counties — the south-east pays back faster, the north-west slower, but everywhere lands within the same band. After the SEAI grant of up to €1,800 and 0% VAT, a 4 kWp system costs €6,200–€9,200 installed. Full figures by system size are in the solar panels cost Ireland guide.
County averages set expectations — a site assessment gives you real numbers. Get free quotes from SEAI-registered installers in your county, with output estimates for your specific roof.
Get Free Quotes →Frequently Asked Questions
Wexford has the highest solar yield in Ireland at approximately 1,081 kWh per kWp per year (PVGIS v5.3, June 2026), followed by Waterford (1,047) and Wicklow (1,004). These are the only three counties where a standard 4 kWp system generates roughly as much electricity in a year as the average Irish household consumes (about 4,200 kWh).
A 4 kWp solar system in Ireland generates between 3,104 kWh per year (Donegal) and 4,324 kWh per year (Wexford), based on PVGIS data for a south-facing roof at 35° tilt. Most counties fall between 3,500 and 4,000 kWh per year. That covers 74–103% of the average Irish household's annual electricity consumption of roughly 4,200 kWh.
Yes. Donegal has Ireland's lowest solar yield at approximately 776 kWh per kWp per year, but a 4 kWp system there still generates around 3,104 kWh annually — roughly three-quarters of an average household's consumption. The lower yield stretches the payback period by about two years compared to the south-east, but the system still pays for itself well within the 25-year panel warranty, and the SEAI grant of up to €1,800 applies equally in every county.
The gap between Ireland's best county (Wexford, 1,081 kWh/kWp/year) and worst (Donegal, 776 kWh/kWp/year) is 39%. However, most of the country sits in a much tighter band — 20 of the 26 counties fall between 880 and 1,000 kWh/kWp/year, within about 10% of the national median. The difference only becomes financially significant at the geographic extremes.
Sources: PVGIS v5.3 (Photovoltaic Geographical Information System), European Commission Joint Research Centre — yield data queried June 2026 for the main town of each county; Eurostat electricity price statistics; SEAI Solar Electricity Grant.
Published: 1 June 2026. Author: Neil Russell. Data table may be reproduced with attribution and a link to this page.