We pulled the public wind and solar record for Dublin. The wind is not remarkable — it averages 3.6 metres per second and it gets above 8 for two per cent of the year. What is remarkable is when it arrives. In this city the sun and the wind are almost exactly out of phase, and that turns out to matter more than either number on its own.
January has the wind. June has the sun.
In the typical year for Dublin, January carries seventeen per cent of the sunlight and one hundred per cent of the wind energy. June carries one hundred per cent of the sunlight and sixteen per cent of the wind. The two series are near mirror images of each other: measured across the twelve months, their correlation is −0.78.
That is a cleaner inversion than we usually find. On a Greek island we looked at recently the two sources diverged in places and overlapped in others; here they trade places almost month for month. A solar roof in Dublin does most of its work between April and August. A turbine does most of its work between November and February. They fail at opposite ends of the year.
Each series against its own best month, so the shapes can be compared rather than the units.
Why that is the whole argument for running both.
Adding more of one source does not fix the months when that source is absent. Doubling a Dublin solar array doubles a July surplus and changes December by almost nothing, because in December there is very little sunlight to collect twice. The gap in a renewable system is rarely a shortage of capacity. It is a shortage of capacity at the wrong time of year.
Two sources that fail together are one source with extra steps. Two that fail at opposite ends of the calendar are genuinely worth having as a pair, and Dublin is close to the textbook case. That is not a claim about our product; it is a property of the weather over this city, and anyone can check it against the same public dataset we used.
The useful question is not how much a source gives you. It is what it is doing in the month you need it.
Now the part that does not flatter us.
An annual average is close to useless for wind, because the energy available goes as the cube of the speed: doubling the wind gives you eight times the power, so a mean hides everything that matters. The honest way to describe a site is to sort every hour of the year and look at the shape.
Do that for Dublin and you get this. Of 8,760 hours, 1,922 — nearly a quarter of the year — are below 2 m/s, where a low-wind blade set has not started turning. Most of the year, 3,576 hours, sits between 2 and 4 m/s: turning, but gently. Only 902 hours reach 6 to 8 m/s, and just 152 hours in the entire year are above 8. The windiest single hour in the typical year is 12.3 m/s.
The unflattering graphic. Two per cent of the year above 8 m/s is the number a seller leaves out.
So Dublin is a consistent wind site rather than a strong one. Seventy-eight per cent of hours are usable and very few are dramatic. That shapes what you should expect and it shapes which blades belong on the machine: a low-wind set that starts early and keeps turning is worth far more here than a high-wind set waiting for a gale that arrives for a hundred and fifty hours a year.
What we checked before publishing any of it.
We have been caught out by this dataset before. On another site the December wind series turned out to be a stuck value repeated for two thirds of the month, which inflated the annual mean by a third until we found it. So we now test every month before drawing anything: if a single wind speed accounts for an implausible share of a month’s hours, the month is broken.
Dublin passes. Across all twelve months the most repeated single value never exceeds 3.6 per cent of that month’s hours, which is what ordinary weather looks like. Nothing here has been excluded, smoothed or adjusted.
What this page is not.
It is not a survey of your roof. These figures come from a reanalysis model on a grid of tens of kilometres, ten metres above open ground. A courtyard between two buildings, a line of mature trees, or a parapet that accelerates air over an edge will all beat the model by more than the difference between the months on the chart above. A model cannot see your site.
And it is not a customer story. We do not publish who buys from us, where their machines go, or what they paid — not in Ireland and not anywhere else. If you are weighing this up for a building in Dublin, the useful thing to send us is your own situation: what you are trying to run, how exposed the site is, and whether you are storing the energy or using it as it arrives. We will tell you what applies, including when the honest answer is that your site does not suit a turbine.
Dublin’s wind is ordinary. Its timing is not.
That is a better reason to put a turbine next to a solar roof than any figure on a datasheet.
Wind and solar figures are from the European Commission Joint Research Centre’s PVGIS v5.2 typical meteorological year for 53.3498°N 6.2603°W at 13 m elevation, radiation from PVGIS-SARAH2 and wind from ERA5, drawn from 2005 to 2020. Solar is global horizontal irradiation; wind is plotted as the mean cube of the ten-metre wind speed, which is the energy available in the wind and not the output of any turbine. A typical meteorological year composes each month from a different real year, so it describes a normal year rather than any year that happened. The correlation of −0.78 is between the twelve monthly values of the two series as plotted. Hour counts are of all 8,760 hours in that year. No customer, order, address or installation is named, described or shown on this page.