Two customers in Palermo, five kilometres apart, can buy the same machine and get completely different results from it. That is not true of most cities we ship to, and in Palermo the reason is visible from any rooftop: the city sits on a plain that is closed in by high ground, with a 606-metre promontory shutting the top of the gulf. Where you stand inside that shape decides almost everything.
Palermo from above. Count the metres of clear air between one roof and the next — there are barely any. That density is the whole problem in one photograph.
A city behind a 606-metre wall
Monte Pellegrino is an isolated carbonate promontory on the northern edge of Palermo. At 606 metres it is the highest point inside the city boundary, it closes the Gulf of Palermo to the north, and it is visible from essentially everywhere in the city. For our purposes it is something less romantic: a very large windbreak, sitting exactly where the sea breeze would otherwise arrive.
Behind it the old city occupies flat, dense ground, and behind that the land climbs again into the hills. A turbine on a roof in the middle of the old core is standing at the bottom of a bowl, in the wind shadow of every building around it, and roughly nothing on a specification sheet will rescue that site. Move the same machine to the coast, or up onto the slopes where a building stands clear of its neighbours, and it is a different proposition entirely.
The same city drawn as a section. Deliberately schematic and not to scale — the point is shelter and exposure, not metres.
One island, two extremes
It is worth saying that Palermo is only one end of Sicily. At the other, on the east coast some two hundred kilometres away, Etna stands at roughly 3,403 metres — the tallest peak in Italy south of the Alps, and a mountain whose exact height changes when it erupts. Against that, the highest ground inside Palermo's city limits is a 606-metre promontory. The photograph at the top of this page is the eastern end of that range: commercial turbines standing on an exposed Sicilian ridge with Etna smoking behind them.
An island that runs from a 3,400-metre volcano to a sheltered coastal plain does not have one wind climate, it has dozens. That is the real reason we will not quote you a number for “Sicily”. The honest unit here is not the island, or even the city. It is the site.
The wind that ruins the solar day
Then there is the sirocco: a Mediterranean wind that comes off the Sahara and can reach violent speeds by the time it makes landfall. It arrives over Sicily from the south, carrying North African dust with it, and for a solar panel it is straightforwardly bad news. The haze cuts the light, and the dust settles on the glass and stays there until somebody climbs up and washes it off. What is easy to miss is that this is also the strongest wind the island gets.
That is the useful thing about running a panel and a turbine on the same battery in a place like this. They do not fail on the same days. The hazy, dust-laden afternoon that flattens a solar curve is very often a windy one, and the still, glassy August morning that suits the panel perfectly gives the turbine nothing at all.
A panel and a turbine are not twice as reliable. They are unreliable on different days, which is the part that actually matters.
Why Palermo keeps coming up
Palermo is the capital and largest city of Sicily, a 2,700-year-old city on the gulf that carries its name, with something like 1.2 million people in and around it. It is also, quietly, one of the stronger parts of our Italian map — not because we have any romantic attachment to the place, but because that is where the orders come from. Once you know the geography that stops being surprising. A large coastal population, a great many buildings outside the old core that stand on their own, and a season of genuine wind add up to somewhere a turbine can earn its keep.
Cefalù, further along the same coast. Compare it with the first photograph: a town built out onto a headland with open water on both sides is the opposite of a sheltered courtyard, and it is the kind of Sicilian site where a turbine has something to work with.
What we would hold against us, in your position
The sirocco is seasonal and episodic. It is not a resource you can bank on every week, and anyone selling you a turbine on the strength of one dramatic wind is selling you the exception rather than the average. The dust that dirties a panel also finds its way into anything mechanical, and coastal salt air corrodes hardware left outdoors — ours included. Both are maintenance you will genuinely have to do, and we would rather write that down than let you discover it in year three.
And the honest summary of everything above: if your roof is in the middle of the old city, hemmed in on four sides, do not buy a turbine from us. Buy the panel. We would rather sell you half a system that works than a whole one where one half spends its life stationary. If you are on the coast, on the slopes, or on a building that stands clear of what surrounds it — measure the site, and then talk to us.
The section drawing on this page is ours and is schematic rather than surveyed. The three photographs — the turbines below Etna, Palermo from above, and Cefalù — are licensed stock images, not our own, unlike the factory photographs elsewhere on this blog, which are. The figures for Monte Pellegrino and for the city are the published ones, and the sirocco is what the meteorological literature describes: a Mediterranean wind out of the Sahara capable of very high speeds. The turbine figures are our own published specifications and are checkable on the product page.