What it yields where you are
How much solar produces in Potenza
In Potenza a well-oriented system produces 1,381 kWh a year for every kWp installed. A 6 kW system — a home-sized one — makes about 8,288 kWh a year. The figures below come from PVGIS, the European Commission's database.
1,381
kWh a year for every kWp
8,288
kWh a year from a 6 kW system
34°
the best tilt, facing south
01At a glance
A year of sun in Potenza.
A 6 kW system produces
8,288 kWh
About what 4.1 households use in a year.
The best month
July
965 kWh: 2.2 times the worst month.
Hours of sunshine a year
3,578 h
9.8 hours a day on average. In the leanest month it drops to 6.5.
How cloudy the sky is
51%
Average over the year. The cloudiest month is January, at 66%.
Warmest month's temperature
22.6 °C
In the coldest month the average is 3.2 °C.
How much it changes year to year
from −6% to +6%
Sunlight measured over the last twenty years, against the average.
02System sizes
How much a system produces in Potenza
The three sizes people actually put on a house, on the best plane.
3 kW
4,144
Produces each year · kWh
450 W modules: 7
6 kW
8,288
Produces each year · kWh
450 W modules: 13
10 kW
13,813
Produces each year · kWh
450 W modules: 22
03Month by month
Month by month in Potenza
A yearly total doesn't say when the energy arrives, and that's the part that decides whether you need storage.
A 6 kW system yields most in July, with 965 kWh, and least in January and December, with 444: 2.2 times as much. That's why the summer bill goes to zero and the winter one doesn't.
| Month | Output of 6 kW | Sunshine | Cloud | Temperature | Days above 30°C |
|---|---|---|---|---|---|
| January | 444 kWh | 197 h | 66% | 3.2 °C | — |
| February | 494 kWh | 224 h | 61% | 4.7 °C | — |
| March | 673 kWh | 276 h | 60% | 6.1 °C | — |
| April | 758 kWh | 311 h | 56% | 9.6 °C | — |
| May | 834 kWh | 361 h | 56% | 13.8 °C | — |
| June | 868 kWh | 391 h | 36% | 19.1 °C | 4 |
| July | 965 kWh | 425 h | 18% | 22.6 °C | 11 |
| August | 917 kWh | 395 h | 26% | 22.1 °C | 9 |
| September | 733 kWh | 317 h | 45% | 17.4 °C | 1 |
| October | 656 kWh | 270 h | 54% | 13.5 °C | — |
| November | 496 kWh | 203 h | 66% | 9.0 °C | — |
| December | 444 kWh | 208 h | 63% | 5.2 °C | — |
Heat costs yield: above 25 °C of cell temperature a panel loses about 0.4% per degree, and in summer the cell runs some twenty degrees above the air. Here there are 25 days above 30 °C a year, nearly all between June and August. That loss is already inside the figures above — don't subtract it twice — but it is why July, which gets the most sun of any month, never yields as much as the extra sun would suggest.
Output: our own calculation on PVGIS irradiation, calibrated against PVGIS city by city and month by month. Sunshine, cloud, temperature and hot days: ten-year averages 2015-2024 from the ERA5 reanalysis, via Open-Meteo. Two different sources, in separate columns on purpose.
04Orientation
And if the roof doesn't face south
In Potenza the two sides are not equivalent, and it's worth knowing beforehand: compared with a south-facing roof you lose about 14% facing east and 20% facing west. The sun's geometry is symmetrical and the sky is not: morning air is clearer than afternoon air, or the other way round, and over a full year the difference shows. On a roof facing the wrong way it costs as much as a smaller system.
South-facing, 30°
1,373 kWh/kWp
The benchmark
East-facing, 30°
1,175 kWh/kWp
−14% compared with south
West-facing, 30°
1,092 kWh/kWp
−20% compared with south
05The years
And if next year is cloudy?
Fair question: the sun isn't the same every year. Here is how much it actually varied, from 2005 to 2024.
Over twenty years the poorest was 2010: 6% below average. The most generous was 2022: 6% above. Every other year sits in between. That's why a solar estimate uses the average of many years and not the last one — a bad year doesn't change the maths of a system that lasts twenty-five.
Yearly irradiation from 2005 to 2024 according to the ERA5 reanalysis, via Open-Meteo, against its own average. This is a different database from the one behind the output figures above, which comes from PVGIS and stops at 2023 — which is why the two periods don't match.
06For designers
The technical figures
The ones a designer needs. If you don't know them, you don't need them: everything is above.
Yield per installed kW
1,381 kWh/kWp
How many kWh each kW of panels gives in a year, on the best possible roof.
Best tilt
34°
The angle worth using here, facing south.
Sunlight reaching the ground
1,545 kWh/m²
Solar energy landing on one flat square metre in a year.
Other cities
Your roof isn't an average.
These figures are for an ideal roof in Potenza. The estimate on your address accounts for your roof, the shade and your consumption: two minutes, without leaving your contact details.