Benchmarks & calculation
How high is PV yield per kWp?
In Germany, a photovoltaic system often produces about 800 to 1,200 kWh of electricity per installed kWp per year. This range is a first guide. Location, orientation, roof pitch, shading, weather and system losses determine the value for a specific roof.
Quick calculation: annual yield in kWh = system size in kWp × specific yield in kWh/kWp.
A 10 kWp system with 1,000 kWh/kWp works out at around 10,000 kWh a year.
What does kWh per kWp mean?
Kilowatt peak (kWp) describes the rated power of the modules under standard test conditions. Kilowatt hours (kWh) measure the energy actually produced. The ratio kWh/kWp makes systems of different sizes comparable: 9,000 kWh from 9 kWp is the same specific yield as 12,000 kWh from 12 kWp, 1,000 kWh/kWp in each case.
Benchmarks for Germany
800 to 1,200 kWh/kWp per year works as a rough planning range. Within Germany, the solar resource tends to increase from north to south. A favourable, unshaded south-facing roof can lie above the middle of this range; unfavourable orientation, shading or high losses push the value down. A single average for Germany is therefore no substitute for a calculation for the specific location.
| Situation | Assessment |
|---|---|
| Unshaded south-facing roof, about 30-40° | usually a favourable annual yield |
| East-west roof | often somewhat less per kWp, but a broader daily curve |
| Flat roof | depends strongly on mounting frames and row spacing |
| Partial shading | cannot be given a blanket figure without detailed modelling |
The most important factors
Location and weather data
Irradiance, temperature and cloud cover vary by region and from year to year. The Solar Simulator uses long-term hourly weather data from PVGIS; for Germany, the irradiance is additionally scaled to a finer local pattern with the DUETT climatology of the DWD (Deutscher Wetterdienst, Germany's national weather service).
Roof pitch and orientation
South-facing surfaces with a medium pitch often maximise the annual yield. East-west systems shift generation into the morning and afternoon. The guide to roof pitch and orientation explains more.
System losses and shading
Inverters, cables, module temperature, soiling and mismatch reduce the usable AC yield. In the calculator, system losses and an additional flat-rate shading allowance can be set separately. Complex shadows from dormers, trees or neighbouring houses require detailed on-site planning.
Example: 8 kWp on a residential building
For an unshaded 8 kWp system, a specific yield of 1,050 kWh/kWp is assumed. That gives around 8,400 kWh per year. If the specific yield falls to 900 kWh/kWp because of location, orientation or losses, it is around 7,200 kWh. This range alone shows why system size on its own is not a yield forecast.
Calculate the yield for your own roof
- Select an address or place in the Solar Simulator.
- Enter the installed capacity, roof pitch and orientation.
- Set system losses and known shading realistically.
- Divide the annual figure by the system size to get kWh/kWp.
- Compare variants and check the monthly and daily profiles.
The calculator is a transparent technical estimate, not a promise of yield. The assumptions it uses are set out in the PVGIS methodology; the article Limits of the calculator explains the practical limits.
Frequently asked questions
Is 1,000 kWh per kWp good?
For many locations in Germany it is a plausible guide value. Whether it is good or achievable for a particular roof depends on location, orientation, shading and losses.
Is the specific yield the same every year?
No. Weather varies from year to year. Long-term climate data describe a typical expectation, not the guaranteed yield of a single year.
Can I derive self-consumption from kWh/kWp?
No. Specific yield describes generation. Self-consumption also depends on when electricity is used and, where applicable, on a battery.