Example calculation
How much electricity does a PV system on a detached house produce?
A concrete example shows the order of magnitude. The actual yield depends on the exact location, roof, weather and technical design.
The example system
- Location: southern Germany, unshaded residential area
- Installed capacity: 10 kWp
- Gable roof: 35° pitch, main surface facing south
- System losses: 14%
- No additional flat-rate shading allowance
For a configuration like this, a specific yield in the order of about 1,000 to 1,150 kWh per kWp per year is plausible. The annual AC yield would then be roughly 10,000 to 11,500 kWh. That is a range, not a guarantee.
Rule of thumb: annual yield ≈ system size in kWp × specific yield in kWh/kWp. Example: 10 kWp × 1,050 kWh/kWp = 10,500 kWh per year.
Why the yield is not spread evenly
Most of it is produced in spring and summer. In winter the days are shorter, the sun is lower and cloud cover is more frequent. A system that, on balance over the whole year, produces more electricity than the household uses will therefore not automatically cover every winter day or every night.
East-west roofs often deliver somewhat less annual yield than an ideal south-facing surface, but spread production more widely across the morning and afternoon. That can match a household's consumption better.
Generation is not self-consumption
The Solar Simulator calculates the energy generated, not the economic self-consumption. Self-consumption is the part of the solar electricity that is used in the house at the time it is generated or charged into a battery. Without a consumption profile it cannot be determined reliably.
A household with an annual consumption of 4,000 kWh and 10,500 kWh of solar yield does not automatically use 100% solar electricity. Many kWh are produced at midday in summer and fed into the grid; at night and in winter, grid electricity is still needed. Shifting loads and battery storage can raise the self-consumption rate.
How to create your own scenario
- Select an address or place in the Solar Simulator.
- Set the roof pitch and orientation.
- Enter the module area that can actually be used as kWp.
- Set known shading and system losses realistically.
- Check the monthly and daily curves as well as the annual figure.
Compare several variants instead of reading a single figure as a forecast. For investment decisions, a qualified installer should check the roof layout, structural capacity, shading, electrical design and local requirements.