Which System-related Factors are important for The Power Generation Of A Solar Panel System?

The power generation of the solar panel system depends on numerous factors. In addition to the location factors, the solar PV system plays by selecting the right solar PV panels a role.

1. The installed power of the solar panel system

The installed power of the solar panel system is given in kilowatt peaks. This refers to the nominal output, which the solar panel system can deliver under certain Standard Test Conditions (a global solar radiation of 1,000 W/m2, Air mass of 1.5 and at a solar cell temperature of 25 °C).

In a grid tied solar system, the installed power is adapted as far as possible to the power consumption (Rule of thumb: annual yield = annual power consumption).

In the off-grid solar system, the installed power must be adapted to the consumption profile and the storage possibilities.

2. The possible yield of the solar panel system

The possible yield of the solar panel system is largely determined by the effective global solar radiation on-site and by the local weather conditions (the number of the cloudy and clear days, the amount of air pollution, etc.).

Therefore, it is important to know, how much the average values of the global solar radiation were on-site over the previous years. It is worth mentioning here that online solar calculators also have access to these data to calculate the likely yield of a solar panel system.

When planning a solar PV system, PV software is used to obtain a rough yield forecast. Without this, the calculation of the economic efficiency of the solar PV system is not possible.

When the solar panel system is installed, the effective yields are determined by the meters (Feed-in meter, consumption meter). Solar data logger also provides information about the yield of the solar panel system.

3. Monthly fluctuations in power output (annual cycle)

Due to the seasons and the weather, there are fluctuations in the power output. The availability of power output changes during the year and therefore also the yield.

There are databases, which offer the annual fluctuations (regarding monthly average) of the power output for a particular place and a given year.

Tip: In the case of off-grid solar systems, the annual cycle in yield must be considered when choosing the storage size.

4. Daily fluctuations in power output (diurnal cycle)

The diurnal cycle results from the hourly fluctuations in the power output. Here, it is possible that the diurnal cycle for working days looks completely different as at the weekend.

The diurnal cycle shows the yield variations of the solar PV system more detailed than the annual cycle.

Tip: Depending on the region, an orientation towards the West can make more sense than towards the East, because the early morning fogs can cause fewer yields.