Different year 1 generation figures

[Jake]

Hello,

I am unsure what losses/degradation is being taken into account for the year 1 value shown in the 'PV Energy during the observation period' graph as it is different to the other year 1 figures.

In this case the values are:

The 'PV Generator Energy (AC grid)' / 'Grid export', which does NOT account for first year degradation, is 822,996.55 kWh/yr

The 'Grid export (incl. module degradation)', which obviously does account for first year degradation, is 817,957 kWh/yr

However, the value confusing me is from the 'PV Energy during the observation period' graph which shows a year 1 value of 818,207.5 kWh/yr, why is this and what factors does this value take into account? I assume these are applied to the later years as well?

Thank you

 

 

[hotline_oh]

Hello Jake,

Thank you for your inquiry.

The diagram displays 25 simulated years without taking the commissioning date into account. The value in the 'Grid export (incl. module degradation)' row takes the commissioning date into account, i.e., here the year begins on July 1st and ends on June 30th of the following year.

The value in the 'Grid export (incl. module degradation)' row and the value for the first year in the diagram differ slightly if the commissioning date falls within the year and if module degradation is to be taken into account. The difference is greater the greater the degradation in the first year. This is because module degradation is calculated monthly.

In other words: If the system is commissioned on January 1st, the value in the 'Grid export (incl. module degradation)' row and the value for the first year in the diagram are the same. The first few months are winter months with low irradiation, so module degradation is of little significance. If the system is commissioned on July 1st, the first few months are summer months with high irradiation, and module degradation is more significant. Therefore, the value in the "Grid export (incl. module degradation)" row is lower than the one in the diagram. The values in the diagram are therefore slightly inaccurate.