ᐅ Photovoltaic System for 120 sqm of Living Space – Should the Entire Roof Be Covered?

KingJulien schrieb:

The rest is just simple math.

Only that math alone is not meaningful without thinking. Anyone who, besides the pure yield calculation, does not take into account the distribution of yield over the day and the year can build a system that produces more but delivers less usable energy to the house. With an electricity price for a newly registered system that is about 4,x times higher than the feed-in tariff, optimizing self-consumption makes sense. Suddenly, surfaces that extend the hours of yield rather than maximizing the total yield itself become interesting. Nowadays, even 70-80 degree steep south-facing systems on the facade are attractive for winter yield—almost complete direct consumption within the house.

hampshire schrieb:

By now, even south-facing systems with inclinations of 70–80 degrees (°) are becoming attractive for winter yield—almost complete direct consumption within the house.

Conversely, north roofs are uninteresting due to the lack of winter yield. In this respect, I find a planned installation on a north roof at 35° (°) pitch already questionable.

@hampshire I think we agree.
We are also fully going with NNO. That way, we get generation in the morning.
I’d rather have a fully paid-off 23kWp system on the roof after 15 years than a 12kWp system after 13 years.
Self-sufficiency increases, cost per kWp decreases, the extra side pays for itself, and the environment benefits.
And besides: if you do it, do it right 😎

KingJulien schrieb:

@hampshire I think we agree.
We are fully covering NNE as well. That way, we get production in the morning.
I’d rather have a fully paid-off 23 kWp system on the roof after 15 years than a 12 kWp system after 13 years.
Self-sufficiency increases, cost per kWp decreases, the additional array pays for itself over time, and the environment benefits.
And besides: if you do it properly 😎

Do you also factor in your ongoing expenses and so on, or how do you arrive at that assumption?

Rumbi441 schrieb:

Are you including your ongoing costs, etc., or how do you arrive at that assumption?

This calculation comes from two independent solar installers. One of them would personally only do a south-facing installation.
If someone else calculates, the result will be different.
It’s not about the absolute numbers, but their ratio.
The result remains the same. If I cover my entire roof, the payback period is only slightly longer.

PS: My calculation shows a longer period. But the main point remains the same.

PPS: I am including the ongoing costs, of course.

There are also enthusiasts who cover the north half of purely south-facing roofs to bypass the 70% throttling rule. Another example of the absurd consequences such nonsensical regulations can have.