Photovoltaic Consultation: 45° Gable Roof North/South

With a 45° roof pitch, I only see south as worthwhile,
E and W too small and triangular,

When planning photovoltaics, it makes sense not only to focus on the annual consumption but also to consider the usual consumption curves. Those who have electricity demand in the morning and evening can buy a few kWh less battery by sensibly dimensioning the small east-west areas. Such calculations vary greatly on an individual basis.
Don't forget: each direction needs an MPPT and the south roof possibly 2 to stay within the power range. That means costs.

Does your house connection allow for 2 e-car charging stations?

As a rule, one charging station is sufficient for several e-cars. I have yet to meet a household where two charging stations at the house would be worthwhile, and I have several people with 2 or more e-cars in my circle.

No solar roof tiles for E and W?

Although I am a big fan of solar roof tiles and have them on my own house,
economically that would be nonsense because solar tiles must also fit into the existing system – and that is definitely not the case here.

A friend installed shingles in overlay mounting. They have a format of about one tile height and 4-5 tile widths. That would help get more out of the triangular area. Also quite nice looking. The shingles came from Eckpack in Darmstadt.

Thank you for the ideas and advice. Garage with flat roof ([South or West orientation possible]) is still available. I will discuss this with the companies as well as the east-west orientation. Ideally, the roof is not to exploit the area, but because of a used property, it was not in our control. I would want to avoid major changes to the roof.

It depends on the garage. Is it shaded from one or more directions? If not, then best to lay it flat, not elevated. And if possible/allowed... do it yourself. Photovoltaics are especially not worth it because the specialist companies charge insane prices. A few modules and an inverter don’t cost much. It only gets expensive when the professional performs their voodoo.

On the house roof... only fully do the south side, north is a waste of resources and money.

Because: 13.2 kWp with 9.6 kWh storage currently costs? 20,000 EUR?

With that, you save yourself 4,000 kWh per year, which you would otherwise have to buy, so about 1,400 EUR/a (current prices with my provider). That means 15 years until you have saved the first cent compared to pure grid consumption...

Now think about it, you would also spend a lot of money on the north side with much less yield.

Yes, before anyone complains here. The remaining 8,000 kWh are of course fed into the grid, earning a fantastic 640 EUR per year. But we only took the pure investment costs for the photovoltaic system, no maintenance, no cleaning, no smart meter, no photovoltaic insurance against hail, etc., no interest for the loan for the purchase...
That balances out well.

Even a cash-paid photovoltaic system from a specialist company in the very best south-facing location with 100% self-consumption does not break even in under 10 years...

Here is my calculation. Without KfW, this is unprofitable.

Investment:
Heat pump		32,000.00 €
Photovoltaics 17kWp 10kW battery 1 wallbox		31,000.00 €
KfW		- 17,000.00 €
KfW		- 6,000.00 €
		40,000.00 €
Costs before:
Gas		2,000.00 €
Electricity		2,000.00 €
Diesel		1,900.00 €
Total		5,900.00 €
Costs new
Gas		- €
Electricity		2,750.00 €
Feed-in		- 540.00 €
E-car 20,000 km/year charged only at home.	included in electricity
Total		2,210.00 €
		Cost reduction per year
40,000.00 €	/	3,690.00 €
Written off after		10.8	years

... where did you get the investment costs and other costs from? Or did I overlook them? And, the heat pump is already installed.