ᐅ Experiences with photovoltaic systems including battery storage?
Created on: 11 Dec 2022 13:53
R
Robvoi79
Hello everyone,
I want to have a photovoltaic system installed. It’s a mid-terrace house, with a storage battery and island (off-grid) operation.
I have now received an offer for a system with panels on the south and north sides.
I only have limited knowledge about this topic, so it would be great if someone with expertise could give a rough assessment of the offer.
Just whether it is generally okay and makes sense.
There is a “decision support” document and the offer itself. I have already noticed in the amortization calculation that the “price cap” for the electricity rate has not been considered.
Thank you in advance if anyone takes the time to answer my question.
Thanks
Robert
I want to have a photovoltaic system installed. It’s a mid-terrace house, with a storage battery and island (off-grid) operation.
I have now received an offer for a system with panels on the south and north sides.
I only have limited knowledge about this topic, so it would be great if someone with expertise could give a rough assessment of the offer.
Just whether it is generally okay and makes sense.
There is a “decision support” document and the offer itself. I have already noticed in the amortization calculation that the “price cap” for the electricity rate has not been considered.
Thank you in advance if anyone takes the time to answer my question.
Thanks
Robert
Well, if I simply take the assumed data, I end up with a net gain of roughly €6,000 after 20 years. This calculation excludes additional costs during installation, degradation, insurance, defects, and so on. On the positive side, you benefit from the exemption of VAT liability for self-consumption and the non-inclusion in income tax.
Whether the 50% energy consumption figure is realistic, you will have to assess yourself. It is achievable with storage. However, if the storage system does not last the full 20 years – which is to be expected – your energy consumption will increase sharply without new investments. This would reduce the result stated above.
I find the yield forecast quite low. Is the north side really that poor, or are there difficult conditions, shading, etc.?
Whether the 50% energy consumption figure is realistic, you will have to assess yourself. It is achievable with storage. However, if the storage system does not last the full 20 years – which is to be expected – your energy consumption will increase sharply without new investments. This would reduce the result stated above.
I find the yield forecast quite low. Is the north side really that poor, or are there difficult conditions, shading, etc.?
No idea how he came to that conclusion. It's not exactly north/south. I’d say about a 10-degree deviation.
There are trees on the south side. On the north side, there’s a house that’s slightly taller than mine.
It’s just not a detached property in an open field. So, not ideal.
And he’s calculating with 47 cents per kWh. That rate will soon be capped at 40 cents.
Reliable companies are really hard to find at the moment. There are plenty of scammers.
I would appreciate recommendations (I’m based in NRW, Cologne/Düsseldorf).
There are trees on the south side. On the north side, there’s a house that’s slightly taller than mine.
It’s just not a detached property in an open field. So, not ideal.
And he’s calculating with 47 cents per kWh. That rate will soon be capped at 40 cents.
Reliable companies are really hard to find at the moment. There are plenty of scammers.
I would appreciate recommendations (I’m based in NRW, Cologne/Düsseldorf).
It has always been the case that providers like to present their offers with cleverly calculated future price increases. The question is, what happens after the cap? Will things stabilize somewhat, will prices remain flat, or will they continue to rise?
Using the same calculation as above but with an electricity price of 40 cents per kWh (40¢/kWh), only 3,000 euros remain. At 35 cents per kWh (35¢/kWh), it breaks even. But as mentioned, this is all based on the assumptions above, for example, a storage lifespan of 20 years.
Using the same calculation as above but with an electricity price of 40 cents per kWh (40¢/kWh), only 3,000 euros remain. At 35 cents per kWh (35¢/kWh), it breaks even. But as mentioned, this is all based on the assumptions above, for example, a storage lifespan of 20 years.
Thanks for the assessment. It seems to be more a matter of principle or the peace of mind that comes with being able to produce some electricity yourself if needed (off-grid operation). The question is – for what purpose? If you ever really need it, you probably have other concerns as well.
1. Delete documents immediately! (why I’m specifically not writing here)
The degradation rate is a rough 10%. Real-life data so far shows significantly less (around 3%).
However, the assumptions regarding feed-in tariffs seem optimistic in terms of volume (too much?).
We can hardly assess self-consumption here because we don’t know the other living conditions and devices (heat pump, family size, etc.).
Interest rates are optimistically low or is there a concrete offer?
(On the other hand, in your position you probably already have enough cash, right ;-) ?)
The roof angle appears to be around 35-40°. Why only about 8 kWp?
The 47 cents in the calculation obviously favor the seller. But since you are familiar with Excel, just adjust it yourself...
The degradation rate is a rough 10%. Real-life data so far shows significantly less (around 3%).
However, the assumptions regarding feed-in tariffs seem optimistic in terms of volume (too much?).
We can hardly assess self-consumption here because we don’t know the other living conditions and devices (heat pump, family size, etc.).
Interest rates are optimistically low or is there a concrete offer?
(On the other hand, in your position you probably already have enough cash, right ;-) ?)
The roof angle appears to be around 35-40°. Why only about 8 kWp?
The 47 cents in the calculation obviously favor the seller. But since you are familiar with Excel, just adjust it yourself...
Robvoi79 schrieb:
with storage and island operation What is the goal? To be self-sufficient during extended power outages or just to bridge a short blackout? In the first case, make sure the inverter supports black start functionality.
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