ᐅ Photovoltaic System and Air-to-Water Heat Pump – Profitability for a Single-Family Home Built to KfW 55 Energy Efficiency Standard
Created on: 11 Jan 2022 23:19
M
Maxwell8
Hello,
we are building a fairly large KFW55EE house with external dimensions of approximately 10x14m (33x46 feet) and a roof pitch of 15° (roof surfaces facing north and south).
We have a lot of window area (100m2 (1,076 sq ft)) and expect an energy consumption of about 7-9k kWh per year due to the size.
Heating is provided by underfloor heating with the Tecalor THZ 504 air-to-water heat pump.
Feed-in tariffs are no longer significant, but the electricity price is currently 45 cents/kWh.
We would have to finance the photovoltaic system ourselves because there is no sufficient budget left.
> From a profitability perspective, does a photovoltaic system make sense in our situation?
> What size and costs should we expect?
> Should it be installed directly or should we first prepare with conduits?
> We also have an attached 6x6m (20x20 feet) flat-roof garage on the east side. Would adding photovoltaic panels there be beneficial?
I will, of course, speak with companies but would like to gather some opinions beforehand.
Thank you in advance. 🙂
we are building a fairly large KFW55EE house with external dimensions of approximately 10x14m (33x46 feet) and a roof pitch of 15° (roof surfaces facing north and south).
We have a lot of window area (100m2 (1,076 sq ft)) and expect an energy consumption of about 7-9k kWh per year due to the size.
Heating is provided by underfloor heating with the Tecalor THZ 504 air-to-water heat pump.
Feed-in tariffs are no longer significant, but the electricity price is currently 45 cents/kWh.
We would have to finance the photovoltaic system ourselves because there is no sufficient budget left.
> From a profitability perspective, does a photovoltaic system make sense in our situation?
> What size and costs should we expect?
> Should it be installed directly or should we first prepare with conduits?
> We also have an attached 6x6m (20x20 feet) flat-roof garage on the east side. Would adding photovoltaic panels there be beneficial?
I will, of course, speak with companies but would like to gather some opinions beforehand.
Thank you in advance. 🙂
S
Stefan00114 Jan 2022 14:01WilderSueden schrieb:
And not with ± but compared to a profitable investment yielding, say, 5% per year. However, you first need to find a profitable investment with 5% return that carries the same risk as a photovoltaic system.
Of course, you can always look at the calculation from both sides. Sometimes ETFs are considered completely safe, and the solar system lasts only 10 years, while others predict the collapse of ETFs and argue that the solar system lasts 30 years... everyone will get the result they want.
I will now put forward the bold idea that with the ongoing rise of e-mobility and the demand for e-fuels (surprise! There are other means of transport besides cars that currently burn fossil fuels to our detriment), the global electricity demand will increase significantly. And as with all things, at some point the demand for your solar power might influence the price, even if your grid operator is not required to buy it for more than 6 cents. Then perhaps soon someone will come along offering a few cents more for it. Or a few cents more than a few cents more.
If I understand correctly, this was already the case in 2021 for so-called over-20-year systems. For systems no longer receiving subsidies, an annual average value is calculated that then applies to the feed-in tariff... and due to the increased market electricity prices, this was actually already 7.5 cents (7.5¢) in 2021!
Then there is also the uncertainty of the self-sufficiency gap that I have to cover by purchasing electricity. What does the calculation look like for a deliberately undersized system if electricity prices rise to 50 cents (50¢)? The larger the system, the smaller this gap, and the more comfortable the future. For me, the appeal of a mono-energetic house lies in being as independent as possible. I would install every kilowatt-peak on the roof that fits.
Then there is also the uncertainty of the self-sufficiency gap that I have to cover by purchasing electricity. What does the calculation look like for a deliberately undersized system if electricity prices rise to 50 cents (50¢)? The larger the system, the smaller this gap, and the more comfortable the future. For me, the appeal of a mono-energetic house lies in being as independent as possible. I would install every kilowatt-peak on the roof that fits.
kati1337 schrieb:
I’m going to put forward the bold idea that with the ongoing rise of e-mobility and the need for e-fuels (surprise! There are other modes of transport besides cars that still depend on burning fossil fuels to our disadvantage), global electricity demand will increase significantly. And as with all resources, at some point the demand for your solar power could influence the price, even if the utility company isn’t required to buy it from you for more than 6 cents. Then maybe soon someone will come along offering you a few cents more. Or a few cents more than a few cents more. I doubt that. If e-fuels arrive, it will likely be managed by an oligopoly similar to how gas stations are currently operated. There’s no other way to supply so many people. The existing grid connection points are already limited. I’m afraid that without restrictions on personal consumption, private photovoltaic systems won’t be viable.
D
Deliverer14 Jan 2022 15:28Even the FDP(orsche) realized since yesterday that e-fuels are not a viable solution. ;-)
KingJulien14 Jan 2022 15:37Photovoltaic systems should definitely be sized based on your own energy needs.
Scenario: -5°C (23°F), overcast sky.
The heat pump is running, someone is cooking, the laundry needs to be done, and the electric car also needs some power.
If the roof then provides just enough, the photovoltaic system is not oversized.
Scenario: -5°C (23°F), overcast sky.
The heat pump is running, someone is cooking, the laundry needs to be done, and the electric car also needs some power.
If the roof then provides just enough, the photovoltaic system is not oversized.
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