ᐅ Photovoltaic System: Self-Consumption Rate with Battery Storage and Additional Questions
Created on: 27 Nov 2015 13:23
T
T21150
Dear forum members,
At the beginning of 2016, I will be retrofitting my house with a photovoltaic system. It will have an east/west orientation with about 3.4 kWp per roof side.
The system will include an inverter with a small integrated LiPo battery with a capacity of 2 kWh.
This project is not driven by economic considerations. Overall, I expect to pay roughly the same amount each month for electricity as I do now without the photovoltaic system—at least.
Rather, it is motivated by my interest in experimentation and the fact that I genuinely enjoy working with exciting technical things. Also, I simply take pleasure in generating part of the electricity I consume (beyond the emissions created during production and installation) in a CO2-neutral (or more CO2-neutral) way.
With the small LiPo battery (I don’t have space for a larger capacity solution), the share of self-consumption rises from a little over 30% (without battery) to about 48%, based on calculations and projections. It never pays off financially due to the additional costs—in my opinion, however, maximizing self-consumption of the generated electricity is worthwhile. Just my personal quirk.
The east-west roof orientation is—not necessarily a disadvantage in my view—especially considering further increasing the self-consumption share. The system will deliver power in the morning, at noon, and in the evening, but overall it won’t be quite as efficient as a system with a purely south-facing orientation.
My questions:
1. Who among you already has a photovoltaic system with a buffer battery and can share your individual self-consumption rate?
2. What experiences have you had with east-west orientation for such systems?
3. What tools and methods do you use to further increase your self-consumption? I personally have somewhat “unusual” (?) ideas, such as simply waiting for a sunny day before running the washing machine, and similar approaches. Does this behavior bring any noticeable results?
4. Overall, how satisfied are you with your decision to install a photovoltaic system?
5. My house consumes less energy than what is currently predicted in the energy performance certificate. That is encouraging, but else nothing special.
However, if you add up the necessary electrical auxiliary energy (heating, circulation pumps, solar pump for the existing thermal solar system, controlled ventilation, etc.), a noticeable amount accumulates over the year. With the current primary energy factor for electricity of 2.4, and also with the upcoming year’s factor (primary energy factor for electricity = 1.8).
In combination with the solar system, recalculating the energy certificate would produce a better value since some auxiliary energy would be supplied by the photovoltaic system/battery. Also, the house would then generally generate a larger share of energy from renewable sources.
What do you think: Is it sensible and worthwhile to have the existing certificate recalculated after installation?
I would appreciate it if you could take the time to share your views and experiences with me. Thank you in advance.
Best regards,
Thorsten
At the beginning of 2016, I will be retrofitting my house with a photovoltaic system. It will have an east/west orientation with about 3.4 kWp per roof side.
The system will include an inverter with a small integrated LiPo battery with a capacity of 2 kWh.
This project is not driven by economic considerations. Overall, I expect to pay roughly the same amount each month for electricity as I do now without the photovoltaic system—at least.
Rather, it is motivated by my interest in experimentation and the fact that I genuinely enjoy working with exciting technical things. Also, I simply take pleasure in generating part of the electricity I consume (beyond the emissions created during production and installation) in a CO2-neutral (or more CO2-neutral) way.
With the small LiPo battery (I don’t have space for a larger capacity solution), the share of self-consumption rises from a little over 30% (without battery) to about 48%, based on calculations and projections. It never pays off financially due to the additional costs—in my opinion, however, maximizing self-consumption of the generated electricity is worthwhile. Just my personal quirk.
The east-west roof orientation is—not necessarily a disadvantage in my view—especially considering further increasing the self-consumption share. The system will deliver power in the morning, at noon, and in the evening, but overall it won’t be quite as efficient as a system with a purely south-facing orientation.
My questions:
1. Who among you already has a photovoltaic system with a buffer battery and can share your individual self-consumption rate?
2. What experiences have you had with east-west orientation for such systems?
3. What tools and methods do you use to further increase your self-consumption? I personally have somewhat “unusual” (?) ideas, such as simply waiting for a sunny day before running the washing machine, and similar approaches. Does this behavior bring any noticeable results?
4. Overall, how satisfied are you with your decision to install a photovoltaic system?
5. My house consumes less energy than what is currently predicted in the energy performance certificate. That is encouraging, but else nothing special.
However, if you add up the necessary electrical auxiliary energy (heating, circulation pumps, solar pump for the existing thermal solar system, controlled ventilation, etc.), a noticeable amount accumulates over the year. With the current primary energy factor for electricity of 2.4, and also with the upcoming year’s factor (primary energy factor for electricity = 1.8).
In combination with the solar system, recalculating the energy certificate would produce a better value since some auxiliary energy would be supplied by the photovoltaic system/battery. Also, the house would then generally generate a larger share of energy from renewable sources.
What do you think: Is it sensible and worthwhile to have the existing certificate recalculated after installation?
I would appreciate it if you could take the time to share your views and experiences with me. Thank you in advance.
Best regards,
Thorsten
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nordanney8 Jan 2016 12:53I don’t like calculating what pays off 😉
But if I get paid for the system NOW, the future doesn’t matter to me for the time being.
If the system is only supposed to pay off in 20 years, I have a lot of unknown factors over that period – repairs, failures, efficiency losses, cleanings, possibly changing legal requirements, and so on.
But if I get paid for the system NOW, the future doesn’t matter to me for the time being.
If the system is only supposed to pay off in 20 years, I have a lot of unknown factors over that period – repairs, failures, efficiency losses, cleanings, possibly changing legal requirements, and so on.
N
nordanney8 Jan 2016 13:09Flose89 schrieb:
So just go for it and operate the system plus battery with a green (subsidized) smile? 🙂 Yep!
nordanney schrieb:
Well done, for us it was only 35% in 2015Thank you. It could still be improved a bit if my wife more consistently avoided running the washing machine or dryer in the evening or at night, or programmed them to start at 6:30 a.m. 😉.
But I guess that’s just a minor complaint. It’s not always possible with two little mess-makers.
Besides, you shouldn’t live for the house (the photovoltaic system), but with it... .
If I’m not mistaken, you also use your photovoltaic system to support your heat pump. Of course, that means your feed-in ratio will be lower. The balance between the electricity drawn for the heat pump and the support from self-consumption probably isn’t very favorable, which naturally affects the overall result.
@Flose89
I do consider a maximum 30% feed-in rate quite ambitious.
As far as I know, you can’t just “let the surplus go to waste” because it is always fed into the grid. The only way to “let it go to waste” would be through an off-grid solution – that is, if you are disconnected from the grid. However, this is not approved in Germany and wouldn’t be practical in winter either, when you might suddenly be left in the dark.
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