ᐅ Photovoltaic System: Self-Consumption Rate with Battery Storage and Additional Questions
Created on: 27 Nov 2015 13:23
T
T21150Dear 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
Hi Thorsten,
sorry, I can’t really contribute to your questions, but I have a question in return:
How exactly is a LiPo battery pack installed in a house? Is it placed in a fire-resistant room with an alarm and smoke detector? After all, they do react quite dangerously to overcharging...
The LiPo batteries I use in model airplanes and similar applications, I store in fireproof ammunition boxes—and not without reason!
Best regards,
Andreas
sorry, I can’t really contribute to your questions, but I have a question in return:
How exactly is a LiPo battery pack installed in a house? Is it placed in a fire-resistant room with an alarm and smoke detector? After all, they do react quite dangerously to overcharging...
The LiPo batteries I use in model airplanes and similar applications, I store in fireproof ammunition boxes—and not without reason!
Best regards,
Andreas
B
Bauexperte27 Nov 2015 14:02andimann schrieb:
How is a LiPo battery pack typically installed in a house? I'm interested in that as well.andimann schrieb:
The LiPo batteries I use in model aircraft and similar applications are stored in fireproof ammunition boxes, and for good reason!Exactly. That’s why our partners install the storage system off-site.Best regards, Bauexperte
Hello Andreas,
I am a model builder myself and fly high-performance helicopters up to the 12s class.
The manufacturer (SMA) of the inverter is not very specific in the specifications here. However, I believe a LiFePO battery will be used, not a pure LiPo. The device comes from Germany. I assume this company does not use batteries of questionable origin or specifications, as they have a good reputation to maintain.
Due to the lack of a basement and options for external installation, the inverter plus battery (which is one unit) will be installed in the utility room.
The device will be continuously monitored remotely via the internet. Additionally, multiple safeguards against deep discharge are certainly integrated. I am sure the manufacturer does not allow discharge down to 20%; I suspect they stop at 40% and also limit the charging current so that the battery specifications are not exceeded. Constant temperature, strict adherence to charge and discharge limits, as well as avoiding vibrations and mechanical stress significantly reduce the risk of damage to a LiPo, as you know, being an electric model builder.
In general, there is certainly some risk. Yes. That’s life. There are also refrigerator fires, which are not uncommon.
The utility room in my home is already equipped with smoke detectors, like all other rooms.
Kind regards,
Thorsten
I am a model builder myself and fly high-performance helicopters up to the 12s class.
The manufacturer (SMA) of the inverter is not very specific in the specifications here. However, I believe a LiFePO battery will be used, not a pure LiPo. The device comes from Germany. I assume this company does not use batteries of questionable origin or specifications, as they have a good reputation to maintain.
Due to the lack of a basement and options for external installation, the inverter plus battery (which is one unit) will be installed in the utility room.
The device will be continuously monitored remotely via the internet. Additionally, multiple safeguards against deep discharge are certainly integrated. I am sure the manufacturer does not allow discharge down to 20%; I suspect they stop at 40% and also limit the charging current so that the battery specifications are not exceeded. Constant temperature, strict adherence to charge and discharge limits, as well as avoiding vibrations and mechanical stress significantly reduce the risk of damage to a LiPo, as you know, being an electric model builder.
In general, there is certainly some risk. Yes. That’s life. There are also refrigerator fires, which are not uncommon.
The utility room in my home is already equipped with smoke detectors, like all other rooms.
Kind regards,
Thorsten
So. Now I understand better. I couldn’t contact SMA directly. Without a device serial number (how could I have it, the unit hasn’t arrived yet) and without being an installer...
I then called the installation company and spoke with the specialist there.
Brief summary:
- The batteries are from LG.
- The batteries are “sealed” (--> see my post; these are LiFePO4 batteries, which have minimal fire risk compared to this type). Colloquially, LiPo and LiFePO4 are often confused, although the technical differences are significant!
- The same batteries are also used in commercial aircraft from well-known manufacturers (there aren’t many; I won’t name the specific one mentioned here).
(…From my own experience, I know that a burning house or apartment is definitely not good! But you can get out... a plane burning at 11,000 m (36,000 feet) altitude is a completely different issue. So — I think: there’s no need to worry here, at least not beyond the usual everyday risks!)
- There is a corresponding conformity and safety declaration, which I expect to receive within the next week.
Best regards,
Thorsten
I then called the installation company and spoke with the specialist there.
Brief summary:
- The batteries are from LG.
- The batteries are “sealed” (--> see my post; these are LiFePO4 batteries, which have minimal fire risk compared to this type). Colloquially, LiPo and LiFePO4 are often confused, although the technical differences are significant!
- The same batteries are also used in commercial aircraft from well-known manufacturers (there aren’t many; I won’t name the specific one mentioned here).
(…From my own experience, I know that a burning house or apartment is definitely not good! But you can get out... a plane burning at 11,000 m (36,000 feet) altitude is a completely different issue. So — I think: there’s no need to worry here, at least not beyond the usual everyday risks!)
- There is a corresponding conformity and safety declaration, which I expect to receive within the next week.
Best regards,
Thorsten
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