ᐅ Quote for photovoltaic system including battery storage – storage yes/no?
Created on: 8 Sep 2024 16:53
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haus_bau2025
Hello everyone,
My wife and I are currently planning to build our single-family home of about 140 m2 (1,507 sq ft) and are considering whether to build it to KfW 40 standard or not (mainly for cost reasons). We have received an offer from our construction company for a photovoltaic system with 6 kWp and a high-voltage battery from Varta with 6.5 kWh (6.5 kWh) storage capacity, costing around 18,000 euros. Since the battery alone costs nearly 6,000 euros, and I recall reading here in the forum that many people reject a battery because a) it is too expensive and b) it would be better to invest in additional photovoltaic modules instead, I wanted to ask how you would approach this situation. The plan also includes installing an air-to-water heat pump with central, decentralized, or controlled mechanical ventilation (we are still considering these options as well).
1.) Would you remove the battery and replace it with more photovoltaic modules? If yes, how much kWp capacity would you recommend for a single-family home built to KfW 40/55 standard with "normal use," i.e., occasional home office?
2.) Or would you keep the battery and increase the photovoltaic system capacity with additional modules?
Do you have any other ideas or suggestions regarding what we should pay attention to in connection with the photovoltaic system?
My wife and I are currently planning to build our single-family home of about 140 m2 (1,507 sq ft) and are considering whether to build it to KfW 40 standard or not (mainly for cost reasons). We have received an offer from our construction company for a photovoltaic system with 6 kWp and a high-voltage battery from Varta with 6.5 kWh (6.5 kWh) storage capacity, costing around 18,000 euros. Since the battery alone costs nearly 6,000 euros, and I recall reading here in the forum that many people reject a battery because a) it is too expensive and b) it would be better to invest in additional photovoltaic modules instead, I wanted to ask how you would approach this situation. The plan also includes installing an air-to-water heat pump with central, decentralized, or controlled mechanical ventilation (we are still considering these options as well).
1.) Would you remove the battery and replace it with more photovoltaic modules? If yes, how much kWp capacity would you recommend for a single-family home built to KfW 40/55 standard with "normal use," i.e., occasional home office?
2.) Or would you keep the battery and increase the photovoltaic system capacity with additional modules?
Do you have any other ideas or suggestions regarding what we should pay attention to in connection with the photovoltaic system?
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nordanney8 Sep 2024 17:49I still have an "old" 10 kWp system on the roof. Therefore, no storage unit (whose benefits I am not convinced of in most cases). I use just under 30% of the generated energy myself, and feed just under 7,000 kWh back into the grid. I also draw about 7,000 kWh from the grid.
This year, I planned to install an additional 3 kWp myself, but other construction projects got in the way.
This year, I planned to install an additional 3 kWp myself, but other construction projects got in the way.
I also recommend getting additional quotes, as @Nida35a suggested. I see the solution from Nida35a as more cost-effective and aligned with current trends. Especially since your builder is handling the roof anyway, better synergies should be achievable.
In general, fully utilizing the roof and attic space is gradually becoming worthwhile.
In general, fully utilizing the roof and attic space is gradually becoming worthwhile.
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Buchsbaum0668 Sep 2024 20:51A storage system makes more sense today than ever before. Everything else is simply nonsense. Yes, I know many will criticize me for this, but that’s just the way it is.
A 10 kW storage system should cost less than 5,000 euros. A system with 6.5 kW is clearly undersized. For a single-family house, it should always be between 10 and 15 kW.
It can definitely happen that when your system starts operating, the feed-in tariff or export tariff is abolished. Then you end up with a full-feed-in system, giving away electricity for free while buying grid electricity at a high price.
I still don’t understand why a storage system shouldn’t be worth it. The value-added tax was removed from photovoltaic systems, module prices have fallen by half and are at record lows, and storage system prices have also dropped.
I have a 7.5 kWp system with a 10 kW storage unit and from mid-March until mid-November, I hardly need any electricity from the grid. I still feed in about 3,000 kWh.
But go ahead. Fill your roof completely, feed in at 8 cents (€/kWh or equivalent), and be happy. Then you’ll just have to run your dishwasher only at midday when the sun is shining. I don’t care. For me, everything runs at night, and the usual electricity consumption during the day is covered.
And such a system for a single-family house with a decent storage unit shouldn’t cost more than 10,000 euros.
My electricity consumption has dropped from just under 6,000 kWh to 1,200 kWh. The extra 200 euros in feed-in tariffs won’t get me rich either.
A 10 kW storage system should cost less than 5,000 euros. A system with 6.5 kW is clearly undersized. For a single-family house, it should always be between 10 and 15 kW.
It can definitely happen that when your system starts operating, the feed-in tariff or export tariff is abolished. Then you end up with a full-feed-in system, giving away electricity for free while buying grid electricity at a high price.
I still don’t understand why a storage system shouldn’t be worth it. The value-added tax was removed from photovoltaic systems, module prices have fallen by half and are at record lows, and storage system prices have also dropped.
I have a 7.5 kWp system with a 10 kW storage unit and from mid-March until mid-November, I hardly need any electricity from the grid. I still feed in about 3,000 kWh.
But go ahead. Fill your roof completely, feed in at 8 cents (€/kWh or equivalent), and be happy. Then you’ll just have to run your dishwasher only at midday when the sun is shining. I don’t care. For me, everything runs at night, and the usual electricity consumption during the day is covered.
And such a system for a single-family house with a decent storage unit shouldn’t cost more than 10,000 euros.
My electricity consumption has dropped from just under 6,000 kWh to 1,200 kWh. The extra 200 euros in feed-in tariffs won’t get me rich either.
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RotorMotor8 Sep 2024 21:22Buchsbaum, please share some figures. How much did your storage system cost, and how many kWh does it handle per year?
Unfortunately, battery storage systems rarely benefit the environment and almost never save money. You can easily calculate it: electricity costs 30 cents per kWh, while the feed-in tariff would be 8 cents per kWh.
This means you can save about 22 cents per kWh by using storage. After accounting for conversion losses and similar factors, the savings drop to around 20 cents per kWh.
If everything goes well, the battery can achieve about 200 cycles per year (for smaller batteries; larger ones often only reach about 150 cycles because they can’t be fully charged in winter or fully discharged in summer). So, you can save roughly 30–40 euros per kWh per year through a storage system.
For a 5 kWh battery, that's about 200 euros per year; for a 10 kWh battery, about 300 euros per year. Assuming a lifespan of 10 years, a 5 kWh storage system should cost no more than 2000 euros (including installation and related expenses), and a 10 kWh system a maximum of 3000 euros.
I have deliberately left out interest rates and expected electricity price increases, as they should roughly balance out.
Unfortunately, battery storage systems rarely benefit the environment and almost never save money. You can easily calculate it: electricity costs 30 cents per kWh, while the feed-in tariff would be 8 cents per kWh.
This means you can save about 22 cents per kWh by using storage. After accounting for conversion losses and similar factors, the savings drop to around 20 cents per kWh.
If everything goes well, the battery can achieve about 200 cycles per year (for smaller batteries; larger ones often only reach about 150 cycles because they can’t be fully charged in winter or fully discharged in summer). So, you can save roughly 30–40 euros per kWh per year through a storage system.
For a 5 kWh battery, that's about 200 euros per year; for a 10 kWh battery, about 300 euros per year. Assuming a lifespan of 10 years, a 5 kWh storage system should cost no more than 2000 euros (including installation and related expenses), and a 10 kWh system a maximum of 3000 euros.
I have deliberately left out interest rates and expected electricity price increases, as they should roughly balance out.
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Buchsbaum0668 Sep 2024 21:37Online price for the Huawei Luna 2000 battery storage with 10 kW today is 3,979.00 euros! A really excellent device and the best on the market.
Trina Vertex 450 W modules cost 68.80 euros each.
10 kWp modules cost around 1,400 euros.
Add another hybrid inverter for 860 euros, some installation materials, a smart meter, and the electrician’s work. (Huawei Sun 8 KTL1, three-phase)
With 8,000–9,000 euros, you can get a 10 kW system with storage. And it will be top quality. Such an investment will typically pay off after 6 to 8 years.
As mentioned, prices are currently at a record low.
Trina Vertex 450 W modules cost 68.80 euros each.
10 kWp modules cost around 1,400 euros.
Add another hybrid inverter for 860 euros, some installation materials, a smart meter, and the electrician’s work. (Huawei Sun 8 KTL1, three-phase)
With 8,000–9,000 euros, you can get a 10 kW system with storage. And it will be top quality. Such an investment will typically pay off after 6 to 8 years.
As mentioned, prices are currently at a record low.
R
RotorMotor8 Sep 2024 21:46Buchsbaum066 schrieb:
Online price for the Huawei Luna 2000 storage with 10 kW today is 3979.00 Euro!
Add another hybrid inverter for 860 Euro, some installation materials, a smart meter, and the electrician. (Huawei Sun 8 KTL1, three-phase) So just for the storage, about 5,000€ ($5,400) extra cost.
With 150 cycles per year and a 10-year lifespan, that’s 15,000 kWh total.
At €0.08 / kWh (8 cents per kWh) lost feed-in tariff and 10% losses, a kWh from the storage ends up costing you around €0.45 / kWh (45 cents/kWh).
I currently pay almost half that to my electricity provider... so this sounds like a pretty bad deal.
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