ᐅ Solar energy storage for photovoltaic systems?

We want to install photovoltaic panels on our terraced house. The technician who inspected our roof said that the maximum system size possible is 5 kWp. Question: Is a storage system worthwhile in this case? The technician says yes, but of course he also wants to sell one... I would appreciate an independent assessment. Thank you!

DachundFach schrieb:

We are planning to install photovoltaic panels on our terraced house. The technician who inspected our roof said that a system with a maximum output of 5 kWp would fit. Question: Is it worth installing a battery storage system then? The technician says yes, but of course he wants to sell it... I would appreciate an independent opinion. Thanks!

Economically viable only with subsidies. Are such incentives available in your area? The advantage of purchasing a storage system together with photovoltaic panels is that you can also claim a tax refund for the storage if you register a business. If you retrofit a storage system later, this may not be possible. If you have limited space, make sure the modules are as efficient as possible and avoid filling your roof with 340 W modules.

It probably won't be worth it. A storage system sized around 2-3 kWh would be reasonable, but such small storage units are a) rarely available and b) significantly more expensive per kWh than larger ones. I would advise against it.

Maybe you could start by showing your roof (photos with approximate dimensions, roof pitch, orientation such as north/south, etc.). Then some members here can probably provide more advice. It’s likely that the system size is limited by setback requirements (fire protection)? In that case, you might want to inquire about glass/glass modules as an alternative.

I have a 6.5 kWp system myself with a 3.9 kWh battery (which was heavily subsidized due to KfW40+ standards, VAT refund, etc.).

My experience so far: In summer, the 4 kWh battery almost lasts through the night (from 8:00 p.m. to 8:00 a.m.) and helps avoid the 70% power curtailment during the day (my system is oriented 100% south at a 45° roof pitch). However, in winter, the battery isn’t very useful due to fewer charge cycles and is sometimes even temporarily shut off. Roughly speaking, in my opinion, a battery is worthwhile if the cost is up to €500–700 (about $540–760) per kWh of installed capacity. The higher the electricity price, the sooner it makes sense.

Nope. Batteries are still simply too expensive (especially right now) to be economically viable. The larger the system, the more likely you are to benefit from your storage in winter (when you need it most). However, we are talking about systems over 10 kWp here.

I would also initially invest the (financial) resources into a thorough planning phase and verify whether it is truly not possible to install more than 5 kWp on the roof. While that is better than nothing, it is rather small for our long-term needs with a heat pump and electric car.

What is the roof pitch? Which directions do the roofs face? Are there any garages, carports, or garden sheds?