ᐅ A photovoltaic system that pays for itself and breaks even on a monthly basis

fragg schrieb:

Only install storage with a subsidy. That’s easily €6,000-10,000 (approx. $6,600-$11,000) you’ll never get back otherwise.

In my opinion, but this is just a gut feeling, storage systems are slowly evolving from a niche interest into a useful and cost-neutral component. Of course, this only applies under certain conditions. For existing systems, a hybrid inverter must be present, and for new installations, every available subsidy should be utilized...

Storage isn’t as expensive as it was, for example, three years ago. I’m having a BYD high-voltage storage system with 6.4 kW installed. With activation of the hybrid inverter (500 € [$550]), the total without subsidies is €5,700 ($6,300) including installation. Online, this unit costs around €4,000 ($4,400). Based on the specifications and especially the efficiency, this seems to be one of the best systems currently on the market. Whether it truly is, I don’t know—but after some research, that’s what it appears to be.

For €5,700 ($6,300), I’m currently getting 16,300 kWh (approx. 54,000,000 BTU), so in my view, it’s definitely worth considering.

Golfi90 schrieb:

What is the current typical cost per square meter for a photovoltaic system, including installation and everything? And how much electricity does it generate when installed on a south/east hip roof with a 28° (28°) pitch?

I have absolutely no idea about the typical costs or how much electricity such a system produces.

A battery would probably have to be installed for us... I also have no idea what something like that costs...

For photovoltaics, costs are usually not calculated per square meter but per kWp, and this should be a maximum of around $1,200 net for a system of about 10 kWp. The amount of electricity the system produces can be estimated, for example, using PVGIS. Roughly speaking, in Germany it is about 1,000 kWh per kWp per year.

A battery is generally not economically worthwhile and is more for experimental or personal interest.

Financing through a loan is possible and can be self-sustaining, but the payback time is longer, meaning savings are lower over time.

Zaba12 schrieb:

Currently, I can get 16,300 kWh for 5,700€, so from my point of view, it’s definitely worth considering.

Yes, but you shouldn’t forget the lost feed-in tariff.
I analyzed with Excel how much I could have self-used this year with a 6 kWh battery. That’s nearly 1,000 kWh saved (in terms of consumption), but on the other hand, there are about 200 kWh lost due to storage and charging inefficiencies. I receive about 11 cents compensated and pay 26 cents per kWh. If I assume 30 cents, I save 19 cents/kWh from the battery. So:
(1,000 kWh − 200 kWh) * €0.19 = €152/year.
The battery currently costs me about 8,000€ because I need additional equipment for the PV system. It would therefore pay off after 53 years...

Lumpi_LE schrieb:

Yes, but you shouldn’t forget the lost feed-in tariff.
I analyzed with Excel how much of this year’s 6000 kWh I could actually use myself. That’s just under 1000 kWh savings (in terms of consumption), but on the other hand, there are about 200 kWh losses from the storage and charging process. I get paid a feed-in tariff of about 11 cents, and I pay 26 cents per kWh. Let’s assume 30 cents per kWh savings, so I save 19 cents/kWh from the battery. Therefore:
(1000 kWh - 200 kWh) * €0.19 = €152 per year.
The battery currently costs me about €8000 because I need additional equipment for the storage system. So it would take 53 years to pay off...

Well, I’m at €5700 all inclusive. Not really much better.

Did you calculate from March to September assuming a full charge/discharge cycle every day? The other months are semi-relevant anyway.

I understand what you’re trying to say, but I don’t see how you got those numbers: (1000 kWh - 200 kWh) * €0.19 = €152 per year.

- What percentage loss does the 200 kWh storage/efficiency loss represent? I calculate about 5% efficiency loss due to the high-voltage system.
- How do you arrive at the 1000 kWh figure?
- I think I get about 10.8 cents and pay 30 cents per kWh.

Everyone who installed in 2020 already gets 9.xx cents.

I’m assuming about 200 days of charging/discharging at 6.4 kWh each, minus 5% efficiency losses due to the high-voltage battery. You can make it look better or worse however you want. After 15 years, you’re still a few hundred euros in the red.

I’ve left out taxation and price increases. On the other hand, you save money every year on electricity purchased from the grid.

The lifespan of a system is often stated as 20-25 years. Is that really the case? Do individual cells or modules fail over time, or is a complete replacement necessary at some point?