ᐅ Photovoltaic Systems: What Has Been Your Experience?

That's correct: I think an additional 600-700 cubic meters of gas will be needed.

Then explain why that is nonsense? I still don’t fully understand why thousands of photovoltaic system owners make the same mistake year after year ;-)

Is it just because you pay a power fee and at the same time receive money for feeding electricity into the grid? What matters is the final result.

Anyone claiming that a battery system pays off in the photovoltaic sector is talking nonsense. Right now, there is a lot of optimistic talk and calculations. The incentives may seem attractive at first glance, but on closer inspection, they are misleading. No one tells you that the battery probably won’t last for the 20 years of feed-in. And even then, you still need electricity from the grid, at least during winter.

cybergnom schrieb:
I exclude the purchase price entirely anyway.

But when someone here writes that you can achieve zero energy costs with a photovoltaic system, that is simply nonsense.

You pay a €1,400 (approximately $1,500) advance and receive a €900 (approximately $970) refund. Where is the profit? Or at least, where are the zero costs?

It’s actually quite simple: your calculation is incorrect.
Without photovoltaic, you would pay €2,000 (approximately $2,150) for electricity; with photovoltaic, you pay €1,400 (approximately $1,500). Your savings of €600 (approximately $650) are already included here. That’s why you can’t subtract them again at the end.

You can’t just say: The pants usually cost €100 (approximately $107). I negotiated well and got a price of €80 (approximately $86). And because I saved €20 (approximately $21.50), the pants cost only €60 (approximately $64) in the end.

Mastermind1 schrieb:
Anyone who says a battery system pays off in the photovoltaic sector is talking nonsense. There is a lot of sugarcoating and optimistic calculations going on at the moment.

However, the situation changes when the storage system is practically given to you through the KfW subsidy. That’s when the storage system starts to become financially worthwhile. For example, from the beginning, it was clear to us that we would build to KfW 40 standard; the final step to reach KfW 40+ was the battery storage. Because of the two housing units, we qualify for a repayment grant of €30,000, while without the battery and only meeting KfW 40 standards, it would have been just €20,000. This additional repayment grant of €10,000 easily covered the cost of the 10.5 kW storage system and basically cost me nothing. It’s like the chicken and the egg – if we hadn’t chosen the battery, the grant would have been €10,000 less, but with the battery, the extra grant money effectively paid back into the storage system. So, the battery was free and financially justified from day one. Just the fact that we integrated the photovoltaic system and the battery storage for screed heating (air-to-water heat pump) significantly reduces the incurred costs.

Mastermind1 schrieb:
I didn’t include the tax aspects in my simple calculation.

Mastermind1 schrieb:
So I’m roughly 100€ (about $110) ahead per year.

The calculation as it stands is really oversimplified.

Without photovoltaic, you pay 2000€ (about $2200); with photovoltaic, 1400€ (about $1540) minus the payment of 500€ (about $550) (ignoring taxes for now).

So, a difference of 1500€ (about $1650) per year has to cover the investment, the return on equity, financing costs, as well as maintenance and repair costs, and depreciation (or more clearly a reserve for replacement in x years); and from that, you get an ROI of x years.

But to say that you have zero or even negative energy costs...

KfW40+ also has some drawbacks :-)

- Interest conditions are so-so
- It is no longer possible to fully repay early without prepayment interest
- Feed-in limitation to 60% for 20 years, regardless of whether the battery lasts that long or not
- For tax purposes, you can benefit from increased self-consumption with a battery for at least 5 years according to the tax office

The tax office charges based on the kWh of electricity you feed in, not the 70% that you get back yourself.

KingSong schrieb:
However, it looks different if the battery is practically given to you by the KfW. Then the battery becomes cost-effective. For example, it was clear to us from the start that we would build to KfW 40 standard. The final necessary step to reach 40+ was the battery. With two housing units, we qualify for a repayment grant of €30,000. Without the battery and with just KfW 40, it would have been only €20,000. This additional repayment grant of €10,000 easily covered the 10.5 kW battery and essentially cost me nothing. It’s like the chicken and egg scenario: if we hadn’t taken the battery, we would have received €10,000 less in subsidies; with the battery, we get more, which goes directly back into the battery. So the battery is free and pays off from day one. Just the fact that we integrate the photovoltaic system and battery into the screed heating (air-to-water heat pump) significantly reduces the resulting costs.