ᐅ Photovoltaic System: Costs and Savings Potential – Experiences?

It’s actually not that complicated. You just need to calculate what the system earns for you—meaning self-consumption plus feed-in tariff—and then compare that to the investment. You’re mixing too many things here, and your maintenance costs are way too high.

Example:

A 10 kWp system costs €12,500

It produces 10,000 kWh per year

Of this, 6,500 kWh are fed into the grid and 3,500 kWh are self-consumed.

6,500 kWh × 9.875 cents (my own feed-in tariff) = approximately €650 per year
3,500 kWh × 25.07 cents (my electricity cost) = approximately €875 per year

= approximately €1,525 per year

You can then subtract your interest expenses and, if you want, another €150 for maintenance, repairs, and insurance. I’ll leave the conclusions to you.

Andre77 schrieb:

Since the beginning of May, for example, I have been paying €0.2293 per kWh. Always make sure to switch providers and take advantage of bonuses.

Unfortunately, electricity prices vary by region. In a test with different postal codes, I found almost a 10-cent per kWh difference compared to the Berlin/Stuttgart area.

Starting in 2021, CO2 taxation will be implemented. Currently, it is announced again that the majority of the revenue should benefit the reduction of the Renewable Energy Act surcharge by 75%. This would make the nationwide electricity price about 5 cents per kWh cheaper.

This naturally puts even more pressure on calculations per storage system. The (economic) desire for high self-consumption is also dampened as a result.

DaSch17 schrieb:

Feed-in tariff: 8 cents/kWh (as the completion of the single-family house is planned for 11/2021)

I don’t believe in the 8 cents. On one hand, we are already very close to 8.x today, and on the other hand, the development of the Renewable Energy Act after the 52 GW cap is completely uncertain. Personally, I consider it highly unlikely that the subsidy will increase again. The discussion is more about different models with significantly lower feed-in tariffs (aiming for self-consumption systems).

Conclusion: profitability calculations for 2021 are a waste of time, and current offers will no longer be valid by then anyway.

Andre77 schrieb:

If your roof is only large enough to fit a 7 kWp system, then yes, otherwise fill the entire roof. But this has already been mentioned here. Your roof generates money. The larger the system, the lower the price per kWp. Maintenance costs of €420 per year (about $460) are, in my opinion, set way too high. What exactly do you need to maintain? Don’t forget photo-voltaic insurance, which costs €50-70 per year (about $55-75). And make sure your personal liability insurance covers your solar panels too, in case modules fly off and cause damage to others.

Let the heat pump run on the house electricity. It saves the fee for a second meter. You can get general electricity for less than your 29 cents per kWh. Since early May, for example, I pay €0.2293/kWh (about 22.9 cents). Always keep switching providers and take advantage of bonuses.

You can certainly fit more on the roof. But we would prefer to install only as much as we can realistically consume ourselves. In my opinion, it doesn’t make sense to cover the entire roof with photovoltaic panels if the future of feed-in tariffs remains uncertain.

After researching this a bit, I assume that, in the long term, feed-in tariffs will practically no longer be supported, and that with technical advances, full self-consumption through storage is the future. So why would I install more solar panels than necessary, potentially wasting excess production? It’s better to install fewer panels now and add a battery system in a few years when storage units become more efficient and affordable.

As has been mentioned here, electricity prices depend heavily on the region. There are probably offers for 24-25 cents per kWh, but I prefer to calculate conservatively using 29 cents.

The €420 per year (about $460) includes maintenance/wear, cleaning, and insurance.

halmi schrieb:

It’s really not that complicated, you just need to calculate what the system will bring you, meaning your self-consumption plus feed-in tariff, and compare this against the investment. You are mixing too many things here, and your maintenance costs are also too high.

Example:

10 kWp system costs €12,500 (about $13,600)

It produces 10,000 kWh per year

Of that, 6,500 kWh is fed into the grid, and 3,500 kWh is self-consumed.

6,500 kWh x 9.875 cents (my feed-in tariff) = about €650 per year (about $710)
3,500 kWh x 25.07 cents (my electricity cost) = about €875 per year (about $960)

= about €1,525 per year (about $1,670)

You can then factor in some small interest and, for example, another €150 for maintenance, repairs, and insurance. I’ll leave you to draw your own conclusions.

Your calculation is certainly correct if I want to know when my photovoltaic system pays off. But I am more interested in the economic advantage compared to conventional external electricity supply.

Fuchur schrieb:

I don’t believe in the 8 cents. On one hand, we’re already close to 8.x cents today, and on the other, the development of the Renewable Energy Act after the 52 GW cap is completely open. Personally, I think it’s absolutely impossible that support will increase again. The discussion is more about different models with significantly lower feed-in tariffs (aim: systems for self-consumption).

Conclusion: Profitability calculations for 2021 are a waste of time and current offers won’t even be valid by then.

I share that view, see above.

Therefore, my strategy would be: calculate the photovoltaic system now based on self-consumption, install it on the roof, and take advantage of the feed-in tariff for the first few years. Once investing in a battery becomes worthwhile, purchase one and celebrate becoming independent from external energy sources. Am I completely mistaken in this thinking?

But we have to decide now for or against a photovoltaic system. The overall house plan is being finalized now or by the end of the year.

Why do you need to decide now? Just consider empty conduits and that’s it. Trying to integrate something "conceptual" at this stage only causes costs without any added value.