ᐅ Photovoltaic System – Rough Cost Estimate

HubiTrubi40 schrieb:

How large should the system be? Is there any estimate? We use about 2700 kWh/year.

Do you need to take out financing for the photovoltaic system (the title still says PC – maybe some IT enthusiasts will join) or will you pay cash?

You can quite easily calculate whether and how the system will be worthwhile.

Currently, prices for a 10 kWp system are around €1,200–1,300 per kWp all-in (please don’t complain, these are current average prices across the country – you can find detailed info if you look). So about €12,000 investment.

With that, you will currently cover about 20–25% of your own electricity demand – assuming an external electricity price of 33 cents, you save about 25 cents/kWh, which is around €150 per year (estimated 600 kWh).

Besides that, you will feed roughly 9,400 kWh into the grid at 8.1 cents/kWh, so about €760 per year.

Together that’s around €910 per year – with an investment of €12,000–13,000, the system will pay off in about 13–14 years. Not very attractive, since you could also invest your money elsewhere.

But then the variables come into play:
- annual electricity price increases
- heat pump
- electric car

Depending on how you calculate, the payback period can improve significantly. For example, I have a self-consumption rate of 25%, or about 2,400–2,600 kWh per year (heat pump and car), which makes it look much better. And if the electricity price rises to, say, 50 cents/kWh in 10 years, anyone who installed a photovoltaic system on their house today will be very happy.

What risks are there?
- Performance losses over time, mitigated by performance guarantees often over 85% after 20 years
- Inverter failures, mitigated by sometimes very long warranty periods, but usually the warranty ends after 10 years

The “problem” with small systems like the one you mentioned in your first post is the fixed costs. The scaffolding and setup time don’t care if you install 2 kWp or 50 kWp on the roof. The installation and connection only take a little longer for larger systems. With a small system, these fixed costs are proportionally very high per kWp.

Finally, regarding battery storage. You need to calculate how expensive the stored electricity will be compared to how much you actually use from it. Currently, it often turns out that electricity from the battery is even more expensive than buying from the grid. That’s why I tend not to include a battery in my calculations anymore.

A relative just paid 19,000 for a 4.2 kWp system, a 5 kWh battery storage, and a new meter cabinet, and thinks it's great.

But it's good to see that the realization is gradually sinking in here as well that for the average person, it’s usually not worth it. It only really pays off by a stroke of luck if the system runs trouble-free for 20 years... and after 15 to 20 years, you just break even, meaning you only actually start saving money then.

In winter, the problem is that the 4.2 kWp system hardly produces enough energy to power a heat pump... and you usually charge the electric car in the evening, so you rely on the battery storage. Essentially, you’re charging a battery from a battery... which is a complete disaster in terms of efficiency.

And in summer, you can’t even use up all the energy generated, so you feed it back into the grid for around 6 cents per kWh. Hooray...

[A relative recently spent 19,000 on a 4.2 kWp solar system, a 5 kWh battery storage, and a new electrical panel, and they are very happy with it.

But it’s good to see that the realization is slowly spreading here as well that, for the average person, this usually doesn’t make much sense and only really pays off with a lot of luck if the system runs without issues for 20 years... After 15 to 20 years, you just break even, so you only start saving money from then on.

In winter, the problem is that a 4.2 kWp system barely produces enough energy to power a heat pump... and you usually charge your electric vehicle in the evening, so it relies on the battery storage. In other words, you’re charging one battery from another battery, which is a complete disaster in terms of efficiency. And in summer, you can’t even use all the energy produced, so you feed it into the grid for about 6(?) cents. Great...]

I also have relatives who took an offer from En*al, and I don’t even dare tell them what I think about it. Fortunately, I was able to prevent this with my parents because I was informed in time.

In winter, even a 12 kWp system produces almost nothing usable for the heat pump. You definitely shouldn’t charge an electric vehicle from the battery storage—that makes absolutely no sense.

At least the feed-in tariff is around 8.1 cents, but that’s hardly worth mentioning.

That’s why I basically said earlier that a photovoltaic system is more of a hobby than a business case, at least if you judge it on a manageable time frame.

In times of crisis, however, it serves as a backup, similar to a wood stove when electricity and gas prices skyrocketed. Suddenly, despite the increased cost of wood, it was still comparatively much cheaper, and you had the security of knowing the house would stay warm.]

Allthewayup schrieb:

That's why I basically said earlier that a photovoltaic system is more of a hobby than a business case. At least if you consider a limited time horizon for the evaluation.

I think that is a significant underestimation. Realistically, an unfunded system should break even after about 10 years.
And it’s also good for a clear conscience regarding environmental impact.

nordanney schrieb:

I think that is clearly underestimated. Realistically, a system without financing should break even after about 10 years.
And it’s also good for your green conscience.

However, with a system without financing, you still have to consider the interest you would otherwise earn on the invested money.
And with a financed system, you need to add the interest costs of the financing.

And if possible generation of non-fossil energy is not implemented, then we must also start taking into account the costs caused by environmental damage and climate change. So far, these costs have largely been borne by the government (all of us) in an ironic way and are not included in the individual calculations of returns. This simply means that taxes have to be spent on them.