Photovoltaic system: Costs, saving potential? - Experiences?

We are very well informed here. For photovoltaics, there are separate questionnaires, etc. After submitting the VAT advance returns monthly in the first year, as every founder does, I was automatically switched to quarterly submissions the following year. I then informally applied to stop submitting advance returns altogether, and this request was granted. At no point did I calculate the own consumption monthly and pay VAT on it. These are low, double-digit amounts annually. No one cares if you only report it once a year. I don't understand the fuss about the tax. However, due to previous self-employment, I do have prior knowledge, admittedly. Therefore, I also know that you can simply talk to the people at the tax office, and they can indeed be reasonable. There are things possible that you won’t find on Google.

Hello everyone,

unfortunately, I am not yet very knowledgeable about the topic of "photovoltaic systems." I wanted to start by cautiously approaching a feasibility calculation...

For our planned new building, a geothermal heat pump with a heating energy output of 6,000 kWh as well as 4,000 kWh for hot water is currently planned. After a bit of googling, I found out that the electricity demand for this is probably around 2,600 kWh per year. Additionally, we consume about 3,000 kWh of general electricity annually.

This brings me to a total energy demand of 5,600 kWh. A system with 6.83 kWp would be required for this. According to the internet, total costs including installation are expected to be 13,000 EUR.

If I include this amount in our home loan financing for the new building, I come to an additional monthly annuity/burden of around 40 EUR. Added to this is the basic price for an energy provider contract (you still need that, right?) of 15 EUR per month as well as maintenance costs (repairs; replacement of wear parts; cleaning and insurance) of about 35 EUR per month. In total, that would be 90 EUR per month.

On the other hand, the usual electricity costs of 5,600 kWh x 28 cents/kWh plus a basic fee of 180 EUR per year = 1,748 EUR per year or about 146 EUR per month.

According to my calculation, this results in an advantage of 56 EUR per month.

There are no longer any government subsidies for photovoltaic systems, right? Only solar collectors that provide hot water are still tax-advantaged, correct?

Are my considerations and calculations roughly realistic and correct?

For our planned new building, a ground source heat pump with a thermal energy output of 6,000 kWh for heating and 4,000 kWh for hot water is currently planned. After a bit of googling, I found out that the electricity demand for this should be around 2,600 kWh per year. Additionally, we consume about 3,000 kWh of general electricity annually. I thus come to a total energy requirement of 5,600 kWh. For this, a system with 6.83 kWp would be required. According to the internet, you have to reckon with total costs including installation of 13,000 EUR. In contrast, the usual electricity costs for 5,600 kWh x 28 cents/kWh plus a basic fee of 180 EUR p.a. = 1,748 EUR p.a. or about 146 EUR p.m. Are my considerations and calculations roughly realistic or correct?

If you mainly need the electricity for heating & co between April and September (because 80% of the total electricity quantity occurs then), go ahead. Otherwise: you need a gigantic annual storage, you are severely over-dimensioning (about 5x), or you buy a large part of your electricity and waste a large part of your own production if it cannot be fed in.

Your assumption is wrong, the calculation is complete nonsense and the system is way too expensive.

You will not manage without grid feed-in with any photovoltaic system in Germany.

Try self-consumption + feed-in tariff

Hello everyone, unfortunately, I am not yet very familiar with the topic "photovoltaic system." I wanted to first get my feet wet with a profitability calculation... For our planned new build, a geothermal heat pump with a thermal energy output of 6,000 kWh for heating and 4,000 kWh for hot water is currently planned. After a bit of googling, I found out that the electricity demand for this would be around 2,600 kWh per year. Additionally, we consume about 3,000 kWh of general electricity annually. I thus arrive at a total energy requirement of 5,600 kWh. For this, a system with 6.83 kWp would be required. According to the internet, one must expect total costs including installation of 13,000 EUR. If I include this amount in our home bank loan to finance the new build, I come to an additional monthly annuity/burden of about 40 EUR. Added to this is the basic price for an energy supplier contract (you need that anyway, right?) of 15 EUR per month as well as maintenance expenses (repairs; replacement of wear parts; cleaning and insurance) of about 35 EUR per month. In total, that would be 90 EUR per month. On the other hand, the usual electricity costs of 5,600 kWh x 28 cents/kWh plus a basic fee of 180 EUR per year = 1,748 EUR per year or about 146 EUR per month. According to my calculation, that amounts to an advantage of 56 EUR per month. There is no longer any government subsidy for the photovoltaic system, right? Tax benefits apply only to solar collectors that provide hot water, correct? Are my considerations and calculations roughly realistic or correct?

Complete nonsense. That would mean you can heat your place in summer but have it nice and cold in winter. If that is the case, then go ahead...

unfortunately, I am not yet very knowledgeable when it comes to the topic of "photovoltaic system." I wanted to first get a feel for a profitability calculation...

Yes, that reads as if you are not quite up to speed with photovoltaics yet. But that’s not a problem. Play around with the usual calculators available on the internet.

Are my considerations and calculations roughly realistic and correct?

Your calculations are roughly not wrong but quite incomplete and therefore not realistic. You still have to consider at least 2 factors:

1. Your load curve of electricity consumption: When during the year do you need more electricity and when do you get more electricity yield from your photovoltaic system? I have not yet seen a household where electricity consumption in winter is not significantly higher than in summer. On the other hand, the yield from the photovoltaic system is significantly higher in summer than in winter. As a result, you will not be able to supply yourself with electricity in winter and will have an overproduction in summer. And here we come to

2. For the overproduction of your electricity, you receive a feed-in tariff of - let’s say 9 ct/kWh. That means you have income in summer.

The offer of 13k for a 6.83 kWp system seems high. What exactly is included? Others here in the forum have had significantly larger systems installed for the same money. The electricity price including the meter also seems a bit high to me – especially since you can surely get a heat pump tariff for the heat pump, which is worthwhile.

What is almost certainly true: a photovoltaic system is in most cases a very profitable investment.