Hello everyone,
Despite extensive forum searches and researching sample calculations online, I have not yet found a satisfactory answer: Is a solar panel system on the roof really worth it?
It’s actually quite simple—you compare the additional costs with the ongoing savings on energy bills, add in maintenance costs and so on. Then, of course, you need to account for the opportunity cost of the capital invested. Naturally, you also have to make some assumptions, for example about the future development of electricity prices.
Can anyone share real-life experiences to shed some light on this?
Best regards
HB1
Despite extensive forum searches and researching sample calculations online, I have not yet found a satisfactory answer: Is a solar panel system on the roof really worth it?
It’s actually quite simple—you compare the additional costs with the ongoing savings on energy bills, add in maintenance costs and so on. Then, of course, you need to account for the opportunity cost of the capital invested. Naturally, you also have to make some assumptions, for example about the future development of electricity prices.
Can anyone share real-life experiences to shed some light on this?
Best regards
HB1
We have just decided on a system.
Our building conditions are relatively favorable. A south-facing roof with minimal shading. The size is such that a generator output of 9.9 kWp can be achieved without using expensive high-performance modules.
Under these conditions, the price is approximately €1100-1200 per installed kWp. Depending on the location, one kWp installed generates about 900-1000 kWh per year. For simplicity, assuming 1000 kWh (per kWp), that corresponds to roughly €120 feed-in tariff if nothing is consumed on-site. This means about €1100 per year for our system. This feed-in tariff is legally guaranteed for 20 years. These are the guaranteed revenues.
Depending on the consumption profile, you can directly use about 20-25% of the generated energy. For that portion, you pay not the feed-in tariff of approximately €0.25 per kWh, but only the applicable taxes. This saves you about €0.20 in expenses instead of €0.12 in income.
If we simply calculate with €1200 income per year, the system pays for itself after 10 years. In reality, this will not be exact due to insurance costs, replacement parts (inverter), and lost interest. However, after 13-15 years, you should be in the clear. Overall, this results in a return on investment (ROI) of about 4-6%. That’s not bad. But calculate it specifically for your own situation.
Our building conditions are relatively favorable. A south-facing roof with minimal shading. The size is such that a generator output of 9.9 kWp can be achieved without using expensive high-performance modules.
Under these conditions, the price is approximately €1100-1200 per installed kWp. Depending on the location, one kWp installed generates about 900-1000 kWh per year. For simplicity, assuming 1000 kWh (per kWp), that corresponds to roughly €120 feed-in tariff if nothing is consumed on-site. This means about €1100 per year for our system. This feed-in tariff is legally guaranteed for 20 years. These are the guaranteed revenues.
Depending on the consumption profile, you can directly use about 20-25% of the generated energy. For that portion, you pay not the feed-in tariff of approximately €0.25 per kWh, but only the applicable taxes. This saves you about €0.20 in expenses instead of €0.12 in income.
If we simply calculate with €1200 income per year, the system pays for itself after 10 years. In reality, this will not be exact due to insurance costs, replacement parts (inverter), and lost interest. However, after 13-15 years, you should be in the clear. Overall, this results in a return on investment (ROI) of about 4-6%. That’s not bad. But calculate it specifically for your own situation.
H
Hausbauer113 Jul 2017 20:11I basically understand how to calculate this. However, there are a few pieces of information that are not entirely clear to me: the annual yield. How do I calculate it depending on the roof orientation, roof pitch, and possible shading? And what are the ongoing costs?
The investment costs of a solar system are fairly transparent. The feed-in tariff and the saved electricity costs are also not too problematic. The self-consumption rate is probably somewhere between 20% and 35%.
The investment costs of a solar system are fairly transparent. The feed-in tariff and the saved electricity costs are also not too problematic. The self-consumption rate is probably somewhere between 20% and 35%.
Hausbauer1 schrieb:
The annual yield. How do I calculate this depending on roof orientation, roof pitch, and possible shading? And what are the ongoing costs?Using PVGIS. Just google it.
The solar installer usually does this as well since they calculate the system’s payback period. It’s interesting if their expected yield is higher than what PVGIS would suggest.
Ongoing costs... many people will have insurance. You can also consider a maintenance contract or occasional cleaning. If you want to reduce the return, have your tax advisor handle the paperwork. But otherwise...
K
Knallkörper13 Jul 2017 22:57Hausbauer1 schrieb:
The rate for self-consumption is apparently somewhere between 20% and 35%.I consider this to be too optimistic for most households.
Knallkörper schrieb:
I consider that too optimistic for most households.Of course, it largely depends on the size of the generator and the connected loads.
H
Hausbauer114 Jul 2017 09:18Knallkörper schrieb:
I think that is too optimistic for most households.What do you consider realistic then? I have no idea. My assumption was based on statements I have received on this topic so far.
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