ᐅ A photovoltaic system that pays for itself and breaks even on a monthly basis

Created on: 19 Nov 2019 07:35
G
Golfi90
Hello everyone…

Is it possible, in general terms, to install a photovoltaic system on a roof that pays for itself every month?

In other words, does it generate enough electricity so that a loan taken out for the system is covered by the savings on our electricity bills?

What is the current cost per square meter for a photovoltaic system, including installation and everything else? And how much electricity can it produce if installed on a south-east hip roof with a 28° pitch?

I have absolutely no idea about the amounts involved—both the cost of such a system and the electricity it generates.

We would probably need to install a battery as well… I also don’t know what that would cost.

A few experiences would be great, possibly even with concrete financing tips or personal stories.
S
Specki
19 Nov 2019 20:38
There are two households.
In both, the women are at home around midday, so the washing machine, dryer, and dishwasher can all be scheduled for that time.
One apartment has a wood stove. In winter, cooking is usually never done with electricity there, and the electric kettle for tea is not needed either.
About 8% of the consumption comes from two dehumidifiers running in the basement during the summer months to maintain a good level of humidity. I can set these to operate around midday using a timer.

As you can see, there are several factors on our side that support the idea that 50% is quite realistic, so I have based my calculations on that.
Z
Zaba12
19 Nov 2019 20:45
Specki schrieb:

There are two households.
In both, the women are home around midday, so the washing machine, dryer, and dishwasher can all be scheduled for that time.
One apartment has a wood stove. So in winter, cooking with electricity and using the electric kettle for tea is usually not necessary.
About 8% of the consumption comes from two dehumidifiers running in the basement during the summer months to keep the humidity at a good level. I can set these on a timer for midday as well.

As you can see, there are several factors in our case that suggest 50% self-sufficiency is quite realistic, so that’s what I assumed for myself.

Except for the dehumidifiers, the described setup does not differ from the 30% self-sufficiency figure. To my knowledge, 30% is already the maximum with the woman home at midday and running the dryer and washing machine.

With my electric car but no battery storage, I expected a maximum of 40%.
But that’s irrelevant. It was still a good decision regarding the photovoltaic system.
Interesting calculation. Thanks for that. I find the cost per kWp quite expensive for such a large system. Isn’t it already in the lower nine-hundreds range? Are those full black modules?
S
Specki
19 Nov 2019 20:52
I’ll be able to tell you in a year whether my assumption was correct.

If an electric car arrives in a few years, the situation will definitely look much better since it is usually at home during the day. This way, I can probably cover about 90% of the electricity needed for the car with my photovoltaic system.

By the way, you don’t always have to quote the entire previous post.

Regards
Specki
S
Specki
19 Nov 2019 22:32
Oh, and another factor that benefits the 50% is that the system is significantly oversized in terms of consumption.
F
Fuchur
19 Nov 2019 23:16
Zaba12 schrieb:

I find the cost per kWp in euros quite expensive for such a large system. Isn’t it usually already below 900 euros per kWp?

The offer is reasonable; it also depends on the configuration. We are planning a 26.3 kWp (26.3 kW) system ourselves and have only received two offers in this region. One based on SolarEdge is priced at €940 per kWp (€940 per kW), and one based on SMA is €900 per kWp (€900 per kW) (both from the same provider). All other quotes we obtained are above €1000 per kWp (€1000 per kW).
S
Specki
20 Nov 2019 06:58
Zaba12 schrieb:

I find the cost per kWp/€ quite high for such a large system. Shouldn’t it already be in the lower 900 range? Are these full black modules?

Sorry, I must have missed that.
The house was built in 1964 and has a mortar ridge. This ridge will be completely replaced with a dry ridge, as it’s no longer in very good condition and will likely deteriorate further due to the movement of the tiles.
In addition, there will be a snow guard on one side of the house, about 16 m (52 feet) long.
If you estimate these two items at around €2,000, the price comes to about €886 per kWp.
Since both are carried out by the solar installer and also due to the photovoltaic system, I included them in my profitability calculation.

Regards
Specki