ᐅ How large should the photovoltaic system be?

Created on: 31 Jan 2022 19:50
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MeinHaus45
We received a quote from the electrician for a 10 kWp photovoltaic system. However, I am wondering whether investing in a 10 kWp system is really cost-effective or if a smaller system might be sufficient. Our four-person household consumes around 4,500 kWh in our rented apartment without a heat pump. In our planned single-family house (140 m² (1,507 sq ft), KfW 55 standard), there will be an air-to-water heat pump and possibly an electric car in the future. I am not familiar with the energy consumption of heat pumps, but wouldn’t 8 kWp or even less be enough? We do not want to feed electricity back to the grid, and the feed-in tariff is not a reason for us to choose a larger system.
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borxx
1 Feb 2022 00:34
The question is what "sufficient" means. Your main energy production is in summer, while electricity is mainly needed in winter.

Here are the material prices for the solar installer:

Photovoltaic modules from 400€/kWp (kilowatt peak)
Mounting hardware around 120€/kWp
Hybrid inverter approximately 2,000€
5kW battery storage 4,000€, 10kW 6,000€
Additionally, cable and miscellaneous items estimated at 1,000€

On top of that, scaffolding and labor costs apply...
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Deliverer
1 Feb 2022 11:28
If you have the space to build large and compare a few quotes, the feed-in tariff in 2022 still covers the entire system cost. Self-consumption also significantly increases profitability. In which other part of your house have you received such high support?

This means that regardless of consumption, you should always install panels on all available roof areas (including north-facing, 25° pitch, and flatter roofs) as well as on garages and carports.

A few thoughts to consider:
The system lasts at least 30 years.
In 10 years, no one will voluntarily drive combustion engine vehicles anymore.
Photovoltaic systems provide about 5-10% of their installed capacity in bad weather.
Electric vehicles start charging at only 1.6 kW.
If you want to drive cheaply even in bad weather, now is the time to calculate.
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MeinHaus45
1 Feb 2022 11:58
borxx schrieb:

The question is what "sufficient" means. Your main energy production is in summer, but electricity is mainly needed in winter.

Here’s a brief overview of material prices for the solar installer:

Photovoltaic modules from €400 per kWp
Mounting ~€120 per kWp
Hybrid inverter ~€2,000
5 kW battery storage €4,000, 10 kW €6,000
Plus cables and small parts, flat rate €1,000

On top of that, scaffolding and labor costs...

Are the prices with or without VAT?
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MeinHaus45
1 Feb 2022 12:01
Even if the quoted price of €25,000 including installation and VAT is correct, it would still be €5,000 too much.
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borxx
1 Feb 2022 12:12
Gross prices in this case

the <7 cent production costs (feed-in tariff) including installation and ongoing costs is probably only achievable with self-installation.
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MeinHaus45
1 Feb 2022 12:20
So, I understand this correctly? A 10 kWp system with a 6 kWp storage, including installation, should be achievable for a maximum of €20,000 gross?

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