ᐅ Photovoltaic system on a single-family home

Hello everyone,

I have a few questions regarding photovoltaic systems.

The system we are planning would be commissioned in 2012. The output will be around 8-10 kW, thus falling into the "up to 30 kW" category.

According to the feed-in tariff (Renewable Energy Act 2012), we will receive:

24.43 cents per kWh

and

8.05 cents per kWh for self-consumption, provided that self-consumption does not exceed 30% of the output

and

12.43 cents per kWh for self-consumption, if self-consumption is above 30%.

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Now for the first question:

The feed-in tariff has significantly decreased over the years. Therefore, the part regarding self-consumption is much more interesting to me.

Do I understand correctly that I receive 8.05 or 12.43 cents for every kWh I use myself? If so, can I assume for my calculation that I can use the utility’s electricity price plus the above amounts?

Assumed electricity price from provider: 20 cents per kWh

=> Savings of 20 cents + self-consumption tariff

If this is correct, then I naturally have a greater interest in maximizing my own electricity use.

This probably means I will need batteries.

What would you consider a reasonable battery size?

And is it possible to use the output during the summer months for things like watching TV, etc., so that a high ratio of self-consumption can be achieved during the peak production period?

Thanks a lot for the information and best regards
ostsee

Hello,

ostsee schrieb:
....If that is correct, then of course I have a strong interest in using as much self-generated electricity as possible.

Exactly!

ostsee schrieb:
....Which probably means I need batteries in return.

Absolutely not, because that would shift the disadvantages of storage onto the private user! The key is timely consumption, meaning heating and hot water with a heat pump. Anyone reasonably smart sets, for example, the hot water charging to the period of highest photovoltaic yield. Of course, this requires an appropriate system configuration (heating/hot water).

ostsee schrieb:
...And can the power then also be used in the summer months for things like watching TV, in order to achieve a high self-consumption rate during the period of greatest electricity generation?

You can, but the results are usually disappointing!

Best regards.

What disadvantages do I have with storage? And is there possibly any kind of compromise solution?

ostsee schrieb:
What disadvantages do I have with storage? And is there perhaps any compromise solution?

There are always disadvantages to individual (private) storage. It does not matter whether it is thermal, electrical, or pneumatic; storage is always subject to losses. Therefore, it is generally advantageous not to be personally burdened by it. Photovoltaics => Sell surplus / buy demand! The difference in photovoltaics is financed by the community! ;-)

Best regards.

Hello Baltic Sea

Your calculation and reasoning are basically correct. The question is just when you use electricity?
In my opinion, self-consumption regulations make sense for kindergartens, schools, public facilities, small industrial businesses, etc.
In private households, it only pays off if electricity is really used during the day. That means if one of you works from home (home office), or if one of you stays home all day with the children and cooks, does laundry, etc.
If both of you go to work, and the children are at school in the morning and at friends’, sports, etc. in the afternoon, it probably won’t be worth it...
You should simply monitor your electricity use for a while.

Electricity storage systems are not worthwhile at all right now. Purchase, maintenance, etc. are much more expensive than the “profit” you would get from them. Wait another 10 years, then it might be worth reconsidering 🙂

Best regards
Micha 😎

Hello everyone, it wouldn’t be so bad if we used our photovoltaic electricity for the ground source heat pump, right?