Photovoltaic system: Self-consumption rate with battery and further questions

Self-consumption 2015 (Ratio total household electricity consumption : self-consumption): 70.16 %
(Calculation (electricity purchase + self-consumption) vs. self-consumption)

Correction. One should really post better in a well-rested state.
I had the feeling all along that something in the calculation couldn’t be right.
The calculation method is correct – you just have to follow it:
The correct ratio is: 40.23 %

In my opinion, still very good.

Hi f-pNo!

This morning (I wasn’t fully awake yet) I was already surprised by the first percentage number and then told myself: I’ll wait until I wake up and think about it again!

Thanks for the correction and the information. 40% is really good!

Best regards
Thorsten

Well done, for us it was "only" 35% in 2015

Hello everyone,
I have a question here whether I am on the wrong track or if it pays off. Please share your opinion.

House is Kfw55 – construction started May16
260m² heated floor area – approx. 10KW ground source heat pump
South orientation with 45 degree roof – 6kwp solar system integrated into the roof from Solarworld including installation and Kostal Piko5.5F (8670€ net)
Installed by my carpenter. Integrated into the roof because of the appearance.

Bavaria currently has the 10,000 roofs program running.
That means for "netzdienlicher Photovoltaik" = photovoltaic + battery + heating element and max. 30% feed-in to the grid there is an 8000€ subsidy + KFW subsidy 275 of about 3000€.

That would cover the Solarworld Sunpac Lion storage with 6kw usable energy (9966€ net).
Is my calculation correct? Are the max. 30% feed-in to the grid absolute nonsense or achievable?

Self-consumption is the motto in the future with 12 cents feed-in tariff, right?
I believe I have neglected the problem of low photovoltaic in winter --- high photovoltaic in summer...

Are special devices needed to use the photovoltaic power for the heat pump?

Alternatively, one could also apply for "netzdienlicher Photovoltaik" = photovoltaic + battery and max. 50% feed-in to the grid with a 6000€ subsidy.

Currently only the Kfw application 275 has been submitted – before 31-12-15.

Many thanks and greetings from Bavaria,
Flo

I think I have neglected the problem with winter-low photovoltaic --- summer-high photovoltaic...

That is the big problem when you produce 30kWh or more on beautiful summer days, have no big consumers, and the battery is constantly full... We have a 7,x kWhp system, home office, three children with high washing machine and shower usage and still did not exceed 35% self-consumption. We have 300 sqm to heat, the heat pump electricity consumption in 2015 was only 3,011 kWh for heating/hot water (of which almost 60% was in Jan/Feb/Nov/Dec) – so hardly any consumption in summer and significant overproduction.

Thank you for your response/experience.

The question then is: Does the generous subsidy or the feed-in over 20 years pay off more...

Assuming I "lose" or do not feed in 3000kw per year. The rest is own consumption + the 30%.
3000kw x 0.12 cents x 20 years = €7200... compared to €8000 subsidy --> it's a break-even, right?