In 2015, the total power generation in Germany was 559 TWh. Renewables amount to about 121 TWh, i.e. about 22%. [0]

Newbuild house prices have increased by 40% in the last ten years

That sounds like a lot. From what I can find, construction prices have increased by about 20% since 2005 -- that goes for virtually all kinds of construction, including road construction[1][2]. Must be all the heat exchangers in those new roads... I'm not sure if that figure is corrected for overall inflation, it doesn't appear to be (cumulative inflation in Germany since 2005 is about 15%[3]).

[0] https://www.energy-charts.de/energy_de.htm [1] https://www.destatis.de/DE/Publikationen/Thematisch/Preise/B... [2] https://de.wikipedia.org/wiki/Baupreisindex#/media/File:Baup... [3] http://www.zinsen-berechnen.de/inflationsrechner.php