You're disregarding Art.15 III GG then. Particularly Art. 15 III s. 2,3 GG (of the German version), which regulate reimbursement in the case of nationalisation. Which, again, make it a fairly difficult thing to do. Especially as we all know that Art. 20a GG, which is the only logical argument to base this all on, is just a way of getting out of actually doing something. Pretty much everyone has agreed that it means nothing except for a vague sense of 'direction'.

As for your last point, that could just as easily be interpreted as the energy they produce being in the service of energy production for the entire country, as well as ensuring that coal miners continue to have a job. If that's not a socially beneficial use of coal reserves, not sure what to tell you. Energy self sufficiency is important.

As for your landlord comment, which honestly is an entirely different matter in and of itself, that basically won't fall under 'land, natural resources or means of production', unless one of those Berlin judges decides to do Berlin things.

EDIT (because I forgot the context of what I was replying to)
None of this even takes into account that what the guy above me wrote was about simply 'shutting down coal' tomorrow. Which is a very different thing from taking public ownership, and then running the business into the ground overnight.