The issue with those was that they were indeed very ecologically dirty, especially the lignite mines from Gorj. You can actually see the devastation that they have brought on the ecosystem even from satellite images [1]. I agree though, if one takes a step back and looks at the whole thing (i.e. if you add the socio-economic conditions) this was a very bad decision.
I personally don't think renewables will be able to fill the gap for us. For one thing, transporting all the wind-generated power from the likes of Dobruja to Western Romania and Transylvania using existing power-transport infrastructure is no easy task. Second, I don't see solar taking over, for the simple reason that the fields from Southern Romania which it would best to use for such task are of greater use to agriculture (from an economics pov, that is).
On a more general note, we, Romanians, already have past history related to this, not a successful one at that. I'm talking of the period after the 1970s oil-shock crisis and of the '80s in their entirety, when the then government was very aware of the energy problem and was also very actively trying to tackle it and, in a way, solve it. That's why the discourse that we now hear from the West is in many ways familiar to us Romanians (only cars with odd numbers which should be allowed travel during weekends, energy "rationing" etc), i.e. because we have been in that place before them (and failed).
There are several books from that period who explain the problem in detail and which also write about possible solutions. Most of them are from Editura Politica, such as Energy in a finite world [2], published in 1983, but one of the best, imo, is this one: Energy, whereto? [3], published in 1978, a book which has a very comprehensive list of almost all of the solutions that were available back then. It's very interesting that they also talk about shale gas, and about how it's not a recommended solution because it generates mini-earthquakes (they might have also mentioned the heavy water-use as a negative, I don't remember exactly).
Of course, when the mini-earthquakes did indeed happen in the early 2010s when we try to extract shale-gas in Eastern Romania the powers that be all acted surprised, like "how could all of this have happened?". It's not like there had been actual books written about the subject 30 years prior by people who most probably were still around in one way or another. Which would bring me to one of the most important problems we now have, i.e. the lack of specialists on the subject, but this post is already getting too long.
[1] https://www.google.com/maps/@44.8953743,23.1365373,18333m/da...
[2] https://www.targulcartii.ro/wolf-hafele/energia-intr-o-lume-...
[3] https://www.targulcartii.ro/i-popescu/energia-incotro-scrisu...