I'll reply to both of you here. Luxembourg isn't quite a microstate by most definitions but is indeed small.

On the public transit, the free is very nice, the mediocre service is less nice. Other less nice things is that they are focusing on building more roads and less on better public transit networks(tram extension is nice though), so I rank it as moderately good in that sense when compared to other countries and their public transit networks and mobility plans.

As for why it isn't going full renewable there are a few reasons and could probably go into much more depth but only 1/4 of workers in Luxembourg have nationality there, the others are a mix of cross border workers(France, Belgium, and Germany), EU citizens who moved there, and 3rd country nationals. Only citizens of Luxembourg can vote for the government(EU citizens can vote for EU parliament and all can vote for municipal elections) and they tend to be a bit more conservative. Additionally land is super expensive so that is a barrier to renewables. What I will say though is there is an increase in it with a goal to hit 35% renewable by 2030 and there are quite a few wind turbines but, I would doubt it will get hit with the CSV being the primary party in government at the moment.