The impact of the Russia-Ukraine war is hitting the economies of most European nations hard. Winter is close and most countries are not sure of their power source. But these nations are also facing economic challenges, hence they also need an increase in revenue through tax. I don't think this ban would be very effective because there are other ways to sort out these power challenges like load shedding and rationing. Most of these nations also depend heavily on the revenue they can get from the mining tax in their locality.

Sometimes I keep wondering why the target is always bitcoin when it comes to power issues, while other sectors like gaming and banking also consume more energy. But currently, most bitcoin mining firms have developed new technologies that have made their power source clean, green, and independent. It is also important to state that other nations outside the European Union would be very willing to welcome bitcoin miners. I am sure Africa would be a very good destination for them.  

Even if it affects the price of bitcoin, the impact would be short-lived and minimal.