Sincerely, someone who won't heat their home if it means fossil fuel CO2 emissions.
As one example, Germany imports 1/3 of its oil from Russia and 1/3 of its natural gas.
https://www.cleanenergywire.org/factsheets/germanys-dependen....
Cutting that supply off would cripple their economy, send prices soaring on everything, drive up the price of oil in the global market as Germany + other EU nations tried to purchase elsewhere which would hurt many poorer nations etc.
Not saying it shouldn't be done, but lets not understate the impacts this would have and how incredibly destabilising a price rise of that magnitude on top of the Covid problems could be to the EU as a whole.
Dependance and the ability to rapidly make trade deals are two seperate things. Just because i buy 1/3 of my widget from x, doesn't mean i can't switch to buying 1/3 of my widget from y should i need to. Not everyone in OPEC loves russia.
It is possible for gas prices to rise so quickly that the system bankrupts. It's happening (in a stupidly overcomplex energy market) in the UK, for reasons that have nothing to do with regional instability.
I am no energy market scholar but it seems to me that one result of a conflict in the Ukraine could be the temporary collapse of regional energy markets as countries that produce oil or natural gas energy begin to use protectionism (renationalisation, export bans, domestic-only quotas, whatever works) to try to survive what happens.
Another is the return of dangerous energy extraction methods like fracking.
Also, after some digging i can't seem to find a reliable figure to quote the % of imported energy from russia? the nord was supposed to provide 30% more natural gas than currently utilized, but thats a surplus not a dependency since it was never even turned on.
Energy markets have been moving be alot more decentralized in the recent years, not due to any overt action to do so but because energy usage and distribution is much more akin to high frequency trading among grids.
The other option of course is for the EU to pull a switcheroo and invade Russia.