There is an energy crisis across all regions of Europe; disrupting trade may help some places but hurt others much more and would make it worse in aggregate, so

There is an energy crisis across all regions of Europe; disrupting trade may help some places but hurt others much more and would make it worse in aggregate, so EU treaties prohibit that. I mean, whenever electricity is being exported at high cost, that high cost is an indication that this other place has it even worse; and blocking trade would make electricity cheaper at the exporting place, but cause a larger spike (and possibly even blackouts with the associated economic disruption) at the importing place and also remove the economic incentives to increase surplus production at places who can do it cheaper than others.