Rather than electrical consumption, the main factor limiting something like this is actually the costs of executing such an attack. Purchasing the ASICs for something like this is ridiculously expensive,
Of which the ASICs are out of stock in various manufacturing and official reseller stores 
Has anyone wargamed a 51% attack on Bitcoin? How would it go down. What defensive measures could be taken.
If it was easy to perform. I bet it would have already been done over the past decade Bitcoin has existed and seems to get more and more valuable each passing day.