Sorry but that's BS, It absolutely requires the energy. If it would be running on a privet computer still then anyone with such a computer could double spend which would make it useless regardless of success.
That’s not the point, I didn’t say that it would be a good idea. The point is that it would work with just 100 or a 1000 miners if no one has 51% of computing power, hence the computing power is a consequence of Bitcoin’s success.
But you are wrong, it would absolutely not work.
The only way to make sure no one has 51% and no one can simply get 51% (buy cloud computing for example) is if the 51% is more than what feasibly can be bought or it would at least need to cost more than what you could gain from a double spend.
Also its about hash power not number of miners, that's completely irrelevant. 100 or 1000 miners that means nothing.
