Bitcoin without mining Several months ago I've stumbled an interesting question about the Ripple system: How does Ripple solve the double-spend problem?

Specifically about how double-spending is solved in Ripple. As you can see only @David Schwartz replied to my comments and only he was able to give an answer, given that I think he works for Ripple.

But if he's right, this would be revolutionary in a way, since Bitcoin electricity wasting mining could be replaced by this system.

In any case, my question is: can Bitcoin mining be replaced by a Ripple sort of system? How would that work?
Both Bitcoin and Ripple are systems made of many components. One such component is a method to synchronize transactions and secure against double-spending; Bitcoin uses mining based on proof of work for that, while Ripple uses a consensus mechanism. Another component is the initial issuing of coins - Bitcoin uses mining for that as well, while Ripple uses central issuing. Of course, the key component of Ripple, which Bitcoin lacks, is a credit network with pathfinding.

You could build a system which is like Bitcoin in every way except that it uses consensus for synchronization rather than mining. It is likely that the total energy spent on generating new coins will be lower than the total energy spent on synchronizing transactions; so replacing that part with a mechanism that requires less energy is welcome. However, the consensus mechanism is not as proven as the mining mechanism, and is less decentralized thus less consistent with Bitcoin's overall vision.