> The total energy usage would be reduced 600-fold!
It wouldn't. If X$ worth of bitcoin is handed out every block, then miners competing for that prize are willing to collectively spend up to X$ per block on average.
If they could only mine for part of the time, then they'd simply acquire more hardware and mine at a higher hashrate during the shorter time.
Good point! We'd be living in a world where the lights flicker every ten minutes as gigawatts of power are momentarily switched on and off :) Or miners would have to install gigantic capacitors to fill with charge, just to power their machines for the brief instant of usage!
My example is also missing the obvious next step though - once you are using a trusted source of data (or even a wide selection of trusted sources), the whole blockchain idea becomes pointless, you don't need to do any mining at all, you can let the trusted sources run a distributed database...
It wouldn't. If X$ worth of bitcoin is handed out every block, then miners competing for that prize are willing to collectively spend up to X$ per block on average.
If they could only mine for part of the time, then they'd simply acquire more hardware and mine at a higher hashrate during the shorter time.