If BTC were to go to $500,000 in this era it would cause a catastrophic mining bubble:
$500,000 x 25 = $12,500,000 per block = $75,000,000 per hour
$75 million per hour would drive the mining to attempt to use 675 GW. This is about 30% of all the power generated on the planet.
This seems wrong. The world electricity production 2008 was 20 181 TW according to wikipedia.
0.675 TW / 20181 TW = 0.003%
Quite a lot of energy but nowhere near world production 
Got the units wrong.