To give an idea, lets assume cheap miners will pay $0.05 per KWH.
okay
Lets use your 10 fold scenario so BTC would be worth ~$1500
okay
25 BTC x $1500 x 6 blocks per hour = $225000 per hour
okay
225k / 0.05 = 4.5 million KW or 4500 MW
That equation says, "it will cost $1500 in electricity to mine one BTC".
If it costs $1500 to mine one $1500 BTC, why will anyone do it? For the fees?
Electicity costs today are not 100% of the coinbase being mined. They are maybe 10%, probably closer to 5%. (Ignore Blockchain.info's 650W/Gh/s metric, which is 50x to 100x too high).
Using 10W/Gh/s and 3Ph/s network hash rate results in 30MW today being dedicated to mining. Increase that tenfold (for the sake of argument) and you
may need 300MW of electricty worldwide to mine BTC worth $1500 each. The worldwide generation of electricity today is about 3000 GW.
BTC mining consuming 0.01% of the world's electrical power (say 0.02% of electrical energy, being 24/7 usage) doesn't sound scary to me.
The US alone will install 1.5GW of solar power in 2014, which, given solar power's 20% capacity factor, will cover BTC usage nicely, even in the 10x increase scenario.