The Sunshine to Petrol project is testing a prototype device called the Counter Rotating Ring Receiver Reactor Recuperator (called CR5 for short) which turns CO2 into carbon monoxide which could then form part of a liquid fuel.

CNN: Turning carbon dioxide into fuel

No other virtual currency will even come close to that kind of vibrant liquidity and building walls to ring fence a virtual environment will turn out to be a counter-productive strategy.

FORBES: Virtual Currencies and Roach Motels